Overheating again...

I have tested thermostat, it works, new water pump, radiator checked and its good, radiator fan works, radiator cap changed. no oil in water and no water in engine oil. compression in all cylinder is the same and are good.
still when thermostat is installed water temp goes high.
can it be water temp. sensor?
 
I have tested thermostat, it works, new water pump, radiator checked and its good, radiator fan works, radiator cap changed. no oil in water and no water in engine oil. compression in all cylinder is the same and are good.
still when thermostat is installed water temp goes high.
can it be water temp. sensor?
Any chance the thermostat is installed backwards? (not sure if it can be with the housing, but worth asking)

-Charlie
 
You can test the thermostat by removing it and doing a stove top test (place small pot of water on stove with thermostat in the water, when the water begins to boil, use tongs to remove it and check to see if it opened up). Also, while thermostat is out of vehicle, run the engine and see if you still have a hot/cold hose situation. That would be an easy way to narrow down where the problem is generally.
I've bought new thermostats before that failed, it's not that common, but still exists.

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I have tested thermostat anf it works, but when it is installed on the engine, it does not open. any idea about that?
 
Do you have a temp gun to compare or a scanner that reads live data to compare the ECU temp to the instrument cluster temp?


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Gen 3 4Runner overheating issues

I did a head gasket repair and the truck was running hot. I removed the thermostat and burped the cooling system and the truck ran fine. It is getting colder now so I put the thermostat back in and boom. It’s hot again. Cranking on the heat brings the temp down. It is’t redlining but nearing it. I read an earlier forum about putting the head gaskets in backwards. I don’t believe I did that but I did notice that the replacement gaskets didn’t have the same hole sizes for the water jacket as the old OEM gasket had. I am screwed here and have to pull the engine apart again?
 
Ok, so if I keep driving with the thermostat out and it keeps the truck cool...am I doing damage to the truck? I had the same thing happen when burping the system. I had the geyser shoot out when the thermo would open, so I pulled it and ran it.
Big question. I have a doner engine with 250k miles on it. My original vehicle had 190k. Would it be easier and quicker to swap engines, then do another rebuild? Don’t know if I damaged the engine with a hot spot or something.
 
I'd start with more thorough diagnostics. Leak-down test, OBD2 reader for
accurate temp reading, maybe an infrared reader to see if your radiator is
blocked... Might save you an engine swap.
 
Ok, so I pulled the heads again. I found that the head gasket kit that I got from Partsology blocked or restricted the coolant flow through the engine. Tear down much easier the second time. Going to try an OEM gasket set. Hoping the water jacket openings are more the size of the water jackets. I should have kept the original ones to compare.
 
Ok, after looking at my pictures from the last repair with the blown gasket, it looks like I did have the left gasket on the right side and the right on the left. They look almost identical, but when placed on backwards it completely blocks a water jacket just above the thermostat. This will cause hot spots and could crack the head. I will have my heads pressure tested before I reinstall everything.
 
Ok, so I pulled the heads again. I found that the head gasket kit that I got from Partsology blocked or restricted the coolant flow through the engine. Tear down much easier the second time. Going to try an OEM gasket set. Hoping the water jacket openings are more the size of the water jackets. I should have kept the original ones to compare.

Dang, that really sucks. If it makes you feel better you're not the first person to make that mistake. Remember, RH cylinder head is the passenger side, LH is the driver's side. It's from the perspective of sitting behind the wheel.
 
That sucks. My mom took the '08 Prius into the stealership for a coolant flush on Friday. They didn't burp it properly and she drove down the road and got a warning light and it overheated. They wouldn't help her at that time and she drove it some more and got the same thing. She pulled over and left it by the highway and a friend drove her home. The dealership drove down to fix it on the side of the road. She didn't tell me any of this until today... :frusty: :frusty: :frusty:

And to top it all off because my mom seems to know best and didn't think there was any reason whatsoever to call me when this was happening, even though I do all my own work on my cars because I don't trust any mechanic.... she didn't get ANY documentation of this. She accepted their roadside repair and merrily drove away and told me about it 2 days later...

So I'm going to call them tomorrow (Monday) and demand that I get some documentation of what happened and that if the head gasket blows, they are fixing it. I will be going over to her place in a couple days and I'll go into the dealership if I have to. If I don't get anywhere then I'll stand outside on the sidewalk waving a big placard.

Does this sound reasonable? What are the chances that if the head gasket came through this OK for now, that it could go bad a year down the road with some kind of delayed failure? I don't know how susceptible Prius engines are to overheating compared with 4runners.

I do have a combustion-in-the-coolant tester I could use when I go over there.
 
Sounds like a typical stealership.

FWIW, those combustion in coolant testers (the dye type) or pretty useless. My head gasket was leaking and I did the dye test a half a dozen times and it never even remotely changed colors.

I then did a leak down test and when I pressurized cylinder #3, bubbles came out of the radiator.

Just a heads up.
 
I'm thinking that I'll demand they do a compression test. Of course I'll have to witness it. But they might come back and say their insurance prevents me from being in the shop. In which case I'll demand they pay for an independent third party to do it.
 
Thanks man, it would have been better if they were labeled. I got a set of felpro gaskets, and got the heads at the machine shop to check for any warping and potential cracks in the head. Pick them up tomorrow to start the rebuild. So glad that I am getting good at this. Lol
 
I have an overheat problem with my 02 4Runner, v6, and wanted to see if anyone knows what it could be with these clues - this is my first time trying to fix a problem with this vehicle/any vehicle, which has 200k miles, I got from my parents
-first noticed the problem when the top radiator hose busted and steam came from under hood
-replaced the hose and when driving home noticed the coolant was boiling
-thought the radiator cap could not be holding pressure so I then replaced that, but still it got really hot (on the gauge and physically touching the new hose)
-replaced the thermostat and after driving a little more the temperature gauge was still going to max temp
-removed the radiator and seemed like there was no blockages because I flushed water in the top and it flowed out the bottom
-so I heard maybe the water pump, but my dad said he had that replaced not too long ago, and maybe a new radiator but if water flows through it maybe not, the guy at autozone said coolant temp sensor but I don't know enough about that, another friend/other posts say maybe fan clutch
-did not notice any leaks under the car
-radiator had some pink crud where the hose meets it
 
To me you’re heading towards replacing the head gaskets. It’s worth replacing the rad first.

That system operating properly should maintain below 195f. My 97 stays around 186 to 188 all year around.


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-first noticed the problem when the top radiator hose busted and steam came from under hood
the guy at autozone said coolant temp sensor but I don't know enough about that, another friend/other posts say maybe fan clutch

1) Have you filled and purged the cooling system to make sure there's no air in it? Look up Lisle Spill Free Funnel.
2) Test your fan clutch.
3) Over pressure in the cooling system enough to blow a radiator hose off is indicative of a blown head gasket. Do a compression test to determine if any cylinder is low on compression, then do a cylinder leak down test to determine if you have a blown head gasket. Compression tester and leak down tester should be available for rent at parts stores. Check out Timmy the Toolman's youtube videos for help or any youtube video in general.
4)Autozone/Oreilly's/Advanced Auto/etc employees don't know any more than you do. All they have available to them is what their computer tells them. If they knew enough to be a mechanic, then they would be a mechanic and making more money.
 
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