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Old 09-01-2008, 07:47 AM
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Silly car is starting to run hot again!!

I had been chasing a too warm running 454 since I got this car running.
Last year, I thought I had it all ironed out----APPARANTLY NOT!

Last summer it would run at hiway speeds at 190ish and hang steady.
This summer it seems to want to run quite a bit warmer.
In about July on a 35mi cruise it wanted to run @220 all the way down and back (about 98* in the afternoon and I'm sure it dropped some by 11pm when I started home).

I bumped the timing up a bit, but that did not help.
The car cools right down when idleing to under 200 (twin 12" electrics)

BeCool radiator, Hiflow Tstat 180*, The water pump is the one that came on the engine (GMPP 454HO).

The instant I let off the throttle at cruise----the temp spikes way high.

Not sure if this is a pissy T-Stat or a water pump that is not getting the job done. Sure getting tired of draining the coolant. (about 25% coolant to 75% water).

Now---the engine only has 4500 miles on it----and everything is virtually new. (have about 5 T-stats that I have used in a drawer)

Just fishing for some suggestions.


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Old 09-01-2008, 07:52 AM
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Just a guess, but it does make some sense that it "could" be the water pump. Maybe the water pump is having a hard time keeping the coolant flow going when driving.

As you probably already checked, but lack of airflow across the radiator while driving can do this too.

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Old 09-01-2008, 12:35 PM
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Try a small air dam on bottom front of your radiator.
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Old 09-01-2008, 12:52 PM
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Let's analyze this.
It is running 30* hotter on the road than last year under the same conditions.
It gets real hot when you slow down= the temperature spikes.
Idle is borderline. Temp should never exceed 10* more than thermostat.

What changed?

That tells me that on the road you have a lack of water flow
and slowing down slows the ram air through the radiator and the temperature spikes= insufficient airflow for the heat produced.

I doubt that the wire in your lower radiator hose disappeared since last year.
You should never need a radiator fan below 35 mph.

1) You need a new high flow thermostat? You tried 5?
2) You need to flow check your radiator.
3) You need to verify that your vacuum advance is operating correctly.
4) verify that mechanical advance also.

Unless your engine is fragged=

You have insufficient water flow through the radiator/ or the radiator is too small.
You have insufficient cool airflow with the electric fans to cool it at idle.

JMO after years of experience.

Last edited by ScoTFrenzel; 09-01-2008 at 01:07 PM.
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