L36 Thermostat recommendation

[Greg L.]

What temp thermostat would you guys recommend for a 69 L36? The manual recommends a 195F but I was wondering if a 180F might be better.

Any thoughts?

Greg Linton
#45455

[Michael M.]

Re: L36 Thermostat recommendation

I personally use a 180f in my 68 L36, and it has been fine. I typically use a Robertshaw brand thermostat or one of similar design.

[Michael M.]

Re: L36 Thermostat recommendation

I personally use a 180f in my 68 L36, and it has been fine. I typically use a Robertshaw brand thermostat or one of similar design.

[Chris H.]

Re: L36 Thermostat recommendation

I'd go with stock recommendations. If you drive around in cold weather like me, you'll appreciate the hotter thermostat. If your motor pings a lot in warm weather, you may want to consider a cooler thermostat.

[Chris H.]

Re: L36 Thermostat recommendation

I'd go with stock recommendations. If you drive around in cold weather like me, you'll appreciate the hotter thermostat. If your motor pings a lot in warm weather, you may want to consider a cooler thermostat.

[Dan P.]

Re: L36 Thermostat recommendation

I use a 185 in my '66 L36 and it runs very cool. If my experience is an accurate guide, rather than going with the factory recommended 195, I'd suggest you use a 185 for your '69 since it doesn't have quite the air flow of a mid-year. Also remember higher thermostat temps were recommenced primarily to aid in reducing emissions.

[Duke W.]

Re: L36 Thermostat recommendation

When GM increased thermostat opening temperatures to 195F on emission contolled engines, they also increased the fan clutch engagement temperature, so in hot weather/low speed driving the coolant temperature will likely go above 180 because the fan clutch will not engage until radiator outlet air temperature reaches a higher value than with 180 degree coolant.

It takes in the range of 205 coolant temperature to heat up the radiator exit air enough to tighten the clutch versus about 190 on non-emission control engines with 180 thermostats.

There's really nothing wrong with higher coolant temperatures. In fact, GM Product Performance has been saying for 30 years that higher cylinder wall temperature lowers piston and ring friction.

NASCAR teams like to keep the coolant at about 210 and they don't pull tape off the inlets until it reaches 230.

My recommendation is to stick with a 195F thermostat.

Duke

[Greg L.]

Re: L36 Thermostat recommendation

Thanks guys. I have both temps and it sounds like it's six of one and half a dozen of another...

For engine break-in though would it make any difference which one I used?

[Duke W.]

Re: L36 Thermostat recommendation

No.........