Overheating
Team Owner
Joined: Apr 2008
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From: Middle TN by way of KY, OH, VA, IL, CA, FL, NY, SC, HI
Burning Brakes
Joined: Aug 2013
Posts: 1,071
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From: palm springs ca
I would like to add a possible reason, just a shot in the dark, but being that the condenser is in front of the radiator, the hot air has to obviously go thru it first. I am not a system guy, but know of a few cases where the A/C system was not causing any overheating till it was worked on. Meaning that it was overcharged with oil or gas causing the condenser to get much hotter. Reason being is that it was OK temp wise, then after working on the system it ran hotter. Years ago I did just that. If a little is good a lot is much better! I overcharged the system and the engine ran HOT. Got a education from someone who did A/C all day (my son), and found that dad overcharged and that caused the condenser to get much hotter. To much oil in the system will also cause the same problems.
There were no temps checked before or after, just that there was no more overheating. There are a few NCRS guys that can swear to that as being their problem.
Dom
There were no temps checked before or after, just that there was no more overheating. There are a few NCRS guys that can swear to that as being their problem.
Dom
Drifting
Joined: Oct 2009
Posts: 1,725
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From: marietta, GA
Point the IR gun at the thermostat housing and compare it with the gauge. If the temp is normal I suspect you may need to replace the sending unit which is easy & inexpensive. See if you can find a used or NOS one.
Race Director
Joined: Apr 2005
Posts: 11,265
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From: Bowling Green, Kentucky
Yes Dom..............AC performance (and hence condenser temperature and pressure ) can and will affect engine cooling. Hopefully OP is running his system per SOP.This may not be his issue, but it is good to check.
Larry
Former Vendor
Joined: Jan 2000
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From: Brighton
The cold case 2row (1.25" tubes) should be pretty close to the btu rating of the original aluminum radiator so switching is probably not going to change anything there. I scan read this full thread and I saw 240 f at a couple lights but I didn't see what happens when you cruise over 40-50 mph. If the system cools down then and only has a problem at low speed and idle, the problem is the vacuum can. After 20 years of diagnosing these issue, I'd say 9 of 10 of these low speed/idle problems are a bad vac can or just the wrong function. Some guys have replaced the distributor and have no vacuum advance at all.
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Brett Foote
Former Vendor
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From: Brighton
Will that BB blade fit into the metal shroud on 63-65? I think the stock five blade is 18" and the BB is 19" but not positive.
Last edited by Tom@Dewitt; Apr 19, 2020 at 06:48 PM.
Team Owner
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Army
Melting Slicks
Joined: Sep 2005
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From: merritt island fl
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We're getting way off here. The OP said it only overheats "unless on highway". Also, the fan clutch is obviously defective.
Fix the fan clutch first!
Fix the fan clutch first!
Drifting
Joined: Oct 2009
Posts: 1,939
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From: Palm Bay Florida
Just put the 2747 Hayden clutch and a 17117 Derale 6 blade fan ($72 for both from Summit) and it will run at the thermostat temp. I install at least 2 vintage airs a year and none of them run hot in traffic.
Mark
Mark
Thread Starter
Instructor
Joined: Jun 2013
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From: Louisville KY
Tom D. and Nowhere Man
I think you are right on target. I need to find out how to determine if I have a dead VAC and proceed from there. I tried to mouth suction the hose to the distributor and nothing would move. tried to move the mechanism by hand and it barely moved. I need to dig into the distributor next once I determine how to do that job. Thanks
I think you are right on target. I need to find out how to determine if I have a dead VAC and proceed from there. I tried to mouth suction the hose to the distributor and nothing would move. tried to move the mechanism by hand and it barely moved. I need to dig into the distributor next once I determine how to do that job. Thanks
Last edited by gies222; Apr 25, 2020 at 07:08 PM.
Former Vendor
Joined: Jan 2000
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From: Brighton
Tom D.
I think you are right on target. I need to find out how to determine if I have a dead VAC and proceed from there. I tried to mouth suction the hose to the distributor and nothing would move. tried to move the mechanism by hand and it barely moved. I need to dig into the distributor next once I determine how to do that job. Thanks
I think you are right on target. I need to find out how to determine if I have a dead VAC and proceed from there. I tried to mouth suction the hose to the distributor and nothing would move. tried to move the mechanism by hand and it barely moved. I need to dig into the distributor next once I determine how to do that job. Thanks
Race Director
Joined: Apr 2015
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From: Fresno California
After you get the vacuum advance working, post a picture of your fan, showing it's positioning in the fan shroud and so we can verify it is not installed backwards. Your problem, as others have stated, is that you are not pulling enough air through the radiator at slow speeds. The radiator is fine. If it was not, it would overheat on the highway as well. I suspect a good fan clutch and functional vacuum advance will work wonders here.
Team Owner
Joined: Feb 2003
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From: Sitting in his Nowhere land Hanover Pa
2024 C2 of the Year Finalist - Unmodified
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get yourself a mity vac tool you can use that to pull a vacumn on the advancd can and see when it pulls open or if it holds vacumn. then you can use it as a gauge when the engine is running to get real time data to help you pick the right advance can using the two inch rule. harbor freight sells them
Thread Starter
Instructor
Joined: Jun 2013
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From: Louisville KY
waiting on a fan clutch to be delivered. I finally found a new Delco clutch that was HD (as required) and fit my 3" holes in the 7 blade fan and the holes for the water pump .( I hope!) I know I could have bought a Hayden HD, but I would then need a new fan blade, then a new water pump for the original holes to line up. The hayden 2711 would have fit but it was standard use
Last edited by gies222; Apr 26, 2020 at 12:09 PM.