Is 160F to cold for a L239 ???

Turdmagnet · Veteran Member

Is 160F to cold for a L239 ???

Canadian Poncho · A Poncho Legend!

I remember reading somewhere that it's good for a flathead 6 to run a little hot as they are susceptible to sludge if they run cool.

Fitz · Guru

You can use as you wish the 160 or 180 degree. 20 degree hurt anything. At the time, the 160 degree help driver in hot traffic, adding some longer time to going out traffic without hot engine stalling. The 180 was use to have a hotter heater in winter. All this thermostat thing are gone today with new «perfect» car....

Fitz.

CdnGMfan · Canadian Poncho Superstar!

I know that my 1967 has a 195 degree themostat from the factory, replacing the 180 degree from the earlier models. Of course to run the higher stat you have to have it sensing in an area that sees extremes and does not isolate the extremes from the stat ( like the cylinder head). I guess the capacity and effectiveness of the rest of your cooling system have to be considered if you want to run a hotter stat. Your rad cap should be set to open at 15 psi; if pressure is too low you have a lower boiling point and lower efficiency at transferring heat; too high and you could blow a hose or worse, a head gasket.

Captain Beaumont · Poncho Master!

Welcome from Edmonton,are you into cars?

52Chieftain · Veteran Member

Turdmagnet wrote:
When I got my 51, I followed to original manual recommendation of running a 160F thermostat in it - never had any issues but noticed it only showed about 1/4 on the temperature gauge (no actual temp markings on dial). I've recently done some work on it and guess I have a coolant leak somewhere because the other day on the way home from work it was reading as high as 3/4 on the gauge. The funny thing was I noticed it seemed to be running much better when hotter - she just wanted to go, if you know what I mean. When I got home, the water level was way below the top of the core section of the rad - took about 3 litres to get it back to normal level. Took her back out after filling it, and gauge was back to 1/4 reading.
I'm going out to see if I can find my leak, but was wondering whether I should put a hotter thermostat in it. What do you guys think ??? The majority of my driving is all highway - very seldom am I in city traffic.
In Canada the better thermostat for the flat six is a 180 deg thermo. Believe it or not the 180 will cool better this has to do with thermodynamics. It is all about ambient temperature differences between the coolant and the air temp. I will not bore you with the theory.
The main causes of overheating for the flat six is the build up of sludge in the cooling system. In the old days it was common to have the cooling system flushed after every 10,000 miles and new antifreeze put in. The other cause of overheating was calcification in the radiator cooling tubes. When this happened , we would take the rad out to a rad shop and have both tanks taken off and the tubes rodded with welding rod. Then the tanks were soldiered back on and all other leaks in the rad were repaired.

I have updated the driveline so I'm running about 1700rpm at 55mph - motor rarely sees above 2000rpm between shifts. Does this have anything to do with the "cooler" running temperature ?
The water pump will circulate faster or slower depending on your rear end ratio (different engine RPM), but should have no real effect on cooling. At this speed it is air flow through the rad the does the cooling the fan will have no effect. The engine fan is for low speed and stopped conditions. That is why it is important to keep the rad cooling fins clean from bugs and weed fluff.
I hope this helps from an old retired GM mechanic. TC

-- Edited by 52Chieftain on Thursday 20th of October 2011 12:04:36 PM