Chevy Nova Forum banner

1 - 8 of 8 Posts

·
Premium Member
Joined
·
2,519 Posts
Discussion Starter #1
I have a 160* thermostat, and it was 40* out yesterday. Now that i have this aluminum radiator it meant my coolant temp got down to around 150* several times during stop and go driving.

I'm assuming this is too cool, but before I switch it to a 180* thermostat, what are the downsides of running too cold?

Thanks
 

·
Premium Member
Joined
·
3,257 Posts
One downfall of running too cool is that the oil never gets hot enough to boil out any moisture that condenses in the crankcase. You start to build up the dreaded milkshake look in the pan and valvecovers.
 

·
Registered
Joined
·
9,952 Posts
Dr. Terry McFadden teaches a course at UAF called Arctic Engineering. It is a gold mine of tips, solid engineering, common sense and often little-known facts about coping with day-to-day problems encountered in cold climates.

If you don't like puzzles, skip the next paragraph, but I'm including it here to show the kind of problem that McFadden gives his class. It's a classic of basic engineering rationale, and requires only rudimentary mathematics and a little insight to solve. For malingerers, the answer is given at the end of this column. The problem reads:

"Some experts estimate that the wear on the rings of an internal combustion engine is as high as 0.001" per 1000 miles of operation when the oil temperature is below 170 degrees F. If the maximum allowable wear is 0.006", how long can you run your engine when the oil temperature is below 170 degrees before you wear it out?" (A 6-to-1 engine-to-wheel reduction ratio, an average running speed of 3000 rpm, and 14-inch wheels 28 inches in diameter are assumed.)

The point of this problem is to stress that by far the greatest amount of engine wear takes place before the oil is warmed up. The amount of wear that occurs afterward is insignificant by comparison.

It can be appreciated, therefore, that it is important to warm the oil, as well as the engine block. An engine that is kept warm with a circulating heater or with one that is plugged into the block can usually be started easily, but the oil is not heated and it provides very little lubrication at first. Consequently, the most engine wear occurs during the few minutes immediately after starting.

The ideal situation, of course, is to have a heater for both the engine block and the oil pan. Owners of cars with air-cooled engines like the old Volkswagen beetle know that the oil pan heaters are the only kind of heater that the engine will take (aside from dipstick heaters, and the less said about them, the better).

The answer to the problem given above is that the engine would be technically worn out after just 144 hours of cold operation. Realistically though, those 144 hours represent an awful lot of cold starts.


From http://www.gi.alaska.edu/ScienceForum/ASF7/747.html
 

·
Premium Member
Joined
·
2,519 Posts
Discussion Starter #4
Thanks for the response guys.

And I've been doing some research. It seems that running too cold also leaves carbon deposits in the combustion chamber and on the valves :( I'll definitely be switching to a 180* very very soon.
 

·
Registered
Joined
·
9,952 Posts
I would go straight to a 195° thermostat for winter driving. If your car runs 150° with a 160° thermostat, you want to warm it up at least 30°.
 

·
Premium Member
Joined
·
8,405 Posts
I second the statements about cold operation. As noted most of engine wear occurs when the engine is cold. Despite conventional wisdom about keeping fluids as cold as possible, prolonged cold operation is not beneficial.

You are are also measuring coolant temp which may not be the whole story.
Engine oil temp should be at least 212F before running the engine hard. As noted this is to be sure to boil off condensation. 220-230F is optimum for oil viscosity and flow.
Since there is often a 30 degree difference between coolant tem and oil temp, a 195 thermostat is better for a daily driver especially in the winter months.

If you want to get something cold then cooling off intake air flow will yield performance gains.
 

·
Registered
Joined
·
1,559 Posts
Mike Goble said:
I would go straight to a 195° thermostat for winter driving. If your car runs 150° with a 160° thermostat, you want to warm it up at least 30°.
As a side note, it is well known that manufacturers use a 195 thermostat to aid in cleaner emission output. We had been swapping to 180's for years to try and have a slightly cooler intake. A friend (and fellow mechanic) had told me that a engine with 195 thermostat would burn less fuel. My dad tested this theory and said he saw an improvement in fuel economy with the 195 on every vehicle he tested.
 

·
Registered
Joined
·
32 Posts
tpinovaII said:
As a side note, it is well known that manufacturers use a 195 thermostat to aid in cleaner emission output. We had been swapping to 180's for years to try and have a slightly cooler intake. A friend (and fellow mechanic) had told me that a engine with 195 thermostat would burn less fuel. My dad tested this theory and said he saw an improvement in fuel economy with the 195 on every vehicle he tested.
Wow, these are things i never really thought about. never knew running to cold was bad..:confused: and here i was bragging that my car never got above 155..:( goes to show you learn something new every day...thanks for the info.
 
1 - 8 of 8 Posts
Top