Do you want the Road Tax system to change? Do you have thoughts on the potential changes to the Road Tax system? | No thanks
1996 BMW E36 Heater fault - Blue {P}
Hoping someone can help me here!

I'm now driving a 1996 BMW 316i fitted with manual A/C that my family have owned from new.

We've never had any noticeable heating problems with the car or any bother with the cooling system. However, the heater seems to have stopped blowing warm air, at best I'm able to get some lukewarm ait through if I turn the temperature dials (it has two) to maximum.

According to the temperature gauge the engine is heating to a normal temperature in a reasonable period of time, and I'm certainly not aware of any fluid leaks inside or out, and I'm sure I would have noticed.

Has anyone got any ideas which bit of the system is at fault? I've noticed that when travelling with the A/C on and the heater set at 22 that the air still feels very cool, I'm assuming this is because the A/C system is feeding the cool air through and it isn't getting mixed with any warm air?

Any advice appreciated, I nearly froze to death on the way home, I'm used to having toasty warm cars!

1996 BMW E36 Heater fault - elekie&a/c doctor
Assuming that the coolant level is correct and the engine is reaching operating temperature ,then it is possible that the electric heater control valve is faulty.It is situated on the bulkhead (pass side )between battery & engine.
1996 BMW E36 Heater fault - Blue {P}
Thanks for the info, will try and have a rake around for it in the morning, if I have no luck then it's off to BMW I'm afraid, I just can't be doing with a cold car late at night.

1996 BMW E36 Heater fault - Aprilia
I agree - the electrical coolant valve. They are not too dear if bought from ECP, and fitting is not too difficult. Give it a tap to see if it frees off.
1996 BMW E36 Heater fault - Blue {P}
OK, have been to the dealership today and they want £100+ just to diagnose, and then they will charge for the repair on top of that! Looks like I'm on my own for now!

Will definately be trying harder to find this valve, what should I be looking for? Does it have pipes running through it or something? I had a look under but I don't know a lot about the underbonnet bits so I couldn't really make much sense of it.

1996 BMW E36 Heater fault - Aprilia
Should be easy to find. Look for a bracket assembly with two metal "cans" on it. The heater hoses (about 1" dia) go to it - I think there are three hoses connected to it - but I'm writing from memory.
Check out EuroCar Parts for a replacement unit.
1996 BMW E36 Heater fault - Blue {P}
Thanks Aprilla, you were right about where to find them, but sadly not about what was actually causing my symptoms. :-(

My dad and I gave these little valves a good tapping to see if they freed, but the problem remained.

I took the car to a BMW specialists in Teeside today and they've confirmed that the head gasket has failed, probably around cylinder number four and I'm looking at around £400 - £500 to sort it all out. :-(

There are no overheating symptoms at the moment, but there are exhaust gasses in the coolant and the hoses are all pressurised when they shouldn't be.

The head may need skimming if it has corroded at the point of the failure.

Not the best news I could have hoped for really, I'll be holding crisis talks with the parents as it is still their car, if they want to pay for the fix then they can, if not, it's time to say bye bye to the car because I certainly can't afford to fork out £500 to fix someone else's car! I've already spent £40 odd quid on it just to find out what the problem was as well as over £100 to get it through it's MOT. :-(

1996 BMW E36 Heater fault - Aprilia
Oh dear. That's bad news. Sadly it is not particularly rare for these BMW heads to fail. As you say, there are initially no symptoms other than the hoses going very hard. If you rev the engine you'll see bubbles in the header tank - also the car will run *slightly* hotter (not overheat, but the gauge needle sits slightly higher than it should). If you keep driving it, it'll one day suddenly boil up and blow the water out due to a pocket of combustion gas building up in the head's coolant passages.

What seems to happen is that the head castings can be slightly porous (tiny bubbles in the alloy) and with thermal cycling the tiny bubbles cause the alloy to fracture and you get a little crack - coolant and combustion gases then cause it to corrode.

You *must* skim the head - its not an option. Sometimes skimming doesn't work because the alloy is too porous and you have to get an exchange head (as I have found on a number of occassions!). Whatever you do, make sure it is pressue tested before fitting back on the engine.
1996 BMW E36 Heater fault - Blue {P}
Well, it's in the hands of the gods now, I'm telling them that it'll be the thick end of £500 so that they don't get a nasty suprise...

Will keep you updated...

1996 BMW E36 Heater fault - Aprilia
Actually £500 is not a bad price. If I'd been asked, off the top of my head, I'd have said £700.
1996 BMW E36 Heater fault - Dave N
How does a busted HG cause the heater to stop working?
1996 BMW E36 Heater fault - Crinkly Dave
Ithink it can put gases into the system, which in some cars can migrate to the matrix and cause an "air" lock
1996 BMW E36 Heater fault - Aprilia
How does a busted HG cause the heater to stop working?

Very common first sign of coolant loss or HGF. Combustion gas displaces coolant in the system and interrupts the flow.
1996 BMW E36 Heater fault - Blue {P}
That's exactly what the garages says have happened.

I was quoted this by

If anyone has dealt with them before or has any comments then please let me know, even if it means you have to e-mail me with them. My parents have decided to pay the bill seeing as it is technically their car, but as they have made it clear that I'm on my own with any future catastrophic failures, I want to get this done right.

If anyone does e-mail please post here to let me know that you have sent mail as I don't really check the account that is listed in my profile very often.

1996 BMW E36 Heater fault - Blue {P}
Adski - need your help please!

We had the HG done yesterday at a different local garage *not* the one that I have listed above.

Today the car drove fine to the petrol station and then after about another mile and a half I pulled into my gran'sdriveway and the car was running very badly, it sounded like it was mis-firing, I could also hear some knocking noises from the engine compartment.

On inspection it seems that there is nothing leaking out of the bottom of the car, but the coolant level is well below maximum, there doesn't appear to be any water in the oil from what I can see, but I could be wrong.

I've restarted it a couple of times and it was running rough and cutting out. I sarted it again to move it out of the way of my gran's car and it ran fine for a few seconds, I gently brought the revs up to listen to it and then heard a knock and it went from running fine to shaking and running very roughly and soundling like it was running on two or three clinders in the space of one second.

The garage have mentioned something about the timing chain tensioner which has got me just a little worried.

We don't have breakdown cover so my dad is gonna come home from work and change the spark plugs and check the plugs are all connected properly as it is the only thing that we can do ourselves before we have to pay for the car to be towed somewhere.

If you have ever expereienced anything like this then feel free to share, I'd be grateful for anymore advice.

I think this could be a nail in it's coffin to be honest!

1996 BMW E36 Heater fault - Blue {P}
Erm, no offence to Adski, but what I actually meant was:-

"Aprilla, need your help please!"

1996 BMW E36 Heater fault - Aprilia
Sorry to hear of your problem.

To be honest remote diagnosis of this problem is very difficult.

Basically I think you need to get in touch with the garage that did the job for you. Personally I wouldn't touch the car - if you change plugs etc then they may come back and say that you've caused the problem. Presumably they have a tow-truck and would come and get the car. When I ran a garage we would always stand by our repairs for a sensible length of time, and certainly on something like a HG replacement we would sort out any problems withing 6 months/6000 miles.

There should be no problem with the timing chain and tensioner if it has been reassembled properly. These chains/tensioners will take 100k in their stride and your has done less than that.

I suspect that it could be an ignition fault, or it could be something major gone wrong with the head repair. The loss of water is a worry. Did you have the head pressure tested, as I suggested earlier?

Anyway, I would leave it alone and get the repairing garage out to it. Its their responsibility IMHO.
1996 BMW E36 Heater fault - tony@tooting
I'm not sure if your car has one, (try ringing a dealer and asking the parts dept for the price of one. Make sure you have your full chassis number to hand.) but it could be that the VANOS unit is damaged. It requires a tool to remove/re-fit it properly.
DO NOT DRIVE THE CAR ANYMORE!!!!!!! You may well be doing further damage.
Ring the garage, put them in the picture, and get a second opinion/legal advise, before you take it back.
If you took the car to this garage instead of the specialist, was it because they where even cheeper? As Apirila has said, the first price was VERY good.

Regards Tony
1996 BMW E36 Heater fault - Blue {P}
Thanks for the replies guys.

The car was towed away by the people who fixed it last night, having had a listen to the car thje guy reckons it's the timing chain tensioner that is losing tension and causing the chain to rattle and knock the timing out slightly.

This was based on the fact that for a short while, the car would run sweetly, but then after hitting almost exactly 3K revs it would make a bang and start running rough again complete with lots of rattles and mettalic clanging noises.

They're gonna be looking at it again today and will call back with the news.

It went somewhere else as my parents are paying the bill (it is their car after all) and they found somewhere even cheaper than the place above, lots cheaper.

1996 BMW E36 Heater fault - tony@tooting
The timing chain will have to have been disconnected from the camshaft when the head was removed. So the tensioner will have to have been wound off also. (i have posted this just so that you are aware that they will have moved it when the work was done.) I do hope the the VANOS unit, if fitted, was not damaged, as they are expensive.

Regards Tony
1996 BMW E36 Heater fault - Blue {P}
I think that there is a VANOS fitted, but I'm not sure.

If the car comes back running sweetly can I assume that VANOS, if it has it, is OK? Or will it only come out on an MOT emmissions test or something? And er, sorry to sound dim, but can you remind me what VANOS does again? I think I read about it many moons ago when I was too young to really understand it and I can't remember what it was that I read.

He didn't try to hide the fact that he had the timing chain off when doing the work, would the failure of the tensioner be expected on a 9 year old car or does it sound like it was re-fitted badly? I know you said that it should last 100K Aprilla, but I'm not sure if the age could also cause it to fail. As you know the car doesn't even have 50K on the clock.

1996 BMW E36 Heater fault - Philip Cox

According to 'BMW 3 Series - The Complete Story' by James Taylor, your 316 will be a single overhead cam engine, the cam being driven by a belt rather than chains and it will not have the VANOS fitted. The belt will have a tensioner, but this will probably be a roller type pushing up against the belt and revolving whilst in contact with the belt when the engine is running. These are normally set/tensioned by garage techs, although knowing how bmw are I expect this tension may be done automatically by some sort of spring set-up. (Chains normally have a 'slipper' type tensioner and yes these can be noisy with high mileage and wear on the tensioner.) The belt tensioner though should run quietly, unless the rollers bearing has failed. Other than that I wouldn't like to say what the noise is and why it's now running rough and as others have advised let the garage who did the work sort it out.

Philip Cox
1996 BMW E36 Heater fault - Blue {P}
as others have advised
let the garage who did the work sort it out.

Yep, I've resigned myself to that, was just hoping to have some sort of ideas to prod them along or know if they have a clue what they're doing.

Apparently they spent 6 hours working on it today, and replaced the chain tensioner (they definately reckon it has a chain) all to no effect, it is still running badly.

My only thoughts are that possibly if the timing has been affected, which the metal clanging noises suggested, then maybe it's too late to be replacing tensioners and the engine is already scrap.

Either way I don't think I'll be getting my pride and joy back in a hurry. :-(

1996 BMW E36 Heater fault - Aprilia
I'm pretty sure your 316i engine does not have VANOS on it.

The engine is of a simple design and the timing chain should definitely last 100k+. It will not deteriorate with age alone.

It is a fairly simple job to remove the head on these engines, but the timing chain does have to come off (which in turn involves fiddling about with the piston-type tensioner).

I have a feeling that your garage might have made some mistakes on reassembly - perhaps putting it together with the timing wrong, just guessing though. Anyway, it sounds as if they have made a mess of the job - I would press them to sort it out FOC.
1996 BMW E36 Heater fault - Blue {P}
Right guys, I think the saga is nearly over now. :-)

The garage say the car is running fine again, with just a slight miss, they also say that the computer is telling them that the Lambda sensor is faulted.

They reckon that this could cause it to fail an M.O.T. emmissions test (it only passed one two weeks ago). They want £60 to change the Lambda sensor.

They have asked if diesel has been put in the car in error, I filled the car brimful just before it broke down, but have a receipt to say that it was filled with unleaded, surely if the fuel tanks were mixed up at the garage the car would have had to have had everything drained?

Can someone just give me a brief idiots guide to what the Lambda sensor does, how running the car without one will affect it and whether this will cause any damage.

Family consensus seems to be along the lines of getting the car back and getting rid of it, shame as we've had it from new and it seems like a bit of a sad ending to it's time with us but we've lost confidence in it now.

1996 BMW E36 Heater fault - Blue {P}
Oh, forgot to ask, could the slight misfire that the car has be due to the faulty Lambda sensor and would a faulty sensor be likely to cause the car to have less power or do less miles to the gallon?

Thanks, I promise these will be my last desperate posts about this! Hopefully anyway! :-)

1996 BMW E36 Heater fault - RichardW
Lamba sensor is really an oxygen sensor. It is located in the exhaust before the cat, and sends the amount of oxygen to the ECU which then computes the amount of fuel to add to the engine to ensure the mixture is right for the cat to convert the CO to CO2. I can't see how it is not working now, unless the timing was miles out, and it is covered in soot or something. I would be pointing out in no uncertain terms that it was working fine before they messed up replacing the head gasket, and invite them to change it at their expense!

Is it illogical? It must be Citroen....
1996 BMW E36 Heater fault - AN Other
A car running with a mis-fire will usually knock out the lambda sensor. The garage should pay for this as well, and also make sure the catalytic converter still works, since they don't appreciate a load of neat fuel mixture chucked over them either.
1996 BMW E36 Heater fault - Aprilia
Antifreeze will kill a lambda sensor in short order - so I suspect when the head went that may have taken the sensor with it. £60 is pretty cheap to replace it.

As to the petrol/diesel issue - difficult to say. Can you smell diesel in the tank?
1996 BMW E36 Heater fault - Blue {P}
My dad's gone to pick the car up now, the garage strongly suspect a bad fill of fuel, I don't see how it could be all diesel though as surely a car with nearly £50 worth of diesel in the tank simply wouldn't run at all. They reckon it's more than likely a bad tank of petrol, they were considering draining the full tank and re-filling.

As far as I can tell one of the following is true:)

A) They have messed up with the re-assembly, causing the misfire, causing the Lambda sensor to get knocked out etc. It is known for a fact that the chain tensioner was found to be broken after the car stopped running..

B) It's an unfortunate co-incidence that the chain tensioner has gone, knocking out the timing enough to make the engine run badly, at the same time as I have filled with a bad load of petrol which has contributed to the death of the Lambda sensor.

They are reluctant to fit a new sensor at the moment as they say that if there is bad fuel in there it will just kill the new one as well.

Now I'm even more confused than I was this morning!

1996 BMW E36 Heater fault - Aprilia
Petrol car with a full tank of Diesel wouldn't run.

Can you call the petrol station and ask them if they have had a contamination problem? (they may say 'no' anyway!).

It is certainly a strange chain of events. They must be pretty ham-fisted to break the tensioner - its a straightforward job to reassmeble the chain/tensioner.
1996 BMW E36 Heater fault - Dalglish
They must be pretty ham-fisted to break the tensioner


i thought blue was in the motor trade, and as such he should know that if you pay peanuts for a job, you get ..... . !

bmw's are best not left to cowboys to work on.

1996 BMW E36 Heater fault - tony@tooting
IF, the timing chain was loose enough to cause the valves to make contact with the pistons, (Ie the valve timing has slipped) then it it POSSIBLE that the valves may have suffred some damage, and so causing the mis-fire. A garage can do a test called a "cylinder leakage "test that will show if the valves are damaged, and is much more accurate than a standard compression test.
Why do they say thet the Lambda sensor has failed? Are they looking at the live data from the sensor? In whch case it's "Huston we have a problem." (A failed sensor will normally give poor fuel economy, and poor performance.) Or, are they saying that they have found a fault code in the memory? This may have been triggered once the head gasket failed, timing chain fault, or is still "live" due to the missfire, or a genuine failed sensor.
I would say take the car on a run, (It you trust it!) in fourth gear (If possible) of over 30 miles, at a constant speed of at least 60 MPH. This will burn off any deposits on the sensor. Then get the ECU codes cleared, and see it it then returns after a test drive.
As for the Diesel, as you said that it was "Filled to the brim", take the fuel cap off, and leave it off for a couple of minutes. (away from the car if it is not tied on.) Then smell the cap. If you can not smell Diesel, then there is none in the tank. (as Diesel is a heavy oil, it will not evaporate as quickly as the petrol will.)
PLESAE ensure that you keep a daily check on the oil, and water levels over the next few weeks. (Do so on level ground, not in the kerb, with a cold engine.)

Regards Tony
1996 BMW E36 Heater fault - tony@tooting
Actually, it's not good idea to take the car for a run, if the engine is mis-firing, as this is sure to melt the exhaust cat.
The mis will therefore have to be sorted first.

Regards Tony
1996 BMW E36 Heater fault - Blue {P}
I of course am aware of the peanuts monkeys thing, that's why I looked up a specialist on the internet who I thought would do a good job, unfortunately the car just didn't get sent there! :-)

I've been up and down to Newcastle in it and it is badly misfiring, I think if the Cat is gonna go then it will already be too late, but then I'm of the opinion that the engine is probably fried anyway.

I reckon that only two things will have broken the Lambda sensor, either the timing being out (which it defintely was), or, my first fill of contaminated petrol ever. Now I wonder which is most likely...

I'll put this to my dad and see what he reckons we should do, although personally I don't even think a new sensor will fix this, it runs so badly. They reckon that the sensor is definately ruined as it is covered in black soot and the computer is saying that it is.

And the stench of unburnt petrol when I stop is a bit disconcerting!

Will keep you updated as and when things change.

1996 BMW E36 Heater fault - tony@tooting
Hate to say this, but "Huston, we have a problem...."
If the car is misfiring, and you can smell the fuel, then this is what is happening.
The fuel goes into the engine and is then, for whatever reason, not burnt. So a cylinder full of un-used air, (Back to the fuel later) goes down the exhaust pipe. This is picked up by the lambda sensor, that then sends a message to the ECU that there is too much air in the exhaust. The ECU thinks "Ah! Lean mixture! And will therfore put in more fuel. Ther is however a limit as to how muck extra it will be alowed to put in. If this is exceeded, then the ECU will flag that the sensor is at fault, or to be more accurate, that is does not like the signal that it is getting. A rich mixture will soot the sensor up.
As for the fuel, then ends up in the exhaust cat, where it will then get burnt, and cause the the monolyth to melt.

So a few quick reminder questions to ask,
Did the car misfire before?
Did it have poor performance/economy before?
Could you notice a smell of petrol before?
(I'm refering to before the overheating/heater fault.)

If the answer to the above is no, then I think that it is time that you bit the bullet, book it in at the BMW specialist, WRITE DOWN for them ALL that has gone on, and, get an opinion on the mis-fire.

Good luck. Tony

1996 BMW E36 Heater fault - tony@tooting
I must get a new key board, this one is, eeerrr, making mistakes!

1996 BMW E36 Heater fault - Blue {P}
Thanks mate, that at least explains why the revs surge up and down like the proverbial's knickers.

I've got a funny feeling that the car will end up back in a specialists, but my dad is insistant that we follow the advice given to us by the garage and get rid of the fuel in the tank and re-fill with BP or Shell and then change the Lambda sensor, this apparently will put an end to all of our woes.

I'll report back with what problems the car still has after we have done this. The garage have done such a good job persuading him that it's fuel related that he doesn't even think there ever was a problem with the timing. I've pointed out that if that's the case why have they replaced the timing chain tensioner and why did they say that they could hear the chain rattling as it went slack?

I'm convinced that we're gonna have these problems even after fresh fuel and a change of the Lambda sensor, (which I am going to stand over them and watch them do) When we still have problems it will probably end up in the specialists, but I will let you know how I get on.

1996 BMW E36 Heater fault - tony@tooting
Well, who knows, they may turn out to be right? It's always difficult to give an accurate opinion on anything when your at the other end of a PC.
But if Aprilia has got another weeks wages to bet, I wonder where his money would be?

Please keep us posted.
Have a good weekend. Tony

Ps Oh look! Less mistakes when I type slower!

Not ANOTHER car problem.....
1996 BMW E36 Heater fault - Miller
Incidently, how many miles has this engine done?
1996 BMW E36 Heater fault - Blue {P}
About 48,000 genuine miles from new, would have to look at the clock on it to be certain, definately less than 50K though.

1996 BMW E36 Heater fault - Blue {P}
Quick update, the car is leaking oil all over the drive, suspected to be the Rocker gasket which the garage say they have had off twice "so it's bound to be leaking". Great, they could have replaced it when dismantling it.

Anyway, as the garage was going to charge us to replace the gasket we took it to another garage to get a second opinion, he went underneath the car and straight away asked me what other work we have had done recently.

I told him and he said we needed to take the car back to the garage it was fixed at as there is coolant dribbling down the back of the cylinder block along with the leaking oil;. Also water coming out of the back of the exhaust system.

And then to top it all off I've noticed that there are exhaust gases coming into the cabin which are causing me to have a dry throat and feel a bit rotten if I sit in it too long.

Needless to say I'm beginning to regret ever getting rid of my Mondeo which my mate who I sold it to is very happy with, he says it's giving very reliable service, and my parents bitterly regret going to this garage!

The car is going back in on Thursday, so will give an update with what is going on then, I think this thread is mainly running for it's entertainment value now!

1996 BMW E36 Heater fault - Aprilia
Personally I would STOP right now with this garage. They have proved that they cannot do the job and are only likely to do more damage. This is a simple engine to work on and there is really no excuse for the problems you have suffered.

Take it to a VAT-registered BMW independent. Pay him to do a written report on the work done so far. Then pay him to sort out your engine.
Then put in a small claim court action against your current garage - claim for cost of rectification work, inspection cost and a small sum for inconvenience and loss of use.

You WILL win (I have done engineers' reports for people in the past and the SCC always seem to decide in the customer's favour).
1996 BMW E36 Heater fault - tony@tooting
If they have tryed to charge you for replacing the rocker cover gasket, then they are sure to try to charge you for recfifying their other mistakes.
This has indeed turned into a very sorry tale of woe. At least now your parents have seen the light, and have finaly lost faith in this garage.
As you where happy with the car before, I still think that it is worth getting the car repaired elsewhere, and then proceed as Aprilia has advised.

Regards Tony
1996 BMW E36 Heater fault - Blue {P}
SUCCESS!!! :-)

My dad and me set to work changing the rocker gasket ourselves today, when we got the cover off we found that the old gasket hadn't been put back in properly and had been cut by the head when it was tightened down.

Aprilla will know what I'm on about when I say that there's a sort of half moon shaped bit of rubber at the back of the block on the gasket. This had cut off altogether and was floating around inside the rocker cover, leaving a gaping hole in the gasket for oil to spray out of.

We replaced the gasket and now the engine runs sweetly again!

We're gonna change the Lambda ourselves at the weekend to ensure that this is ok and take it from there.

Once that's all done I'm going to get our usual MOT place to run it through an emmissions test and see how it does, if it's knackered then I'm going to get shot and might replace it with a nice 04 plate Mondeo Zetec that I've got my eye on, but so far, fingers crossed, she seems to be all sorted.

And all of it down to some pure incompetence when re-assembling the rocker. Not amusing!

1996 BMW E36 Heater fault - Aprilia
IIRC the half-moon seal is a seperate part anyway and should be installed with a bit of sealant on it.
Glad you fixed it, anyhow. The garage were obviously a bunch of cowboys.
1996 BMW E36 Heater fault - Blue {P}
Oh, will be keeping an eye on that then, we didn't use any sealant!

Just relieved that it seems to be ok.

1996 BMW E36 Heater fault - tony@tooting
I'm not supprised that the car ran like a pile of poo with the half moon missing. This will cause unmeasured air into the engine, and then the engine will try to compensate. Please do NOT yet replace the sensor, but do the long run as I earlyer advised, to try to clean the sensor. Then get the emmisions checked. If they are Ok then the sensor will not need to be replaced.

Regards Tony

(ps, Looks like the Mondeo is on hold then.)
1996 BMW E36 Heater fault - Blue {P}


This time it broke down with all the same symptoms as last time except when my dad has taken the spark plugs out one of them has snapped, the end seems to have dropped into the engine.

Replaced that with a new spark and it still doesn't run.

It's making the same clanking noises from the engine, no power and cuts out.

The car is going to be towed to a specialists on Monday and we'll let them know the whole story about what's happened with it.

I think it's time for a new engine, and time for me to look for a new car...


Ask Honest John Right column

Value my car