41 Buick help

[Guest transslam]

Im trying to fix my overheating problem and have read about the coolant bypass valve caused problems on these cars. Mine still has the valve in it and it was stuck, I got it working but I think it may still be my problem. I read that they replaced these with a fixed orfis but I have not had any luck finding one. Anyone have any ideas on fixing this? Its mainly used for cold warm up, I'm in east tx so I don't really need it so deleting is an option for me if I can.

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[Guest 41 sedanette]

hi sorry i cant help but would just like to say i have the same car, 46s fastback 1941..love it.. good luck

[Guest Grant Magrath]

We have a 1947 engine in our 39 coupe, and that has the modified water pump without the bypass. If your bypass is working, but you're still having problems, I'd be looking at your radiator if I were you!

Cheers

Grant

[Ben Bruce aka First Born]

Grant is right, transslam. If the radiator has not been at least rodded out it is suspect. Almost all cooling problems boil down to a plugged radiator.

Ben

[Guest Tim Romans]

Just to third what everyone is saying, have a look at your radiator, especially for hints of leakage, pinholes, etc. Those can also cause it to overheat. Your car is beautiful (I have a 46 SSE fastback.)

Cheers!

Tim

[danhar1960]

Im trying to fix my overheating problem and have read about the coolant bypass valve caused problems on these cars. Mine still has the valve in it and it was stuck, I got it working but I think it may still be my problem. I read that they replaced these with a fixed orfis but I have not had any luck finding one. Anyone have any ideas on fixing this? Its mainly used for cold warm up, I'm in east tx so I don't really need it so deleting is an option for me if I can.

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Mate,

If you think you have problems now, you'll send your over heating problem into overdrive if you remove that bypass valve. It has to be there. Leave it there !!! I would concur with the others. The problem is usually (nearly always) a partially blocked radiator. It's a pain but have it rodded, not just flushed. It will be one of the best things you'll ever do for your old beasty.

Danny

[Guest Straight eight]

I switched mine to the fixed orfice modification, and it worked fine. Someone in the BCA is making and selling them. You may try the search for this site and see if it comes up. I'll keep looking. As I recall the fellow below either has or can manufacture the modified thermo housing per Buick specifications.

I purchased the thermostat housing P/N 1335319 from Rivsgr8@aol.com Here are previous examples of others with your problem. http://forums.aaca.org/f115/1939-buick-special-cooling-problems-172564.html

Cliff

Edited June 16, 2012 by Straight eight (see edit history)

[Guest transslam]

Talked with a guy from Bob's Automobilia who was familiar with the thermostat housing problem and he told me a lot of people knock a freeze plug in the bottom of it with a 3/8 or 1/2" hole drilled in the middle and that the valve's primary use was for cold engine warm up. Im in east tx where engine warm up is not a issue. So im going to give that a try.

[Buicknutty]

If I am understanding you correctly, the bypass valve controls the water flow to heater and defroster cores, if your car has both, and lets one shut the flow off during the warm months. These valves tend to leak, and that is often the issue with them, but I wouldn't expect it to have much effect on the cooling of the engine.

On my '41, the water passages in the block still had a LOT of crap in them and the back part was the worst, and that was after a couple of serious flushes. I knocked all the frost plugs all out and spent considerable time cleaning and flushing.

70 years is a long time for stuff to accumulate, and if yours hasn't been done, it will be due for a good cleaning.

My rad was also quite plugged, and unfortunately I needed a recore.

Keith