1964 Mercury Comet Engine temperature

JOHN GARDNER

MEMBER
1964 MERCURY COMET
V8
2WD
AUTOMATIC
31,000 MILES

If the temperature outside is over 85 degrees then the engine will over heat while at a stop light. The engine will cool down once the car is back in motion. The heater has been used on summer days to protect the engine from over heating. Not fun. With temperatures over 98 degrees then the engine over heats and not even the heater will help cool the engine. If the temperature outside is 45 degrees or colder then the car does not seem to heat up enough. On winter days the engine must warm-up in park for 15 minutes or more for the temp gage to reach normal temperature. After this warm-up period, the heater will warm the interior of the car and defrost the windshield. However, when driven in cold weather, the engine cools down and the heater stops blowing warm air. I have changed the thermostat three times, checking it by placing in boiling water. I have drained and flushed the radiator and the engine then refilled with mixed 50/50 coolant. Radiator and engine same number of miles. No obvious leaks have been found. Water pump flow test good. What else can I do?

1 Reply

HMAC300

MECHANIC
48,601 POSTS

Wow sounds like you've done a bunch of stuff to try to get it cool. There are a few things left though. First get the car to overheat if you can or if it will. Once it overheats, shut the car off and feel different spots on the radiator. It should be the same temperature all over. If you feel cold spots and see loose/corroded fins, your raidator isn't doing it's job even if you flushed it out. If it were me, that would be the first thing I'd check. You could also have a bad temp guage, if you have a way to check the upper hose for temp do that, but that's a hard thing to do. Then check to see if you or if the car has a clutch far or shroud. I can't remember that far back on shrouds, it may even have a tiny one on thetop for "hand protection". Have the radiator cap checked or just put anew one on as old ones go bad alot of times and won't let the system build up ressure-hence - overheating. Other than that I'd have to go for a head gasket. One thing if the system pops and bangs like when it overheat, DO NOT IN ANYWAY TRY TO OPEN THE RADIATOR CAP. You will get severly burned if you do. One other thing you should have a thermostat of at least 180, preferably 195.