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Joined: Jun 2006
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From: Atlanta GEORGIA
Hot...Hot...Hot...
My '79 L82 runs hot at highway speeds with AC on in warm weather. I installed new Northern aluminum radiator (w/seals) with dual SPAL fans which seems to work better than the original brass rad with the stock electric fan. Its seems to do OK driving around town but I think if I could resolve the problem at highway speeds, it would be great overall. I'd also lke to remove the stock mechanical fan and shrowd to gain more HP. I do have a stock lower air dam in good condition but not sure if its a good design since I have this cooling issue at high speeds. Thanks in advance for any recommendations !
Race Director
Joined: Aug 2004
Posts: 10,628
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From: Duvall, WA
A few checkables:
Timing (you should be at 38 degrees BTDC total with vacuum disconnected). If it's too far retarded, it can cause heat.
If your lower radiator hose doesn't have a spring, it may be collapsing at speed.
You mention you have new radiator seals, but is the piece that goes between the hood and radiator support in place?
How hot is it running at highway speeds? Is your tempurature gauge accurate?
Timing (you should be at 38 degrees BTDC total with vacuum disconnected). If it's too far retarded, it can cause heat.
If your lower radiator hose doesn't have a spring, it may be collapsing at speed.
You mention you have new radiator seals, but is the piece that goes between the hood and radiator support in place?
How hot is it running at highway speeds? Is your tempurature gauge accurate?
Melting Slicks
Joined: May 1999
Posts: 2,897
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From: Moon Township PA
First, verify that your temp gauge is accurate. Shoot the upper rad hose, the upper part of the rad, and the thermostat housing with an IR gun to verify that the gauge is indeed reading high temps. Get a hold of your Assembly Instruction Manual and your Judging Guide to see what type of shrouding should be there for the top of the rad to the hood as well as the bottom scoop.
Race Director
Joined: Mar 2006
Posts: 14,112
Likes: 28
From: Florida
In addition to the above suggestions,
Have your spals on all the time with the a/c
Take out your coolant drain plugs in the block to see if the passages at the sleeves are plugged with crud.
This is a common overlooked area and an engine will overheat even with a new rad.
Have 1 spal as a pusher for the condenser in addition to pullers for the rad. Pullers have more cfm, but require a shroud. I think the pusher reduction is close to 50% cfm. This setup will easily replace the stock fan.
Keep the air dam.
Heating up at cruise speed is generally a reduced coolant system capacity problem.
Have your spals on all the time with the a/c
Take out your coolant drain plugs in the block to see if the passages at the sleeves are plugged with crud.
This is a common overlooked area and an engine will overheat even with a new rad.
Have 1 spal as a pusher for the condenser in addition to pullers for the rad. Pullers have more cfm, but require a shroud. I think the pusher reduction is close to 50% cfm. This setup will easily replace the stock fan.
Keep the air dam.
Heating up at cruise speed is generally a reduced coolant system capacity problem.
Thread Starter
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Joined: Jun 2006
Posts: 66
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From: Atlanta GEORGIA
Originally Posted by rcread
A few checkables:
Timing (you should be at 38 degrees BTDC total with vacuum disconnected). If it's too far retarded, it can cause heat.
If your lower radiator hose doesn't have a spring, it may be collapsing at speed.
You mention you have new radiator seals, but is the piece that goes between the hood and radiator support in place?
How hot is it running at highway speeds? Is your tempurature gauge accurate?
Timing (you should be at 38 degrees BTDC total with vacuum disconnected). If it's too far retarded, it can cause heat.
If your lower radiator hose doesn't have a spring, it may be collapsing at speed.
You mention you have new radiator seals, but is the piece that goes between the hood and radiator support in place?
How hot is it running at highway speeds? Is your tempurature gauge accurate?
Thread Starter
Advanced
Joined: Jun 2006
Posts: 66
Likes: 0
From: Atlanta GEORGIA
I pulled out the thermostat after reading many posts on this forum suggesting different things to try. This one was the least expensive ($.99 for the gasket) and gave me the most dramatic result. Even on the hwy, it never went past the 220* mark on the temp gage.
Thanks Everyone!
Thanks Everyone!
