160 degree thermostat
Safety Car
Joined: Feb 1999
Posts: 3,504
Likes: 4
From: Mexico Beach FL
Originally Posted by Tom Piper
Those with "conventional flow" cooling systems like the L98 should ignore this post.
Quote from the linked article above:
"There is a range where both optimum performance as well as minimal wear share similar characteristics. That number lies in the 175-180 degree range as shown by the overlap in the chart which correspondingly requires a 180 degree thermostat. "
When warmed up with a 160 degree thermostat, the lowest "block" temperature (in the winter) my LT1 runs is 172 degrees. Most of the time my LT1 block temperature in Florida is about 185 degrees with a 160 degree thermostat due to reverse flow. The heads, however, are lower in temperature.
So, according to the article, I am very close to the "optimum performance with minimal wear" area with a 160 degree thermostat.
In addition, I should point out I have AFR heads. And, I noticed a higher temperature with AFR heads vs stock heads. So, I am not sure how this would affect "block" temperature with OEM heads....it may be too cool.
But, for my application, the 160 degree thermostat is almost ideal.
Tom Piper
Quote from the linked article above:
"There is a range where both optimum performance as well as minimal wear share similar characteristics. That number lies in the 175-180 degree range as shown by the overlap in the chart which correspondingly requires a 180 degree thermostat. "
When warmed up with a 160 degree thermostat, the lowest "block" temperature (in the winter) my LT1 runs is 172 degrees. Most of the time my LT1 block temperature in Florida is about 185 degrees with a 160 degree thermostat due to reverse flow. The heads, however, are lower in temperature.
So, according to the article, I am very close to the "optimum performance with minimal wear" area with a 160 degree thermostat.
In addition, I should point out I have AFR heads. And, I noticed a higher temperature with AFR heads vs stock heads. So, I am not sure how this would affect "block" temperature with OEM heads....it may be too cool.
But, for my application, the 160 degree thermostat is almost ideal.
Tom Piper
With my AFR heads, my oil temperatures run about 15 degrees hotter than the OEM heads -- I'm guessing that's due to more spring pressure and a higher lift cam.
So, with a 160 degree thermostat in my LT1, even in the winter when my block temperature averages its lowest of about 181 degrees, my oil temperature reaches at least 208 degrees even on a short run.
I'm guessing that the block temperature at a minimum of 172 degrees (and usually 180) coupled with the oil temperature reaching at least 208 degrees is why my engine with 50K miles when I took it apart had no measurable wear on the cylinder walls -- in fact, they still had the cross-hatch pattern the entire length of the bore.
My point of all this is: I don't think that there is a "one size fits all" scenerio here. It depends on whether you have conventional or reverse flow and what modifications you have. I certainly would not want even a 180 degree thermostat in mine -- my oil termperatures running easy on a cold day would be at least 220 to 225 degrees....on a hot day, I would be in the 240 degree range before I was above 2K rpm.
Tom Piper
Last edited by Tom Piper; Oct 11, 2005 at 06:35 PM.
Team Owner
Joined: Sep 2002
Posts: 22,209
Likes: 12
From: OBAMA IS HITLER
Tom, I've got AFR heads as well, and the hottest I ever ran in the dead of summer was 215* for oil temps. This is with my modded L98. My coolant never gets much past 195* (unless I turn on the a/c then it skyrockets). I have a 180* t-stat and my fans are reprogrammed to operate real close to 180 as well.
Safety Car
Joined: Feb 1999
Posts: 3,504
Likes: 4
From: Mexico Beach FL
Originally Posted by Hot Rod 90
Tom, I've got AFR heads as well, and the hottest I ever ran in the dead of summer was 215* for oil temps. This is with my modded L98. My coolant never gets much past 195* (unless I turn on the a/c then it skyrockets). I have a 180* t-stat and my fans are reprogrammed to operate real close to 180 as well.
With a 160 degree thermostat, like you, without the AC, on a hot day (98+ degrees), I rarely get above 195 degrees block coolant temperature (I'm specifying block temperature because, unlike the L98, my heads are cooler than the block). However, I never see oil temperatures, in the summer, under 215. If I run it, even slightly hard, my oil temperatures go to 230 easily....keep in mind, my block temperature is at 195 the entire time, meaning my heads are running less than 195.
On a hot day with the AC on, my oil temperatures can easily reach 230 to 240 at idle!!
Tom Piper
Last edited by Tom Piper; Oct 11, 2005 at 06:52 PM.
