Anyone have any thoughts on running water temp at 160 degrees instead of 180. I got my 350/350 with a 160 thermostat installed. The oil pressesure ran a little high. I thought it best to go to a 180 degree thermostat, and bring the oil pressure back to a more normal range. Also, I think oil temperature runs about 15 degrees hotter than the water temp. Therefore, with a 180 degree thermostat the oil temp should be about 195 degrees, a good temperature for oil lubrecating properties. The other side of the coin may be that cooler water temperature means cooler (more dense) air and better power.
Any thoughts?

 

if you run synthetic oil the temp. is not as big of a factor, as it is with dino oil. as for the thermostat, may be some of the other forum members can chime in, i dont think running a 160 would matter a whole lot with regard to getting a cold air charge coming in as in it wouldnt make a difference because if the stat opens at 160 or 180 its still going to reach operating temp, its just a matter of time, if you want that cold air or fresh air coming in chop a hole in your hood or get some sort of functional cowling.

-alex

 

My only thoughts are that the engine was designed to operate at a minimum temp of 180 (or whatever the recommended thermostat temp). When you operate too far above or below the minimum recommended temp the engine will not perform optimally. I say this in reference to a daily driver....if you are racing it could be a different story...

Cheers,

Crunch

 

Thanks for responding. With the 160 deg thermostat the final operating temp of the engine cooling water really does stay lower than with the 180 deg thermostat. I may start running fake oil and go with the cooler thermostat.

 

A lower temp thermostat opens earlier and delays the engine from reaching its normal operating temperature. It really won't run much, if any cooler. It also won't keep it from overheating...just make it take slightly longer to do so.

There's really no reason not to use the 160 thermostat, just don't look at it being a magic bullet to keep the engine from running hot. What's normal for the engine to operate at is what's normal for it barring a problem such as a restriction, bad hose, etc.

 

160º t-stat is NOT good idea.
you should be running either a 180º or 195º depending on whether or not you still have all the emission equipment on your car. If the emission equipment is on than run a 195º as that is what was factory and to allow the emissions equipment to operate properly it was designed to run at higher operating temps. If ther emission equipment has been removed that you can drop down delow that to a 180º t-stat.

keep in mind that the t-stat will NOT dictate at what operating temp the motrowill go up to, it only controls the minimum operating temp and at a minimum operating temp 160º is too low and it won't allow the temp to be high enough to burn off excess vapor in the crankcase allowing condensation and sludge to form in the oil.
Pull that 160º t-stat and install one of the higher temp ones depending on how your motor is set-up.

This has been discussed and debated to death on here so you can also search for other posts and threads on this topic and will probably find papges and pages of answers. i'm surprised that anyone on here is still answering that a 160º t-stat is acceptable to run (that, and some people that still feel that it's a good idea to run without any t-stat at all! )

 

Engines ran without thermostats for years...because there wasn't any need for them--until heaters were put into cars. Then people wanted the heat sooner; hence, thermostats. Without one, the engine and cooling system will find its own balance. Generally, the lower the operating temperature of an internal combustion engine, the longer it will live. There is probably an "ideal" temperature for engine operating efficiency, but it is likely no higher than 180 deg....since that is where most manufacturers designed them to run....until emissions controls. If you are GREEN, hotter is better; of course your engine might burn up or you might get lousy mileage...but you can save the planet! Long rant for "You will be just fine if you run a 160 deg. thermostat."

 

My engine builder told me to run a 180* thermostat. My engine has forged pistons, so until the engine is hot, the pistons have more clearance than is optimal and damage could occur if the engine is run hard when still cold. He considers 160* to still be cold.

 

maybe you will be fine.............. but the car won't be, not in the long run.
It's beyond my abilities to comprehend how and why people continue to think a 160 t-stat is as good or better to run than a 180 or 195. It's not.
A lower operating temp will not make an engine last longer, and in reality if you had an engine running at 160 actual operating temp it would not last as long as one running between 180-220 because of all the sludge build-up you would get from the engine not being able to burn off excess vapors.
i'd rather run my motors at 200 rather than 160 any day of the week.

My '65 has a 180 t-stat and runs 180-190 all day long and my '78 which still has it's emissions equipment on it has a 195 t-stat and runs 195-215 depending on conditions. Both those ranges are safer temps than running at 160.

Lower operating temps being better than higher temps (to a point, I'm not suggesting that running at 240 is a good idea) is a fallacy. If it's too low it's worst.

 

I could put a 120 degree therm. in mine.....it's still going to run at 180. The 180 is usually the way to go.
Larry

 

that's correct, it probably will run at a "normal" 180 but there are cars with very effective cooling systems in them such as a higher capacity rad, puller fans, etc that could feasibly keep the car at a temp as low as the t-stat so if you had a 160 t-stat the cooling system could keep it that low although in the vast majority of cases even with a lower temp t-stat the operating temps will be somewhere between 180-210.

 

Improvements by a Hot Rodder

1-Change the thermostat from the factory early180 or later 195 to a better 160°

2-Spend the next 6 month's and umpteen dollars trying to figure out why the engine runs too hot even with an aluminum rad that is approx 30° more efficent on average than the oem.

 

Any temperature thermostat will NOT compensate for a poorly selected cooling system. Folks who think that they can throw on a large cooling capacity radiator and eliminate cooling problems don't really understand cooling systems. The radiator, pump, thermostat, etc. all have to work together. The original radiator/pump system worked very well...when the components were in good condition. And anyone on the forum can "claim" a 160 deg. thermostat will cause engine problems. But they can't prove it...because it just isn't the case. I have a 160 deg. thermostat in my '71, auto, w/ A/C coupe; it works just fine...even in 115 deg. days in Phoenix. And, yes, it is the original radiator and a direct-replacement water pump. Others may put in a 160 deg. thermostat and have their engine level off at 180 deg. That is not the fault of the thermostat, it's just that their engine runs hotter (maybe because they put in a high-flow water pump along with their standard-issue GM radiator). 160 deg. water temperature DOES NOT cause an internal combustion engine to operate poorly.

 

Guys, 7T1vette is absolutely correct, a 160 thermostat will not hurt an engine. A thermostat only dictates the MINIMUM temp an engine can run, NOT the actual operational temp. That is determined by the overall cooling system design, components used, the amount of heat being put out by the engine, ambient temps and air flow through the radiator. In nearly all normal operational conditions, an engine will end up running warmer than that 160* thermostat.

Sludge and condensation build up and is determined by OIL TEMP, not coolant temp. Most people will find that oil temp in normal use will be, something like 50* or more above (though, yes there can be exceptions) the coolant temp. That puts a 160* thermostat right at the bottom threshold of oil the temp getting up to the 212* minumum needed to boil off condensation, and that's in freezing weather where the thermostat may actually be coolant temp. In all other conditions, you can expect that running a 160* thermostat will result in oil the temp being well above that 212* minimum.

Case in point: I actually run a 160* thermostat myself in my old '57. No sludge, no sign of moisture, no problem. When I change the oil, it looks just like my new smog cars' oil, can't tell which oil came out of which car. There is just no problem here. This is real world experience, not some half baked theory.

Then we come to horsepower. If your cooling system is so robust that you could actually keep running coolant temps at or near thermostat temp, then a 160* car would make more power than say a 180* thermostat car, all other things being equal. Guys see that kind of thing all the time, when they play with coolant temps on the dyno. And one of the magazines did a test on just that a year or so ago. Sure enough, the coldest thermostat tested made the most hp. And at the same time, that cooler temp goes a long way towards helping prevent detonation. It's all good, where's the downside for non-emissions controlled hotrods?

A fair number of guys run NO thermostat, without issue. Though I personally wouldn't recommend it, because in some applications, the oil may not get hot enough to boil off the condensation.

There are more important things worry about than a thermostat being too cold.

 

yes, it's very true a t-stat only dictates minimum operating temps, see my first post in this thread and I said the same thing myself.

guys, you can argue for running a 160 t-stat all you want but if you ask the true experts (and no, i do not under any circumstances consider myself one by any means but I do listen to them and gain knowledge from them) they will all disagree with you that running a 160 t-stat is a good idea. Not one will recommend using a 160 t-stat.
Check with people like JohnZ (used to work in the Corvette engineering dept with Duntov) Lars, Tom DeWitt, etc.
I have NEVER, in post ofter post, after post ever seen them say or recommend running a 160 t-stat, they always recomend running a 180 or 195.

Do what you want with your own cars but saying and /or recommending a 160 as just as good or better is simply throwing out wrong information and misinforming people.

i'm done with this

 

Who's throwing out wrong information here? Luckily you're done with this. All you are saying is, supposed statements from others, with no facts nor data to back up what you say. I'd be interested in hearing the "experts" state the facts along with real world data to back it up, as to how a 160* can possibly be bad for a non-emissions hotrod, when actual real world experience shows otherwise. Particularly when under most operating circumstances, the thermostat is open and isn't even in play anyway.

 

If you are talking about modern era cars with computer controls....that's an entirely different issue. Just about anything built from the early 1980's and after requires a 195 deg. thermostat. Why? Not because it runs better; not because it lives longer. Because the emissions controls on those cars require 195 deg. water temp. to meet their emissions requirements. And if you change the thermostat to lower the operating temp, stuff won't work properly because the computer was programmed to reach a minimum temp before things "kicked in"..... like the lockup clutch in the transmission (automatics)...like running on something other than the base operating program....etc., etc. Whole different can of worms that has nothing to do with engine life, power production, or operating efficiency.

 

Operating temperature vs power and longevity!

 

sigh.....

supposed statement with no facts?
where are your facts?

here are some of mine:
From John Hinckley ( JohnZ here on CF), retired Chev. engineer and also currently Technical Writer for Corvette Enthusiast magazine and considered one of the foremost experts in the Corvette world.
Here is an article he wrote on the C2 / C3 cooling systems - BTW, this same article is also posted up on the DeWitts website because of it's accuracy:
http://lbfun.com/Corvette/Tech/vettetech.html
scroll down to the section called: ---cooling---
find article called:
cooling.pdf
by: John Hinckley

To save you the search and reading I copied the pertinent section and bolded the relative point:

"THERMOSTAT: Probably the most misunderstood component in the cooling system, the thermostat has absolutely nothing to do with controlling maximum engine operating temperature. Period. What does it do? At cold start, it blocks the flow of coolant out of the engine until the trapped coolant reaches the thermostat’s rated temperature, at which point it opens and permits coolant to begin circulating. This aids rapid warm up, which reduces cylinder bore and piston-ring wear by bringing the engine up to operating temperature relatively quickly. Once it’s open, it modulates the flow of coolant through its calibrated restriction so coolant temperature never drops below its rated opening point, assuming the cooling system is efficient enough to cool the engine down to that level. In most cars, it’s essentially wide open all the time, and only the heat transfer efficiency of the radiator and the airflow through the radiator determine the engine’s maximum operating temperature.
If you have a 180º thermostat and your engine operates at 220º, changing to a 160º thermostat won’t change your operating temperature one bit – you need more radiator, more airflow, or both, to reduce operating temperature. If you have an extremely efficient cooling system with more heat-rejection capability than your engine needs (runs at 180º with a 180º thermostat), changing to a 160º thermostat may result in reducing your operating temperature to 160º, but this is rare except in cold weather.
Furthermore, 160º is too cold; OEM testing has proven that the rate of cylinder bore and piston-ring wear at 160º is double the wear rate at 180º, and a coolant temperature of 160º won’t let the oil in the pan get hot enough to boil off condensed moisture and blow-by contaminants, which then remain in suspension and accelerate the formation of acidic sludge. 160º thermostats were specified in the 1930s for the old alcohol-based anti-freezes, which would boil off and evaporate at 185º; there’s no other reason for them. "

another experts opinion: This time from SWCDuke who use to hang in the C1/C2 forum. He is another GM engineer, specializing in Engine Systems Engineering.
http://forums.corvetteforum.com/show...ight=themostat
see his post # 4

A post from JohnZ again confirming the same thing: Assuming the cooling system has enough capacity to keep the temps fown to the t-stat rating (rare) running 160º is not good:
http://forums.corvetteforum.com/show...ight=themostat
see John's post # 16

more:
http://forums.corvetteforum.com/show...operating+temp

http://forums.corvetteforum.com/show...operating+temp

I could keep going on with more posts but honestly, i'm too tired of the entire subject now today.
I also see that before I posted this a link was posted to an article also stating the same thing John Hinkley is stating of the increased wear on the motor at lower operating temps. Thatr is just more confirmation of my point.

so.... hopefully you can see that lower operating temps are bad for a motor in the real world. Yes, you may actually gain some small increase of HP at the lower temp but at the expense of the motor by doing so.
Again, I agree 100% that in most cases even if you do run a 160º t-stat that chances are the motor is still going to run at operating temps above that so all of this becomes irelevant, but in cases where the cooling system has enough cooling capacity to keep the operating temps at the same level as the t-stat you are bringing on trouble because the operating temps are now too low.

bye

 

OK, so we're supposed to ignore what we see in the real world with our own cars and in dyno tests, and believe something that pops up on the web, with no supporting data to back it up. Hmmm........ That all sounds nice in print, and for that matter I saw the same thing in a book some time back, maybe they are both repeating the exact same info. The bottom line is, the cooler you keep the coolant during a dyno test, the more hp you make. The cooler you keep the coolant at the track, the quicker you go. Also a lot of Hotrods are borderline on detonation with pump gas, and cooler temps certainly help keep you out of trouble there as well. Those are real world facts that just don't match his graph, which shows about 175* being the coldest for ideal performance. I know 427 Hotrod has some cool coolant dyno data, probably off the top of his head about all this, maybe he'll chime in with it.

As for the wear thing, I've asked guys about that who build their own motors and don't run thermostats at all. They've all told me that they have not seen any abnormal wear issues with their motors running exta cool. So that doesn't match his graph either.

Geez, I would think people would believe what they see with their own two eyes, rather than some printed word they came across somewhere.
Maybe we should say it like this, it might be in everyone's best interest to run an oil temp gauge. Then if they see at least 212* under normal operating conditions, they're good to go.