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Please help! I recently developed some overheating problems and I cant quite pinpoint the problem and I cant find anyone with the same issue. My temp guage will start at cold as rise as normal but once it gets a tick past halfway it stops moving. Problem is the engine is overheating. I tested the fans, they work fine when the ac is on, I also replaced the thermostat thinking it was stuck and ended up drilling a air hole in it because it was an autozone thermostat which didn't have that hole.still didn't fix the issue. I'm leaning towards coolant temp sensor. Any ideas?
 

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1987 Supra Turbo R154 Pearl White, Blue Velour
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First off I suggest a Mishimoto thermostat. I just put one on my 7M-GTE and it works so much better than the new O'Reilly one I bought earlier this year. They are more expensive but it's very well built.

Second, the coolant temp sensor going bad won't make your engine overheat. I mean it might not report that it's overheating and is bad, but if the engine is overheating, that's its own issue :)

What are you over heating symptoms? Coolant tank over flowing? Knock and ping? Steam coming out somewhere?

How many miles on the car?
 

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Discussion Starter #3

First off I suggest a Mishimoto thermostat. I just put one on my 7M-GTE and it works so much better than the new O'Reilly one I bought earlier this year. They are more expensive but it's very well built.

Second, the coolant temp sensor going bad won't make your engine overheat. I mean it might not report that it's overheating and is bad, but if the engine is overheating, that's its own issue :)

What are you over heating symptoms? Coolant tank over flowing? Knock and ping? Steam coming out somewhere?

How many miles on the car?
Over 200k and coolant boils and if it overheats too much it pours out of the overflow and I believe that's where most of the steam was coming from. Now that I'm aware that its overheating the furthest it will get is the coolant boiling. Thing is. My temp guage is not telling me that the vehicle is overheating. Therefore the fans won't kick on because the car doesn't know its hot.
 

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Over 200k and coolant boils and if it overheats too much it pours out of the overflow and I believe that's where most of the steam was coming from. Now that I'm aware that its overheating the furthest it will get is the coolant boiling. Thing is. My temp guage is not telling me that the vehicle is overheating. Therefore the fans won't kick on because the car doesn't know its hot.
I have also flushed the coolant a few times and there wasn't much oil in it at all. And when I purge the cooling system at around 2k for about 5 minutes the bubbles will stop, so I'm not getting strong signs of blown head gasket.
 

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Have you bled the cooling system properly? Its highly possible that you have an airlock in your cooling system, which is causing your temps to climb. Park your car facing up an incline, and bring it to temp and keep topping up as the air bubbles escape and ensure your heater is set to full hot when you are bleeding it, too.

I would get a genuine Toyota thermostat and stop using cheaper alternatives for such an important function, as the price difference isnt worth the potential for greater losses.
 

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Have you bled the cooling system properly? Its highly possible that you have an airlock in your cooling system, which is causing your temps to climb. Park your car facing up an incline, and bring it to temp and keep topping up as the air bubbles escape and ensure your heater is set to full hot when you are bleeding it, too.

I would get a genuine Toyota thermostat and stop using cheaper alternatives for such an important function, as the price difference isnt worth the potential for greater losses.
Thank you so much! My plan is to buy a OEM tstat, but that was very helpful I had no idea how else to release air if it was trapped in the block.
 

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1987 Supra Turbo R154 Pearl White, Blue Velour
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Also I installed a Peak flush&fill T-Valve on my heater hose near the firewall. I have discovered that even with the front of the car only slightly elevated in my driveway, i can use that cap to release the air pocket and have no issues with gurgle. Seems to burp fine.

The water and steam coming out of the overflow tank though is a classic BHG and overheating symptom on 7M engines. Mine was bad back in 97 before I had it replaced. Which car model/engine do you have?
 

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Also I installed a Peak flush&fill T-Valve on my heater hose near the firewall. I have discovered that even with the front of the car only slightly elevated in my driveway, i can use that cap to release the air pocket and have no issues with gurgle. Seems to burp fine.

The water and steam coming out of the overflow tank though is a classic BHG and overheating symptom on 7M engines. Mine was bad back in 97 before I had it replaced. Which car model/engine do you have?
I'm not 100% on what model of 2j it is its ge andit's in a lexus gs300 year 2002
 
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