I have a 57 Buick Roadmaster series 75 that i just replaced the thermostat and had the radiator re-cored but the temperature is reading HOT. After about 10 min the upper radiator hose begins to heat up but the radiator remains cold to the touch. I know that all I have left is the water pump and temperature sending unit. I guess my question is how I check the sending unit and/or water pump. Any advice is helpful and appreciated, thanks in advance. Leon
I may have a book that covers that year but I'll have to look for it. IF it was me I'd ignore the gauge for now and install a mechanical one even it its only temporary. HOT is nice to know but I want to see a number. Just for fun though you can try grounding and ungrounding the wire to the sender and see what the gauge does. The ones I'm familiar with read HOT when grounded. I check the water pump by watching for flow when the thermostat opens. You need to know the engine temp is over the opening temp for the thermostat, hense the gauge. I've heard of people installing thermostats backwards. The sensing part, with the spring, goes into the engine. You might have air in the system which won't come out until the thermostat opens. Once in a while new parts are bad. I've seen loose fan belts make a car run hot. When I started my engine after the resto it ran hot in ten minutes. I had the radiator to a shop and he gave it back saying it was ready to go. The paint was nice but it didn't transfer heat worth a damn. A new radiator solved the problem. There are a lot of possibilites. You may have nothing wrong but the gauge. Find out the actual temp and post back.
temp sensor Friend of mine has an infrared temp sensor that can give surface temps and would give you a clue on actual temps of the engine and radiator. You might check with your car buddies or the shop that did your work if they have one. My 56 has gas filled bulb type temp gauge so don't know if the ground wire thing will help you. Also make sure your heat riser gate on the passenger side exhaust is opening. Good luck. Roger
heating Take off the radiator cap with the engine cold. Start the car and put a candy thermometer in the radiator neck. When the temp gauge in the car says it's hot check the candy thermometer to see what the temp realy is. When the thermostat opens you should be able to see coolent circulating in the radiator by looking down the radiator neck with a flashlight. If it's circulating the water pump is working, at least at low engine speed.
I looked in the service manual and found a section about the exhaust manifold valve. It says if stuck in the closed position it will cause overheating. Since this car has been sitting up for some time I think this will solve my problem. (I hope) Next weekend I will try to see if that is it. I'll probably change the thermostat for the second time just to be safe. Be back soon.
Exhaust gate valve That's what I mentioned in my previous reply. I called it a heat riser valve but it is that counter weighted flapper on the passenger side manifold. Since your car is a 57 Roadmaster I think according to your avtar it probably has dual exhaust so you might be able to feel the tail pipes and get an idea if you are getting the same flow from both sides. Good luck. Roger
Sorry Roger, but I didn't know what that was.Yes it has duals. I want to think that this is it because i also get smoke\exhaust coming from that side but cannot pin point where its coming from. My exhaust is not in best shape, meaning that they are in pieces and has rusted away. The manifold is in good shape and thats where it seems to be coming from. Roger have you had any dealing with this problem and if so what should I do. I sprayed some WD-40 on it yesterday and today and will do so everday until the weekend when i can work on it.
Exhaust gate valve I also had my radiator recored which soved my overheating problem. After seeing the old core I was amazed that any coolant got through. The shop that did the radiator also checked the exhaust valve and said it was OK and I do get equal flow from both tail pipes. In my shop manual it says to clean it with kerosene but good old WD40 may do it. I do know that I have tried to rotate that counter weight with out the engine running and it doesn't move. With the engine running you might be able to take a long screw driver and see if will rotate. Hope that is your problem and you can free it up. I know how frustrating these things can be. Let us know how it turns out. There are other possibilities like a restriction in the old exhaust. If the old muffler is realy rotten it can cause restriction also. I also put new glass packs on mine and it runs better so restriction in any part of the exhaust system isn't good. Good luck. Roger
Roger, thanks for all your help. These things I probably would of never found out. I hope this will be it because I was waiting to solve this before I took it to the transmission shop.
My 57 was running hot this summer. Rad looked clean enough inside and I had flushed and put new antifreeze in.I pulled the rad out and got it cleaned at a rad shop. When they pressure checked after cleaning, it was full of holes.I recored with a 4 core replacement and cooling is excellent now.
I had the radiator recored a couple of month ago. I really don't think its the radiator because its not even getting hot.
Well, well. I tried moving what I think is the heat riser to open the exhaust, Which was on the other side of the spring itself. I didn't see the spring move nor do I know if its suppose to. I guess now I will take off the exhaust pipe to actually look inside of the manifold. I don't know if its opening or not. This is really bothering me. I want to say its a bad gauge but to afraid i will harm the motor. I'am not sure how to test the gauge. Boy do I need a drink.
sorry Leon, I have no idea what happened to that old book I had. You should be able to turn the shaft on the valve by grabbing the counter weight. If it's stuck you need to get it loose.
I turned it and it didnt stop the temp gauge thats why i think it not moving but im not sure thats what it is. i am out of options.
While I'm no expert on older cars the problem areas should be the same. If the engine is hot and the top radiator hose is hot, to hot to hold, but the radiator is cold it's a problem of flow. First thing I'd check is when the engine is running check the lower radiator hose to make sure it is not collapsing because the water pump is pulling the water through the lower hose and it can be pulled shut cutting off your flow. Then take your old thermostat and take the guts out to make a restrictor and install it, this will eliminate the stat as the problem. You can then take both radiator hoses loose, turn the upper hose with the opening up and pour water in it as fast as you can and see how fast it runs out the lower hose, should run out as fast as you can put it in. If the heat riser is closed or partially closed that tends to hold more heat in the engine which then has to be handled by the radiator, while this can be a contributing factor I think your problem is circulation of coolant. Dave B
Thanks Dave. The radiator does get hot its just the car hasn't been on long enough. I found that my heat riser is not turning allowing exhaust to pass through. I can turn the counter weight but that's all what turns.The flange and stem inside does not turn. I think this is my problem and hope that i can free it up. So far I used carb cleaner and PB Blaster but no luck. It's only been one day so far. I going to continue to use PB until it comes loose.
Your probably going to have to remove the manifold to fix this. The butterfly must be reattached to the shaft for it to be sure and stay open when the engine heats up. Or unless your going concours resto you can eliminate it altogeather. Just slows down the warmup proccess of the engine, no one even thinks about them when they install headers do they? ou: Dave B
Ok, so what you are saying is I don't need the flange at all? Because i could just break off the flange and leave the rest without taking the whole manifold off.
Don't need Agree that you don't need it unless you plan to do a lot of winter driving. I don't. Got curious about mine and started it up to see what the counter weight did. I now believe my gate inside the manifold had already been removed. Don't know what it looks like, maybe some more experienced mechanics can tell you. Sounds like you can see in the end of the manifold on yours. After my engine had warmed up a little I was able to turn the weight both ways and didn't get any reduction in exhaust out the passenger side tail pipe so that makes me think a previous owner had already removed the interior flapper gate thingy from the shaft that goes through from the weight to the bimetalic spring which is supposed to open it. Hope you can get out OK. You definitely don't need the thing. It's only purpose was to speed up warm up of the carburetor and engine. Roger
