Hi all,

I am having problems with my 307 in the station wagon overheating. I was on the way to camping pulling the tent trailer when 20 minutes into the trip the car stalled. I got out and opened the hood and noticed that the coolant in the overflow was bubbling. The temperature showed about 200 degrees.
I let it cool down and changed the thermostat on the side of the road and kept going. Everything seemed fine for about an hour and the temperature was about 180 steady all the way when all of a sudden I noticed the temperature was in the red so I pulled over and it was overheated again.

Any ideas of what I can look at to figure this out would be greatly appreciated so I can get home without any more trouble.

Thanks,
Rene

 

There's not much to the cooling system.
Inspect the radiator, fan, clutch, shroud, air dam, water pump and drive belt, heater core, and heater control valve. You already did the thermostat.
If you recently removed the ac compressor on the 307 the belts may slip as well.

 

If this was an accurate 200*, it really isn't considered overheating, as the 307 was usually equipped with a 195* t-stat.
However if the coolant in the overflow tank is bubbling, that is bad - over 214*.
Overheating on the highway pretty much eliminates the fan and clutch.

If the water pump belts are tight, then perhaps there is a blockage floating about somewhere, or maybe the water pump impeller is getting lose on it's shaft. When was the water pump replaced last?

Last thing, does the lower rad hose have the big spring in it to keep it from collapsing due to the pump's suction? Squeeze it and it should not collapse. A spring for it can be from a pop-up sprinkler spray head available at any hardware store.

Seems strange how it will stay at 180, then all of a sudden overheat.

 

Ditto that.
If the water pump is good, I'd be looking at rodding out the radiator.
If you have 100k+ miles on it, it gonna need it anyway.
Jim

 

I know it doesn't really apply here due to the different cooling system, but on the LT1's the symptons you describe are a sure sign of an air pocket trapped in the system.

On your car I'd probably backflush the radiator and replace the pressure cap. That'll eliminate any pressure spikes you may see which could cause these symptoms.

Then take the belt off the pump and wiggle the pulley to check for play. Last time I replaced a water pump there was so much play in it that the impeller actually cut a grove into the block that was as deep as the groves on a record. (A record is a disk that people listened to music on back in the old days )

 

be sure the lower radiator hose isn't collapsing. if there isn't a spring in the lower hose, install one.

 

Thanks for the ideas everyone,

I am going to flush the rad for sure when I get back and I am leaving the camper at the campground for a few days untill I get it sorted out.
I got a tranny cooler from my father in law that I will install as well and replace the hoses as well. I had some info from a retired mechanic camping next to us. He suggested to replace the clutch fan because we drove it around to heat it up and checked the fan and it was still running free. He said it should have locked up when it got hot.

Thanks again,

Rene

 

Easy way to check it, is to momentarily raise the engine RPM to 2000, or so. If the hose does not collapse, it is not the problem.

Norm

 

I would change the rad cap first, cuz it's the easiest and cheapest to do...ta dah