BMW 3 Series Compact E36 316se M42 engine - loosing / using water and strange cooling heating

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Sun 10 Mar 2013 15:55
BMW 3 Series Compact E36 316se M42 engine - loosing / using water and strange cooling heating - scottblox

Hi,

Here are the symtoms.

Using or loosing around a litre of water a week (around 250 miles)

Onced Topped up:

When driving the a normal speeds temp gage sits at half way and heater works as you would expect.

When in slow moving traffic the temp gauge drops to around the first marker above the blue zone. I can hear the radiator fan kick in for a few seconds then it stops (Just 3-4 secs) the heater temp is ok but not great.

When sat at idle the temp gauge drops off to just above the blue zone and the heater blows luke warm at best.

Once water ran low:

As expected the heater blows cold in all driving conditions.

The temp gauge sits between first marker and half but eventual drops off to as you run out of water.

General

The car drives great, no loss of power, strange noises or other indications other than water loss.

lay underneth it for 20 mins with engine at 2000rpm and I couldn't see any dripping or tell tale signs of a leak. Carpets are dry and there doesn't seem to be any sign of a leak from the heater matrix. While running it I couldn't see the temp gauge but the rad fan was doing its 3 second burst thing.

There is no mayo or yoghurt on the dip stick or oil cap and haven took the car to my local garage they told me they dont 'think' its the head gasket. He also said he was unable to get it to over heat and couldn't find anything. Although I don't know how hard he looked as I left the car with him while I was at work and he didn't charge me for and invest, so I suspect he didn't do to much.

Spoke to an indipendant BMW specialist (He didn't see the car) and he said it is extreamly rare for them to have the head gasket go.

So you see my issue, I cant find a leak and the garage are telling me that its not the head gasket(and there's no mayo) and to confuse me more, the temp drops off in traffic rather than it over heating.

Help please, and let me thank you in advance for taking the time to reply

Scott

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Sun 10 Mar 2013 16:46
BMW 3 Series Compact E36 316se M42 engine - loosing / using water and strange cooling heating - andyp

Sounds like head gasket failure to me.

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Sun 10 Mar 2013 16:55
BMW 3 Series Compact E36 316se M42 engine - loosing / using water and strange cooling heating - Collos25

I think you will find the HG has gone ,I have been playing with BMWs for many many years and what you describe is very common.The lack of mayo is meaningless I have seen cars engines with loads of mayo but the head has not gone and vice a versa.You could look at the water pump but they normally give no problems they are mechanically driven on the left hand side of the block looking towards the windscreen.You could also check the thermostat but water loss no apparent leaks the water has to be going somewhere and in your case its going up the exhaust. The temp gauge is measuring the air temp when slowed down due to the lack of water in the system.

There is one more check you can carry out it is possible that for some reason the water has gone low and allowed air into the system you need to bleed the system.Run the engine without the water filler cap when the stat opens the air will come out it may take some time for all the air to come out.

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