Ancient Corolla overheating- head gasket?
Discussion
Our aged and weary '95 Corolla 1.3 overheated a couple of days ago. I added water, and it did it again. I asked the garage to change the thermostat but the recommended removing it altogether as it is so hot here it isn't really needed. It was indeed knackered, and sized partially open.
Took it out for a test drive and after a half hour, pulled over, left it running, seems okay, then we drove home and shut the motor off, and I could immediately hear rumbling from inside the car, it is bubbling like crazy into the expansion tank.
I flushed the system after the first overheat, the fan is working, comes on when it gets hot, so, head gasket leaking a bit and pressuring the cooling system?
No water or emulsion in the oil.
We're in the Philippines and it has been really hot the last few days.
Took it out for a test drive and after a half hour, pulled over, left it running, seems okay, then we drove home and shut the motor off, and I could immediately hear rumbling from inside the car, it is bubbling like crazy into the expansion tank.
I flushed the system after the first overheat, the fan is working, comes on when it gets hot, so, head gasket leaking a bit and pressuring the cooling system?
No water or emulsion in the oil.
We're in the Philippines and it has been really hot the last few days.
King Herald said:
Our aged and weary '95 Corolla 1.3 overheated a couple of days ago. I added water, and it did it again. I asked the garage to change the thermostat but the recommended removing it altogether as it is so hot here it isn't really needed. It was indeed knackered, and sized partially open.
Took it out for a test drive and after a half hour, pulled over, left it running, seems okay, then we drove home and shut the motor off, and I could immediately hear rumbling from inside the car, it is bubbling like crazy into the expansion tank.
I flushed the system after the first overheat, the fan is working, comes on when it gets hot, so, head gasket leaking a bit and pressuring the cooling system?
No water or emulsion in the oil.
We're in the Philippines and it has been really hot the last few days.
Back in the "olden days" cars did overheat just because it's hot. On a 1995 which has only ever had (tap?) water in it I'd conclude a radiator that's clogged with limescale. How much did you flush it? did you use a specialist product?Took it out for a test drive and after a half hour, pulled over, left it running, seems okay, then we drove home and shut the motor off, and I could immediately hear rumbling from inside the car, it is bubbling like crazy into the expansion tank.
I flushed the system after the first overheat, the fan is working, comes on when it gets hot, so, head gasket leaking a bit and pressuring the cooling system?
No water or emulsion in the oil.
We're in the Philippines and it has been really hot the last few days.
Check the oil cap for mayonnaise which will give away a blown head gasket.
More often than not, the cause is a depressurised system - either a duff radiator cap or possibly the cap on the expansion tank stripped it's threads. It's much cheaper to eliminate these first.
The other thing, of course, is an air lock after removal of the thermostat - start the car with the rad cap off and wait for it to heat up and then rev it gently and squeeze all hoses until all air has glooped out - put the heater on hot when you do this to get the full circuit in. Once it has finsihed glooping (mind your eyes as it can do an impression of a mini-geyser), replace the cap and try again.
Depressurisation can also occur through minute splits in hoses which are not obvious because it escapes as steam so there are no wet patches. Also check the water pump hasn't gone - that is obvious as you will have rusty water spray marks all round it.
Finally, don't forget the rads can silt and fur up on iron block engines and a good reverse hose through the rad will help clear it (though the glooping sounds like an air issue)
More often than not, the cause is a depressurised system - either a duff radiator cap or possibly the cap on the expansion tank stripped it's threads. It's much cheaper to eliminate these first.
The other thing, of course, is an air lock after removal of the thermostat - start the car with the rad cap off and wait for it to heat up and then rev it gently and squeeze all hoses until all air has glooped out - put the heater on hot when you do this to get the full circuit in. Once it has finsihed glooping (mind your eyes as it can do an impression of a mini-geyser), replace the cap and try again.
Depressurisation can also occur through minute splits in hoses which are not obvious because it escapes as steam so there are no wet patches. Also check the water pump hasn't gone - that is obvious as you will have rusty water spray marks all round it.
Finally, don't forget the rads can silt and fur up on iron block engines and a good reverse hose through the rad will help clear it (though the glooping sounds like an air issue)
Edited by LuS1fer on Thursday 26th April 13:56
I think I'll try a new rad cap first.
I checked the rad for cold spots with my infra red heat gun and it appears to heat up evenly enough along its length and area.
No bubbles when the motor is run with the rad cap off either, just a rise in level a little as you rev the motor.
It seems odd that it will drive for twenty minutes in 35C heat and be okay, then when turned off later it is bubbling and spewing. May be heat soak after shut down.
The temp gauge only reads a tad over normal, even when it is bubbling through the expansion tank.
No mayo in the oil either, but the level was very low, this thing drinks as much oil as petrol.
I checked the rad for cold spots with my infra red heat gun and it appears to heat up evenly enough along its length and area.
No bubbles when the motor is run with the rad cap off either, just a rise in level a little as you rev the motor.
It seems odd that it will drive for twenty minutes in 35C heat and be okay, then when turned off later it is bubbling and spewing. May be heat soak after shut down.
The temp gauge only reads a tad over normal, even when it is bubbling through the expansion tank.
No mayo in the oil either, but the level was very low, this thing drinks as much oil as petrol.
Edited by King Herald on Thursday 26th April 23:47
Anyway, I took the little 'un to school this morning, which is a 30 minute drive, and when I got home I checked the motor before I turned it off, all good, then after I turned it off, and it was okay, no temperature higher than 90C anywhere on the rad or hoses, no blowing out the expansion tank either.
Something odd going on here, unless the cooling is marginal, right on the edge. It is still hot weather here even at 7am, and a fast drive along the dual carriageway thing to her school and back should have got the motor temp up.
Something odd going on here, unless the cooling is marginal, right on the edge. It is still hot weather here even at 7am, and a fast drive along the dual carriageway thing to her school and back should have got the motor temp up.
Mayo in the oil filler cap DOES NOT mean the head gasket has failed. A very common and much put about myth.
Its very common in cars that do a lot of short journeys where the engine doesn't get up to temperature so boiling off the water from burning fuel.
A litre of petrol produces approximately a litre of water plus other nasties & that's also the reason why exhausts rot from the inside, again, faster on those that only do short journeys.
Do you have an unexplained loss of coolant?
Is the pressure cap in good order & sealing as it should?
As already said, are the hoses all in good condition & clips tight?
Get the coolant checked for the presence of combustion gases.
Get the system pressure tested.
The blocked radiator as already mentioned is another likely cause, very common on older cars. Flushing, although worth a try & might give a clue to blockage, is generally a waste of time, as is fitting a second hand radiator which may be no better than what you've got. Are there any cool spots on the radiator?
Antifreeze & other coolant additives contain inhibitors which help to prevent corrosion inside the engine water passages - which will cause silting up even quicker.
Check the outside of the radiator as well, is the matrix blocked with mud, leaves, dead flies etc? Are the fins in good order or corroded away?
A properly working thermostat ensures the engine gets up to proper working temperature quickly. If you remove it you will affect this & it can have issues with the water flow through the engine & heater matrix. Frequently overcooling is the result & the engine does not get up to working temp. Removal is often a ploy used by the unscrupulous to disguise a car with an overheating issue to get rid of it.
Its very common in cars that do a lot of short journeys where the engine doesn't get up to temperature so boiling off the water from burning fuel.
A litre of petrol produces approximately a litre of water plus other nasties & that's also the reason why exhausts rot from the inside, again, faster on those that only do short journeys.
Do you have an unexplained loss of coolant?
Is the pressure cap in good order & sealing as it should?
As already said, are the hoses all in good condition & clips tight?
Get the coolant checked for the presence of combustion gases.
Get the system pressure tested.
The blocked radiator as already mentioned is another likely cause, very common on older cars. Flushing, although worth a try & might give a clue to blockage, is generally a waste of time, as is fitting a second hand radiator which may be no better than what you've got. Are there any cool spots on the radiator?
Antifreeze & other coolant additives contain inhibitors which help to prevent corrosion inside the engine water passages - which will cause silting up even quicker.
Check the outside of the radiator as well, is the matrix blocked with mud, leaves, dead flies etc? Are the fins in good order or corroded away?
A properly working thermostat ensures the engine gets up to proper working temperature quickly. If you remove it you will affect this & it can have issues with the water flow through the engine & heater matrix. Frequently overcooling is the result & the engine does not get up to working temp. Removal is often a ploy used by the unscrupulous to disguise a car with an overheating issue to get rid of it.
Edited by paintman on Friday 27th April 09:21
The wife went out yesterday afternoon in it, drove for an hour, traffic and highway, and it ran perfectly, no bubbling after shut down, gauge reading normal throughout. I ran my temperature gun over it, max anywhere is 95-98C. Whatever was wrong seems to have cured itself. Air-lock maybe??
I'd rather have a thermostat in it than not, but the local consensus seems to be to take them out. I think I'll fit one when I can get round to it.
Emulsion in the oil could mean an oil passageway to water head gasket leak, but that would not really cause overheating, unless it also broached the combustion chamber, I'd think.
A clogged rad is a possibility, given the age and general lack of proper maintenance cars get over here. I might try and source a new one, just to be on the safe side.
Just food for thought, the dark grey bodywork reached 66C in the sun yesterday afternoon! 150f in old money.
If ever we buy a new car, it will be white, or very light in colour. 
I'd rather have a thermostat in it than not, but the local consensus seems to be to take them out. I think I'll fit one when I can get round to it.
Emulsion in the oil could mean an oil passageway to water head gasket leak, but that would not really cause overheating, unless it also broached the combustion chamber, I'd think.
A clogged rad is a possibility, given the age and general lack of proper maintenance cars get over here. I might try and source a new one, just to be on the safe side.
Just food for thought, the dark grey bodywork reached 66C in the sun yesterday afternoon! 150f in old money.
If ever we buy a new car, it will be white, or very light in colour. I had a play with it again today, as I'd put another bottle of 'flushing' juice in it, and I peered down the rad cap hole and noticed a bunch of s
t sitting on top the holes for the core. so, I pulled the rad out intending to take it to the rad shop for a clean/service/re-core, but then I remembered the gallon of muriatic acid sat in my shed........ muahaha 
15 minutes soaking full of that and you'd not believe the amount of flakey thin rusty stuff than came out when I back-flushed it with the hose!
Stuck it all together and the wife and I went out to run errands. Even idling outside the bank, with the head lining inside of the car so hot you can hardly touch it, and still the needle didn't waiver. Job sorted???.
It is odd how the temperature gauge sits rock steady at halfway up the gauge even without a thermostat to regulate it.
t sitting on top the holes for the core. so, I pulled the rad out intending to take it to the rad shop for a clean/service/re-core, but then I remembered the gallon of muriatic acid sat in my shed........ muahaha 15 minutes soaking full of that and you'd not believe the amount of flakey thin rusty stuff than came out when I back-flushed it with the hose!
Stuck it all together and the wife and I went out to run errands. Even idling outside the bank, with the head lining inside of the car so hot you can hardly touch it, and still the needle didn't waiver. Job sorted???.
It is odd how the temperature gauge sits rock steady at halfway up the gauge even without a thermostat to regulate it.
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