ZZ4 engine temp question
#1
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Car: 84 Pontiac Trans Am
Engine: 383 small block
Transmission: 700r4
Axle/Gears: 373 w detroit locker
ZZ4 engine temp question
This one's got me scratchin' my head. I have an '84 Trans Am, ZZ4 with aluminum heads that have been ported, jet hot coated shorty headers, a different cam than originally came with it, and I'm running an oil cooler. It's got a brand new radiator (plastic tanks with aluminum 3 cores), a 16" electric pull fan on the inside and a 12" electric push fan on the outside. I have a 195 degree thermostat (newly replaced).
Here's the scenario: When I'm sitting in traffic or driving around town I usually dont have any problems at all and it stays at 180/195 with no problem, but as soon as I get on it or drive on the interstate/highway for periods of time it will start to rise gradually to 220, 230 even up to 250 (I've only let it get to 250 once!). When it gets hot though, it still runs great, no bubbling or funny smell, no symptoms of overheating at all, just those high numbers and as soon as I start slowing down to come to a stop the temp will come down steadily back to 180/195. I originally thought it was the factory gauge, so I hooked up my auto meter gauge and while the factory gauge *was* about 10 degrees off, these numbers still seem too high. -Oh, also, when I installed the auto meter gauge to the sending unit, I hooked it up in the head where the factory one was located instead of the aluminum intake.-
If anyone has any insight into why it's doing this or how to fix it, I'd greatly appreciate it.
Here's the scenario: When I'm sitting in traffic or driving around town I usually dont have any problems at all and it stays at 180/195 with no problem, but as soon as I get on it or drive on the interstate/highway for periods of time it will start to rise gradually to 220, 230 even up to 250 (I've only let it get to 250 once!). When it gets hot though, it still runs great, no bubbling or funny smell, no symptoms of overheating at all, just those high numbers and as soon as I start slowing down to come to a stop the temp will come down steadily back to 180/195. I originally thought it was the factory gauge, so I hooked up my auto meter gauge and while the factory gauge *was* about 10 degrees off, these numbers still seem too high. -Oh, also, when I installed the auto meter gauge to the sending unit, I hooked it up in the head where the factory one was located instead of the aluminum intake.-
If anyone has any insight into why it's doing this or how to fix it, I'd greatly appreciate it.
Last edited by bigschramm; 02-17-2013 at 01:07 PM. Reason: forgot to put something in.
#2
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Car: 1987 iroc z
Engine: 305 tpi for now
Transmission: 700r4
Axle/Gears: 3:24
Re: ZZ4 engine temp question
Since temp is fine at stop lights id say thermostat is fine. im guessing your not getting enougj air through your radiator. i had this happen in a foxbody i built. the fans wer putting out enough at idle, but couldnt keep up at wot or even cruising speed. Make sure you have a shroud on there. i removed the electric fans on the stang and put on the original with regular fan and problem solved. i think it was just the shroud though.
#3
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Re: ZZ4 engine temp question
Do you have the plastic "chin spoiler" bolted on under the radiator support (and is it in good condition). They are CRITICAL to getting good airflow (and therefore cooling) through the radiator at highway speeds. Some cars you can take 'em or leave 'em, but not on a 3rd Gen F-body. Must have.
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Car: 84 Pontiac Trans Am
Engine: 383 small block
Transmission: 700r4
Axle/Gears: 373 w detroit locker
Re: ZZ4 engine temp question
Do you have the plastic "chin spoiler" bolted on under the radiator support (and is it in good condition). They are CRITICAL to getting good airflow (and therefore cooling) through the radiator at highway speeds. Some cars you can take 'em or leave 'em, but not on a 3rd Gen F-body. Must have.
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MacRocZ (11-02-2020)
#6
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Car: 84 Pontiac Trans Am
Engine: 383 small block
Transmission: 700r4
Axle/Gears: 373 w detroit locker
Re: ZZ4 engine temp question
Yeah I ended up pulling the condenser out also because it looked like it was all nasty,(no leaves though).. As for as the air-dam good call it fell off a couple months ago (before I really ever really took it on the highway) I hung it on my shop wall and didint think nothing of it!! But when the rain stops here in the good ole Sunny Pan Handle of Florida.. Im gonna reinstalle it!
#7
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Car: 84 Pontiac Trans Am
Engine: 383 small block
Transmission: 700r4
Axle/Gears: 373 w detroit locker
Re: ZZ4 engine temp question
Since temp is fine at stop lights id say thermostat is fine. im guessing your not getting enougj air through your radiator. i had this happen in a foxbody i built. the fans wer putting out enough at idle, but couldnt keep up at wot or even cruising speed. Make sure you have a shroud on there. i removed the electric fans on the stang and put on the original with regular fan and problem solved. i think it was just the shroud though.
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#9
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Car: 1989 IROCz T-top & 1988 Convertible
Engine: 350 TPI x2
Axle/Gears: 3.73/4.11
Re: ZZ4 engine temp question
Still got that 3rd gen?
Im in Pensacola!
Always looking for fellow 3rd Gen'ers
Im in Pensacola!
Always looking for fellow 3rd Gen'ers
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