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Discussion Starter · #1 ·
Newb question I'm sure. but i'm replacing the radiator and thermostat. any recommendations? I did a search on here and the consensus seems to be a "fail-safe" 195 degree thermostat. is that correct? as far as radiator.. I was planning on a replacement from auto zone as this jeep is just a daily driver. I will be doing a few more road trips (200-300) miles in it this summer/fall and maybe a couple trails. thanks for the help
 

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I'm almost positive the 195 is what I put on my '91 4.0 I6.
As for the radiator I have no clue.. Good luck :D
 

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They should stock come with 195 but when ur on the trail if u like going slow put a 165 that way don't over heat my Jeep was getting hot so I replaced radiator and a 165 in mine
 

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Discussion Starter · #4 ·
thanks for the info. I'll prob end up with the 195. Still torn between an aftermarket radiator or just the typical auto zone one. Haven't heard much about them.. just that they do have a decent warranty. I'll let you all know what I decide in the coming couple weeks
 

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Ask Ageless Stranger he's a Mod on here and he had to replace his last year and I know he did endless research knowing him.
 

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195* T-stat is factory, and that's what you want to stick with. If you're radiator is stock and it hasn't started leaking yet, it will. I replaced mine with an all metal radiator made by CSF. I bought it from Radiatorbarn.com. Option 2 once you do the search. ;)
 

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Discussion Starter · #7 ·
I will look into those. Yeah my radiator has numerous holes in it. Jeep's been neglected for some time and it's 140k plus miles now. Im rebuilding it and whipping it into shape.
 

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definitely 195

Virtually all engines are designed to run more efficiently at 195. It is my experience that the 165 thermostat will, in no way, reduce over heating. It just determines the temperature at which the cooling starts. If it is going to overheat with a 195, it IS going to overheat with a 165. It is just that the engine won't operate as efficiently.

Regarding the radiator. If you are planning on doing some off road when it is hot, and especially if high humidity, then you definitely want to bite the bullet now and get at least a 2 core unit.

The cooling capacity of the radiator is a function of its area. The frontal area is determined by the length and width. That determines how much air can pass through at a given velocity. If you want more cooling with that given surface, then you have to increase the velocity. Unless you go to an electric fan and get exotic, there isn't much you can do there.

The main way to increase the cooling capacity is to increase the thickness of the radiator. If you double the thickness you immediately increase the cooling capacity almost double.

The cooling is actually accomplished by the fins between the tubes drawing the heat out of the tube and the air passing over the fins. If the fins get plugged, that reduces the cooling.

If you increase the area by doubling or tripling the core (dual or 3 core) you will increase the cooling but not actually doubling or tripling. The air first passes over the first tube/fin and it is heated. The amount of cooling is based on the air flow and the "delta T" or differential temperature between the fin and the air.

When the air gets to the 2nd tube/fin it is warmed so the "delta T" is less and the cooling will be less. Same with the 3rd core.

If you aren't anticipating any really slow, heavy pulling, then the original set up should be more than adequate. If you are anticipating slow, heavy, pulling (typical of off roading and can be no more than very slowly driving up a steep incline) then you want to upgrade to at least one more core than present.

If you have an automatic, you also have the tranny cooling built into the radiator and probalby already have a dual core. If you have A/C you have another radiator in front of the main radiator for the refrigerant. That heats the air and creates a lower "delta T" across the tube/fins of the radiator.

Since heat is the worst enemy of an auto tranny, it is even more important to increase the size of the radiator, and even to install a separate, transmission cooler.f

If you are in a situation where you are seeing it overheat because it is going very slow, then it is time to bring in the gearing. Get down into a lower gear where you can get the engine speed up to 2500 or 3,000 and get the vehicle can pulling the air through.
 

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if you put a 165 t stat the engine might not go or have a hard time going into closed loop. stick with the 195, factory did the research for you already.
 
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