165 degree T-stat OK?

[White75]

Is a 165 degree thermostat OK to use? What problems if any could it cause.

 

[JohnZ]

Is a 165 degree thermostat OK to use? What problems if any could it cause.

165* thermostats were used in the 40's and 50's for cars with the old alcohol-based anti-freeze that would boil off at 180*.

If you're trying to cure a cooling problem, the thermostat has nothing to do with it - it only controls the MINIMUM operating temperature, so the heater works in the winter. Operating temperature upper limit is controlled by the radiator and the airflow through it, as the thermostat is wide open most of the time.

Using a 165* thermostat (if your cooling system is efficient enough to cool the engine down to that level) is a bad idea; the oil will never get hot enough to boil off the moisture condensate and blow-by contaminants in the pan which make the oil acidic and tend to form sludge.

You might want to read this:

http://www.lbfun.com/warehouse/tech_info/cooling system/cooling.pdf

 

[Copdogcorvettes]

Is a 165 degree thermostat OK to use? What problems if any could it cause.

There is nothing wrong with using a 165 stat; if you live in an area that the temp is high year round.

I'm an old school guy; the rule has always been Fords run their best at around 145 degrees. Chevy SB's Run their best at 185-195 degrees. All this means is to get the best from your motor it needs to run at the higher temp. I use a 185 degree stat in my 78'.

Gary

 

[petes74ttop]

I use a 'Robert Shaw' or a 'Mr Gasket' 180* they both come with small holes to prevent an air lock and they are made to 'Fail' in the open position.

 

[White75]

Thanks for the replies. I don't think there is an overheating problem. when I got it the coolant was low and the thermostat was stuck open. I haven't driven it enough yet to see if there is a cooling problem (although the rust covering the water pump leads me to believe that something may be up (but could be because it doen't appear to have been painted)
Living in Houston, TX it does get hot and with some stop and go traffic to be expected I though that erring on the side of caution and getting a lower temp T-stat would be a good idea. I'm going to keep an eye on the temps and see where they ride.

 

[Vettehead Mikey]

If you do actually have an overheating problem a lower temp thermostat won't fix it.

 

[Tuna]

What JohnZ said - the stat only controls the minimum temperature the coolant will stabilize at. The stat also affects the way the heater works and the minimum temperature the oil will see (once stabilized). Sometimes it's better for the oil to have a hotter stat and allow the over all engine temp to get above 180 faster just to evaporate moisture that gets in the oil and engine.

If you live in a warm area (and Houston, Tx probably qualifies) the 165 stat shouldn't worry you too much as far as the heater is concerned or the oil temperature.

Now if the current stat is sticking closed and causing overheating, then you gotta replace it. If it sticking open it has to go also as that would keep the engine from warming up properly.

 

[White75]

I had purchased and installed the 165 before I made this post. I got the Mr Gasket one which is supposed to fail in the open position. I got to run her a bit yesterday when getting inspected and registered (can drive her legally now) and the temp was right under 200 on the highway and in stop and go traffic (damned construction).
The old t-stat was a 180 and was the original one but the spring on it was broken.
Thanks!