sloperlad Posted January 3, 2022 Share Posted January 3, 2022 Have noticed the 38 temp gauge sits between half and 3 /4 , on a highway run at 50 - 55mph. I realise these old chariots have big iron blocks which generate a lot of heat and have flushed the radiator and block, added a high quality engine coolant, climate correct as where I abode is usually warm. Is this a normal operating temp as original fan is on vehicle or has anyone had a thematic fan installed and run at a lower temp. Link to comment Share on other sites More sharing options...
5219 Posted January 3, 2022 Share Posted January 3, 2022 I don't think that there is a good answer to this question unless the actual temperature of the coolant is known. The gauges, especially after all of these years, are not very precise. The owner's manual for my 1940 LaSalle warns that the gauge may read "Hot" during exceptionally hard driving and that this is not cause for alarm. If you are concerned, you need to measure the temperature of the coolant. 2 1 Link to comment Share on other sites More sharing options...
michealbernal Posted January 3, 2022 Share Posted January 3, 2022 You might consider getting one of those inferred heat sensing thermometers and doing some readings on the block and radiator core looking for hot or cold areas. This would let you know if you have clogged cooling passages and where they are. I have found that many times on older engines the rust and corrosion has a way of setteling out and becoming hardened in place and it requires the removal of the freeze plugs and prying the rust/corrosion loose with a long thin metal rod and then flushing it out. Good luck 1 Link to comment Share on other sites More sharing options...
EmTee Posted January 4, 2022 Share Posted January 4, 2022 21 hours ago, sloperlad said: on a highway run at 50 - 55mph. At this speed the fan is irrelevant. Based on my experience with my '38, I'd look at the radiator. If flow through the radiator is insufficient the temperature will go up as the engine is working hard and the pump is trying to push a lot of water. If blockage is really bad, as in my case, coolant will back up and be pushed out of the overflow tube. Is there any evidence of that with your car? 3 Link to comment Share on other sites More sharing options...
Bloo Posted January 4, 2022 Share Posted January 4, 2022 There is a bypass valve near the thermostat that can bypass too easily and cause the engine to run hot. It can be replaced with a core plug with a hole drilled in it. That was Buick's own fix from a service bulletin. Someone in here should know the details. 3 Link to comment Share on other sites More sharing options...
sloperlad Posted January 4, 2022 Author Share Posted January 4, 2022 8 hours ago, EmTee said: At this speed the fan is irrelevant. Based on my experience with my '38, I'd look at the radiator. If flow through the radiator is insufficient the temperature will go up as the engine is working hard and the pump is trying to push a lot of water. If blockage is really bad, as in my case, coolant will back up and be pushed out of the overflow tube. Is there any evidence of that with your car? No evidence. Radiator is clean as per engine block. Not sure if these vehicles have thermostat. Is this temp reading I am getting going to effect the motor or is it normal. Daytime temp is about 28 to 32 degrees centigrade . Link to comment Share on other sites More sharing options...
sloperlad Posted January 4, 2022 Author Share Posted January 4, 2022 Just now, sloperlad said: No evidence. Radiator is clean as per engine block. Not sure if these vehicles have thermostat. Is this temp reading I am getting going to effect the motor or is it normal. Daytime temp is about 28 to 32 degrees centigrade . Maybe a rebuild could be in order as it looks like came out of a old tractor. Link to comment Share on other sites More sharing options...
Ben Bruce aka First Born Posted January 4, 2022 Share Posted January 4, 2022 3 hours ago, sloperlad said: No evidence. Radiator is clean as per engine block. Not sure if these vehicles have thermostat. Is this temp reading I am getting going to effect the motor or is it normal. Daytime temp is about 28 to 32 degrees centigrade . Of course it has a thermostat!! The radiator is partially plugged. Ben Link to comment Share on other sites More sharing options...
rodneybeauchamp Posted June 20, 2022 Share Posted June 20, 2022 Hi John, the radiator is a fresh recore using an industrial core which matched what a PO had fitted. A PO had attempted to repair the water pump but it ended up putting the fan into the radiator at 5.30 in the morning which I did not appreciate. At a cost of about AUS$1000.00 a reputable shop redid it for me. I also replaced the fan pulley and fan (fractionally larger from Ron Noonan) as the radiator made a mess of it. I also did the thermostat bypass modification (see my blog on this forum) with a tested thermostat. Flushed the block. Cooling system should be fine. Rodney 😀😀😀😀😀😀😀 Link to comment Share on other sites More sharing options...
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