Opinions needed
Instructor
Joined: Apr 2011
Posts: 161
Likes: 17
From: NW CT
Anyway, getting back to the original question: YES 160* T stat is fine. Its not likely the temp will stay there but its a start. And to the poster that is concerned about sludge: That occurs from not allowing the engine to ever reach normal temps. It is NOT from constant 160-180 temps. Sludge can form when short drives, such as a few blocks to the store or work every day and the engine never burns off condensation.
Note the engine to the left of this post. Does that look like an engine that would enjoy being over 200 degrees?
Hell no! It prefers 160-180. And the owner prefers that also.
Note the engine to the left of this post. Does that look like an engine that would enjoy being over 200 degrees?
Hell no! It prefers 160-180. And the owner prefers that also.
For a engine that came stock with a 195deg thermostat it is never reaching normal temp if it never gets past 170.
Its apples and oranges to compare your motor to a low compression factory motor. I just don't think 160-170 is hot enough to really drive moisture out of the oil. From what Ive observed on a stock engines with an oil temp gauges is that the oil temp is just slightly above water temp at low load. So just puttering around with a 165 water temp the oil might only be at 175.
Water boils at 212. So in my street car I would shoot for 195deg water temp to get the oil temp just over 212 to boil the moisture out.
I don't think I am alone in this line of thinking. Go see what the GM engineers picked even before the "smog" times. 1968 327 OE temp: 195F. 1968 427 OE temp: 195F
If we where not talking about a street car and this was a modified high compression motor where detonation is the biggest worry above all else then that would be a totally different story.
I'm not google or a cooling system scientist. This is just how I figure it
Thread Starter
Instructor
Joined: Sep 2018
Posts: 165
Likes: 64
From: Lakeville MN
Well proof is in the results, I had a 160 thermostat and the coolant temp sat right at 160, even stuck in traffic. I just put in a 195 stat a couple hours ago and took it out into stop and go traffic and it sits right at about 195, right where it should. The above discussion convinced me that a little more heat in the engine is a good thing.
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,118
From: Crossville TN
I would agree that normal operating temperature should be in the 180-190*F range. And that would be expected with a stock 350 V8 with 180*F or lower T-stat installed.
If the vehicle has swapped radiators for one with much more cooling capacity, it IS possible for the fully warmed engine to run at T-stat rated temps. But, that is certainly NOT the normal for a stock configuration cooling system.
And, I stand by my statement that if a cooling system with a 180*F T-stat installed has a stable running temp of 190*F or higher, it will STILL run at that temperature with a 160*F T-stat installed. The T-stat sets the LOWEST running temp possible in any cooling system. But, it does NOT limit the actual running temperature of the engine. That is established by the actual capability of the cooling system's capacity to remove heat.
If the vehicle has swapped radiators for one with much more cooling capacity, it IS possible for the fully warmed engine to run at T-stat rated temps. But, that is certainly NOT the normal for a stock configuration cooling system.
And, I stand by my statement that if a cooling system with a 180*F T-stat installed has a stable running temp of 190*F or higher, it will STILL run at that temperature with a 160*F T-stat installed. The T-stat sets the LOWEST running temp possible in any cooling system. But, it does NOT limit the actual running temperature of the engine. That is established by the actual capability of the cooling system's capacity to remove heat.
Safety Car
Joined: Oct 2007
Posts: 4,222
Likes: 1,080
From: South Florida
Wat
If the T-stat is 160
and the engine is sitting at 161*F+ on the inlet
it means the radiator/fans/airflow is insufficient to carry enough heat away to close the T-stat (bring temp down)
It means the entire cooling system needs to be 'fixed'.
Not because you want the water 160, but because it clearly has a problem rejecting heat...
If the T-stat is 160
and the engine is sitting at 161*F+ on the inlet
it means the radiator/fans/airflow is insufficient to carry enough heat away to close the T-stat (bring temp down)
It means the entire cooling system needs to be 'fixed'.
Not because you want the water 160, but because it clearly has a problem rejecting heat...
Had a 1976 L-82, 4-sp
Joined: Mar 2011
Posts: 5,338
Likes: 1,213
From: Some days your the dog and some days your the hydrant.
Royal Canadian Navy
And, I stand by my statement that if a cooling system with a 180*F T-stat installed has a stable running temp of 190*F or higher, it will STILL run at that temperature with a 160*F T-stat installed. Yep! But if it's running higher than 190* with a 180* ts, then there is a cooling problem e.g. rad is too small or scaled up. If the rad has a high capacity, then a 160* ts will keep the engine at 160*-ish. The OP just posted his results and I don't doubt his results whatsoever.
The T-stat sets the LOWEST running temp possible in any cooling system. That's one function of a ts but there's more to it than that. "Lowest" running temp is the "normal" engine operating temp. Also decreases warm up time, prevents engine from overheating. And, it sets the engine's operating temp vice the temp in the cooling system. Not all heat generated by an engine is removed by the coolant.
But, it does NOT limit the actual running temperature of the engine. Yes, it does.
That is established by the actual capability of the cooling system's capacity to remove heat. The majority of heat removed from the engine is done by the (properly sized/capacity) radiator i.e. heat exchanger, by cooling the coolant heated by the engine and lowering the temperature of the coolant for re-entry into the engine to displace the heated coolant. This process is controlled by the ts by varying the opening the ts's valve to maintain a near constant engine temperature dictated by the ts's rating.
Pretty simple for most folks to understand but for some reason some folks don't get it. In a nutshell, to remove more heat from an engine, put in a bigger rad. To run an engine at 160* will require more heat removal but easy to accomplish by putting in a bigger rad. If I want my engine to run at 500*, for arguments sake, I would use a ts rated at 500* and use a much, much smaller rad. Maybe the size of my heating core, lol!
Heel & Toe
Joined: Jun 2019
Posts: 22
Likes: 2
From: Cincinnati, Oh
Interesting thread. So my 2 cents is this. I've been a mechanic for over 40 years. I've built drag cars and crewed on top alcohol cars. In our drag car engines with SBC's, we would take out the T-stat and install a washer to restrict the flow slightly. Also what ended up working well was to take the guts of a t-stat out. That sufficiently testricted flow for what we wrre trying to achieve, returning to the pits under 210 derees.
That being said, a stock cooling system is design with a maximum capacity, plus a certain percetage. I know for a fact that when a thermostat sticks open, the egine will run cool., providing the cooling system was in good condition. I haven't studied this for a while but i know the thermostat will regulate itself to maintain the temperature it is designed for. A 160 will maintain 160 degrees, a 185 will maintain 185 and so on. Engines run hot due to other conditions. Modified engines will run hotter, i think most readers here understand that. I think th OP actually answered the question, he installed a 195 stat and the engine ran at....... 195.
Now lets discuss thermal dynamics and motor oil viscosity....... 😀
That being said, a stock cooling system is design with a maximum capacity, plus a certain percetage. I know for a fact that when a thermostat sticks open, the egine will run cool., providing the cooling system was in good condition. I haven't studied this for a while but i know the thermostat will regulate itself to maintain the temperature it is designed for. A 160 will maintain 160 degrees, a 185 will maintain 185 and so on. Engines run hot due to other conditions. Modified engines will run hotter, i think most readers here understand that. I think th OP actually answered the question, he installed a 195 stat and the engine ran at....... 195.
Now lets discuss thermal dynamics and motor oil viscosity....... 😀
