I found the quote at the bottom of this page on a part of this forum, good to know. I'd like a little more info.

My case: My father gave me his stock 78SA with the L84. I too was alarmed at how hot it ran. I cut my teeth on this vintage rig and have been a mechanic all my life and am completely up to date with the latest and greatest... Just for a little background.

Let me ask 'you' what you think. This is a nice car, it drives well and is in really decent shape, but not so good that I would feel bad about moding it... it has the typical storage issues like leaks and squeeks which I have been addressing when money and time permit.

This is what I want to do to cool her down.

Remove the plastic distributer cover.

Place a small air deflector on the underside just behind the bumper. (It looks like the one they put on the early 90's cutless would be very discrete and fit nicely.)

Install a two stage electric fan bank.

Install working louvers on the hood.

Remove the thermostat.

I also am feeling quite abit of heat coming through the fire wall, I have had to bypass the heater core because it is seeping and is fogging the windshield, so I know its not the plenums not shutting down the heat, there is none. Do these car normally leak engine heat into the cabin?

I know that no heater core may be contributing to the heating issue.

???????

 

One of the first things to check on a C3 of any vintage is the network of foam seals around the radiator and core support that force the air to go THROUGH instead of AROUND the radiator. Because these were early-generation smogmobiles GM had them set up to run SLIGHTLY hot (205-210 degrees). If the seals are deteriorated it tends to allow pressures to equalize from the front to the back of the radiator, inhibiting flow THROUGH the radiator. You may be surprised at what a difference you'll see just by putting fresh ones in there. Trick aftermarket fans, expensive aluminum radiators, hi-tech water pumps, etc. are all great ideas but you might be able to calm it down just by replacing some relatively cheap foam pieces before you spring for all that.

 

I will, that is why I asked. We had our first 90 deg. day in upstate NY, I thought she was gonna pop her top.

 

The cars never came close to overheating when new. Find out what's wrong and fix it instead of trying to re-engineer.

 

Agree, I also plan on checking to see how accurate the gage is. It might just be that simple. Any ideas about the cabin temp?

 

What you want to do is leaning toward overkill. Have the stock radiator cleaned and leak tested. Replace the stock radiator and shroud seals. Check the radiator cap. Run a 195 degree thermostat. Check the fan clutch. Does the car have the stock fan?

The engine is an L-82.

 

It does have the stock fan, I already picked up a 180 deg theromstat, I thought I could go cooler because she 2 has modern cats on her. The cap is new. I'll pull the rad when I get shroud seals and see what is going on there. I was also thinking that she might have too much advance and or stuck advance weights and or the advance plate is stuck. I can't hear it knock but it has old school galss packs on it so I might not be able to hear it. It's been a while since I have worked on one of these guys... it coming back to me. I just put it on the road Monday and am shaking things out.

 

If your talking about excessive engine temps you could try running some Wetter Water made by Redline in the rad. I did that with mine cause it was running hot 210-230 on our hot summer days and it has cooled it down to 185 or so even while sitting and idling for awhile.

Good luck