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350 ci running hot please help!

I love my Chevy Chevette!
Posts: 1
Joined: 07/13
Posted: 07/04/13 07:16 AM

Hi guys I'm new here and new to the 350 world. I have an 85 trans am with a 350 swapped into if. I'm having some trouble with it running to hot. I have eliminated all vacuum leaks, re tuned ( rods, springs, jets) the carberator, checked the timing and cooling system. It warms up as normal then the temp continues to creep up to 240 if driving at all. If I let it idle it comes back down to about 180°. The motor runs very crisp so I am having trouble believing it is a carberator issue. A bit of guidance with the vacuum system would be appreciated. I believe the issue lies there because after a short period of driving the fuel tank builds vacuum. When I open it it sucks air in.  I live in arizona and as it gets hotter out the car keeps getting warmer. Any help would be greatly appreciated.  

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I mow my lawn and find Chevys
Posts: 2337
Joined: 03/10
Posted: 07/04/13 10:50 AM

sounds like you might not have the lower air dam/deflecter in place?     it will DEFINETLEY overheat without it!     is yours in place?    heres a link to a 3 piece one, probably for your car?    they did make a 1 piece one for camaros and some 'birds.

  if your on a budget ive seen guys make them out of sheetmetal.   you need to shove air up, and into the rad.   theres no grille area to a 3rd gen bird.    probably why your overheating while driving?  

   get a vented gas cap for your gas tank or leave the cap loose.  

  what kinda fan/fans are you running?      shroud installed?  

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I have an SS396 tatoo
Posts: 251
Joined: 03/13
Posted: 07/04/13 02:14 PM


my sister had one...  that or the single gm replacement air dam is what i used to correct the issue.

being a bottom breather..

with the air dam broken.. there was not enough air pressure  built up in front of the air dam to force it thru the radiator from front to back...  

when i measured with an HVAC dual port pressure gauge.. above 57MPH.. there was more pressure on the engine side of the radiator than there was in front of it.. so the air flow was going forward.. while the fans were trying to pull back.. so it was a stalemate.. engine overheated..

installed the single width rigid air dam from the GM parts department.. cured the issue..

warning... i know that you might have been in there changing the electric fan motors...

there are a bunch of shapes of them.. and i had gotten an after market version.. that was missing the spacer behind the drive plate... so when the fan was tightened down.. it pushed the drive flange backwards off the flats on the shaft  the fan motor then did not have a direct connection to spin the fan...

if you go junk yarding for replacement fan motors.. take a fish scale..    check the weight of the fan motors... buy the heavy versions..   look for some from cars with larger fan blades..

this is the factory fan motor numbering

**137318 MOTOR KIT,ENG COOL FAN (ELEC)LABELED 22073985(1985-89)(1985-91)F

the lower deflector kit might be this partial part number

047   **395557 DEFLECTOR, RAD LWR AIR (1983-87 W/W62) 82-87  

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