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Which thermostat should I get?

thatK30guy

thatK30guy

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For my '98 Jimmy with 4.3?

O'Reilly shows 3 different temp ranges and I don't know which one to get. :confused:
 
Id say 185*.. 165* can be considered the same as not having one in there at all opens up too soon and 200-210* is cutting it too close for my standards
 
If it's still efi then you need 195°. Iirc, the lower temp t-stats will cause the computer to run in open loop something or other all the time. Anyway, it's not supposed to be good for it. :dunno: (I don't speak efi very well)
 
badmix said:
Id say 185*.. 165* can be considered the same as not having one in there at all opens up too soon and 200-210* is cutting it too close for my standards
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nvrenuf said:
If it's still efi then you need 195°. Iirc, the lower temp t-stats will cause the computer to run in open loop something or other all the time. Anyway, it's not supposed to be good for it. :dunno: (I don't speak efi very well)
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I checked for the recommendations to use a Jet chip and they say to use an 180 degree 'stat.

I have been thinking of upgrading to a chip for some more performance. :whistle:
 
The info I put into the alldata system said that you need the 195 degree thermostat, that is with an all stock system. Granted I don't know if it is an x motor or the other, but with the x motor that's what you need.

Is it marked on the old one?
 
Its stock for now, with the 4.3 and 4L60E combo.

I may just get one to put on right now as I have cold air blowing all the time out the vents.

I haven't removed the old one yet. I need to get all the parts on hand before I tear anything apart.
 
pull the heater core hoses off. take garden hose and back flush the heater core 2-3x per side. and do it in 1 hose then in the other hose .

s10 and lots of newer stuff have huge problems with junk building up in the heater core. and if gm and dex-cool crap it will be basicly pluged.

and stock with 195 is best. if lower its like running with the choke on all the time.

and skip the chip from jet . cookie cutter crap.
 
there is a 'w' code and an 'x' code for the motor, can't remember but I think it is the 8th digit in the vin. Is it 2x or 4x?
 
use a 195 for stock application, I ran a 180 in a Camaro I had once with a TPI motor, it had a performance chip, the 180 ran fine and passed emissions just fine, but it also did use a bit more fuel, of course the performance was alittle better too though. Main reason for the 180 is those things have problems with overheating, the electric fan switch didn't turn the fans on until about 205* Out in Phoenix, by the time you hit that temp, your headin up pretty quickly.

Anyways, running a 195* in the other half ton with the 4.3 and a larger radiator, it stays at the t-stat level all the time, runs great.

I believe those 200+ temp t-stats are more for use in very cold climates, like my Burb in Indiana, it won't get up to the 195* setting, too good of a radiator and clutch fan, pulling too much air through it.
 
195 is my vote. After seeing this question come up a lot I did a lot of research and found that 160 degree and even 180 degree thermostats often don't allow the engine to get up to proper operating temps (about 200-250 degrees for most modern engines) which results in a slew of issues. Here are my other posts:

The normal and most efficient operating temp for your engine is about 200 - 220 degrees. Therefore it's operating perfectly. Why do you think the thermostat is 195? It's because it opens at 195 degrees. GM and every other manufacturer did tons of research to figure this out and provide the best performance and longevity of your engine. They didn't just guess ...

Your truck is only overheating at about 265 degrees. 210? Completely normal. That's where mine runs.

A 160 thermostat will cause your engine to always run rich, because it will think it's not warmed up, so the choke basically will always be on, which will result in lower MPG, less power, and more emissions. In addition, the lack of heat will cause poor combustion, increased condensation in the exhaust which will rust it from the inside out, and finally the heat won't allow the oil to heat up which will cause it to turn to sludge. Finally, the lack of heat allows carbon build up in the cylinders.

Worst of all, your heater will suck in the winter time, especially with 0 degree weather!!!

All in all, the 160 thermostat won't be immediately apparent, but in a year or two you will wonder why all these other problems are cropping up.

Even with a 160 thermostat it won't fix your overheating problem. It will only cause other issues. If your truck is overheating, having the thermostat open sooner won't make your truck run cooler under load. It'll just run worse every other time.

What you need to do is flush your cooling system with a chemical CLEANER, check your water pump, check your cap, and pressure test the cooling system. If the cap or a leak is not keeping the water under pressure, then the block heats up and boils the water off the sides of the coolant passages. That puts air in the system, which makes it so that the coolant is not touching the block, and voila - over heating.
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and

Most Chevy 350's operate at peak efficiency in the 200-212 degree range. You don't have to run a thermostat, but you are cheating yourself out of power and mileage.

From http://www.arrowheadradiator.com/pre...m_failures.htm

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. On newer vehicles with computerized engine controls, the wrong thermostat can cause major performance and emission problems if the engine fails to reach the proper operating temperature.
The heat of the engine also helps prevent acid formation in the oil, burns off excess vapors, and removes condensation which turns your oil to sludge. In addition, the heat helps prevent exhaust condensation which will rust our your exhaust system sooner.
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So, lower coolant temps are just causing more wear and less performance all around. You won't know until you go 100k miles and have to do a rebuild, when someone running a higher temp can just keep changing the oil. In the terms of MPG, you are throwing away money every time you fill up at $3.00+ a gallon.

I used to run a 160 thermostat in my cars when I was younger, but someone pointed out that engines have a thermostat for a reason and me second guessing over 100 years of research and development by putting a non-stock thermostat in makes me the fool. It turns out that the 160 degree thermostat was used for alcohol-based coolant. Am I really smarter than thousands of mechanical engineers who have tested thousands of cars over millions of miles? No, I am not, but I am learning! :)
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Have to remember though a lot of that "research" had to do with emissions as well, keeping those emissions down, running the engines hotter to help burn off the stuff.

I'd still use the 195, as that's what they are designed for in the computer programming as well.
 
My Suburban has a 180 degree thermostat in it, and it goes into closed loop and runs fine according to a GM TECH 1 scan tool.

I am not sure what my 1990 K5 has in it, but it runs very cold. It passed emissions in California.

Martin
 
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