Smoky/Rattly Volvo 850 TDI - Rubberdubber
I have an 850 TDI, 96 model, great car and I have owned it for about 8 months now but it is nearing MOT time and I am concerned about two things which i am hoping maybe some other people may have experienced.
First it is smoky under accelleration (Black/Grey), the slower you drive it the more you will get next time you accellerate, this is the main MOT concern,
Secondly I have had a rattle only when the car is hot and only on tickover. At first I thought it was just engine covers etc but I have now tightened all that kind of thing up and it is still there. Somthing which might be significant is that whenever i put my foot on the clutch it goes away.
Anyone got any experience/ideas, I would be very grateful
thanks
Rubberdubber
Smoky/Rattly Volvo 850 TDI - cheddar
I think this is the Audi 5 cyl engine, it is a bit smokey by contemporary standards, take it for a good run before the MOT, perhaps with a dose of Millers in the tank, make sure it is throughly warm when you take it to the MOT centre.

The rattle will be the clutch release bearing, should be nothing to worry about unless they are know to fail on this model, someone will be along to clarify this shortly no doubt.
Smoky/Rattly Volvo 850 TDI - Rubberdubber
It is the Audi 5 cylinder and it has done about 130k. A mate of mine had an old 740 a while back which was the VW 6 cylinder, also Smoky. I can't understand why you don't seem to see smoky Audis, what does Volvo do to them? Don't get me wrong it's a great car and I decided when I got it to take a fairly laid back approach to things and see what developed, answer Nothing so far it just goes and goes with no hint of complaint. I have been running the car with Millers in it but it doesn't seem to make much difference, I will give it a good dose before the MOT though. Hope the release bearing is as you say, the noise doesn't seem any worse to me since i got it and i have done a good few thousand miles now.
Thanks again
Rubberdubber
Smoky/Rattly Volvo 850 TDI - cheddar
Reckon it is just as smokey in A6's. Best of luck!
Smoky/Rattly Volvo 850 TDI - Number_Cruncher
Does the ratle go when you get the clutch pedal to below where the biting point is, or does the rattle go as soon as you have any pressure on the pedal.

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If the rattle only disappears once the clutch is below the biting point;

This would point to a rattle in the input side of the gearbox, or potentially in the clutch driven plate. As the rattle only happens when it is hot, this is when the gearbox oil is thin. You might consider renewing the gearbox oil if this is the case.

This type of gearbox rattle is made worse by any torsional vibration coming from the engine. It can be an early warning of one cylinder beginning not to pull its weight, and fire evenly. If you find that the gearbox oil change doesn't get rid of the rattle, and, as you have a smoke issue, it may be worth having the injectors tested. How are the valve clearances set on this engine?

end if clause

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number_cruncher
Smoky/Rattly Volvo 850 TDI - cheddar
This type of gearbox rattle is made worse by any torsional
vibration coming from the engine. It can be an early
warning of one cylinder beginning not to pull its weight, and
fire evenly.

>>

Reckon this might unduly worry Rubberdubber NC, when it is probably nothing more than the release bearing rattling.
Smoky/Rattly Volvo 850 TDI - Number_Cruncher
Which is why I took the precaution of saying **if** the noise goes away only when the biting point is reached. Please read my post Cheddar.

number_cruncher
Smoky/Rattly Volvo 850 TDI - cheddar
I did read you post, NC, just pointing out that Rubbrdubber started off with a slight rattle that is probably only a clutch release bearing and now maybe thinks he has a worn out engine.

I assume when you refer to the clutch reaching biting point you mean on the way up, i.e. when the clutch starts to load the gear box shafts and take out any play. However to be clear Rubberdubber says the rattle is at idle only and goes when he puts his foot ON the clutch. Perhaps read the original post again NC.
Smoky/Rattly Volvo 850 TDI - Number_Cruncher
Cheddar,

You assume incorrectly.

Number_Cruncher
Smoky/Rattly Volvo 850 TDI - cheddar
Cheddar,
You assume incorrectly.
Number_Cruncher


Perhaps clarify then?
Smoky/Rattly Volvo 850 TDI - Rubberdubber
Whoaa there! let's not fall out. To settle the argument I just went out and started the car up, it was out today anyway so was quite warm. I would say the rattle is about half way up/down on the pedal, probably around the biting point. So I guess this means maybe i should change the gearbox oil, at the ,mileage it's probably not a bad idea anyway but brings up a problem I almost forgot about. When I serviced the car I couldn't find the gearbox level plug, does anyone know where it is? Also what is the recommended way of draining the oil, I am not sure about the Volvo but most cars now don't have a drain plug.
I appreciate all the replies/advice/opinions and there is always more than one way to skin a banana.
Cheers
Rubberdubber
Smoky/Rattly Volvo 850 TDI - Number_Cruncher
I dealt with a car with similar symptoms last year.

One of my friends, until recently, had a very nice BMW 325. We talked about the jobs he was doing on it, and he mentioned he was servicing it. I should also say he is fastidious in the extreme.

A number of months later, he drove the 100 miles or so to visit us for the weekend. Upon his arrival, I went out to greet him, and heard his rattling car. The symptoms were exactly as Rubberdubber has now given - a rattle, on tickover only, that goes away once the clutch is below biting point.

Using my stethoscope, we found that the noise was coming from the bellhousing, or front of the gearbox.

We didn't act imediately, because my friend said the noise only happens after long journeys, and in his ordinary day to day driving it didn't tick over much ;-).

It took me a week or two to work out what to advise my friend to do. I asked him to double check his plug gaps, and reset his tappets, making doubly sure not to get any too tight. The plugs were OK, one or two of the tappets were a bit tight (his keeness for a quiet running engine got the better of him). Slackening his tappets made the tick over smoother, which got rid of the rattle. The tick over wasn't a problem to begin with - really quite a subtle fault.

I know it sounds odd that a gearbox rattle can be fixed by adjusting the tappets, but it is true.

So, when I heard Rubberdubber symptoms, this fault came to mind, which is why in my initial response, I enclosed my advice in an if clause.

Rubberdubber, please, by all means change your gearbox oil - my friend did his when he did the service, so I didn't suggest he did it again :-).

If your rattle persists, consider faults which could make your car begin to tick over ever so slightly rough.

In conjunction with the smoke, this is why I suggest perhaps looking at the injectors.

Cheddar, I apologise if I was a little terse with you.

Number_Cruncher
Smoky/Rattly Volvo 850 TDI - adverse camber
with regards to the smoke, there is a recommendation from volvo (or so I am told) that the egr valve pipe be cleaned/replaced or blocked off.

But it is quite an old engine design now.
Smoky/Rattly Volvo 850 TDI - cheddar
Cheddar, I apologise if I was a little terse with you.


Accepted with thanks! OK what you are saying is clear and makes sense however I still say it could simply be the release bearing.


Regards.

 

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