Does your water temp move at all on track?

[grumps]

My temp gauge started to read just below half a few months back so i replaced the thermostat (gen) which made no difference,Oil temp is just as before! Any ideas?
Regards Pete

[alexk]

My temp gauge started to read just below half a few months back so i replaced the thermostat (gen) which made no difference,Oil temp is just as before! Any ideas?
Regards Pete

I think your fan coupling has an issue and is always engaged (part number 2) and cools down the engine constantly.
Do you hear a "noise" .. .fan noise when you drive slowly with open windows ?

http://bmwfans.info/parts/catalog/E4..._fan_coupling/

[shane@mbtech]

My temp gauge started to read just below half a few months back so i replaced the thermostat (gen) which made no difference,Oil temp is just as before! Any ideas?
Regards Pete

I think your fan coupling has an issue and is always engaged (part number 2) and cools down the engine constantly.
Do you hear a "noise" .. .fan noise when you drive slowly with open windows ?

http://bmwfans.info/parts/catalog/E4..._fan_coupling/

As Alex says it is possibly your fans, but could also be faulty temp sender, so many possibilities. Better to read a tad low than too high

[grumps]

I had a new viscous coupling fitted late last year under warranty! as lawsy suggested i think its probably down to the sensor as it makes no difference if the weather is hot or cold and if the ac is on or off

[alexk]

I had the same high temp problem today on track. Almost touched the beggining of red.

It was quite hot @ 30 degrees.

As soon as I backed off the throttle, it immediately dropped.
Then, I continued revving up to 5500 and didn't have a problem.
I suspect it's the viscous fan as with the engine hot, it doesn't engage properly (lawsy knows the check I am sure).
Also, for a year now when I would slow down from high speeds in germany, the temp would drop a bit.
I will start with the viscous coupling of the fan.

shimmy, how do you explain that the HG problem results to increased temperature, when there is no impact in the water or oil flow ?
I am just trying to understand why there would be a temp issue.

[shimmy]

I don't know, I'm no mechanic but I replaced viscous fan and no change (exactly same symptoms as you)

Don't forget HG leak is cylinder to cylinder, not water or oil related.

It can only be found on track at full throttle then 2 secs of the throttle and water temp drops (but oil temps stay higher). Therefore logic says the enine is affecting oil temps not water initially so I can't be fan, water radiator, pump, pipes, thermostat.

It must be oil related so engine is affecting it via timing, fuel, coils, injectors or oil cooling is affected by blocked rad or dodgy sensor.

When I replaced my HG i also changed coilpacks, refurbed injectors, oil filter and it went

Shimmy

I had the same high temp problem today on track. Almost touched the beggining of red.

It was quite hot @ 30 degrees.

As soon as I backed off the throttle, it immediately dropped.
Then, I continued revving up to 5500 and didn't have a problem.
I suspect it's the viscous fan as with the engine hot, it doesn't engage properly (lawsy knows the check I am sure).
Also, for a year now when I would slow down from high speeds in germany, the temp would drop a bit.
I will start with the viscous coupling of the fan.

shimmy, how do you explain that the HG problem results to increased temperature, when there is no impact in the water or oil flow ?
I am just trying to understand why there would be a temp issue.

[shimmy]

Ok the facts as I see them...

1. Oil temp rises to 2/3
2. Then water temp rises to 3/4 and then on to red slowly
3. Only happens at full throttle,
4. Initially happens only on warmer days
5 Only on Trackdays (presume this coz 100%throttle uncommon on road)
6 Off full throttle temp of water drops quickly

Mine happened last at Snett, then started to run badly at higher revs, then diagnosed as failed HG between cylinders 5/6 worse and others.

Now question is does the HG failing and leakage between cylinders cause the engine oil temps to rise OR does something else cause the oil to rise and then result in a failed HG cause of raised engine temps?

Now as Oil temps rise first noticably I think this means that the engine is getting hotter before the water temps are, so therefore the water cooling system can't be at fault.

[shane@mbtech]

I had the same high temp problem today on track. Almost touched the beggining of red.

It was quite hot @ 30 degrees.

As soon as I backed off the throttle, it immediately dropped.
Then, I continued revving up to 5500 and didn't have a problem.
I suspect it's the viscous fan as with the engine hot, it doesn't engage properly (lawsy knows the check I am sure).
Also, for a year now when I would slow down from high speeds in germany, the temp would drop a bit.
I will start with the viscous coupling of the fan.

shimmy, how do you explain that the HG problem results to increased temperature, when there is no impact in the water or oil flow ?
I am just trying to understand why there would be a temp issue.

Its not the viscous as the viscous is only effective below say 10-15mph. It might still spin but its efforts are wasted as the speed you are travelling pushes more air through the rad than the viscous could ever pull through it.


In most cars overheating can cause the headgasket to fail.

The hg can fail between the 2 cylinders which increases cylinder temps, which in turn will increase water temps. Which in turn can then cause the HG to fail more so, its a viscious circle.

There are varying factors.

First thing to check is cooling system, if all is ok, then onto engine side.

Fuel pump, fuel injectors, engine timing faults, remaps can all cause det, if not perfect. When det occurs, cyl temps increase, cyl temps increase which causes more det- see where its going.


Or it could simply be an inherent fault due to the nature of the beast. The s54 engine has very small gaps between cylinders. Over a prolonged period of time with extreme operating conditions (track), and with a few miles, the gasket can fail, which results in overheating which accelerates HG failure. LOSE LOSE.

I have noticed over the last 12 months a big rise in /HG failures on both M3 and CSL.

I believe it is just the nature of the beast.

[shane@mbtech]

If I had another CSL, without doubt I would fit a motorsport thermostat.
Esp if it was on track.

[DuncanR]

Anyway, for a HG check it doesn't matter too much if the car is not red hot, as your looking for anomalies between the cylinders. Hot readings would just show around 15psi higher on each cylinder.

I dont go along with this, it should be remembered that with any temp increase ALL dimensions get BIGGER ! ... and that includes clearances and any gaps or cracks.

My temp gauge usually sits just past halfway or 100 during Ring or track day work, and falls back to just below half after about a minute, at which point I consider switching engine off, I never switch off if reading is above 100.

If I had another CSL, without doubt I would fit a motorsport thermostat.
Esp if it was on track.

Part no and supplier Lawsy, good shout that man !

[alexk]

Ok the facts as I see them...

1. Oil temp rises to 2/3
2. Then water temp rises to 3/4 and then on to red slowly
3. Only happens at full throttle,
4. Initially happens only on warmer days
5 Only on Trackdays (presume this coz 100%throttle uncommon on road)
6 Off full throttle temp of water drops quickly

Mine happened last at Snett, then started to run badly at higher revs, then diagnosed as failed HG between cylinders 5/6 worse and others.

Now question is does the HG failing and leakage between cylinders cause the engine oil temps to rise OR does something else cause the oil to rise and then result in a failed HG cause of raised engine temps?

Now as Oil temps rise first noticably I think this means that the engine is getting hotter before the water temps are, so therefore the water cooling system can't be at fault.

shimmy, I am no pro but the family biz is bmw cars.
I have seen in the past many issues in BMWs that started with the viscus fan or water pump.
As lawsy said, then it's a chain.

I don't want to doubt what you are saying, but I find this strange.

Lawsy says :
>>
The hg can fail between the 2 cylinders which increases cylinder temps, which in turn will increase water temps. Which in turn can then cause the HG to fail more so, its a viscious circle.
<<

Why if we have compression loss between 2 cylinders, the temp rises ?
I would expect the knocking sensors will detect this and adjust the ignition and injection.
The car would run very poorly etc.

I will take out my spark plugs today and also run the diagnostic to see for any strange knocking/compression values between the cylinders and update you.

PS : I am not rulling out the HG but at 84k km and always using good fuel, low env temperatures, never had a knocking failure and the water temp decreasing after stops from the autobahn, I find it unlikely that my car has a HG issue

[alexk]

I dont go along with this, it should be remembered that with any temp increase ALL dimensions get BIGGER ! ... and that includes clearances and any gaps or cracks.

My temp gauge usually sits just past halfway or 100 during Ring or track day work, and falls back to just below half after about a minute, at which point I consider switching engine off, I never switch off if reading is above 100.

Part no and supplier Lawsy, good shout that man !

It's this one -> 11531417215

http://www.turnermotorsport.com/p-3-...-degree-c.aspx

[shane@mbtech]

shimmy, I am no pro but the family biz is bmw cars.
I have seen in the past many issues in BMWs that started with the viscus fan or water pump.
As lawsy said, then it's a chain.

I don't want to doubt what you are saying, but I find this strange.

Lawsy says :
>>
The hg can fail between the 2 cylinders which increases cylinder temps, which in turn will increase water temps. Which in turn can then cause the HG to fail more so, its a viscious circle.
<<

Why if we have compression loss between 2 cylinders, the temp rises ?
I would expect the knocking sensors will detect this and adjust the ignition and injection.
The car would run very poorly etc.

I will take out my spark plugs today and also run the diagnostic to see for any strange knocking/compression values between the cylinders and update you.

PS : I am not rulling out the HG but at 84k km and always using good fuel, low env temperatures, never had a knocking failure and the water temp decreasing after stops from the autobahn, I find it unlikely that my car has a HG issue

Try the stat first Alex

Simple and cheap, try the motorsport or tropical one

[shimmy]

Try the stat first Alex

Simple and cheap, try the motorsport or tropical one

Hmmmm agree, cheap check.

But if water temps are good until oil temps rise, can't see it helping

I think it's an engine issue. Timing, map, fuel, injectors Or HG on its way out.

Don't forget its ONLY at full throttle (and on track this tends to be when air flow at its best) and its not when standing.

[AlexGTT]

Any unexpected high temps on track at WOT always points to HG failure between cylinders if said temps then fall quickly when slowing. Most HG failures blow into coolant or oil system which is easy to diagnose. E46 M nearly always between cylinders. Less easy to spot and can remain minor until complete fire ring failure shows itself with a noteable miss-fire.

Any problems like this an I'd have a cylinder leak down test, NOT compression test.