Sergio1vaz

I have a 1965 Ford Mustang w/ 302. Newly rebuilt engine. The car when idle or in traffic begins to overheat. It gets as high as 230 and climbing, but when I get going, it comes down to about 190. Here is what i have done so far. I replaced the gauge. A new thermostat (put in the correct way). New intake. New 3 row aluminum radiator. 50/50 . Replaced the fan with a clutch fan, and it's 2-1/4 inches from the radiator. I had a fan shroud on the previous radiator and still overheated. I have yet to put one on this new one. I took the car to a shop to get the timing corrected. When I turn the car off it does NOT sound like boiling or overflowing into the overflow comp. It simply sounds normal. I changed the gauge twice, thinking it was the gauge but no change. 15 lbs radiator cap. I took it to two different shops but no luck in reaching the problem..HELP!!!!

merc64

Did the car overheat prior to the engine rebuild? I only ask because if you're not careful it's easy to put the head gaskets on wrong and block a water passage.

palerider

Good troubleshooting article in mustang monthly

http://www.mustangmonthly.com/techar...g/viewall.html

DeWitts Radiator

Most of my experience is with Corvettes but when I hear these symptoms it usually means an issue with the vacuum advance on the distributor (assuming Mustangs have one?) I know my old 69 Plymouth did so I'll bet all cars of that era used the same technology.

Very few people will confirm the proper function of the vacuum advance when doing the timing because it is "assumed" the vacuum can is a good one. However these cans have a rubber diaphram inside and they will dry out and crack. If the can is connected to a ported (metered) connection and not full manifold vacuum it will not provide the correct advance too.

This condition can be easily checked by connecting and disconnecting the vacuum advance hose to see if it adds additional timing to the static timing specs. It can also be easily confirmed to be the source of the heat generation by simply running the car to temperature (about 210) during idle and then add an additional 10-15 degrees manually by turning the distributor. The temperature rise should stop and then reverse, but don't drive the car this way. This is only a diagnostic test to confirm the problem. Hope that helps

Sergio1vaz

I don't recall the car overheating previously but then again I didn't drive it much. What gets me is why does the cars temp go down when driving without traffic? Wouldn't the head gasket make the car overheat regardless of the speed? I understand that at higher speed, more air comes in to the engine compartment... I'm just thinking out loud here.. Is there a way to double check this without opening up?

I will check on the vacuum issue also...

merc64

Here's a pretty good link on the head gasket. It even shows a picture of how you can look without pulling the heads off.

http://www.jalopyjournal.com/forum/s...d.php?t=531966