Thermostat poll, 160 vs 180

[Mart]

Well I have seen a lot of threads on this but no definite answers, so maybe a poll will help, mainly because I am in my garage with a 160 in one hand and a 180 in the other.

lets see what you guys think.

Mart

 

[Vettefan87]

I actually have a 160 T-stat, but the next time i actually drive my vette again it will have a 180. C4C5specialist down at the cruisfest talked about how a 160 created thermo shock when it hit the first two cylinders.

 

[Mart]

Whatever happened to C4C5 he has not been around here in a while?

I'm not sure I get this thermo shock thing!!!

 

[Vettefan87]

Yea i dont know where he has been. Maybe this thread will get his attention. But from what I understand it to be is when the coolant is so cold when it hits the two front cylinders it kind of shocks them which could warp them and also cause engine vibration??

 

[Mart]

I would be nice to have him comment here.

As I understand it thermal shock is usally going from extreme temp to extreme temp. So what temp does your 160 actually run at, because once your at 160, I'm not sure 10-20 degrees counts as thermal shock.

Mart

 

[Mart]

C'mon guys lets hear what y'all have in your vette.

Hello C4C5 where are you???

 

[Vettelt193]

yeah, if I understand that correctly, he is saying that the cold coolant hits the inside of the engine and the drastic temperature change affects things... if this is the case, the lowest thermostat you can buy would be the best one because the engine would be at a much cooler temperature when the cold coolant starts to flow into the engine.


I have been using 160 degree stat for years. I have had no problems with it, and know that the car runs better with it.... but, the difference between the two is not that much. I think the factory 195 degree stats are the ones that are real garbage... 180 or less and you are fine.

 

[Bob Chadwick]

I accidently hit 160 but meant 180.

The thermostat only sets the minimum temperature so it has no impact on what your car runs in the heat of the Summer, unless you have one of those cars whose cooling system can keep the car temperature that low. Mine can't.

There have been numerous posts about 160 degrees being too cold for the engine and creating excessive wear from longer warmup times and during cooler weather driving when the car runs at the thermostat temp.

I pulled this from another thread on the 160 degree thermostat.

A 160 'stat will have absolutely no effect whatsoever on your summer engine operating temperature, as it's full open all the time anyway; the 'stat only controls MINIMUM operating temperature, like in the winter, when low ambient outside air temperature allows your radiator to cool the engine down to or below the 'stat rating. 160 degrees doesn't do you much good in cold weather when you need the heater to operate, and it also won't let the oil get hot enough to boil off condensation and blow-by contaminants which then stay in the engine, get acidic, and form sludge.

160 'stats were used in the old days (40+ years ago) when cheap alcohol-based anti-freezes were used, so the alcohol base wouldn't boil off; they have no place in a modern cooling system, and have no benefits at all (except to the people who sell them and tell people they will solve overheating problems - they won't).

 

[DRTH VTR]

C'mon guys lets hear what y'all have in your vette.

Hello C4C5 where are you???

He has been around, at least in the C5 section. Also, check Corvettemechanic.com

 

[C-4 Now]

I've run 180 for 8 years. No problems except in traffic & air on 90+ degree days. I haven't heard thermal shock thing before would like to hear more.

 

[Mart]

As far as JohnZ's comment, who drives thier Vette in the winter??

I have had a 180 in since I bought the car, and I thought I had a 195, I have never seen 180 unless I just started the car.

Mine usually runs at about 200-210with the 180 in, so I figure I'll try the 160 and see what happens.

And as Vettelt193 mentioned if you have the 160 in then the engine is running cooler so the coolant should be cooler, these differences that may be called thermo shock would be the same with either thermostat, think about it.

Mart

 

[DRTH VTR]

Paul (c4c5) has posted that the LS1 was designed to operate with coolant temperatures higher than 160 degrees. Cooler temperatures do not allow the cylinder bores to expand to the correct dimensions, resulting in cylinder wall scuffing. I do not know if this applies to the LT1 or LT4.

 

[Bob Chadwick]

As far as JohnZ's comment, who drives thier Vette in the winter??

Mine usually runs at about 200-210with the 180 in, so I figure I'll try the 160 and see what happens.

Where you live your Summer equates to our Spring and Fall here in the South.

I suspect it will still run at 200 - 210 just will take a little longer to get there.

 

[Remo]

Hot Subject - Not

I'm no expert on this subject but for late model Vettes with electronically controlled fuel injection - changing thermostats to something other than OEM spec can have some ugly results. Lowering the thermostat temp will cause the computer to richen the fuel mixture. This of course will result in reduced fuel milage and over the long haul could do some cylinder damage. The C4's and especially the C5's were designed to run at mucher higher temperatures than most folks are accustomed too. Stick with the factory recommended thermostat and stop all this hand wringing.

Remo:cool

 

[Mart]

Hey Remo,

What's the average temp of your C5 when just out fo ra cruise and when sitting in trafic.

Mart

 

[Tuna]

I'm using the 160. Have been for 10 years. I have a computer chip that turns on my fans sooner so I didn't want the fans and the thermostat fighting each other for control. Even on the coldest days in OK, I never see less than 175 after it is warmed up. On summer days, the temp while cruising is usually in the 185-190 range. I can't complain. I'll stick with the 160.

 

[Remo]

Hey Remo,

What's the average temp of your C5 when just out fo ra cruise and when sitting in trafic.

Mart

Mart,

Just cruising and around towns the temp. runs 190. In the city, in traffic on a warm day it will reach 225. Temp will drop like a rock as soon as traffic opens up.

Remo:cool

 

[Mart]

WOW this is not what I expected as for the results.

So far a split, hmmmm......

I think that for the most part a 180 is appropriate, but I think that performance wise 160 may help keep it a bit cooler under harsher conditions. Also the age of the car probably comes into play.

 

[JHL]

I have read several comments that low engine temps dramatically increase wear. What you need is your engine at a nice steady temp and you air and fuel mixture to be as cold as possible. Here is only one small write up I found which probably is not very technical but if you search around you will find lot's of comments in a similar vane. I don't vouch for the validity of the following comments but as I said I have read similar quotes before so there must be something in it.

J.



by Steve Jack
HOTRODSRJ@AOL.COM
Concept One Pulleys
Jackstands at Old Cars Only

A few of you good folks must have spotted other articles that I have done either in print or online about this subject. At the request of a few folks here I am putting this up for what it's worth and expanding some information about this as well. The argument is about running 160 degree thermostats and the good and/or bad results. Now keep in mind that thermostats have absolutely NO effect on your systems ability to cool, simply a regulator of the range it operates in. So, if you think a 160 will cure an engine running at 220 with a 180 thermostat...forgetaboutit! This is not about cooling capacity at all.

The graph to follow illustrates the importance of how critical optimum coolant temperature is to the longevity and performance your engine. Cooler water makes horsepower and warmer water minimizes engine cylinder and bearing wear...or so it's thought, but only to their own limits and ranges. 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. FWIW, higher operating temperatures of today's engines are to fight combustion by-products and pollution. Also, engine oils are designed to work over a specific temperature range with optimum performance starting at temperatures that require the coolant to be the very same 175ish range. And don't forget the moisture issue. Have you ever seen water vapor coming from your tailpipes? Sure..and the very same thing happens INSIDE your engine. YOur engine forms moisture inside when it cools and condensates on the walls of the inside. This moisture the is washed down into the oil when started and then awaits vaporization by internal temperatures rising enough to bring the moisture to the appropriate corrected vapor point (boiling). If enough moisture is left behind it combines with combustion byproducts to form acids that become dissolved in the oil itself. The oil becomes more acidic as the age of the oil progresses and picks on certain parts eventually. Also moisture will corrode other surfaces. So, it's important to get these engines to a satisfying operating temperature as soon as possible. Usually oil pooling temps are about 30 to 40 degrees higher than the coolant temps. This is a generalised statement and can vary with load and engine design but you can see why you want your oil over 212 degrees to boil out the moiture immediately! A 160 thermostat usually does NOT accomplish this temperature.

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. The 160's were invented for and commonly used in older, open loop cooling systems where only 6 pound radiator caps were used, and low 212 degree boiling points were the limit. We know better now.

Many early hot rodders found the 160's to be a smiggin better performing than the 190's, however the in between 180 appears to satisfy both ends of the spectrum. The correct water temperature and thus resulting metal operating temperatures required for the cylinders to achieve a minimum specific temperature in order to allow a fully mixed Air/Fuel charge to combust efficiently is a minimum of 180 degrees coincidentally. If you use 160s be aware that this can have a degrading effect over a time on your engine. I know alot of rodders still using them however to whatever ends they want...and that's okay. Heck, I know guys that run NO thermostat and most of you know that's another book to be covered. I just report what I learn...and you decide what's best for you. I hope this satisfies you information junkies out there. Steve Jack
HOTRODSRJ@AOL.COM
Concept One Pulleys
Jackstands at Old Cars Only

 

[Mart]

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.

In the article it mentions an optimum performance and wear number. This number, from what I am hearing from you guys is not achievable with a 180 thermostat, (I know mine is'nt) but a couple have mentioned that (Tuna) that thier 160 is giving temps of 175 - 195 depending on condition. This seems pretty reasonable to me.