[john.west]

Hi all, Hopefully somebody may be able to assist me with a potential problem in my 1996 Toyota Carina E SLI 1.6. Think the engine code is 4AFE on it. The car has a separate cap on the top of the radiator and a coolant reservoir with a small hose which attaches to the top of the radiator...somewhat different to my previous car in which it would appear the radiator was a unit you could not add coolant to but any coolant was added via the small plastic tank. It would appear in the Carina that the coolant in the separate tank is not even warm...even after a long drive...done over 40 miles this evening and checked it after. Furthemore I don't think there is even any movement or circulation of the coolant in this bottle. I noticed Friday evening that the coolant was a wee bit low in it and topped it up. The coolant which I topped up with was a somewhat different colour. Have drove circa 60 miles since Friday evening and when I was looking at coolant this evening it looked like the coolant which I topped up with was still pretty much sitting on top of coolant already in the tank.

Could somebody tell me if this tank is somewhat of an overflow facility or should it be part of the normal circulation of the coolant throughout the running of the motor. If the coolant in it is cold as in after my 40 mile drive does this spell trouble? Also there is no pressure when I remove the top of this bottle after a trip but there is a lot of pressure underneath the radiator cap if I attempt to remove it. The radiator itself seemed hot only pretty much at the very top near the cap and the rest of the radiator was quite cold. While I would expect the radiator to be cold near the bottom I would also expect it to be pretty warm to a mid way point or so down. Finally the pipe from engine to top of radiator seems somewhat airlocked after journey. Not bulging as if its about to explode but some pressure in it all the same. There is plenty of toasty warm air inside the car and the temperature needle rises to an ever slightly below mid way point after 5 to 10 minutes driving from cold and seems to sit at the exact same spot constant. It would appear that there is no gunk underneath oil cap and oil is very clean looking also.

Could anyone let me know if the problem I am experiencing may be related to headgaskt failure or could there be other potential problem(s)?

[jimmyw]

Well I would guess that the thermostat is dodgy. If you have the engine running from cold, after a while you should see movement of water from the rad into the tank/expansion tank if not, that's it. Other wise might be blocked rad.

[CJhaughey]

Whats the problem?
Your car is running fine, no coolant loss, no over heating= no reason to think anything is wrong.

If you start messing about and flushing rads and so on, you may find you do indeed make a problem for yourself.
If the temp needle moves above that spot then start worrying, until then leave it alone and just drive the car.

[john.west]

Originally Posted by jimmyw

Well I would guess that the thermostat is dodgy. If you have the engine running from cold, after a while you should see movement of water from the rad into the tank/expansion tank if not, that's it. Other wise might be blocked rad.

Thanks jimmyw. Guess I'll get to a garage as soon as I can. Hopefully it is something as small as a dodgy thermostat. If it is a dodgy thermostat should I not be getting any warm air inside or is this not necessairly the case?

[john.west]

Originally Posted by CJhaughey

Whats the problem?
Your car is running fine, no coolant loss, no over heating= no reason to think anything is wrong.

If you start messing about and flushing rads and so on, you may find you do indeed make a problem for yourself.
If the temp needle moves above that spot then start worrying, until then leave it alone and just drive the car.

Thanks CJhaughey. I don't have any intention of changing the coolant myself as I wouldn't have the know how and reckon as you mention I could then potentially be looking at air locks and what not. The thing that is worrying me though is the fact that the coolant in the expansion tank remains cold after a considerable journey and the fact that the upper pipe from engine block to rad appears to be getting air-locked. Don't want to come to a situation where I am stuck in traffic for a long time on a warm day and engine overheats and head warps etc... Just trying to be safe rather than sorry as have had way too much expensive trouble with blown head gaskets in the past

[jimmyw]

The warm heater does sound a bit confusing right enough , but the only reason I am guessing the thermostat is that from your description it does appear that there is no movement of coolant from the rad and also the temp gauge not moving up enough also.

[Nissan doctor]

Aa simple sniff test would show if your head gasket is gone.

The overflow bottle you are describing will not be pressureised or warm unless the engine has been running very hot.

Toyota's do suffer with rad cores failing but this would give you overheating problems.

Check your water and oil levals and then leave the car running in your drive untill the fan kicks in, if the fan does kick in it means that your thermostat is working and so is your fan switch/temp sensor. If your temperature dial goes no higher then normal when stationary then head out for a spin around the block. If the head gasket is allowing the cooling system to pressurise then thats when she will start over heating. If, however, the temp remains ok then it seems everything is fine.

[john.west]

Originally Posted by jimmyw

The warm heater does sound a bit confusing right enough , but the only reason I am guessing the thermostat is that from your description it does appear that there is no movement of coolant from the rad and also the temp gauge not moving up enough also.

It has got me wondering also jimmyw. The steady readily available warm air would seem to indicate to me that all is well and I have circulation. I say that without being an expert or anything but having said that I have had my fair share of blown headgaskets in cars down through the years so would know the things to look for too. The temperature guage is moving up to practically half way point, precisely where one would expect it to move up to and sitting there without budging around...so can't say it looks dodgy in that regard.

Originally Posted by Nissan doctor

Aa simple sniff test would show if your head gasket is gone.

The overflow bottle you are describing will not be pressureised or warm unless the engine has been running very hot.

Toyota's do suffer with rad cores failing but this would give you overheating problems.

Check your water and oil levals and then leave the car running in your drive untill the fan kicks in, if the fan does kick in it means that your thermostat is working and so is your fan switch/temp sensor. If your temperature dial goes no higher then normal when stationary then head out for a spin around the block. If the head gasket is allowing the cooling system to pressurise then thats when she will start over heating. If, however, the temp remains ok then it seems everything is fine.

Thanks Nissan Doctor. Could you confirm what you mean by sniff test though please...I assume you mean testing the coolant for impurities to indicate if headgasket is blown but I may well be wrong on this assumption also. That does put my mind at rest somewhat that the coolant in the overflow bottle does not necessarily become hot unless the engine is running very hot. I'm wondering why there is a min point in this bottle though if it is strictly an overflow facility?

Oil and water levels look spot on. Took cap off radiator this evening with engine cold and it was full. Oil is up to max as is coolant in overflow bottle.
There are no immediately apparent overheating problems as I don't think I would have gone 40 miles in one go without steam blowing out from under the bonnet at some stage.

THe only thing that is worrying me majorly now is the fact that the pipe from engine block to top of rad seems somewhat airlocked when car is in use. Maybe I am over-reacting. I finished up work quickly today to go to a garage a friend recommended only to find he opens Monday to Saturday and is off on Monday. Ah well, may pop along tomorrow if only to put my mind at rest. Will let ye know how I fair.

[beam99]

The bottle on the side is an expansion bottle, if the rad goes low on coolant the coolant is then taking from this bottle to keep the rad at it's max . The coolant in this bottle will be cold and no pressure in it. If you have no leaks from the system, warm air inside from heater and the rad fan is cutting in and out and there is no oil in water, or water in oil, and you can drive the vehicle for long distances without overheating and temp gauge inside sits between half way and 3 quat way i reckon you have no problems.