Jarryd#29

Just wondering if anyone runs thier corvette without a thermostat and what kind of effects it may have rather then running with a thermostat.
anyone??

Thanks
91 vette

impact1968

I ran mine with no stat last summer (in florida heat, 90's) for something to do one day. The engine warmed up alot faster, and ran much hotter in town and on the interstate.

My guess is that the water is traveling to fast and dosen't spend enough time in the radiator to cool.

Living in a part of the country where it dosen't get so hot will surely have a different outcome.

engle1147

Pro:
You'll have an $5 extra in your pocket.
Car will be lighter without a T stat.
Engine's coolant will be in great chemical condition from fewer really hot heat cycles when you got to replace the heads.

Con:
The engine may never reach a decent operating temperature for one thing.
Heater core function won't be worth a damn.
Aside from regulating the heated coolant it also provides a restriction which will help remove any air from inside the block or heads.
Air pockets/hot spots are not a good thing with aluminum heads.
etc.
etc.




Your going to want to install a T stat

383vett

Normally slower warmup, possible lower than optimal temps, and increased engine wear. Other than that, the car will be 2 ounces lighter.

redrose

contrary to thermodynamic principles and not true...higher flow rate will INCREASE heat transfer in both engine and radiator, lowering temps.

perp is actually the 'impeller' found in most auto water pumps, designed to function with system HEAD (resistance) that includes a t-stat...deletion of t-stat often causes pump operation to 'go off the curve', impeller 'cavitates' and flow rate drops substantially...if t-stat is deleted, install a 'restrictor' orifice (basically just a flat washer, check your local circle track parts vendor) to 'stay on the pump curve', also GM Perf Parts 'had' (still ?) a cast impeller in 'std' rotation for ~$8 with better 'curve' ...for more detailed explanation, giggle 'pump curves' or N.P.S.H. (Net Positive Suction Head) or talk to any HVAC engineer

Flame Red

Don't do it, enough said...

jfb

Thanks redrose for explaining well, the fallacy of faster coolant flowrate causing higher temps so I didn't have to! I've been alone here for a long time when this gem shows up.

CorvetteMike2024

Im on your side. You have provided me with a weath of knowlege from your posts to keep my vette running.

Thank you for sharing your knowlege with us all.

Corvette Mike

Mark85Vett

if you run too cool, you'll have the problem of running in open loop all the time...you'll be lucky if you get 12 mpg.
The arguement on the pros/cons has gone on for years and would take up volumes. That said, the cars were designed to run with a thermostat, and it won't do any good to run without one as far as any noticeable advantages...personally, I run a 180...it gets the oil hot enough to burn off any condensate and other crud, you have acceptable heat for the passenger compartment, and I feel its a nice balance of the run it hotter/run it cooler arguement...but that's just me. Hope this helps!!

427c4vette

From theMarch 2010 issue Chevy High Performance, page 56,
"If you choose not to run a thermostat, coolant may be flowing too quickly to allow the coolant sufficient time to dissipate heat through the radiator. Moroso's water outlet restrictor kit slows the flow of coolant down through the system, so the radiator can do its job."
- Rick Moroso
Two points about why sometimes engines overheat without a thermostat.
1) what redrose said.
2) Sometimes there is sufficient head pressure for the pump to actually flow a higher rate. Then the higher velocity causes cavitation to occur either in the radiator or the engine block which reduces heat transfer. Reducing flow reduces pressure drops allowing the radiator (and/or engine block) to do its job, not because the coolant has more time to do its job.

cv67

Id trust the engineers at GM thought about this one.

TJM

Not that it matters, since you see the light, but the cooler you run your block/ heads [ or Heads/block?? ] relative to it's rated operating temperature the LESS power you get.

You ought to see the equations on THAT!!!

TJM

HlhnEast

I havent run my Vette without a thermo but I can tell you that some engines DO run hotter without a thermo because the water moves too fast thru the radiator to have sufficient heat transfer. My 4 cylinder Isuzu HAD to have a thermo in it to not overheat.

I just replaced the thermo in my car because it was stuck open and the engine did not heat up enough (contradiction to the above statement) to allow the 4+3 overdrive to activate.

As stated above, trust what GM engineered into a thermo, there are lots of reasons why, some not as obvious as others.

redrose

have not seen the equations, but have seen 'real time' on dynoed bbc that torque increased as water flow was reduced/water discharge temp taken higher (inlet cooling water was from a remote large source and was constant)...more fun was: iron heads vs alum heads, with both types made mechanically as similar as possible (yes they had the $ to do this), and the IRON heads made most power.

note that 'durability' (aka engine life) was NOT a consideration of those tests.

jfb

First, you have no idea what the flow rate was on your Isuzu with no thermostat, so you cannot say the coolant flow was too fast. Second, heat transfer doesn't become less with higher coolant flow rate. Flow rate increases with increasing thermostat opening and engine temp DECREASES due to higher coolant flow rate. As explained by redrose, your waterpump requires some backpressure to pump water and removing the thermostat greatly reduces backpressure and therefore coolant flow rate. It is LOW coolant flow rate that causes high engine temps!!!!!!!!!!!!!!!!!!!!!!!!!

mtwoolford

I would never run without a thermostat of some type....please note the emphasis on "some".

The water pump is a centrifugal type, all centrifugal pumps must have some resitance on the discharge side to develope pressure and ensure flow....it's the nature of the beast.

When people remove the thermostat entirely and then encounter cooling problems it is NOT because the coolant is circulating "too fast" either to pick up the heat from the engine or to transfer it to the radiator. It is because the pump function itself has been compromised.

If you want to eliminate the thermostat, I suggest, you, like circle track racers, run a restrictor plate in place of the thermostat. This is a flat disc with a hole in the middle that replaces the thermostat; the hole in the center comes in a variety of sizes, allowing experimentation.

OR more SIMPLY, take an old thermostat, clip the prongs that hold the middle pellet, remove the pellet, and reinstall the remaing disc as a restrictor plate. Simple. Cheap. Fool proof. It will be like a thermostat thats always 100% open.

The engine may run cooler, sometimes much cooler.

Additionally, if you are having cooling issues, it removes the thermostat from the list of possibilities, and allows you to zero in on other possible causes.

Yes, new thermostats, even new, expensive, top of the line thermostats can hang up and fail to open. This I know.

The down side is that your heater / defroster will not work very well, or will take much longer to get up to proper temperature.

WORSE, in a cold enough climate, your engine will not get warm enough to evaporate water and water vapors from your crankcase and oil system, which eventually will lead to rust, sludge and acid erosion.

BUT, if you live in hot enough climate, running a restrictor plate can be cheap insurance.

tpi 421 vette

There really is no advantage to not running a thermostat. Your engine needs to see a certain amount of heat to make power, and go in closed loop, and have your heater work properly. My best dyno runs were after a few runs where there was heat in the engine. You really want a engine with some heat in it and cool air. But you don't want a cold engine. A thermostat just determines the minumim coolant temperature.

86PACER

Exactly.

leyzaola

hi, wich one is the pellet? the copper thing inserted in the rubber "valve"?

tblt44

I ran my old toyota p/u 4 cyl. 1984 with no stat,it took a long time to get warm, no other problems.
Would I do it now no,back than I did what I had to when it got stuck closed,than lazy and never put one in.