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Discussion Starter #1
I was driving in the Nova yesterday to a car show, doing about 70 on the freeway and the temp was running about 185* which is normal. As I exited the freeway the temp started creeping up. After about 1 mile it got up to 220*:eek:

On the drive home it seemed fine, but then after about 5 miles it started doing the same thing. as long as i'm moving it's o.k. As soon as I slow down or stop is whem the temp starts to go up

I have a mild 383 with the Summit universal radiator, Derale 17" fan with a shroud, fan comes on at 180*, off at 170*, Edelbrock water pump, and a 180* thermostat and a 16# cap.

I've been running this cooling set-up for a while (9 months) with no issues at all.

Does this sound like a bad thermostat or a bad water pump?
 

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If it only seams to heat up when movement is slow, it would seam to be more of a fan issue. Lack of air flow.

If the water pump or thermostat was not working, it would always be hot.
 

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Is the radiator full? How about the shroud? Is the fan placed properly in the shroud? The fan blades should only stick about 1/2 way into the shroud. Are the sides of the shroud sealed off?
 

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Discussion Starter #5
Is the radiator full? How about the shroud? Is the fan placed properly in the shroud? The fan blades should only stick about 1/2 way into the shroud. Are the sides of the shroud sealed off?
Radiator is full

Electric fan mounted on a 66RICH shroud

Put a pressure tester on the cap and on the radiator to see if theres a small pin hole.
That was the first I checked after checking the coolant level.


The thing that has me puzzled is, I drove it last weekend and it was fine. I probably have about 1000 trouble free miles on the radiator/shroud/fan set-up. This just kind of popped up all of the sudden. I'm gonna check everything over again and make sure I'm not missing something simple.
 

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Hey Bill,
Are you sure the fan is operating? Could it be intermintant? Maybe check over your fan wiring or temporarily (sp) splice in a test lamp that you can see inside the car. Wire the light in parallel with the fan motor. If the fan is running the light will be on.
Ron
 

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Discussion Starter #9
The fan is coming on. When it first started getting hot I pulled over real quick, popped the hood , and verified it was on.

I pulled the thermostat last night and it appears to be bent.


Here's what I think happened.

I think the thermostat stuck causing the temp to spike. I'll pick up a new one today and check it out, then go from there.

Then on the drive home from the show, although it got hotter than normal, it didn't pass 200*. I'm assuming that might be due to the slight loss of coolant from the initial overheating.

Like I said earlier, i've been running this exact set-up for about 1000 miles with no problems at all. In fact this is the set-up that was on it at the John Force show and that alone was a 220 mile round trip, plus the car was loaded down on that trip.:confused:

I'll keep you guys posted.
 

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Discussion Starter #10
Fixed

Went and bought another thermostat, same brand a previous one. When I opened the package it looked worse than the I took out of the car that I suspected was sticking. So I returned that one and bought a 180* Stant Super Stat.

Let it run in the garage for about 1/2 an hour, then drove it about 30 miles and the needle didnt get any higher than 180*:D:D

I love it when it's a simple fix:yes:
 

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Simple is always nice, I had a 71 El Camino with a bb which had similar heating problems. A new big ol' alum rad, new fan and shroud, new thermostat and a additional electric fan later and it ended up being a broken impeller in the water pump (which was not even 6 months old). I often get frustrated that my dog cant talk to tell me whats wrong or what she wants...perfect analogy for classic cars.
 
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