VCCA Home Forums Thread Like Summary - Overheating problem

Hello everyone. I'm all of a sudden having an overheating problem. I have a 35 Standard Coach and after many years of restoration I wanted to take it to a car show. I had the radiator done a few years ago. I also flushed the block. I have never had a problem with overheating. I have had it idling in my garage for over an hour at a time many times and the temp never passed 180. I have driven it up and down the street a few times without problems. I finally put in the glass and garnish moldings and wanted to take it to a car show. I didn't even get 1/4 of a mile and the temp went to 212. Water and steam spewing out the radiator cap. Got it home and thought it might be the thermostat so took it out. Same problem. Car overheats in 10 minutes. flushed the radiator and ran the car. Same thing. Didi this about 6 times and then filled with antifreeze. Same thing. Have no clue why, all of a sudden. Any suggestions would be helpful. Thanks.

Well, it wasn't fixed as good as I thought. Started it up the other day and BAM right to 212! I played with it a bit and said done and left it. I had run some radiator flush/cleaner through it which didn't do anything. Got too frustrated and didn't want to do something stupid and screw it up more. Tossed and turned for 2 nights wondering what it could be and dreading that it was the head gasket. I decided I was going to get it fixed today no matter what. I took off all the hoses and took out the thermostat. I started by filling the radiator with water. It was draining VERY slowly. I was expecting it to be free flowing considering that I had already flushed and back flushed it the other day. Obviously, a blockage. I blocked the upper hose connection an put the garden hose on full and backflushed it again. Water came out the top of the radiator but not at any great rate. The cap from the antifreeze container fits perfectly over the bottom radiator hose nipple. I drilled a hole in the cap and put it on. I took my compressor and blew air from the bottom to the top of the radiator. Water went everywhere. I filled it back up and the water came through the hole in the cap like a slow running water fountain. I filled it again and blew it out again and the rusty water came out somewhat stronger. Making progress. I did it a few more times and by the end the water was spewing out of the hole in the cap out of the engine compartment onto the front fender and no rusty water. I guess the radiator is free and clear. I flushed the heater and the block until all ran clear. I put everything back together and filled with water. I started the car and instead of overheating in 10 minutes, it took 40 minutes to get to 180. I let it run for over an hour and it never passed 180. WHOOPIE! I examined some of the crap that came out of the radiator when I backflushed it and it seemed to be soft fibrous material. I also noticed when I shut the car off, the water pump was leaking out of the shaft. Putting 2 and 2 together I figured the stuff that was in the radiator was the packing for the pump. Didn't know the packing would come apart and go into the radiator. So when I repack the pump, I should be all set to go. Just a coincidence that the packing came apart and blocked the radiator the same day that I tweaked the distributor. Chased my tail for a week but finally done. Thanks all for all the tips and advice. Pete V

Well the problem is fixed. I put the distributor back to where I started and it ran cooler. The water pump was leaking a bit. I think the gasket got folded when I put it in so I took it out and made a new gasket. For some reason, the thermostat that worked fine yesterday when tested isn't opening today when I tested it again. Bought a new one. While I had the thermostat and water pump out I flushed the block forwards and backwards and the radiator to both ways. It worked better for a bit. Took almost 40 minutes before it overheated. I was pissed and shook the car sideways and the block burped and the temp dropped back to 180. So I spent a week changing thermostats and water pumps just because I moved the timing. Lesson learned. Thanks all for the advice. Glad I didn't have to take the head off. Now it's just a matter of tweaking the timing just a teeny bit at a time to get the best performance.

That does seem strange doesn't it.

Too much water pump grease forced past the packing will apparently plug a radiator, although I've never had it happen myself.

Hello everyone,
I did the evaporust. After a few days of idling until it started to overheat then shut it off until cold and repeat a few hours later, I drained it out. It was very black. I refilled the block with water and repeated the process a couple of more times to flush out the rest of the evaporust. Finally came out clean water. Was still overheating but not as fast. Determined that the radiator was still semi clogged. When adding water had to pour it in slow and wait for the radiator to fill. I pulled off a heater hose and filled through the radiator until water came out the hose. Took my compressor at 100psi and burst air through it. It backflushed the radiator from the bottom up. Pieces of insulation and seat stuffing etc. came flying out of the top of the radiator. Kept doing short blasts until there was no more water in the block. Refilled and repeated about 5 or 6 times until no more stuff came out. Refilled it with water and let it idle for almost an hour. Didn't pass 180 degrees. let it cool and then took it for a ride. I have a 165 thermostat in it. Didn't go above that. Lost no water. I noticed that when I poured water into the radiator it took it as fast as I could pour it in. Seems to be clean and clear now. Tomorrow I will backflush it one last time and fill it with antifreeze. I think I'm good. Thanks to everyone for their help and suggestions.