ZX636RIDER03

So I was at the track this past weekend running on road course (Sonoma Raceway) and after my 3rd session I noticed that my coolant reservoir was boiling over. I thought that it may had been from me over filling my radiator which was then over filling the reservoir. By the end of the 4th session I was coming off the track with my temp gauge way up and then pretty much almost all of the coolant was dumping out of the reservoir onto the paddock once. I'm trying to get and idea what could cause this to happen, could this be from an air pocket pressurizing the system, head gasket creating air in the coolant pressurizing the system, bad thermostat or dysfunctional water pump? Just trying to get an idea where to start, I would assume that if the head gasket was leaking then white smoke would come out the tail pipe or there may be water in the oil.

Any thoughts on this would be greatly appreciated.

Thanks,

Injuneer

Check oil. Test coolant for hydrocarbons.

What was the coolant temp gauge reading when all this was happening?

Could be a simple as a weak spring on the pressure cap. Could be a lot more serious.

ZX636RIDER03

The temp of the engine once I had parked the car had risen to about 250 or right before the redline on the temp gauge.

I'll see if I can get ahold of a tool so that I can check the system for Hydrocarbons.

ZX636RIDER03

Ok, ran home on my lunch at did a quick carbon test on the system after letting the engine idle for 10-15 minutes. The chemical at first took a little time to discolor, but as the engine heated up, the chemical would change pretty gradually to yellow indicated that carbon was present.

So now the question is, is this the head gasket? cracked head?

When I did the rebuild i boosted my compression ratio up with new internals, and used the standard felpro head gasket with an ARP head bolt kit. What other things could cause combustion gases to pass into the coolant?

Thanks,

ZX636RIDER03

Still having this problem, primarily after racing the engine for about 20 minutes on a road course. With Hydrocarbons present, would this indicate that I have a faulty head gasket which is pressurizing the coolant system, leading to the fluid boiling over?

I replaced the radiator cap, and have attempted to bleed the system of air as well, but no luck.

Thanks,

Tom

pizzi-man

Did you chase your problem down?

Z28Freak86

I had this problem, mine was just a bad thermostat. Not a hard item to replace (cheap too)

Injuneer

Hydrocarbons (not "carbon") in the coolant is generally due to a leaking head gasket.

ACE1252

Cooling system pressure tester can help out as well. Get one at Autozone(loan a tool program).

You put it on the radiator and pressurize the system(not above rated cap pressure). 10psi or so has been good for me in the past, but you may need to go higher...just don't go above rated cap pressure(18psi I think....but verify that). See if it holds pressure. They are very handy in finding leaks. You can also fire the engine up with it attached for a short period....see if it shoots up in pressure quickly or has a wildly vibrating needle. This can verify a head gasket sealing problem.

Are you sure that you have not reversed a couple of cooling lines? It's easy to do and you may be dumping the coolant into the reservoir instead of the radiator. I'm speaking of the steam return from the back of the head. Make sure that and all the cooling lines are in the proper location.

The bad news for you is that getting the heads up in the 250-260 range can warp them. I overheated my LT1 years ago(by mistake...cooling fan fuse blew....temp gauge pegged while I was looking at a laptop connected to the car....) and it did warp both heads(block was fine)....they were out 0.003" or so. This was enough to allow the coolant to get past the gaskets.

ZX636RIDER03

Havent figured this one out yet. I'm going to check the coolant lines to ensure that they are configured correctly, although I'm preparing myself to start tearing into the engine to replace the head gaskets. Since there are hydrocarbons present in the coolant and the symptoms have increasingly gotten worse, this is what I'm betting on. I kept thinking that there was air in the system due to an air pocket. purchased a radiator vacuum kit to fill the system and its still doing the same thing.

Anyone have any thoughts on the cometics MLS head gaskets? Or are the felpro's just fine?

Also thinking that one possibility that could have resulted in this was a blockage that I had on the driver side exhaust headers where it met the cross pipe. Since the exhaust was not able to escape efficiently, the next weakest point would be the head gasket.

ACE1252

Have you put a cooling system pressure tester on it yet? If not, why not?

You don't need a vacuum kit to get air out of the LT1. The LT1 cooling system is easy to work on.....people complicate the process by screwing with the air bleeders too much and they can even pull air into the system under the right conditions.

All you really need is a Lisle spill free funnel(to run it with the cap off the radiator and it keeps the coolant from going everywhere while getting up to thermostat temp) and you are good to go.

To outline the process...

• Assuming the engine is stone cold.
• Protect the Opti with towels under bleeders.
• Fill the coolant reservoir to full hot...if over full hot, suck it out with a hand pump.
• Open both bleeders.
• If the coolant has been completely drained, add in two GM coolant system sealing pellets(this is per the GM F-body manual). I do this every complete coolant drain....I also use dex-cool. Not sure if the pellets are for green coolant. I would assume so, but I need to check on that....
• Fill the radiator with coolant.
• Close each bleeder once a steady stream of coolant flows from each of them when filling. After which, you DO NOT touch the bleeders again.
• Fill the radiator all the way up. Leave radiator cap off.
• Put on the Lisle funnel.
• Fire up the engine. Turn HVAC system(inside car) on, temp to hot with fan speed to max. Let the engine get to temp(~180*).
• Be ready to add more coolant, into the radiator, once the thermostat opens. Keep the Lisle funnel half full. This insures that fluid level is above the engine level. This will help move air pockets in the engine. Review fluid mechanics for full explanation.
• Once at 180* (or thermostat temp)blip the throttle a few times. It will help remove any trapped air in the engine. This is standard protocol for any engine.
• Don't let the engine get over 200*...if it gets to 212* you will have a mess(boiling coolant). Yes, I've mistakenly done this before....like a freaking volcano out the radiator.
• After a several good blips, shut it down. Remove the funnel.
• Install the radiator cap.
• Check the coolant reservoir when the engine is stone cold(and not before a complete cool down). Coolant reservoir should be at cold level. Open the radiator cap, it should be full to the neck.

Injuneer

Mechanical Engineer harassing an Electrical Engineer.....

If you are running a 50/50 mix of water/ethylene glycol, the atmospheric boiling point is ~223-225*F.

ACE1252

Haha, I was just giving him extra room for error, yeah, yeah, that's it!!!

Hehe, all I know is that I saw over 200 and it looked like old faithful had moved into my engine bay!! It made a dang big mess and I stand corrected.