160 degree thermostat install

[TooFast]

I just read a bunch of conflicting data on installing a 160 degree thermostat on a stock C5, from: it will improve HP to the engine will run too cool and your oil temp will never get hot enough for optimum performance. Anybody have the real deal on whether or not you should change out the thermo and if it does any damage over a stock unit. I am getting ready to change my coolant out and was contemplating going to a 160 thermo. :confused

 

[Rex S]

A 160 will only "help" if the ECM is set up for it and other mods. If your car is mainly a driver with maybe some limited drag time, ther is nothing to be had from a lower temp 'stat and there is a good chance the car will fail smog with it. Low temp 'stats have there place but not in a driver.

 

[TooFast]

What if it is a garage queen, only driven summer time. Will be installing TI catback in a few weeks, plan to change to 1.85 rockers and yellow springs, and high flow air intake (vararam). Change the 'stat?

 

[warren s]

OK, here we go again…….

You car will NOT FAIL anything with a 160 TStat.

Having a 160 Tstat alone DOES NOT mean it will run at 160 degrees coolant temps, it will just take longer to reach higher operating temps.

You still need a manual fan control to keep the coolant temps down unless you are moving.

Oil temps will still easily reach “normal”

It all depends on the type of driving you do and the ambient air temperature

A lower temp Tstat is part of a number of inexpensive mods you can do to INCREMENTALLY increase performance at the track as compared to running at much higher temps that C5s hit when idling for a few minutes.

My car is a summer time weekend car, between a manual fan switch, a 160 Tstat, and the zip tie mod – I decreased my ET by 2/10 ths, get about 2 mpg more and the engine bay isn’t searing hot when I open the hood. (I turn on the fans at 200 instead of letting the cycle between 235 and 210)

I also installed a Vararam, LS6 manifold, and a cat back exhaust – my best ET was a 12.61, not the fastest C5 in the world, but it sure impressed me for a pretty much stock car.

C5 Corvette Simple Mods C5 pictures from corvettes photos on webshots

Vararam & manifold pictures from hobbies & interests photos on webshots

 

[c4c5specialist]

HI there,

The truth is it all depends on the clearancing of your engine, vs if the 160 will hurt your engine.

I have disassembled 3 different engines with scuffing on the #1 and #2 pistons because they ran 160 thermostats and ran the car very hard.

Others, never had an issue, so its a roll of the dice.

The reason is when the thermostat opens, the lower temperature coolant hits the 2 front cylinders and contracts the bores.

allthebest, c4c5

 

[warren s]

That is a very interesting theory / observation. How was it determind that the scuffing was actually caused by the thermostat setting?

 

[c4c5specialist]

Piston to bore tolerances were all .0011 on the 3 failed engines.

However, 2002 and newer, I have seen tolerancing from .0005 to .0025.

Even the cylinders towards the rear, tolerances were all the same.

So, what is the variable ???? Fuel injector flow rates were all equal within .02 unit flow per second. Spark plugs were all 41-985 and no appreciable wear.

What is the only variable that can correlate ?? 160 degree thermostat in each of the 3.

And the most interesting part of that, is that scuffing on the skirts and bores were all exactly in line with the coolant passage to the block.

What other determination can be made ?

Allthebest, c4c5

 

[warren s]

That’s seems very dubious to me. What’s the normal variance on LS1s? What was the actual cause of failure of these 3 engines?


I can understand that being an issue if the thermostat “snapped open” and dumped large amounts of much lower temperature coolant into the water jackets. . How does that happen when the thermostat opens slowly and lets the lower temp coolant just start to trickle in to the water jacket? And being a 160 tstat, wouldn’t the it be open way before the engine reaches an extremely high coolant temperature that would cause the possibility of sending much lower temperature coolant in to a much hotter water jacket?

 

[c4c5specialist]

Actual failure was engine noise due to piston rock, from scuffing.

Those who do this modification must be aware of potential issues.

These engines and their tolerances are not engineered to be run with 160 thermostats or they would have had them from the factory.

Allthebest, c4c5

 

[warren s]

No, they were not designed to be run with allot of the modifications many Corvette owners perform on their vehicles.

I respectfully disagree that this modification specifically causes engine failures however.

Thank you for the insight.

 

[TooFast]

Wow, and thanks guys for the insightful discussion on the subject. I think I am going to wait until I have actually done all of my mods and get a tune before I think about changing to a 160 Tstat.

 

[Boeingdriver]

Actual failure was engine noise due to piston rock, from scuffing.

Those who do this modification must be aware of potential issues.

These engines and their tolerances are not engineered to be run with 160 thermostats or they would have had them from the factory.

Allthebest, c4c5

Paul: This is what you were talking about in answer to that question about piston-slap on start up, right? Was the pistion you had in the presentation the scuffed unit from the failed engine?

 

[c4c5specialist]

HI there,
The one without the black coating was one out of a scuffed engine, yes.

And yes, that was part of my presentation about the carbon buildup.

However, that particular question was about adding the 160 stat, and why you can also add carbon build up TO an engine with one of those.

Its not a large difference, but given the actual question about it, I felt it was important that they understand the difference.

Allthebest, c4c5

 

[ernestD]

wow!good stuff to know-some things are better left alone!

 

[Edmond]

So far, my mods are:

Long tube headers
RPM level IV transmission
C6 Z06 clutch
Blackwing air intake
MGW short throw

Computer tune will be done this week

I have a 160* sitting here, will install it soon as well as fresh coolant.