Help random overheating/temp spike!

[ImperfectSupra]

Well it looks like I found my problem it was my heater core it had a slight leak that wasn't noticeable and it kept getting air into the system. It completely went last night all over my foot so I had to bypass it which has cured the spike problem, and it is no longer over heating. Thanks for all the help tho guys.

im glad u found the real cause of your problem. everytime i have my a/c running it seems like the drain hose is plugged up or my evaporator is leaking cause i never see any ac drainage under the car it will almost always end up on the floor of the passenger side. can a plugged or leaking evaporator cause the same promblem u have with the heater core letting air in the cooling system?

 

[Supracentral]

i have a problam like this. i just put a brand new from toyota t stat and when i drive around the temp will spike then go down a few times.. it vever did this when i was running no t stat so im thinking its a bad t stat? maby its sticking?

The very first thing I do when I get a new thermostat is put it in a pot of water with a thermometer and heat it on the stove to see when it opens. Quality control on those things SUCK.

If that works out fine, try removing the jiggle valve or drilling a 1/8" hole near the top of the stat.

Kind of like the attached pic, just not 3 holes (that's a bit excessive...)

 

[apexi287]

Ok thread update. Problem not fixed:wtf:. It seemed to have fixed the problem for maybe a night but now it's back I even installed a new water pump as well as upper rad. hose before the heater core went on me. I figured I could just burp the system again today at work on a slight incline and revving the motor to get all the air pockets out of the heater core hoses that are slightly arched higher then the rad. but to no avail. When I burp it the bubble will come to a dead stop sometimes random ones other times nothing, It seemed for sure I had it well and good this time but no, after I drive for a little bit it will spike back up.

I thought I was ok on my way home today about 5 or so miles on the highway and light to light until I came to enter my neighborhood. I took a hard sharp left turn into my back street which is extremely curvy and fun and thats when it spiked, right when I took that left turn and got on it at the same time.

Anybody?:cry:

 

[sneakypete]

Also depending on the load of the motor it'll decrease the temp, if I'm in third it'll usually rise a little bit and any other gear it'll drop to normal, also everyonce in a while if I accelerate hard through gears the temp gauge will drop under normal temps but will then go right back to normal after.

:1zhelp:

i had the exact situation with me a few years ago. after all the troubleshooting, i tryed changing the temp sender and still no change. it turned out that the temp sender wire (green w/ red stripe) was frayed and was making the temp gage go crazy. after i fixed the wire... problem solved
hope this helps
-pete

 

[Supracentral]

I thought I was ok on my way home today about 5 or so miles on the highway and light to light until I came to enter my neighborhood. I took a hard sharp left turn into my back street which is extremely curvy and fun and thats when it spiked, right when I took that left turn and got on it at the same time.

It's starting to sound like a gauge problem, not a temp problem. Are there any signs of the car overheating OTHER than the gauge. Does it seem hot? Does it boil after you turn it off?

 

[apexi287]

It seems hot and boils. Everytime I start too I pull over turn the car off and it's boiling over and the resevoir cap has popped off.

 

[Supracentral]

Ah, ok, this is definitely not just electrical then...

Did you try the stuff I posted about the thermostat?

 

[apexi287]

I removed the jiggle valve but didn't heat it up in a pot of water I didn't want to doubt something that was new but I guess I should give that a try. Any other advice if that doesn't seem to cure it?

 

[87nasupra]

Thats exactly what happened to mine. It was a partially clogged NEW radiator from the factory. While driving straight, under load it wouldn't overheat. Take it on a winding road, even while crusing, it would overheat. Try jacking it up on one side and run it to normal tempature. See what it does. If nothing happens try the other side.....its how i figured out that my radiator was screwed up.

 

[jdub]

Post #14

It sounds like your thermostat is sticking. The reason I asked about the CT26 coolant lines is they act like a bypass to relieve pressure...I blocked mine off and had a similar problem to yours...the blocked lines caused the thermostat to stick closed. The difference is when the thermostat finally opened on my car, the overheat stopped. I removed the jiggle valve on the thermostat and it solved the problem.

What brand of thermostat are you using? Are you sure the e-fans you are using are moving enough air? If you've got a older stock radiator, it might be partially blocked.

 

[apexi287]

Thats exactly what happened to mine. It was a partially clogged NEW radiator from the factory. While driving straight, under load it wouldn't overheat. Take it on a winding road, even while crusing, it would overheat. Try jacking it up on one side and run it to normal tempature. See what it does. If nothing happens try the other side.....its how i figured out that my radiator was screwed up.

What am I looking for to happen? Overheat air pockets free'd up?

Post #14

My turbo coolant lines aren't bypassed. And the radiator is new, I also removed the jiggle valve. Nothing worked

 

[jdub]

My point is it's hard to help when you don't get answers.

Edit: As in 20 posts ago.

 

[apexi287]

My point is it's hard to help when you don't get answers.

I just answered those to supracentral.

 

[87nasupra]

If its a bad radiator then its not flowing across the whole rad. It's only flowing through certain parts. Jacking it up on one side will tell you where its flowing and where the problem would be IF there is a blockage.

 

[apexi287]

Alright I'm going to add something else, after I did the HG job the car had a ruff idle. Everyone and I at my shop identified it as a miss, but after replacing my plugs and wires it didn't change no air leaks either nothing. I figured it was just from blocking off my egr as my old car acted the same way with a blocked off egr, sort of a lumpy idle/miss sound too it but still drove hard. I had a lot of smoke on startup but there was also a lot of carb cleaner and TB cleaner in the cylinders it went away a couple minutes or so after. It also will sometimes smokes on startup but not always.

About an hour ago I took the car to the steepest hill I could find and burped the system once again(and I mean steep) I have a brand new e-brake cable and it barely held. But once again after I get on it a couple times it spikes.

So I guess what I'm saying is I'm doubting the seal of the HG now but at the same time stumped as to why it would be after the block test passed twice, and when putting compressed air into the cylinders I got no air bubbles out of the coolant.

I still haven't verified the condition of the rad. but with the symptoms I'm doubting that's it.

What to you guys think? I don't want to have to buy another HG and do it all over again but if it has to be done then I will, hopefully friday if I can verify this before then.

Opinions?:1zhelp:

 

[apexi287]

Anybody? I'm hoping to get this pinpointed by the end of the week I can't keep driving it this way, and it's all I can do being my only car.

 

[ImperfectSupra]

Alright I'm going to add something else, after I did the HG job the car had a ruff idle. Everyone and I at my shop identified it as a miss, but after replacing my plugs and wires it didn't change no air leaks either nothing. I figured it was just from blocking off my egr as my old car acted the same way with a blocked off egr, sort of a lumpy idle/miss sound too it but still drove hard. I had a lot of smoke on startup but there was also a lot of carb cleaner and TB cleaner in the cylinders it went away a couple minutes or so after. It also will sometimes smokes on startup but not always.

About an hour ago I took the car to the steepest hill I could find and burped the system once again(and I mean steep) I have a brand new e-brake cable and it barely held. But once again after I get on it a couple times it spikes.

So I guess what I'm saying is I'm doubting the seal of the HG now but at the same time stumped as to why it would be after the block test passed twice, and when putting compressed air into the cylinders I got no air bubbles out of the coolant.

I still haven't verified the condition of the rad. but with the symptoms I'm doubting that's it.

What to you guys think? I don't want to have to buy another HG and do it all over again but if it has to be done then I will, hopefully friday if I can verify this before then.

Opinions?:1zhelp:

your car is sounding more like mine with each post. im taking my car to toyota on monday to try to figure this out. im tired of all the figuring out stuff. its been months and my car would do good one week and bad the next. anyways i will tell u how this goes after monday. im thinking that i have a cracked block of bhg.

 

[sneakypete]

im telling you... i had the same symptoms... i even took it to toyota and they wouldnt look even look at it.. said they wouldnt touch it unless it was stock... anyway.... follow the wire from the temp sender to the ecu... almost positive its the wire. i think its the gage.

 

[Supracentral]

im telling you... i had the same symptoms... i even took it to toyota and they wouldnt look even look at it.. said they wouldnt touch it unless it was stock... anyway.... follow the wire from the temp sender to the ecu... almost positive its the wire. i think its the gage.

His engine is boiling over when he pulls over. It's not the gauge...

 

[starscream5000]

Edit:: Missed an entire page of posts, hate it when I do that

You put a MHG on correct? Did you pull the motor during the change and ensure that the head AND block were flat by machining them down, along with getting the surface smooth enough to accomodate the requirements of the MHG?

What did you torque your ARP's to?