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Thermostate Question

VAhasnoWAVES

VAhasnoWAVES

NAXJA Forum User
Location
Lake City, Mi
i beleive my xj (99) has a 190 thermostat in it. the previous owner stated he installed it to keep the engine running cooler than it did with a 210 thermostat. this resulted in the engine running cooler, and the heat not blowing all that warm. this wasnt a problem until i recently moved from virginia beach up to lake city, Mi. ive looked into simply installing a new thermostat but my shallow research says that 190 is what was stock. my question is, does the thermostat degree dictate the gauge read out? what im saying is that will a properly functioning 190 thermostat regulate the engine temperature at 190 resulting in the engine temp reading at such? or will the "stock" 190 thermostat read right at 210, like my past xj did?

i live in the snow belt and need some more warmth in the cab. a thermostat is fairly cheap, so i think im simply going to replace it before looking to the heater core or flushing the system. i hate turning wrenches in the cold. was just curious what i was working with.
 
The stock thermostat is a 195 degree AFAIK. You want to use one, if you use a lower temp one, all it does is make the engine come up to normal operating temp slower, leaving you in open loop mode for longer and wasting gas / causing pollution.
 
As kastein mentioned, you want a 195. That is probably what the guy meant but he said 190.

Do you have a coolant temp gauge? If so, what is the engine temp at? Your target temp is 200-210 farenheit. Maintaining that temperature is job #1; cab heat is a byproduct of consistent engine heat.

Along with the thermostat (I like factory stats from Jeep), consider other routine cooling system maintenance. No substitute for that. That includes flush/fill, flush heater core, new radiator cap. Fill with a 50-50 mix of conventional (green) coolant. Verify strength when all is said and done with a hydrometer. A 50-50 mix is good down to -34 degrees and is best for all climates.
 
they are all correct about the 195 T-stat! (90-4.0), i did all and now im reading 160-190 degree on my gauge! before i could not get away from 230-RED! sorry to poach in. any idea's?
 
tj'sxj said:
they are all correct about the 195 T-stat! (90-4.0), i did all and now im reading 160-190 degree on my gauge! before i could not get away from 230-RED! sorry to poach in. any idea's?
Click to expand...

What is the brand of thermostat you installed? I have seen a number of flaky stats right out of the box. I still suspect the stat for your problem. Especially because you went from one end of the temp spectrum to the other and the only thing you did was change the stat? I buy my stats directly from Jeep; I've had the best reliability with them.
 
coolant levels have been consistant for months and colors doesnt look anything suspicious. a flush wouldnt hurt anything though im sure.

my gauge reads right around 190. through the hot summer and now into the cold winter the temp is consistant.
 
not sure of the name on my T-stat, its the better of 2 at the parts store- better flow and reliability! so it says!
i just HATE buying from dealer cuz there mark-up!!
 
VA,

I would suggest flushing your heater core. The amount of coolant flow is probably restricted. A 195* stat should not prevent your vehicle from getting heat. So souble check that stat heat range. My 195 keeps the temp gauge right at 210*, needle straight up.

I have also seen stats bad right out of the box. Place in a pot of warm water and slowly bring to a boil. Have a thermometer handy so you can determine at what temp it actually opens. The opening will be +/- 5*F

keep us informed,
Tom
 
I like the NAPA high flow stat. I found that it has a much higher cross sectional area when open then others. Been a few years and can"t remember the PN.
My 90 was problamatic many years ago. I did everything but go to a new radiator. I had the original cored and it was 30% blocked. Still did not fix the problem entirely. With every cooling related part replaced, it was still marginal.

I didn't like the noise the engine was making so I pulled the head. The machine shop said it was pretty bad and if I was going to keep the Jeep, I should do the rings too. Did that. After assembly, no more cooling problem.

It never makes sense to me that everyone makes such wild modifications to the cooling systems on the Renix modes. I bought mine new and towed a 19' camper for a couple of years here in Oregon. Traveled throught he Cascades and to the coast and never had a cooling problem with the stock set up.

If there is a flaw, it is in the radiator size, too small. When you add the condensor and transmission cooler to the front, it becomes marginal long term.
 
Boatwrench said:
VA,

I would suggest flushing your heater core. The amount of coolant flow is probably restricted.
Click to expand...
Great idea, not sure why I didn't mention this also in my first post. It's correct, especially in the older models with the heater control valve that keeps fluid stagnant in there when the heat isn't on. Do a reverse flush by determining the way the fluid normally goes through, disconnecting the lines from the heater control valve, and feeding the outlet tube with a garden hose while collecting the waste fluid + water + gunk with a 5 gallon pail.

EDIT: also go easy on it, don't overpressure it by blocking the outlet or anything, if it's old enough it might be on the edge of bursting and replacing a heater core is something you want to avoid for as long as possible because it's a pain unless you already have the dash torn apart for something else.
 
winterbeater said:
Thermostat with relief lever? :huh:
Click to expand...

Busted...:gag:

I have radiator caps on the mind because found out today our mechanics in preventative maintenance didn't know the caps needed to be tested. Heck they didn't even know the buses were equipped with pressure caps. :nono:
 
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