94 celica st overheating issue, 1994 celica st 1.8L overheating issue. Options

[rapid36]

Hi i have a 94 celica ST with the 1.8L motor. I bought a used motor from online that had 132k miles on it. i dropped it in and i replaced the following on the car:
1. rear main seal
2. oil pan gasket
3. torque converter
4. radiator swapped out with 3 row performance radiator meant for gt4.
5. added a 15 row transmission cooler
6. new air filter
7. new spark plugs
8. new spark plug wires
9. new front o2 sensor
10. new fuel filter
11. straight pipe headers
12. high flow cat
13. aftermarket muffler
14. new belts all the way around

and so when at idle everything seems fine and when i drive around town everything is fine but only when i get on the highway going 65MPH it starts to overheat very quickly and then i pull over and let it idle and it seems to go back down then i drive again and then at this point going any speed is making it overheat. i have no check engine light. and i checked the thermostat and it works and i checked the water pump and it works. i just flushed my cooling system and no luck there. I dont get why its overheating on me. I checked the compression and all cyclinders show 150. no noises are being made and when it gets hot the car runs fine no missing or other issues just gets hot. Anyone have any ideas?

[VavAlephVav]

im not sure about the 1.8 but the 2.2 is supposed to be more like 175 on compression. When you overheat it has is lost any coolant?
with mine the headgasket is leaking exhaust into the coolant system. If I drive nice and easy keeping the engine below 3k rpm its fine, but when I rev it any higher it will over heat. even though there is still plenty of antifreeze in the radiator the top end of the motor has filled with exhaust gas.
also you can unplug the fan switch at the bottom of the radiator so that the fans will run whenever the key is on and see if that helps.
any motor from the early 90's has the shetty headgasket material, if it's never been replaced that's probably the deal. make sure to get a multi-layered steel MLS gasket.
there is a test kit that will prove if you have exhaust gas in the radiator.
https://www.youtube.com/watch?v=QjUkh7SZu5c

[rapid36]

im not sure about the 1.8 but the 2.2 is supposed to be more like 175 on compression. When you overheat it has is lost any coolant?
with mine the headgasket is leaking exhaust into the coolant system. If I drive nice and easy keeping the engine below 3k rpm its fine, but when I rev it any higher it will over heat. even though there is still plenty of antifreeze in the radiator the top end of the motor has filled with exhaust gas.
also you can unplug the fan switch at the bottom of the radiator so that the fans will run whenever the key is on and see if that helps.
any motor from the early 90's has the shetty headgasket material, if it's never been replaced that's probably the deal. make sure to get a multi-layered steel MLS gasket.
there is a test kit that will prove if you have exhaust gas in the radiator.
https://www.youtube.com/watch?v=QjUkh7SZu5c

Thank you so much for the information! i will check out that link! also i do not loose any coolant maybe a tiny tiny bit from the overflow hole but thats about it. thats very interesting about the head gasket!!!! i will have to look into that hopefully its a relatively easy check.

[VavAlephVav]

yep that's it, the exhaust overpresurizes the coolant system and you loose antifreeze from it blowing back out the overflow bottle and out the little hole at the top.

also if you have the timing too far advanced that may cause it to overheat as well. did you set it with a timing light or just kind of guess at it?

This post has been edited by VavAlephVav: Sep 1, 2014 - 9:04 PM

[rapid36]

I timed it correctly with a timing light and the Haynes book calls for -10 degrees so that's what i timed it at. its funny how this car can never stay together i dropped the transmission like 3 times and the motor twice lol seems like it doesn't want to be put together. ill go by napa tomorrow and pick up that tester! I'll post back with the results. ill try to post in depth pictures of what im seeing so you all can see whats going on and hopefully after i figure this out that it will help others in the future. if anyone has any other ideas please let me know and ill go do tests or answer you back if i already did a certain test.

P.S. its really funny i never heard of the exhaust messing with the cooling system. you just taught me something today thank you! and out of curiosity since my compression showed good in all cylinders wouldn't the compression test show a weak cylinder if i had a bad head gasket?

[VavAlephVav]

the more common problem is that exhaust leaks out, but coolant doesn't leak in. /shrug idk why. but I have been told that proper compression should be a little higher, around 175.


This post has been edited by VavAlephVav: Sep 1, 2014 - 11:14 PM

[rapid36]

strange. i looked in the book and they didnt give a specific range of what was acceptable but they did say that they all should be consistent. if not then i would have problems. they are all consistent in my case, ill do more research online and see if i can get a better idea about this. also im guessing that the coolant wouldnt leak in if the exhuast gas has pressure and is forcing itself into the cooling system which might be why im not seeing any coolant inside my cyclinders and thank god im not cause i dont want to risk hydro locking it. so far its all positive i cant wait for the test tomorrow. hopefully it wont be a slap in the face and at the same time if it does show negative then at least i know what i would have to do to fix it lol. so i got mixed feelings about it.

[VavAlephVav]

http://bgbonline.celicatech.com/

[rapid36]

NICE FIND!! I looked at the cooling system section and it said no special bleeding is required. i looked around on forums and saw that people needed to bleed thier systems in order for their overheating issue to stop so along with the block tester i will also be getting a no spill funnel and trying to bleed the air out, all i did was just squeeze the upper radiator hose like 10 times. not sure if that was sufficient lol. How about you guys? did you guys have to do any kind of bleeding to your celicas? if so how did you do it?

[VavAlephVav]

It is supposed to be an "automatic" bleeding system. But that assumes your radiator cap is good and releases at the right pressure And the vacuum valve works once it cools down.
Maybe you only need a new radiator cap.

This post has been edited by VavAlephVav: Sep 2, 2014 - 5:13 PM

[Smaay]

im 95.87% sure its your head gasket. a compression test will confirm.

[Noahwhite2014]

im not sure about the 1.8 but the 2.2 is supposed to be more like 175 on compression. When you overheat it has is lost any coolant?
with mine the headgasket is leaking exhaust into the coolant system. If I drive nice and easy keeping the engine below 3k rpm its fine, but when I rev it any higher it will over heat. even though there is still plenty of antifreeze in the radiator the top end of the motor has filled with exhaust gas.
also you can unplug the fan switch at the bottom of the radiator so that the fans will run whenever the key is on and see if that helps.
any motor from the early 90's has the shetty headgasket material, if it's never been replaced that's probably the deal. make sure to get a multi-layered steel MLS gasket.
there is a test kit that will prove if you have exhaust gas in the radiator.
https://www.youtube.com/watch?v=QjUkh7SZu5c

Last time i did my compression on my 1.8 it was about 188 all around. I'm fairly sure its a blow head gasket as everyone else seems to think as well. But don't just take our word for it. Do the compression. And get back with the numbers on each cylinder.

[VavAlephVav]

Ya I was told 175 was a minimum compression level.
Mine leaks so bad that if you start it with the radiator cap off you can rev the motor by the throttle cable and watch the bubbles form in the radiator.

[rapid36]

lol i dont know why people are saying do a compression test and get back to you with the numbers. sorry but did you not read the first post? i did a compression test and i got 150psi on all cylinders. however im not saying its not the problem just letting you guys know that i already did the test and it was posted previously.

ANYWAYS lol, i got the "Block Tester" which will tell me if there is any exhuast fumes in the cooling system. I got this yesterday so ill do my best to make time today to perform the test and get back to everyone . And sorry if i didnt mention this before but when i bought the radiator it came with a new cap and i inspected it and everything seems in good working order.

So heres what im hoping to accomplish today:
1. bleed the cooling system.
if i still have the overheating condition then i will be doing the exhaust fumes in cooling system test.

I will post back tonight with updates!

P.S. You guys have been such a huge help in giving me advice on fixing this issue thank you a ton for everything guys!

[rapid36]

Ya I was told 175 was a minimum compression level.
Mine leaks so bad that if you start it with the radiator cap off you can rev the motor by the throttle cable and watch the bubbles form in the radiator.

What was your compression numbers? did they differ from cylinder to cylinder? if you have around the same compression as me then that would help me with diagnosing my issue .

[rapid36]

FIXED!!!!!! all I had to do is bleed the cooling. I didn't use a spill free funnel and I bearly saw any air bubbles escape and I didn't have to put in Any coolant which is another reason why I didn't think there was a lot of air in the system. Thank you everyone for all of your help. I also did the block tester and it passed that test. No exhaust fumes

[VavAlephVav]

Sweet.
I'd keep an eye on it for a while just to be sure. If you let it get real hot the head will warp, and then you really will need a head gasket.

[rapid36]

Sweet.
I'd keep an eye on it for a while just to be sure. If you let it get real hot the head will warp, and then you really will need a head gasket.

Ya for sure. im watching it like a hawk lol. i dont want any warping then i would also have to have the head milled back to spec.