Mystery of the vanishing coolant?
#16
Agree it's worthwhile, and a great diagnostic tool, but once the HG starts to leak under boost enough to detect, they only seem to get worse from there. It's good for avoiding catastrophic failures and might let you nurse the HG a while, but once the coolant pressure starts to spike when on boost, it's probably just a matter of time....
#17
Highly recommended 'cheap' mod - add a pressure sensor to your coolant expansion tank and datalog the results. You will see the signs of a failing headgasket there long before it does any damage. I have that sensor (an oil pressure or fuel pressure sensor will work fine) hooked into my ECU and programmed to kill boost if it sees over 17psi (you have to set is just at or slightly above above you cap pressure).
I also found a nice bleeder to replace the stock screw - http://www.summitracing.com/parts/de...Fe1QOgod-jIA7A you just push it in and it will vent the air. it takes all of 2 seconds and it can be done after each track session to double check the coolant system.
Hmmm...I wonder why I pass on all my little secrets? I should charge you guys for these gems!!!
I also found a nice bleeder to replace the stock screw - http://www.summitracing.com/parts/de...Fe1QOgod-jIA7A you just push it in and it will vent the air. it takes all of 2 seconds and it can be done after each track session to double check the coolant system.
Hmmm...I wonder why I pass on all my little secrets? I should charge you guys for these gems!!!
You set your sensor up for a maximum of 18psi and if it goes over that you know you have a HG problem.
#18
#19
Wonder if you still have a Heater in the Car? Pressure Tester can miss the Hose going from the Heater Control Valve [takes Vacuum to operate and is 'suppose' to fail Open] to the Firewall. When that Hose leaks, Coolant falls right onto the Exhaust Pipe and turns to steam.
#20
I too had a mystery coolant leak. It turned out that there was a hairline fracture in one of the hose nipples on the expansion tank. Oddly, pressure testing when cold didn't really reveal it. It wasn't until we tested at a warm temperature did we discover it.
#21
Highly recommended 'cheap' mod - add a pressure sensor to your coolant expansion tank and datalog the results. You will see the signs of a failing headgasket there long before it does any damage. I have that sensor (an oil pressure or fuel pressure sensor will work fine) hooked into my ECU and programmed to kill boost if it sees over 17psi (you have to set is just at or slightly above above you cap pressure).
I also found a nice bleeder to replace the stock screw - http://www.summitracing.com/parts/de...Fe1QOgod-jIA7A you just push it in and it will vent the air. it takes all of 2 seconds and it can be done after each track session to double check the coolant system.
Hmmm...I wonder why I pass on all my little secrets? I should charge you guys for these gems!!!
I also found a nice bleeder to replace the stock screw - http://www.summitracing.com/parts/de...Fe1QOgod-jIA7A you just push it in and it will vent the air. it takes all of 2 seconds and it can be done after each track session to double check the coolant system.
Hmmm...I wonder why I pass on all my little secrets? I should charge you guys for these gems!!!
#23
Highly recommended 'cheap' mod - add a pressure sensor to your coolant expansion tank and datalog the results. You will see the signs of a failing headgasket there long before it does any damage. I have that sensor (an oil pressure or fuel pressure sensor will work fine) hooked into my ECU and programmed to kill boost if it sees over 17psi (you have to set is just at or slightly above above you cap pressure).
I also found a nice bleeder to replace the stock screw - http://www.summitracing.com/parts/de...Fe1QOgod-jIA7A you just push it in and it will vent the air. it takes all of 2 seconds and it can be done after each track session to double check the coolant system.
Hmmm...I wonder why I pass on all my little secrets? I should charge you guys for these gems!!!
I also found a nice bleeder to replace the stock screw - http://www.summitracing.com/parts/de...Fe1QOgod-jIA7A you just push it in and it will vent the air. it takes all of 2 seconds and it can be done after each track session to double check the coolant system.
Hmmm...I wonder why I pass on all my little secrets? I should charge you guys for these gems!!!
#24
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From: Marietta, NY
A common failure on a head gasket is the #4 to coolant jacket breach - when that happens the pressure from the cylinder will over pressure the coolant jacket in the block and start blowing out the coolant from the expansion tank. Depending on how bad the breach is it will take a little while for the coolant temp to spike - and once that happens its usually too late to back off, the damage is already done.
#25
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Some track cars seem to develop localized boiling and they create air pocket over time - once you have enough air you will get more boiling and eventual a major overheat. This will help get the air out of the system.
#26
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From: Marietta, NY
Agree it's worthwhile, and a great diagnostic tool, but once the HG starts to leak under boost enough to detect, they only seem to get worse from there. It's good for avoiding catastrophic failures and might let you nurse the HG a while, but once the coolant pressure starts to spike when on boost, it's probably just a matter of time....
#27
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wouldn't he see a spike on the temp guage due to the steam bubble in the head... accompanied with vapor [near coolant temp] exiting out the overflow vent.... but before the rest of the engine actually overheated ?? ....thinking the guage spiking would be like advanced warning.
#28
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From: Marietta, NY
wouldn't he see a spike on the temp guage due to the steam bubble in the head... accompanied with vapor [near coolant temp] exiting out the overflow vent.... but before the rest of the engine actually overheated ?? ....thinking the guage spiking would be like advanced warning.
The order of events would be the increase in pressure due to the breech and then, after a while, the increase in temp due to air in the system. The steam comes after the increase in temps due to air in the system. By then you are well down the road to serious head gasket failure.
#29
Data showed that our water temps may have gone from 90-92 degrees so they didn't climb or spike radically. We don't have the stock tank setup either. Have a single smaller bottle with cap and a secondary tank elsewhere. I suspect the headgasket leaked and the water must have escaped out of the 2nd container which eventually vents to atmo. Just that we would have expected to see evidence of the leak at 5 ltrs?
There was no water in the bores or oil. Going to test on dyno to make sure it's the h/g and then change it. Just wasn't expecting to have this issue so soon like many of us have had running higher boost and E85 with Cometic h/gs. That we were able to top up the first time with a couple of ltrs and run another session shows how these gaskets can work. With a stock gasket it's game over and with a road driven car, it's a looooong tow home.
There was no water in the bores or oil. Going to test on dyno to make sure it's the h/g and then change it. Just wasn't expecting to have this issue so soon like many of us have had running higher boost and E85 with Cometic h/gs. That we were able to top up the first time with a couple of ltrs and run another session shows how these gaskets can work. With a stock gasket it's game over and with a road driven car, it's a looooong tow home.
#30
Patrick I once had a tiny pinhole in one of the hoses. It would ONLY leak during or immediately after hard driving. It would fire out this tiny little stream of coolant but as soon as it cooled slightly (like idling) it would close up and stop leaking. I could only find it by driving hard, stopping really fast and getting the hood open really fast to catch it. It didnt cause 5 liters to disappear but it was significant enough.