Deleted my ast on new setup, filled the car up for first start the other night at 10F outside. Thought I had gotten all the air out of the system but apprently not.

Gauge read 180F, drove about two blocks down road and add coolant light comes on, then gauge shoots to 225F. Sensor is in the filler neck for water temp, so I'm hoping it was just reading the air.

Turn off engine and then intense boiling occurs, surging and bubbling noises like crazy.

After it subsided I popped the filler cap to find my level was unfilled by about a gallon with a ton of air releasing.

The car was not run very long at all, the temps of the block couldnt have gotten to high as it was 10F. Can air in the system/this occurance have caused damage?

Is this Just as bad to your motor as heaving a full system heat up to its boiling point under load and steam over? Surelly not?

 

rule of thumb, if the cooling system is empty and only takes 1 gallon then there is an air pocket preventing it from filling. a standard system takes 2 gallons, one with an aftermarket radiator about 2.5 gallons.

it's easiest to just remove the hose to the top of the throttle body and fill it until coolant comes out of the ports. no hassle with bleeding the system that way.

225F isn't horrible but if the engine is original then that still could be enough to do some damage to the seals if they were marginal. if the engine has been rebuilt in the last 5 years i wouldn't worry about it. coolant temp senders don't work off of reading air pockets so your reading of 225F was close to accurate, it only take 10 minutes even in those circumstances for an engine with a massive air pocket to reach that temp. the engine doesn't care what the temp is outside if there is nothing in it to cool it off, it just takes a short bit longer to get that high when the engine starts at a colder temperature.

 

Motor only has 7k miles

Seems to be running fine as of now. However my new aluminum overflow keeps climbing a few cm's after each running session. Not pulling back into the system. Going to check the overflow hose for leak...but hoping this isn't a sign of a small seal leak.

Only way to confirm is hydrocarbon test?

 

HC test, pressure test and see if the plugs come up wet or just drive it and worry about it when the symptoms start to really tell.

it could simply be a faulty cap and restriction in the overflow hose.

 

Running a summit racing overflow which has a hose running inside to the bottom to pull coolant back up into the system. Running a stainless braided rubber hose with clamps to the filler neck and overflow. Hose is a little too large of diameter for filler neck nipple, but I'm using fuel line compression clamp. It may just be too loose to seal. I would assume a bad seal would cause constant fill-up while the motor is running. Im just getting a slow inching upwards after every warm-up.


AHH these dang motors make me so paranoid with coolant errors!!

Thanks for the help.

 

the coolant buzzer will tell you first, but i would be sure the return system has no leaks so that it can pull coolant back under a vacuum.

ideally i prefer the pressure cap to only vent when the pressure actually exceeds the system limit, so a faulty cap will show other system issues and lower the boiling point of the coolant. if the cap mounted to the AST can't hold 13psi then i'd replace it.

that assumes you do have an actual pressure cap on that summit tank, otherwise if it is an open inlet port then there is nothing actually regulating system pressure which is where your problem is. it's just too hard to tell with the small picture to see the configuration.

 

Not using an ast, cap on filler neck is 13psi and should then vent to the overflow.

Thanks

 

does the port on top of the catch tank have a tube to extend to the bottom of the tank? is there more ports tied to that tank?

 

Yes, hose running to the catch tank runs through the tank and down into the tank. No other ports

 

then if the cap on the engine is not new i'd probably start by replacing it, then check the hose to the tank. any small spots where it can leak will kill the suction function. and be sure there's no junk or debris inside the filler neck which will break the cap's sealing capability.

 

Yes brand new cap, brand new neck, brand new line, brand new clamps, and new overflow.

I guess I swap out the line w a smaller diameter hose just rule out the possibility of a leak

 

i would try that first and check to be sure nothing got under the cap seat.

if it still happens i would check the system with a pressure tester to see how much pressure it is actually building. if the hoses are getting extremely hard then you may be in trouble..

 

Ok good idea, ill make sure large radiator hoses aren't expanding too hard. If it passes the pressure test and still overfills ill move on to hydrocarbon test.

But I hope your right, seems unlikely that 225-235f from air pockets would cause damage. Boiling didn't occur until motor shut off anyhow