Does your water temp move at all on track?

[funtime]

Just come back from the ring, had a good time but worried about a possible temperature issue...

Here's what it did.. - bare in mind it was 25-27 degrees whilst doing this:

I was running most of the time with the aircon off and the heating fans set to around 20 degrees at about half power.

The temp gauge towards the end of the lap would be around the 2/3rds marker and oil around 125.

Then on Monday they opened the F1 circuit aswell so each lap was just over 15 miles. My mate drove the CSL as he knows the track very well and when he drove we had the aircon on all the way round with the fans on nearly full power blowing cold, by about 2/3rds of the way round i noticed the water temp was almost in the red, and by the end of the lap it was just in the red, but after going under the gantry on the back straight and coming off the power coasting to the exit of the track it had already returned to half way on the water temp.

This got me worried, although the only thing that made me feel slightly better about it is that his M3 was doing exactly the same, so I put it down the the hot weather and longer track, although i was still surprised it got as high as it did.

The next time we went out, I put the heaters on full chat at 32 degrees, and had the windows open a touch to stop us melting, and by doing this the temp never went above the 2/3rds marker.

I did some reading yesterday and saw Shimmys troubles and a few others on here and instantly feared the worst so I did a compression check this morning.

Results are fine and don't show any signs of a HG failure which is a relief, but im just worried now about what else it could be.

I'm guessing you boys don't do all hot track days with the windows open and the heaters pumping at 32 degrees!

Any help and suggestions much appreciated

Another thing to note - my temp gauge never seems to sit bang in the middle either, normal driving it sits just under the half way marker and then a spout of hard driving you can actually see it move to just over the half way.

Could this all just point to a dodgy thermostat?!

[shimmy]

My guess would be that if oil is going over 2/3 followed by water going over 3/4 towards red then HG is favourite. I'll be surprised if its not even if yo have checked it.

Very common on high mileage cars, Dunc, Rob, me, Daz, and a few other have had HG changed.

I think early symptom if high temps on track on hot days first.

Get compression test asap (cylinders 5/6 will be worse) to rule it out before you start, like I did, rafting around with stats, rads, water, fans, oil coolers,

My car used to do hot days with a/c running no temp issues the slowly on hot days on track it started creeping up. Since HG changed no issues

[funtime]

Originally Posted by shimmy

My guess would be that if oil is going over 2/3 followed by water going over 3/4 towards red then HG is favourite. I'll be surprised if its not even if yo have checked it.

Very common on high mileage cars, Dunc, Rob, me, Daz, and a few other have had HG changed.

I think early symptom if high temps on track on hot days first.

Get compression test asap (cylinders 5/6 will be worse) to rule it out before you start, like I did, rafting around with stats, rads, water, fans, oil coolers,

My car used to do hot days with a/c running no temp issues the slowly on hot days on track it started creeping up. Since HG changed no issues

Well like I said i did fear the worst and so got the compression test done this morning - results are as follows (bare in mind the engine was not red hot so readings are a little low across the board)

1 - 149
2 - 154
3 - 155
4 - 157
5 - 159
6 - 151

So whilst I appreciate what your saying I wouldn't have thought the above results would suggest a HG?

Any other thoughts?

Also whilst doing the compression check we couldn't help notice the pollen filter had not been replaced for a very long time... but it's just had an Inspection 2

[shimmy]

Shouldn't compression tests be done hot?

I couldn't replicate my overheating anywhere but on track, warm day, full power.

Cleaned rads, replaced stats and sensors, viscous fans, etc etc. US forums have loads of this and if you think about it if you only get it at full chat, warm day, so plenty of air and fan is not an issue. Temp of oil ruses first followed by water so it seems to be engine caused not water cooling system.

I narrowed it down to injectors, map or fuel related. Removed Map and still happened then HG failed proper and after fixed it never happened again

[funtime]

Originally Posted by shimmy

Shouldn't compression tests be done hot?

I couldn't replicate my overheating anywhere but on track, warm day, full power.

Cleaned rads, replaced stats and sensors, viscous fans, etc etc. US forums have loads of this and if you think about it if you only get it at full chat, warm day, so plenty of air and fan is not an issue. Temp of oil ruses first followed by water so it seems to be engine caused not water cooling system.

I narrowed it down to injectors, map or fuel related. Removed Map and still happened then HG failed proper and after fixed it never happened again

Yes ideally - it wasn't done cold, just not as hot as it should have been. Was rushing and the engine had cooled for an hour or so because i realised i didn't have the right adapter to reach down the thin spark plug access holes and connect the compression tester.

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.

It does make sense what you say with regard to oil temp rising first causing the water temp to budge, although the other M3 that was with us had the same sort of oil temps 125/130 but his water temp didn't budge at all.

I'll give Simpson's a ring on Tuesday and see what they think...

Didn't you end up replacing your engine shortly after the headgasket Shimmy? was that the result of damage caused by the failed headgasket in the first place?

[shimmy]

No, bottom end, spun a shell.



If you look at the gasket the spaces between cylinders are very small and my belief is that when engine gets warm/ hot the compressions between the two cylinders drop very slightly when at full whack and you get overheating at 100% throttle.

My original throughts Were that the occasional near overheating caused the HG failure but as I never found a reason for the overheating and it went away at that time, I can only conclude the reverse.

As you car is higher than average mileage and you get E46 with 60-80k miles ith HG failures pretty commonly now days that have never been on track, i personally would do a thorough check first.