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overheating problem ??????


Turbotrio

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ok, i have absolutely no freaking clue what is wrong so i figured id see if anyone might have any ideas.

 

symptoms: car overheats randomly--especially after hard runs under boost. it will idle all day long and not overheat. it will run at a constant 55mph and not overheat. but if the car even gets a hint that youre thinking about getting on it it overheats :confused:

 

whats been done/replaced so far:

1) thermostat--on #4 right now so dont think its it

2) new radiator--in case stocker was leaking or somehow clogged

3) system flushed--about 12 times at this point (most not voluntary)

4) new radiator cap--again, on 3rd different one right now

5) water wetter added to coolant and less coolant than normal vs water

6) water pump is original but works fine

7) coolant leak test today with ZERO leaks found

8) two different compression tests done and headgasket is fine

9) tonight we directed hoses over the front-mount to get air straight into the radiator with no luck

10) all hoses checked 12 times and no cracks/tears/visible wear

11) added a permacool high-performance fan so it has two strong fans now

 

basically, the temp gauge sits just shy of halfway until repeated hard 3rd/4th gear pulls. then it raises slightly to exactly halfway--at which point fluid starts dumping out of the overflow bottle (this has been verified by poor cars following behind me--sorry ricky) and it loses so much it then overheats. everytime i pull over and let it cool back down i add atleast a gallon of coolant. WTF???

 

i have absolutely no idea what the hell is wrong. the only guess right now is that the front-mount is too big (3 1/2" thick) and is blocking all the air-flow to the radiator. keep in mind this same fmic is on a few thousand cars (prolly close to 50 at the dsm-shootout when it was close to 100 degrees) and no one else seems to be having the same problem.

 

any ideas ??????

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What's the temp rating on the thermostat? If it's not 160* or 170*, then go back for another. (Stock 1G is 190* while the 2G is lower.)

 

Are your fans kicking on? Passenger side kicks with temp, driver's kicks with A/C or if temp gets out of hand. Have you wired both fans together?

 

Do you have A/C? Did you take out the A/C radiator? Do you run with the A/C fan on? If you have the A/C still, pull the relay and run with the fan on.

 

Original water pump?!? :smack:

 

Jamie

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jamie,

fans are both wired to run 24/7 and no i dont have a/c so the condenser is gone (which should be a little *less* restriction). both kick on when the key turns and stay that way til i shut her down.

 

thermo was a 195 then i went to a 180 now im back to a 195 again thinking that *maybe* the coolant wasnt staying in the radiator long enough to fully cool and thus helping the overheating problem. either way, the car overheats :(

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Guest xxxyyyzzz

:confused: Here's a shot in the dark:

 

Have you checked to see if your air/fuel ratio is still fine under load/across the rev band? The thinking here is that if you're leaning out your egt shoots up and with all the exhaust plumbing packed into a small turbo car that could possibly be enough to make it misbehave... Just a thought.

 

"Jesse! Step away from the box..."

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Guest 614Streets

</font>

  • Radiator core blocked by Intercooler</font>
  • Radiator Cap faulty</font>
  • Ignition Retarded too far
    </font>

Check to make sure your cap is okay and still holds pressure.

That Intercooler may be blocking enough airflow and the radiator may be to insuficient for your upgraded engine. If this is case look for a 4 core aluminum unit.

I assume your not too retarded in the Ignition , just a reminder.

 

EDIT: Just read 3rd cap. Sorry.

 

[ 12 November 2002, 09:41 AM: Message edited by: 614streets Performance ]

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Originally posted by Jasons TSi:

1. Have you had the overheating problem since the intercooler install?

 

2. is it possible the head gasket is on up-side-down, possibly blocking coolant passages?

1. yes--but the fmic was done the same time MANY other things were done--including the entire engine.

 

2. at this point i guess anythings possible :confused:

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Originally posted by 614streets Performance:

</font>

  • Radiator core blocked by Intercooler</font>
  • Radiator Cap faulty</font>
  • Ignition Retarded too far
    </font>

Check to make sure your cap is okay and still holds pressure.

That Intercooler may be blocking enough airflow and the radiator may be to insuficient for your upgraded engine. If this is case look for a 4 core aluminum unit.

I assume your not too retarded in the Ignition , just a reminder.

EDIT: Just read 3rd cap. Sorry.

np. ignition is actually advanced 10 degrees. radiator cap is good.

 

and if i KNEW FOR SURE the aluminum radiator would solve the problem id have already spent the $400.

 

i dunno.

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Originally posted by StraightouttaLocash:

:confused: Here's a shot in the dark:

 

Have you checked to see if your air/fuel ratio is still fine under load/across the rev band? The thinking here is that if you're leaning out your egt shoots up and with all the exhaust plumbing packed into a small turbo car that could possibly be enough to make it misbehave... Just a thought.

egts are LOW LOW LOW and air/fuel is pegged rich :confused:
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Guest 614Streets

It sounds like youve covered all your bases. Im sure youve checked the water pump flow at higher rpms(visual check). Is the cam custom and is the cam timing correct?

Assuming the problem is not internal and everything checks out Id propose the Larger Radiator and a bit more Ignition Advance and if needed corresponding boost trim. Also slip down to a 160 stat. Thats if everything else is dead on. Do you have numeric Temp gauge?

 

I helped install the same FMIC on a stock radiator DSM and we did not see a overheat issue. :confused:

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I am by no means an mechanic, but I want to off a suggestion: Headgasket, as mentioned before. I would suggest getting a block tester (sniffer) to see if there is any exhaust in the overflowed coolant. At the same time, I would check the torque specs of the headbolts. I assume your running more boost than stock, and they could be "moving" under increased loads causing.

 

I also saw a problem in the big fmic, but that might not be where the real problem is. I suggest putting the boost back to stock and making a few hard runs to see if it overheats.

 

Let us know...

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Jeff, when Mike and I drove his Talon back from Florida the same exact problem occured did all the same tests and pissed me off just as much the car had a small combustion leak but to did not occur under idle conditions with no boost. It would only happen under full boost runs. Two 3rd,4th gear runs and the thing had the overflow spiting a gallon and then it would overheat. Solution new headgasket. Horn blows so does the headgasket. :D
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Originally posted by Powers:

Jeff, when Mike and I drove his Talon back from Florida the same exact problem occured did all the same tests and pissed me off just as much the car had a small combustion leak but to did not occur under idle conditions with no boost. It would only happen under full boost runs. Two 3rd,4th gear runs and the thing had the overflow spiting a gallon and then it would overheat. Solution new headgasket. Horn blows so does the headgasket. :D

compression test was good. then had ricart do another headgasket test that uses some blue fluid that will turn yellow if there is a headgasket leak. nada. headgasket is a-ok.
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compression test would be good at idle. all the extra pressure from the boost can blow past the headgasket but only under load with boost. wich can cause you too over heat. hard to explain but all the extra pressure can effectivley force the head up under load. it would only have to move a little. the gasket is prolly good but the bolts suck. are they the torque to yield kind? if they are get head studs so you have even clamping force without movement
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Originally posted by BROKEN BUICK:

hard to explain but all the extra pressure can effectivley force the head up under load. it would only have to move a little. the gasket is prolly good but the bolts suck. are they the torque to yield kind? if they are get head studs so you have even clamping force without movement

full arp headbolts and they have been retorqued twice. ive run a max of 15-17psi thus far--which is nothing for that car. ran around with a much smaller front-mount on 19psi for over a year without the first cooling problem.....
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