Overheating Problems, HELP!

[Chaps]

My commodore has recently had problems with over heating the hot and cold gauge is below half but when I get out of the car I can hear bubbling as if it is boiling, it is never after constant driving just after sitting in traffic, is there a problem with the radiator cap? Or something more? Cheers.

[1dvsbstd]

My commodore has recently had problems with over heating the hot and cold gauge is below half but when I get out of the car I can hear bubbling as if it is boiling, it is never after constant driving just after sitting in traffic, is there a problem with the radiator cap? Or something more? Cheers.

well tbh mate have you checked your coolant levels? checked for leaks? flushed the radiator and put new stuff in? check the radiator cap..? sounds to me like ure cooking your engine

sizzle sizzle

[Chaps]

Yeah ny mechanic had all that done and had no answer for it besides it could be my cap, just thinking others my have some ideas...

[MikeCuzzy]

Yeah I would have thought coolant levels too, my first guess would be cap. Don't go removing when it's bubbling... that would be the opposite of good. Some tosser did that the other month in a town not far from mine, 2nd degree burns for him.

[Chaps]

Yeah nah I won't be making that mistake, Mabey I'll just grab a new cap from the local car yard and see what happens

[oska]

replace your cap and thermostat before you blow your radiator

[edals]

If for god knows what reason for you had to remove the radiator cap when its hot, use a massive beach towel & keep all your weight on it then slowly release. I have had to do it once on the side of a freeway late at night cause my thermostat failed, had to do it quick was in a bad spot, never again.
But yes replace your Cap & thermostat and do a full flush, check for leaks

[oska]

If for god knows what reason for you had to remove the radiator cap when its hot, use a massive beach towel & keep all your weight on it then slowly release. I have had to do it once on the side of a freeway late at night cause my thermostat failed, had to do it quick was in a bad spot, never again.
But yes replace your Cap & thermostat and do a full flush, check for leaks

if you do it with the engine running it doesn't explode in your face but do take care

[adjustin]

Righto chaps, I've got the same problem...

it started with a heater tap blowing off, replaced that. Discovered a radiator leak, tried all options before eventual replacement. At the same time I got the radiator put in, got the thermostat replaced.
immediately after getting it home, same problem as you have described, air rushing through the system as if boiling, though temp is ok.
Eventually, (month or two later) replaced water pump, flushed head radiator and hoses. Thought I had fixed the problem, as I refilled the levels and bled system properly (have become quite proficient with this task) and heater ran well, car operated at what I thought was close to normal op tems.
very next morning, same blowbac through radiator! Grrrrrrrrrrr
Now the only thing I can think it might be are these three options:
thermostat not functioning properly and causing pressure above the head via steam, which is release when water pump is not functioning;
radiator cap is old and could have lost it's sealing abilities ( these are high pressure radiator systems)
or my head gasket is stuffed, though I think less likely, as no water in oil and no real identifiable steam in exhaust.
For me, I'll try the cap and t stat 1st, much cheaper than trying the head gasket.
It is very frustrating though, but this is the end result of not maintaining my cooling system properly for an extended time.
One other thing I'm curious about, does your air con still work. as the air con and radiator are linked perhaps they may be related? thats a long shot though, and I'd rather be wrong...
juz

[adjustin]

also, if you suspect the head gasket is stuffed, apparently there is a simple test and decent mechanic can do, it is a cap they swap for your radiator that identifies exhaust emissions in your radiator, this would be a clear indication that there is leak between the two.
good luck

[wortus]

Where is the bubbling sound coming from? If it's in the overflow bottle try a new cap or a friend had to bend the tabs on his to increase the grip against the radiator as coolant was escaping under pressure when hot but not sucking back in as the engine cooled.
If it's over heating at idle this may mean an air flow problem. Check that the fans are coming on or run your aircon at idle which will start at least one of the fans and see if it still happens.
Also check for oil in your radiator or coolant in your oil which indicates a problem with either your head gaskets or inlet manifold gaskets. The inlet manifold on my VY came loose and oil got into the radiator. It didn't overheat but I'd imagine it would eventually fail.

[PirateJoe]

I'd be checking the operation of everything in the cooling system Chaps, dont just guess here and there. It could but be a thermostat but I'd be checking the temp gauge in your car at the same time to ensure the reading is correct.
If you hear air or bubbling/boiling, remember a cooling system is a sealed system designed to prevent this so the fluid doesnt boil. So you have either an faulty thermostat, air lock, faulty rad cap or exhaust gas entering the system.
A CO dye test can be carried out on the car easily to determine if there's exhaust gases entering.
The fact that it only happens in traffic - in traffic there's no natural flow of air through the radiator, Have you checked the fans are coming on?
Remember if you have to drive and the temp is climbing you can crank the air on full heat and open all your windows. It will help a little to cool the car down, but not massively.
Time for some diagnosis. Good luck mate.

[edals]

if you do it with the engine running it doesn't explode in your face but do take care

Learn something new everyday lol
But it was over heating so best not to let it cook and run without coolant lol

[PirateJoe]

if you do it with the engine running it doesn't explode in your face but do take care

Never try this, if it's overheating there will be an excess of pressure in a sealed system and as soon as the pressurised water is at atmospheric temperature it will want to boil.
It will blow out of the radiator, a pressurised overflow tank system is slightly different yes, but still not recommended if you dont know what your doing.

You can also crack a head while opening an overheated radiator, best to leave it to cool down first.

[adjustin]

all good points that have previously been considered. End result, $8.65 for a new radiator cap fixed the blowback issue in my car. Hasn't made any of the noise since replacing it this morning.
I now have a fully (except hoses) reconditioned cooling system, which at 12 years old it was needed anyway.

Definate answer to air rushing out of radiator into overflow after turning the car off, new radiator cap..., if you can eliminate the water pump, thermostat, radiator, (humour)

I know I didn't start this thread but I am glad I found it, so thank you to all involved. No doubt we'll cross threads again, I own an aging holden.

good luck chaps

[Mick1988]

as the air con and radiator are linked perhaps they may be related?

Please explain??

[PirateJoe]

↑↑*Best Pauline Hanson voice*↑↑

[Killr6]

hey guys i had the same problem with my vt, when driving all of sudden the fans would come on and the car would overheat... so as i drove it to the mechanic my blew just outside the mechanic (i was lucky) what happened was my heater valve tap, thermostat went all because my water pump had a leak, which i didnt even know of, then a few days later my radiator had a huge crack in it, cost me about $800 to fix all up.

check those things from my past experience with the problem, hope it helps.