What Am I Missing? (Cooling system q's)

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Jul 2, 2011 | 06:27 PM

ted13b

Thread Starter

Racer

Joined: Dec 2010

Posts: 281

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From: Holbrook MA

What Am I Missing? (Cooling system q's)

I took my recently acquired 77 L48 auto for it's first, warm weather highway cruise today. Around town it's steady at 190-200, but on the highway at 65 it eventually climbed to 210-220 and stayed there. The car runs well and the radiator and hoses appear to be recent. The car didn't overheat, but the temp seemed a little high for 85 degree weather. I took a look under the hood and it seems I may be missing a baffle sealing the top of the radiator to the ac condenser. I've looked in the catalogs but all I see is a piece of foam...is that all there is? And what's considered normal operating temp?

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Jul 2, 2011 | 06:50 PM

mds3013

Melting Slicks

Joined: Mar 2009

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When my '77 was a DD back in '81 it would climb to 210 then the fan clutch would come in over about 5 seconds and you could really hear the fan pulling air. Temp. would then drop to 200 and the fan clutch would slowly drop out in about the same amount of time. This process would repeat with the A/C on in TX weather. Car never boiled over or had any issues. I believe this is normal behavior for our cars. Seals, fan clutch and front spoiler that directs air through radiator are very important. mike...

Jul 2, 2011 | 06:59 PM

KevinK

Drifting

Joined: Jun 2007

Posts: 1,404

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From: Ansonia/NYC CT

I have a 76 that runs at a consistent 180, no matter how hard I run it, and that's with 9.2 to 1 comp. Make sure your rad is in good working order, and check the fan clutch.

Jul 2, 2011 | 07:19 PM

redwingvette

Safety Car

Joined: Aug 2001

Posts: 3,685

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From: Waterford Mi

Also check that all your radiator seals are in place. The fan does little for cooling at highway speeds. The air has to forced through the radiator by the air dam and the seals.

Jul 2, 2011 | 07:34 PM

...Roger...

Race Director

Joined: May 2006

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From: Dayton, Ohio

Yep you've got a couple big holes there.

Jul 2, 2011 | 08:17 PM

KevinK

Drifting

Joined: Jun 2007

Posts: 1,404

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From: Ansonia/NYC CT

Believe it or not, I was chasing down an overheating issue, and it turned out to be a bad fan clutch. That fan does a LOT more than you might think.

Jul 3, 2011 | 12:56 PM

ted13b

Thread Starter

Racer

Joined: Dec 2010

Posts: 281

Likes: 4

From: Holbrook MA

My big question, though...is there something missing between the top of the radiator and the core support? It's wide open, and it looks like air could go thru the AC condenser and over the radiator. Should there be a piece of foam there, or a filler panel?

Jul 3, 2011 | 01:50 PM

noonie

Race Director

Joined: Mar 2006

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From: Florida

It was open on my 77 too, but I didn't have any run hot issues.
I would certainly close it up, probably with some thin rubber.

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Jul 3, 2011 | 01:55 PM

...Roger...

Race Director

Joined: May 2006

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From: Dayton, Ohio

One thing to try is to buy a round piece of pipe insulation and feed it under the fresh air scoop so it goes from side to side and drive it to see if it helps. $2 is a cheap trial.
http://www.homedepot.com/Plumbing-Pi...atalogId=10053

Jul 3, 2011 | 02:35 PM

#10

crazyeight

Advanced

Joined: Jan 2010

Posts: 65

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From: Houston TX

Quote:

Originally Posted by ...Roger...

I just did this and it seems to help. I have 2 crappy 10" electric fans and with seals at the top of bottom of the radiator I've been running usually 200* in 100* Houston weather. If I sit too long I get up to 210*. But I definately recommend using pipe insulation to seal top and bottom of the radiator until you can get the proper seal.

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