Oil(?) in coolant expansion tank after light track session.
 

Hi community,

I got a short story to tell and I'm seeking a second opinion on the subject.
Last weekend i wen for a local track day sessions.
The day was warm, around 77F and sunny.
Sessions was 10min long on a tight technical track, mostly 3rd/4th gear.
During the session i was monitoring the enging via Torque app and BT dongle.
Coolant temps was around 188F (due to low temp thermostat in Cosworth kit).
Oil temps at hte start was around 194F to 240F at the end.
Bare in mind I did not push it hard at every corner all the time.
Car is still on a factory Michelin tires so i was not expecting to beat the laptimes.
After the session I let the car cool down, by taking it for a few min drive on a long straight road and later sti on idel on hte parking lot for a few min more.

Later during the evening after car cools down i started it again and for a brief 5-10sec after the start I've noticed a white smoke from the exhaust. It was not so dense while smoke but still definately a smoke, not a water vapour.
It stops pretty fast to my suprise and relief. I can not tell You the smell of it now, I was too suprised to check it.
After that car was running fine, no issues, temps was all ok, no strange noises, no low level of coolant, oil dipstick showed oil in the same place with no signs of contamination.

On the next day, first cold start similiar situation happen, only less smoke this time, also for a few secs, similiar while smoke but it looked little dilluted.
I decided not to participate in the track day any more and just enjoy the pitstop life with friends.

Third day event was ending, and this time first cold start did not showed any white smoke at all, so my journey home was calmer.
Car was running fine on the motorway, temps was all on the green.

Next day when i took it out of the garage and start it, suprise suprise, white smoke appear during teh start for a few seconds.
I decided to check what i can, and I started to look around the engine for some signs.

First I thought it could be an oil blow-by, but no, throttle body was dry and clean.
Then I checked the oil on the dipstick - no signs of contaminant.
Then was the coolant, or more specific cooling expansion tank and radiator cap.
After taking out the pipe from the expansion tank I've noticed this
https://i.imgur.com/PUj2s9C.jpg

After taking off the radiator cap I've noticed some little flakes of some sort (will upload a movie so You can check that later).
Then I took it for a drive to see if the issue expand, but it did not. I was driving around in traffic, stop and go, off and on to check if the problem is visible on the hot enginge but no, no smoke whatsoever.

So my question to You guys is did I kiled one of the head gaskets, cracked a block, or something else? I hope i did nto get a hydrolock because of that (my inner paranoid kicking in).
I think maybe the safest way to check if there's any coolant in the cylinders it will be to remove the spark plugs and use that little inspection cameras, or just try to crank it and see if any liquid will spill out.

I will check the car once more this weekend and will try to record a cold start to confirm if the issue is still repeatable.


Any input will be appreciated.
Please forgive me any language mistakes ;)

Hi eMCee

Questions:

How many miles on your car?

Is it still under warranty?

What power mods do you have, if any?

Is there any oil floating on the top of the liquid in the coolant tank?

I suggest you not overreact. See how it runs/looks this weekend.


humfrz

You might be at the very early stages of a head gasket leak or some other corruption between the cooling system and the combustion chamber. I don't know what you have available in Poland but there are kits that chemically analyze the coolant for combustion gas contamination. This will not tell you exactly what has failed but it can point you in the general direction of failure. Here is an example of what I am talking about:

https://www.amazon.com/Lisle-75500-C.../dp/B0007ZDRUI

Good luck on troubleshooting the problem.

Well, the good news is it didn't overheat anything.

If you're worried do a leak down on your coolant system. If it holds a vacuum you're GTG.

Hi humfrz,

Approx 37k miles.
Out of warranty.
Cosworth Supercharger kit only.
No oil floating on the top of the coolant, but I think I saw some of that brownish cream on the bottom (or maybe it was just a dirty tank from the outside).
I will double check that with some pics.



Hi mrspindlelegs,
Thanks for the tip, yeah I saw that kit on a few YT videos
I need to look around if they got that in poland or germany.



Hi Trueweltall,
Thanks for a suggestion.
As stated above I think more troubleshooting is needed to narrow down the issue.
I will keep You guys updated when i manage to do some of the testing.

Cheers.

Head gasket is starting to go. Well, one of them at least.

Head gasket.

Did you confirm a bad head gasket? If so, what brand and thickness did you go with?

What type of head bolts? Have seen heads lift wit stock bolts. Might need to try something like ARP.