get my car back Thursday - EXCITED

**shimmy** · 18-09-2009, 11:57 AM

ok, so just a reminder........

since June/July i have had a little irregular throttle response low revs and around 2-3k revs. also in august i had a day at Donny where the water temp guage went very close tot he red zone after 4-5 quick laps on a hot track day.

Snetterton this month the car wasnt quite right and felt like it lacked power which the data logger seemed to back up compared to last year

So went down to Simpsons last week to get it checked out. Misfiring a little worse on the way down. Ant, Julian and Jo did a compression leak test ont he cylinders straight away while i made a cup of coffee and low and behold cylinders 5 & 6 were low and leaking to each other. Whipped off the head then and there and found that the gasket had failed between 5 & 6 and just about between a couple of other cylinders (the gasket is very thin at these points by the way. (pics to follow)

They immediately checked the head for warping and the block for detonation damage but all looked ok.

So the question we mulled over, but never solved, was "did a failing head gasket cause the overheating and throttle issues OR did the overheating cause the head gasket to fail and the throttle issues OR did some sort of failure of another element like coil or injectors casue under fueling (run lean) and therefore over heat the car and cause the gasket to fail.

Who knows!!!

But within 4 days they had replaced the gasket and head bolts, and sorted out the car. Road test and dyno test and 355bhp and all looked well.

I also asked them to do a 60k mile replacement and service and we agreed to;

1. replace water pump (becasue it was starting to wobble)
2. replace thermostat (because i had already bought one)
3. relace both water temp senders (cheap)
4. remove the rads (water, oil and a/c) and clean them out inside and out. Remove the rubber and stones and dirt and bend back the fins to get them efficient again.
5. Replace the coil packs (mine were original and not the latest ones)
6. Refurbish the injectors (found to be running 5-10% down
7. Replace knock sensors
8 replace air filter
9. replace fuel filter

Vanos checked out ok a number of times.

My gut feeling for anybody that has a pending RED LINE water temp on track after high revs, but returns to normal after one corner easing off, is this but i could be wrong;

It is not the cooling system failing (although a tired cooling system in need of maintennace may not help and make it occur quicker) - many many posts about this in USA but nobody has found a solution from the cooling system other than massive oil cooler and rad which i think just hides the problem.
It is not a Head Gasket failing by itself! Could be though!
BUt i think something like the injectors running inefficiently and lean, is causiing all or some of the cylinders to detonate a little and heat up when running at full revs. Causes the head gasket to overheat and fail.

So had the car yesterday, took it for a test drive and..............oh fuck............misfire, worse than before.
Drove back to Simpsons and onto the Laptop checking fault codes............panic. Julian had only put back in my old refurbed injectors since it was run ok on the dyno, so checked them and all ok, BUT Lambda sensor had failed and so we they changed it.............EVERYHTING 100% OK

Car was quiet, smooth, powerful, no heat problems and running 80-95 on the oil and lss than 12 oclock on the water guages.

Need a track day now!

search words E46 M3 CSL overheating head gasket coils plugs, radiators water pump cylinders 5 6 track day

18-09-2009, 11:57 AM	#11
shimmy CSL Register Uber-poster! Join Date: Apr 2008 Location: Uk Posts: 14,646 Casino cash: $43909	ok, so just a reminder........ since June/July i have had a little irregular throttle response low revs and around 2-3k revs. also in august i had a day at Donny where the water temp guage went very close tot he red zone after 4-5 quick laps on a hot track day. Snetterton this month the car wasnt quite right and felt like it lacked power which the data logger seemed to back up compared to last year So went down to Simpsons last week to get it checked out. Misfiring a little worse on the way down. Ant, Julian and Jo did a compression leak test ont he cylinders straight away while i made a cup of coffee and low and behold cylinders 5 & 6 were low and leaking to each other. Whipped off the head then and there and found that the gasket had failed between 5 & 6 and just about between a couple of other cylinders (the gasket is very thin at these points by the way. (pics to follow) They immediately checked the head for warping and the block for detonation damage but all looked ok. So the question we mulled over, but never solved, was "did a failing head gasket cause the overheating and throttle issues OR did the overheating cause the head gasket to fail and the throttle issues OR did some sort of failure of another element like coil or injectors casue under fueling (run lean) and therefore over heat the car and cause the gasket to fail. Who knows!!! But within 4 days they had replaced the gasket and head bolts, and sorted out the car. Road test and dyno test and 355bhp and all looked well. I also asked them to do a 60k mile replacement and service and we agreed to; 1. replace water pump (becasue it was starting to wobble) 2. replace thermostat (because i had already bought one) 3. relace both water temp senders (cheap) 4. remove the rads (water, oil and a/c) and clean them out inside and out. Remove the rubber and stones and dirt and bend back the fins to get them efficient again. 5. Replace the coil packs (mine were original and not the latest ones) 6. Refurbish the injectors (found to be running 5-10% down 7. Replace knock sensors 8 replace air filter 9. replace fuel filter Vanos checked out ok a number of times. My gut feeling for anybody that has a pending RED LINE water temp on track after high revs, but returns to normal after one corner easing off, is this but i could be wrong; It is not the cooling system failing (although a tired cooling system in need of maintennace may not help and make it occur quicker) - many many posts about this in USA but nobody has found a solution from the cooling system other than massive oil cooler and rad which i think just hides the problem. It is not a Head Gasket failing by itself! Could be though! BUt i think something like the injectors running inefficiently and lean, is causiing all or some of the cylinders to detonate a little and heat up when running at full revs. Causes the head gasket to overheat and fail. So had the car yesterday, took it for a test drive and..............oh fuck............misfire, worse than before. Drove back to Simpsons and onto the Laptop checking fault codes............panic. Julian had only put back in my old refurbed injectors since it was run ok on the dyno, so checked them and all ok, BUT Lambda sensor had failed and so we they changed it.............EVERYHTING 100% OK Car was quiet, smooth, powerful, no heat problems and running 80-95 on the oil and lss than 12 oclock on the water guages. Need a track day now! search words E46 M3 CSL overheating head gasket coils plugs, radiators water pump cylinders 5 6 track day Last edited by shimmy; 28-09-2009 at 11:19 PM.