1936 Buick Over heating problem HELP!

[vtwintony]

My 36 Buick coupe is over heating but it is very gradual. I drove it about 60 miles south of here

and it starts out at about 170 deg and very slowly creeps up. at about 25 miles it's up to about

190 then at about 50 or so miles it at about 205. If you get off the highway it will shoot way up to

220 or higher unless you keep the RPMs up to keep the fan going fast enough to keep it cooler. I have an after market gauge on it to keep track of the problem. Then she likes to boil over when you shut her down. On the other hand, I can run around town even jump on the highway for 10 miles and not have any problem even after I shut it down. Any one have any ideas. The radiator has been swapped out and put back because it didn't change things. The timing I think is good. What am I missing. There is a valve going to the heater but dosen't change things on or off. HELP!

Tony

[Mark Shaw]

There are several things that could be the cause of your problem. The radiator is always the first suspect, but here are two inexpensive things to check first.

Check your hoses, especially the lower hose. It may collapse from the pump suction after it warms up. (That would explain why it takes awhile). It should also have a spiral wire inside it to prevent you from squeezing it together with your fingers when it is warm.

You also indicated that "You think" the timing is OK. Try advancing the timing a bit and see if there is any difference.

[vtwintony]

Mark,

I checked the hoses and the spring inside is present and I have played with the timing

without much luck. I'm just lost.

Thank you!

Tony

[Steve_bigD]

Usually this gradual overheating is due to flow restriction in the cooling system and as the engine generates more heat at higher RPMs the temp climbs. The first suspect is the radiator. I had such a problem with my 38 special and had the radiator boiled out but it didn't help much. I then had it rebuilt with a heavy duty core and that solved it.

Other things that could cause this other than what was already mentioned are:

Massive sludge buildup in the engine (I have seen a 248 special engine have the rear two cylinders completely blocked with hardened sludge. Had to be chiseled out)

Eroded vanes or internal housing on the water pump.

Slipping fan belt.

Missing bypass valve. Buick used a spring loaded bypass valve in the thermostst housing to circulate coolant when the engine is cold. If the valve is missing or the spring weak it will allow coolant to circulate back through the engine block partially bypassing the radiator. Many Buick engines have had this valve removed along with the thermostat by unknowledgable backyard mechanics trying to get more coolant flow.

Missing thermostat. This could allow a fast enough flow to cause cavitation which reduces cooling transfer.

Water transfers heat better than antifreeze so in the summer you can use plain water with a can of water pump lube/anti-rust added. In the winter go back to antifreeze which should be OK for cooling in the cooler temps.

Lastly, in you experience a sudden increase of temperature upon stopping after a high speed run it could be a leak from the combustion into the cooling system. I also has this problem. Turns out I had two cracked valve seats but it could also be caused by a bad head gasket. This will also cause high speed overheating and foaming of the antifreeze (not plain water). In my car the pressure from the conbustion leak got so high after a high speed run that it pushed coolant out of the overflow tube.

Hope this helps.

Steve D

[Fred Rawling]

Have you checked the timing. Sometimes too far advanced will cause it to heat up.

[Paul White]

On 10/27/2006 at 7:43 AM, Steve_bigD said:

Usually this gradual overheating is due to flow restriction in the cooling system and as the engine generates more heat at higher RPMs the temp climbs. The first suspect is the radiator. I had such a problem with my 38 special and had the radiator boiled out but it didn't help much. I then had it rebuilt with a heavy duty core and that solved it.

Other things that could cause this other than what was already mentioned are:

Massive sludge buildup in the engine (I have seen a 248 special engine have the rear two cylinders completely blocked with hardened sludge. Had to be chiseled out)

Eroded vanes or internal housing on the water pump.

Slipping fan belt.

Missing bypass valve. Buick used a spring loaded bypass valve in the thermostst housing to circulate coolant when the engine is cold. If the valve is missing or the spring weak it will allow coolant to circulate back through the engine block partially bypassing the radiator. Many Buick engines have had this valve removed along with the thermostat by unknowledgable backyard mechanics trying to get more coolant flow.

Missing thermostat. This could allow a fast enough flow to cause cavitation which reduces cooling transfer.

Water transfers heat better than antifreeze so in the summer you can use plain water with a can of water pump lube/anti-rust added. In the winter go back to antifreeze which should be OK for cooling in the cooler temps.

Lastly, in you experience a sudden increase of temperature upon stopping after a high speed run it could be a leak from the combustion into the cooling system. I also has this problem. Turns out I had two cracked valve seats but it could also be caused by a bad head gasket. This will also cause high speed overheating and foaming of the antifreeze (not plain water). In my car the pressure from the conbustion leak got so high after a high speed run that it pushed coolant out of the overflow tube.

Hope this helps.

Steve D

This threat was a great help in diagnosing my overheating problem, I found the bottom hose had no spring in it. Swapped it for one that did and it now runs under load, on a hottish day at a steady 160. Good advice it timeless I suppose....

Edited April 9, 2018 by Paul White (see edit history)

[BuicksBuicks]

My '37 248 had a far  FAR worse overheating problem.  Five miles was my maximum mileage per drive before overheating. Then I used "Evapo-Rust", a radiator additive that dissolves rust. After two hours at high idle and I couldn't make my engine overheat with the most strenuous driving. Amazon carries it and probably auto parts stores. Its an outstanding product.

 

I am in no way connected to the manufacturer of this product.

[suchan]

Good advice here. I had a  '38 Special that would overheat on the highway, but not around town. Needed a new radiator. To help avoid boilover on shutoff, let the engine run for a few minutes after you stop so the engine can cool off gradually.

[dibarlaw]

I also did all the above with my 1937 Special. (The place that did some driver restoration work said that they cleaned the block and radiator). On our way to the Springfield Nationals  the radiator got stopped up. (We only made 57 miles from home).Residual sludge in the block purged itself into the clean radiator. It was then packed up good. My radiator guy could not clean it out again.  I did the Evapo rust treatment (cycled 3 times) and had a new heavy duty radiator core installed.

 

                                                                                                                                 What came out was black as coal.

  What I strained out of the recycle tub.

No overheating on my 2500 mile round trip to the Nationals at Brookfield. Rarely would reach 180 after an all day run in 95 degree + temperatures. AND... I added a GANO in line filter.

 

I never want to pull that  radiator again!

 

 

Edited April 10, 2018 by dibarlaw (see edit history)

[Morgan Wright]

After reading this thread, I'm going to do the evapo-rust treatment on my '40. I know it has tons of rust inside and guess it's only a matter of time before something gets clogged.

 

"If it ain't broke, fix it before it is"