temp problem

[s7mgte]

my temperature gauge will be fine right in the middle then it will go op to hot fast for like 10-30 seconds sometimes then drop right back down to normal.. i have burped the system and got a good amount of air out of it.. i thought it was fine.. where could air be coming from to get back in it.. and its random..i can drive it on the main highways for hrs and it wont move then ill randomly go to the store the next day and it will start jumping all around.. Or also could it be my thermostat getting stuck closed..? it just getting really annoying because i put a new headgasket and all in it and dont feel like frying something. its an 88 turbo supra.

[RavenMaster]

I had the same issue and it was my thermostat.

[ATL88Supra]

open up the rad cap and smell it, ya you know what i am talking about...

[supraman74]

My car did this also but it was a loose connection at the sensor on the thermo housing...

[s7mgte]

I had the same issue and it was my thermostat.

you didnt have air in the system at all?.. i think i may be getting air in mine.

[jdub]

Have it pressure tested.

[RavenMaster]

you didnt have air in the system at all?.. i think i may be getting air in mine.

Ah sry I just saw that. No i didnt have much air if any really in my system at all. However since thermostats are supposed to break OPEN now then im not sure. It might veery well be a loose connection. Next time it happens pull over to the side, leave your car running and open the hood. See if there are any steam appearing from any connections or look on the ground with your car running and see if there is any fluid leaking.

[mkiii222]

Mine does the same thing, but when I tap the plastic in front of the temp gauge it goes back down. Try it the next time it spikes. If it goes back down after a healthy smack then it's a bad solder joint in the gauge area. I've just been too lazy to pull the dash apart to fix mine.

[87M-GTE]

Mine also wnaders randomly. Ill be going down the road at operating temp, get on it a little bit, neddle goes up, tap the guage cluster and it goes back down, also by turning the heat on and it goes down. I was thinking air in my system, the thermostat or a lose conection.

[Frank Rizzo]

I just find it funny that we have all these "me too!" posts and yet not one of them gets the hint.

Ah that's right, that's the loose connection gauge!! DOH!!

Personally, I'd run a block test before a pressure test. Just because I've had BHG's go undetected by a 15psi cooling system pressure test. But if you think I'm FOS then at least listen to the guy with the orange name.

[Who]

First change the thermo. I had one close shut once. Personally I don't think your thermo would work and not work from highway to city driving but it will take you 10 minutes to eliminate one variable.
Than start from the worst case scenario to the least.
While your burping the system and bringing the car up to normal temp start your block test for a BHG. If that passes bend on one knee and give thanks to the Almighty.

Do a pressure system test. Now you have eliminated any leaks.

If that passes check your fan clutch. Your fan draws air through the rad and keeps your car cool in city driving or idle when your not on the highway pushing air though the rad. If your temp does go up and your auxiliary fans kick in and the temp drops that could tell you your fan clutch going on the fritz.

Find a second method to test temp of the coolant. Variations in temp with your second method would verify that you gauge is being true to you.

The old saying "The gauge must be wrong" has cost allot of people money and heartache. The gauge is wrong or a loose wire should be you last best guess.

I am new to the supra scene so if I have made any mistakes please correct me. No flaming plz.

[s7mgte]

First change the thermo. I had one close shut once. Personally I don't think your thermo would work and not work from highway to city driving but it will take you 10 minutes to eliminate one variable.
Than start from the worst case scenario to the least.
While your burping the system and bringing the car up to normal temp start your block test for a BHG. If that passes bend on one knee and give thanks to the Almighty.

Do a pressure system test. Now you have eliminated any leaks.

If that passes check your fan clutch. Your fan draws air through the rad and keeps your car cool in city driving or idle when your not on the highway pushing air though the rad. If your temp does go up and your auxiliary fans kick in and the temp drops that could tell you your fan clutch going on the fritz.

Find a second method to test temp of the coolant. Variations in temp with your second method would verify that you gauge is being true to you.

The old saying "The gauge must be wrong" has cost allot of people money and heartache. The gauge is wrong or a loose wire should be you last best guess.

I am new to the supra scene so if I have made any mistakes please correct me. No flaming plz.
well i just put a titan motorsports metal head gasket in with arp head studs and nuts about 600 miles ago.. and its been doing this like the whole time.. soo i dont think its that

[jetjock]

^ That makes sense ;)

[gtsfirefighter]

well i just put a titan motorsports metal head gasket in with arp head studs and nuts about 600 miles ago.. and its been doing this like the whole time.. soo i dont think its that


Huh?

It's been doing this ever since you replaced the headgasket or ever since you've had the car?????

[ATL88Supra]

did you get the block decked and checked for smoothness ?

did you get the head milled ?

that MHG is worthless if you dont do both of those things, if you did not you are lucky you got 600 miles out of it

[s7mgte]

did you get the block decked and checked for smoothness ?

did you get the head milled ?

that MHG is worthless if you dont do both of those things, if you did not you are lucky you got 600 miles out of it
i got the head milled and ive heard you dont need the block milled being that it usually doesnt get warped. so i left that alone. i got to bleed to system properly i think.. i changed the thermostat today and the temp did the same thing. also i taped the gauge and it still didnt change so i know its not those 2 things.. has to be more air in system.

[Frank Rizzo]

ive heard you dont need the block milled

They talk alot, don't they?

[ATL88Supra]

dude you ALWAYS Deck the block, there is no room for error on the 7mgte if you used a MHG and DID NOT deck the Block then you just wasted money and time, it wont suprise me at all if you are blown

and who ever said that you did not have to deck it was a goddamn fucking moron

[s7mgte]

dude you ALWAYS Deck the block, there is no room for error on the 7mgte if you used a MHG and DID NOT deck the Block then you just wasted money and time, it wont suprise me at all if you are blown

and who ever said that you did not have to deck it was a goddamn fucking moron

well ive heard it from mechanics too.. reason being the head is aluminum and the block is cast iron. also im not sure if this matters but i thought my heater core was going so i just bypassed it with a hose and a few adapters. Figured id add that in in case it matters. and also if i blown.. dont you think i would see coolant in my oil and lose boost and all kinds of other things?

[ATL88Supra]

its not about warpage, its about smoothness, the mateing needs to be PERFECT thats why you deck the block....................... and if they did say that they dont know how to work on a import motor,

its most likely blowing air in to the water jacket there for pushing the coolent out and filling the system with air

[1992supraman]

mine was kind of doing that. After 30 min of highway it would creep up ever so slightly and then with the heater on it would go away. found a small hole in the radiator. replaced and now fixed.

[jdub]

its not about warpage, its about smoothness, the mateing needs to be PERFECT thats why you deck the block....................... and if they did say that they dont know how to work on a import motor,

its most likely blowing air in to the water jacket there for pushing the coolent out and filling the system with air



The TSRM (Pg EM-74, Step 3) says max warpage for the block deck is .05m or .002".
Then it says if it exceeds the above, replace the block.

I wonder why the TSRM would say that ;)
Maybe it's because a warped block won't allow a HG to seal? That's exactly why...a flat block deck is even more important a factor for the seal of any MHG...RA only applies to a MHG.

[ATL88Supra]

The TSRM (Pg EM-74, Step 3) says max warpage for the block deck is .05m or .002".
Then it says if it exceeds the above, replace the block.

I wonder why the TSRM would say that ;)
Maybe it's because a warped block won't allow a HG to seal? That's exactly why...a flat block deck is even more important a factor for the seal of any MHG...RA only applies to a MHG.

jdub, the chances his block was warped to start with is rare, but the very fact that he did not have his blocked decked be it for warpage or smoothness

is a dead give away on his problem, RA is being looked at sence he had a MHG put on
as stated here: "Originally Posted by s7mgte
well i just put a titan motorsports metal head gasket in with arp head studs and nuts about 600 miles ago.. and its been doing this like the whole time.. soo i dont think its that"

but as you said yes the block should be checked and i know this but what i ment in the org post was it was more about RA then warpage when moveing to MHG even those RA and warpage is one in a same it is the same thing really GAh i am confuseing my self now.

[jdub]

I understand. But, to say "its not about warpage, its about smoothness" is incorrect. Regardless of the odds, the block should be checked for warpage and that's for any HG...a warped deck will just about assure it's not going to seal.

Also...like I've said a couple times now (in different threads), get the damn coolant system pressure tested and do the NAPA block test. That way we can all stop guessing! ;)

[s7mgte]

I understand. But, to say "its not about warpage, its about smoothness" is incorrect. Regardless of the odds, the block should be checked for warpage and that's for any HG...a warped deck will just about assure it's not going to seal.

Also...like I've said a couple times now (in different threads), get the damn coolant system pressure tested and do the NAPA block test. That way we can all stop guessing! ;)
im getting the napa block tester tomorrow so ill let everyone know.. haha.. also smoothness.. it was very smooth i had the air compresser powered whiz wheel on it. she was shining before i put it on. im hoping for the best.. and also i forogt to say this. ive heard from people who knoew the kid who had my supra before me. they said it had coolant problems so i wonder.. hmm?

[jdub]

You used a rotary abrasive to clean the block deck?

:eek3:

[adicken1]

LOL!! Histerical!!

[s7mgte]

You used a rotary abrasive to clean the block deck?

:eek3:
haaa yess that is exactly what i used to clean the block deck to clean off all the pieces and particals of the cometic one.. trust me though it was very smooth..

[jdub]

Dude...that is not good. It may look smooth, but you induced "waves" in the block deck. It only takes 1 or 2 thou of material removal in any one area to cause the HG (especially a MHG) not to seal.

There is no way that block deck is flat. Like I said before, flatness is just as or more important than smoothness for a MHG to seal. You very likely FUBAR'ed the block.

[ATL88Supra]

/facepalm

[p5150]

I didnt see that you had checked the wire that connects to the coolant temp sensor on your thermostat housing. If you are lucky it is just loose and grounding out on occasion and causing the indication to go full hot.

[s7mgte]

Dude...that is not good. It may look smooth, but you induced "waves" in the block deck. It only takes 1 or 2 thou of material removal in any one area to cause the HG (especially a MHG) not to seal.

There is no way that block deck is flat. Like I said before, flatness is just as or more important than smoothness for a MHG to seal. You very likely FUBAR'ed the block.
nope haha no blown head gasket. its fixed now with no overheating. i had the heater core by passed with a hose and hose adapters i hooked up because i thought the heater core was busted.. i hooked it back up today normal. and now it is perfect. temp gauge stays right where it should the whole time. maybe it was something with the pressure or something.

[jetjock]

Lmao. Let us know how that works out for you...