160 Thermostat or 180?

cco175ranger · Jun 24, 2006

Just had a quick question. I am about to replace my radiator, water pump, hoses, cap and a few other things before taking a nice long summer road trip. I am currently at 8 inches of lift on 35's. My a/c will be used because well... It works like new hahaha. Question is should I run a 160 degree thermostat or a 180. I know I'm not gonna run the 195 cause I already run a little to warm as it is. Will a 160 cause any problems? Detonation or not allow the computer to go closed loop? Thanks for all and any helpful info!

PS: I ran a search first but didn't find much on this specific question.

87manche · Jun 24, 2006

180 minimum. 160 will likely cause it to stay open loop. On my 87 the ECu goes into closed loop at about 170. Why not the 195? You say you run warm, but your'e going to replace the entire cooling system. it was designed to run with a 195, with a new cooling system it should run there.

Jim Mesthene · Jun 24, 2006

Use the 195. That's what it was designed for and will provide the best fuel economy and power.
With your new radiator, you should have no fear of boiling over. Although it may run at the boiling point of water, you'll still be 65 degrees shy of boiling coolant under pressure. Running at a cooler temperature will result in you buying gas to shed heat through the radiator and nothing more. If you imagine it will take longer to overheat in case of failure, think how long it will take to boil over if you start at 160 degrees insted of 195; about 45 seconds longer.

Eagle · Jun 24, 2006

The purpose of a thermostat is to keep the temperature UP, not down. If you run too hot with a 195, you'll run too hot with a 180 or a 160 because it means your cooling system isn't doing the job. Since you are replacing the cooling system, you should be using the 195 degree t-stat.

But .. I know you won't believe me until you try it. Use the 180, because 160 is too cold for the EFI system to go into closed loop mode,(if the cooling system allows it to stay near 160).

Yooper · Jun 25, 2006

This may sound a little unbelievable, but when I replaced my thermostat that was sticking open with a new 195 I gained almost 2 miles a gallon.

SCW · Jun 25, 2006

Yooper said:
This may sound a little unbelievable, but when I replaced my thermostat that was sticking open with a new 195 I gained almost 2 miles a gallon.

Yep- I replaced mine and the guy at NAPA gave me a 180, lost 2mpg. I have the new 195 sitting here waiting for ambition to put it in.

churky89 · Jun 25, 2006

Get the 195.....FAILSAFE.....These t stats are designed to stay open IF they fail....Which means the engine should not over heat...or boilover..costs a coupla $$ more but worth it...

cco175ranger · Jun 26, 2006

Well I guess thats it then! haha I will run a 195 and hopefully maintain what little fuel economy I have left!!! Thanxs for all the great advice and I'll let ya know how it all turns out.

dmillion · Jun 26, 2006

Yooper said:
This may sound a little unbelievable, but when I replaced my thermostat that was sticking open with a new 195 I gained almost 2 miles a gallon.

Not at all unbelievable. In fact, anyone who really understands how an internal combustion engine works, and what a thermostat does and doesn't do, would not only believe this result, but would EXPECT this result!

RickyN29 · Jun 26, 2006

Yeah, absolutely a 195. Hell, one winter, I ran a 205 cause my jeep wouldn't ever seem to get up to temp.

160 Thermostat or 180?

cco175ranger

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Jim Mesthene

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Eagle

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Yooper

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SCW

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