Mechanically, nothing has really changed except roller cams. Crankshafts still spin in babbit bearings and aluminum pistons slide up and down in an iron cylinder.

The oil isn't the issue. The internal clearances were designed to be correct at a certain temperature. If it's not within the optimum temperature range, the clearances will be either to loose or to tight. That's when the excess wear happens.

 

Forget what I say. I'm just a bloke with a bunch of cars and access to the internet.

What's your answer to these experts below?

From the Dewitt's Radiator web-site:

http://www.dewitts.com/download/cooling.pdf

...is this direct quote:

"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 and sludge. 160º thermostats were specified in
the 1930s for the old alcohol-based antifreezes,
which would boil off and evaporate
at 185º; there’s no other reason for
them."

From this site:

http://www.johnnysradiatorshop.com/files/32341017.doc

...is this quote:

"If the thermostat needs to be replaced, install one with the same temperature rating as the original. Most cars and light trucks since 1971 require thermostats with 192 or 195-degree ratings. Using a cooler thermostat (160 or 180 degree) can increase fuel and oil consumption, ring wear and emissions."

From this site:

http://www.carnut.com/ramblin/cool3.html

...is this quote:

"Years of research show use of 160 degree thermostats is way too low to be considered for performance or engine longevity. As the chart above illustrates, engine wear increased by DOUBLE at 160, than at 185 degrees."

From this book:

http://books.google.com/books?id=lZ5...esult&resnum=8

...is this quote:

"Don't let the would-be automotive expert talk you into taking out the thermostat. If there was a way for Chevy's engineers to ensure that the engine got fast warm-ups to avoid sludge and acid formations - and therefore engine wear- other than controlling the water temperature, you can be sure they would do it in a minute...The hotter the cylinder walls, the less friction loss."

From this site:

http://www.lincolnvscadillac.com/tec...tems/page2.htm

...is this quote:

"To help alleviate a hot-running engine, some think that removing the thermostat and allowing full-time, unrestricted flow of coolant that the engine will run cooler. If your engine is running hot and overheating, assuming that the rest of the cooling system is in good working order and has the capacity to keep your high-dollar, big-horse motor cool, then removing the thermostat is NEVER the correct thing to do."

And from this site:

http://auto.howstuffworks.com/cooling-system1.htm

...is this quote:

"Inside your car's engine, fuel is constantly burning. A lot of the heat from this combustion goes right out the exhaust system, but some of it soaks into the engine, heating it up. The engine runs best when its coolant is about 200 degrees Fahrenheit (93 degrees Celsius). At this temperature:

* The combustion chamber is hot enough to completely vaporize the fuel, providing better combustion and reducing emissions.

* The oil used to lubricate the engine has a lower viscosity (it is thinner), so the engine parts move more freely and the engine wastes less power moving its own components around.

* Metal parts wear less."

If you wish, I could post another 100 links with similar quotes.

Again, please explain why the experts above have it all wrong.

And then, your turn. Show us a credible source(s) that recommends that we swap to a 160 degree thermostat for street performance. Here's a good place to start: www.google.com

 

You really do not know of what you speak. I have had cars that produced faster 1/4 miles at 180 than 160 degrees - and if I dropped to 120 degrees would I make more power?


Your HS is a prime example.

 

Okaaaay.

They are pointing the finger at "OEM", which I assume is GM. Show me the GM data and I may have comments on it, but this is not applicable to what I was saying about the water in the oil.

Well, they use the term "boil off", so I guess they cover themselves somewhat by doing so, but what I have been saying is that you don't have to boil the water to get it to come out of the oil. Show me where they say that the oil temp HAS TO exceed the boiling temp of water to drive off the condensate, and I will happily call If Tom DeWitt would like to speak about this in person, I would be happy to stop by their booth if I make it back to Carlisle in August. Otherwise, he can feel free to pm, e-mail or call me.

I take no issue with what is written here. I also fail to see how it contradicts what I have been saying.

I would need to know more about how the test was conducted to have any intelligent comment here. Again, I don't see how this contradicts what I have been posting. But, their conclusion is based on a common fallacy, that replacing my 180 thermo with a 160 degree one will result in the reduction of the operating temperature of my engine. While this could happen, it happens in reality a tiny fraction of the time, assuming both the 180 and 160 are operating properly. These guys are on the edge of if you ask me.

If you are on a trip and your thermostat fails and your car overheats, there is absolutely no reason why you can't take the broken thermostat out and run without one to get you where you are going. Leaving it that way will likely increase your start-up wear over the long term, as the engine will take longer to get into the optimal operating range, so I wouldn't recommend it. Their blanket statement "The hotter the cylinder walls, the less friction loss" is just plain . Heating the cylinder walls above the operating temp range of the engine will increase ring and cylinder wear due to insufficient clearance between the piston and the cylinder.

I'll give half credit here. I was 100% in agreement until "...then removing the thermostat is NEVER the correct thing to do." While I think it is likely unnecessary to remove the thermostat completely (testing it to make sure it is working properly, and if so, reinstalling it has always worked for me), I see nothing wrong with going without one while diagnosing an overheating problem just to remove one varialble. I would, of course, recommend re-installing one once the system has been properly repaired.

This guy is obviously one of the "engine omnicient". "How stuff works" is about as reliable as Wikipedia for technical answers, read, not at all. This is a perfect example of why. This guy professes that 200 degrees is the ultimate coolant temperature for all engines, I guess he doesn't care at what temperature they were designed to operate. If you want to take your technical advice from him, go ahead.

If you want to, but I will bore quickly of this game. Just because a thousand people say it is right, doesn't make it right.

I did the best I could, without getting ridiculously long-winded (I think).

I run a 180 degree thermostat in my car because that's what the engineers who designed my engine recommended. I have switched to a 160 for specific reasons, but then later when the opportunity presented itself, I switched back to a 180. Both work fine.

 

Sage advice to be sure.

BTW, I love your avatar!

PK

 

So now we're to swap to 160 themostats because you say the quotes from the experts above are "BS".

Convincing.

 

So who are the experts??? Lingenfelter?

From the Lingenfelter web site regarding their 160 degree thermostat:

"Reducing coolant temperature will help produce more horsepower and improve your performance and drivability. The thermostat is an easy to install component and requires no modifications."

SLP (who make the Firehawk for Pontiac)?

From the SLP (Street Legal Performance) web site regarding one of their 160 degree thermostats:

"This low-temp thermostat can dramatically reduce the operating temperature of your LS1 or LS2, increasing power, ensuring consistent performance, and extending engine-component longevity. This OEM-quality piece comes with complete instructions and all hardware required for a quick and easy installation."

 

Huh? I don't ever recall recommending that anyone change their thermostat from anything to anything. I jumped into this thread because of something you posted about needing to get the oil above 212 F to remove the condensate. I still stand behind the idea that this is BS, and have explained in technical and non-technical terms why. You have not addressed any of those explanations. FWIW, I am pretty sure I can hold my own with self-proclaimed "cooling experts" any day of the week. Like I said, if Tom DeWitt, or anyone at DeWitts would like to have a conversation about it, I would be happy to oblige as I am sure i would learn something about the ins and outs of auto radiators. However, I doubt they are going to change my world on the technical dynamics at work since they follow basic Newtonian physics, but I'd be willing to give them a shot.

You don't seem to be reading my posts very well, but I'll state it again since it is a slow day: I go with the manufacturers recommended thermostat unless I have some specific reason not to. Once the reason is resolved, I have gone back to the stock stat. You want a recommendation? I recommend everyone do the same. Happy now?

 

Look what I started, I should be in CONGRESS!!!But that aside there is a lot of good info here, even though I can get a good laugh now and then.

 

I am no thermodynamics expert, or claim to be any kind of rocket scientist type, but if I were trying to get my engine temps down, I would try something like...I don't know maybe ....hmmm... something like a bigger better RADIATOR!! Seems to me a cooling system is gonna run at whatever it is gonna run at, regardless of what the thermostat is rated at. The degree designation of the thermostat is only quoted to reflect when it opens... so once I hit, say 160 for example, it opens but after that, it sure seems to me that the radiator is playing the bigger role for cooling since the chances are that my coolant temps are going to shoot past 160 and stay there while I am running the engine. The thermostat is not really playing much of a role in cooling at that point. Sure seems to me the thermostat is more of a getting the engine up to temp quickly function than make the car run at a given temp function.

 

We just like to look at your avatar.

 

Yea shes HOT!!!!!!!!!!Maybe she needs a thermostat or I do!!!!!!!!!!

 

Toddalin, can you post the links to those quotes. One sounds like an ad, and I find it hard to believe Lingenfelter would suggest a reduced operating temperature for street performance.

But thanks, finally. We might see a supporting doc to counter the well written and credible recommendations against the use of a 160* stat.

 

Sure they are ads. But they are ads on the companies own web sites and you only need to go to them (and others) to see the ads for yourself.

If Lingenfelter didn't believe that a 160 degree thermostat offered a performance advantage over a 180 degree thermostat, would he offer it on his web site and note that it provided an advantage?

Just because he sells the product doesn't make him any less reputable than those who don't.

http://www.lingenfelter.com/mm5/merc...Category_Code=

 

here is my testing with no changes other then stat...........

i have run a 160 stat in winter and my car runs at 160
i have run a 160 stat in summer and my car runs at 170-175

i have run a 185 stat in winter car runs at 175-185
i have run a 185 stat in summer car runs at 190

so in winter i run a 185 stat and in summer the 160 that way i dont have to turn on the thermo fan so much. i think vapourisation will occur at all these temps and the difference is insignificant .

i do have one point but if i start my car and give it a flogging when its only at 140 it will have no HP at all. who said low engine temps give good HP? same thing with my gf,s toyota and same thing with my mazda. could all 3 cars be mutants?

 

If this ad:

http://www.lingenfelter.com/mm5/merc...Category_Code=

...is your support for the recommendation for a 160 degree thermostat in a Gen I engine, go back to the well: www.google.com

Gen II engines have reverse flow cooling and the stat regulates cool water from the radiator; not hot water that's already passed through the engine.

Also, in a reverse flow cooling system, the heads are cooled first then lower engine is cooled last meaning the cylinder walls stay warm (reduced friction), and the oil remains at temps high enough to cook out the wastes.

But at least you're working to support your opinion with documentation; something that's missing from the "160* is better arguement" so far.

 

You're ony looking at the one thermostat that I provided the link to. They have others for standard flow-type engines also.

 

Ok, think of it this way...the coolant in the engine circulates in the engine until the thermostat opens allowing it to flow into the radiator.

If the coolant exits the engine at a 160 degrees instead of 180 or 195 degrees it is bound to lower the operating temp of the engine.

It is a system designed to maintain a particular operating temp. The radiator doesn't do it's job until the thermostat does it's job.

Once the operating temperature drops below the thermostats temperature rating the thermostat closes and the coolant circulates in the engine again in order to maintain that goal of 160, 180 or 195.

So, the thermostat doesn't just open up and then it's done, it opens and closes according to the temperature of the coolant.

cc

 

I understand how it works. In my Vette, it opens up and it's done as my Vette runs around 200 to 210 or so. During normal conditions with a fully warmed engine, the thermostat will allow an unrestricted flow of coolant to the radiator. A thermostat is for the minimum operating temperature, it does nothing for a system that runs hotter than that.... hence my statement about a radiator being the bigger factor in the equation.

 

This is true, but if a cooling system is designed properly and in good working condition, The temperature will never rise above the opening point of the thermostat. No matter what thermostat may be installed.

I have a 502 with a 180 thermostat. My temps go to 180 and stays there.