Yet again an overheating issue :( - Toyota Nation Forum : Toyota Car and Truck Forums

Raistlin73 · 04-21-2010, 04:24 AM

Ok i have an issue with my 1990 imported Celica. It is an ST184 with a 5sfe motor the one with a separate coil ( not built into dizzy ). After about 20 min of driving the car just starts to overheat quickly. I have placed a new radiator and cap in as well as removed the thermostat ( didnt put the new one in cos the aftermarket one when trying to open would catch on the inside of the head and not open :S )

There is no visable leaks, no water in oil or oil in water. The timing is fine and the weather is not extremely hot. Just before the temperature shoots up the heater inside starts to blow out cold air so i thought is must be an air lock so i pull over and sure enough i need to put in about 1-2 litres of water in it and then it drives fine for about another 20-30 min. This happens driving on a highway as well as going around congested streets.

I have had this issue since i have had the car but it just seems to be worse now that i drive the car on a more regular basis. a normal 40 min trip to work is starting to take me 1.5 hrs

On a side note all the fans are working are working fine and i have put on new radiator hoses. The water loss has only seemed to happen after i took out the thermostat as well

Any help would be great cheers

93celicaconv · 04-21-2010, 06:46 AM

Are you getting a white vapor coming out the exhaust pipe?

I would run out to a mechanic/shop that can put an analyzer on your cooling system, checking for exhaust gases in the cooling system.

Actually, you could do something similar. You could make sure your radiator is full with coolant/water with a cold engine, leave the radiator cap off, then start the engine and let it come up to temperature (you will have some coolant come out the top of the radiator). When the engine is up to normal operating temperature, do you see any bubbles coming out the top? Rev the engine up a few times to 3,000 RPM. See any bubbles then, or more of them?

I'm thinking you have a headgasket failure, and you are pushing exhaust into the cooling system, and cooling into the combusion chamber, where it is being evaporated in the engine and pushed out the exhaust as a gas.

Otherwise, if you are always having to put coolant in your system, and you have no visible external leaks, the engine is the only place it can be going.

Raistlin73 · 04-21-2010, 07:12 AM

i did have a chem test done on the radiator about 3 months ago and it was fine. but i might get that done again. i am not getting any vapour out of the exhaust and have only noticed bubbles once i have reved the motor and it looks more like the water pump pushing it through creating it more than anything as the bubbles last for like 5 - 10 seconds.

I will get another chem test just to make sure and post results as soon as i have them

thank you.

Bitter · 04-21-2010, 07:12 AM

you can have a pinhole thats leaking only when hot somewhere.

93celicaconv · 04-21-2010, 07:53 AM

Quote:

Originally Posted by Raistlin73

There is no visable leaks, no water in oil or oil in water. The timing is fine and the weather is not extremely hot. Just before the temperature shoots up the heater inside starts to blow out cold air so i thought is must be an air lock so i pull over and sure enough i need to put in about 1-2 litres of water in it and then it drives fine for about another 20-30 min. This happens driving on a highway as well as going around congested streets.

In looking at this description (loosing 1-2 ltres of water every 20-30 min.) doesn't sound like a pin hole leak.

Regarding bubbles, in a normal cooling system, there is no air in it, so the pump cannot generate bubbles. I suppose if there is air trapped in the system, then you might see the effects of trapped air. Can you make sure you eliminate all trapped air by burping the system, then see if you still generate any bubbles?

theadidasmunky · 04-21-2010, 07:22 PM

just went through all this about a month ago. water pump seal. for whatever reason when our cars were made back in the day toyota chose to use a paper water pump seal. its kinda like a real thin velvet material. i changed the water pump and timing belt while i was down there. good luck!

93celicaconv · 04-22-2010, 06:27 AM

Quote:

Originally Posted by theadidasmunky

just went through all this about a month ago. water pump seal. for whatever reason when our cars were made back in the day toyota chose to use a paper water pump seal. its kinda like a real thin velvet material. i changed the water pump and timing belt while i was down there. good luck!

Did you have a visible coolant leak with the problem with the water pump seal?

Raistlin73 says he is losing 1-2 liters of coolant every 20-30 minutes with no sign of a visible coolant leak externally. I would think a bad water pump seal, leaking at this rate, would cause a visible external leak, namely seeing coolant under the engine in this case. He isn't seeing that, so I don't think he has a water pump seal issue.

Raistlin73 · 04-22-2010, 07:45 AM

Ok well i got another chem test done and no leak in head gasket woot

I have burped the system and made sure i ran the car ( idle ) for a good 15min and made sure that the water lvl was good and full and no air pockets.
This morning i drove to work ( about 45 min ) and the temp rose to a max of 84c so thats a bonus of late. when i got to work i had to put in about half a litre of water so its a lot better.

i put red dye in the overflow to see if it was being sucked into the motor when it cooled or expelled totally when it got hot. There was no dye in the radiator and it was mostly gone from the overflow bottle so it seams like there is to much pressure in the system and pumping it out

I will have a look at the water pump seal on the weekend just to make sure there is no leak or anything there as well.

Thank you all for the advise trying the things so far seems to have made things a little better.

theadidasmunky · 04-22-2010, 10:26 AM

when parked there was a couple drops. nothing you would notice unless you were looking for it. it leaked mostly while i was driving. i'd go somewhere and then look at the water level and there would be half as much as when i started driving.

93celicaconv · 04-22-2010, 11:12 AM

Got it. The best thing to do, when you see coolant levels dropping and the need to top off, is to let the car sit overnight in the garage, start it up in the morning, and just let it idle there and warm up (maybe 20-30 min.). Then check for visible coolant leaks. Otherwise, if one doesn't take this time, driving could do what happened to you, the adidasmunky, it will leak while driving when the coolaing system is trying to build pressure, but once everything is warmed up, and there is no more cooling system pressure, the leak stops, and the driving often makes seeing the original of a leak nearly impossible.

Pineapple · 04-22-2010, 12:20 PM

Look for green/white power around hose and gasket.
If you just bolt the neck back without thermostat or any gasket, it'll leak like a bitch.

theadidasmunky · 04-22-2010, 03:34 PM

you might not see it leak but after the car has been running for awhile. look at the bottom of the timing belt cover, if its wet that means water pump seal.

Raistlin73 · 04-23-2010, 12:23 AM

Ok i had a friend from work ( who used to be a mechanic ) run 2 chem tests on it.

When the car was at 82c the chem test was positive

we then tried that afternoon when it was cold and it came back negative. So he said it was a hairline crack in the head and it would only start to pump gas into the radiator once the car had warmed up to higher temp thats why when the other chem tests were done at about 74c they came back negative.

So looks like i am up for a new head woot :P

Thank you all for your help was greatly appreciated

93celicaconv · 04-23-2010, 06:50 AM

Quote:

Originally Posted by Raistlin73

Ok i had a friend from work ( who used to be a mechanic ) run 2 chem tests on it.

When the car was at 82c the chem test was positive

we then tried that afternoon when it was cold and it came back negative. So he said it was a hairline crack in the head and it would only start to pump gas into the radiator once the car had warmed up to higher temp thats why when the other chem tests were done at about 74c they came back negative.

So looks like i am up for a new head woot :P

Thank you all for your help was greatly appreciated

When you had a friend do a "chem" test, what was the test looking for? I'm not familiar with this term, "chem".

Usually, test strips are used in coolant to test for pH, alkalinity, etc. A coolant analyzer test is used on the cooling system when it is hooked up to the top of the radiator (cap off, plug in) and pulls an expelled air while the engine is running into a liquid with a color dye in it, and if that dye color turns to another color, it indicates exhaust gases getting into the cooling system.

Which test did you have done?

If the latter, then yes, something is causing exhaust gases to get into your cooling system, and that would explain a lot of your issues. It doesn't mean your head is cracked, it could still be a defective headgasket. You would need to remove the head and have it dye tested to see if you can find the crack before condemning it.

But I'm still confused. All along, you said you had this "chem" test done, and it came back negative, even during the time you were having this problem. Is it possible you got a false positive on one test, when all the others were negative? Something just doesn't seem right.

Raistlin73 · 04-23-2010, 05:43 PM

It was the A coolant analyzer test that he performed.
I asked him a similar question and he said if the crack in the head is small enough it will only give you the positive reading once the motor has reached a high enough temperature to expand the crack wide enough to allow the gasses to escape into the system hence when it was cold it didn't give the reading. He did say it may be a head gasket but in his past experience with it giving readings like it did is generally a head that is the issue.