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TJ Heat

2K views 19 replies 7 participants last post by  erickpl 
#1 ·
Of course it's friggin cold (17 degrees) this morning, but I drove the Jeep today, which normally has an awesome heater. However, I could NOT get warm and neither would the Jeep. The thermostat never got 3/4 of the way to the FIRST hash mark between 100 and 210.

I am wondering if I need to do a flush, change of thermostat, and refill of coolant. The level in my overflow is a bit lower than usual, but nothing major. The last time I flushed/filled the radiator and changed the thermostat was when I had the Jeep back in California and put in a new radiator back in late 03 or early 04.

What would you recommend for a flushing procedure? Or is there something else I need to look at? I am not sure in the internal heat (or lack of) is due to a bad heater core, or due to the thermostat not letting the warmed up coolant flow back to it. I just dunno.

Input would be appreciated.
 
#2 ·
1st of all 17 degrees is not cold... I would love to wake up to that temperature being in North Dakota. We are at -21 degrees this morning and the Hi Is only -8.

Anyway it does sound like you need a flush since its been a few years, but it sounds like your thermostate is stuck open, not allowing it to heat up the way it should.
 
#4 ·
That seems to be the consensus.

Now what is a good (and environmentally friendly/safe) way to do this? I want to be sure to flush the entire system, including the heater core. So any writeups would be appreciated.

Any suggestions on coolant? I have a CSF radiator that I put in.
 
#5 ·
Enviromentally friendly and safe huh? Take it to a garage. :D I would say just be sure you are able to capture all the contents of the radiator, engine block and heater core and put in a safe container till you can get rid of it. I always flushed the heater core separate from everything else. Do a forward flush then a backwards flush, and keep repeating till you get clean clear water. As for antifreeze i put in what Jeep recomends, either the Mopar brand Antifreeze with HOAT or Zerex G-05. Most parts stores around here does not carry the Zerex, but the Napa stores does.
 
#7 · (Edited)
I had bought a flush kit from the parts store. I hooked up the kit to the intake hose and ran water through the system, then hooked it up to the exit line on the radiator and flushed it that way. Do this repeatedly till you get clean water. Do the exact same thing to the heater core but seperatly. The heater core can trap sludge and stuff because its smaller. Sorry i don't have any pictures of this but if you have a flush kit and a haynes repair manual those help out alot.

Do you have someplace heated to do this? If its only 17 degrees it will be a little cool to be flushing with plain water.
 
#8 ·
Guess picking up a flush kit is on the list too. :)

Dumb question: Which is the exit line and which is the intake? I don't watch the coolant cycle through. :)

I do have a Haynes manual, so I'll check it out when I get home.

I do have a garage, but I doubt I'll tackle this until it warms up at least a bit.
 
#9 ·
I just looked in my haynes manual and it does not show using a flush kit. It just recomends filling up with plain water with your drain plug open till clean water comes out. I don't think thats good enough for me. I would advise the flush kit. Or have a garage do it. I do somethings myself but i still use a garage if im not sure what im doing. I am getting older so i use a garage alot more and more lately.
 
#10 ·
I deleted my last post, i goofed up. But your top radiator hose is the intake for the coolant coming into the radiator, the bottom hose is the exit with coolant leaving the radiator and going into the engine block to cool it. When doing a flush remove your thermostate so water will flow freely to and from the block.
 
#12 ·
Stop, stop at the dealer, get a 185F thermostat and gasket, stop at parts store and get 2oz bottle of Indian Head gasket cement, remove and clean the old thermost block, let it tack up a bit, insert the thermostat and put the gasketed housing on, hold it in place so nothing slips, insert the bolts and hand tighten them, then torque to 15ft/lbs per the 97 FSM, also you should have an 18lb pressure cap on there. Then top off the radiator.
As for coolant, the FSM is very specific, ethelyn Glycol ONLY, no fancy stuff according to them. My 98XJ FSM says the same thing.
I recommend the OEM gasket as I have had some real sealing problems with felpro and some of the other mart gaskets for some reason. The indian Head gasket cement is just added insurance. I've done this in an auto parts parking lot at -10 when my Tstat stuck open, it was so cold the indian head stuff was freezing before I got it on.
 
#13 · (Edited)
I'll check the dealer prices. NAPA has t-stat for under $6.00 and gasket for .79 cents. If not much more, probably just do OEM. I'd really like to use the pre-mixed stuff to make my life easier.

As for a flush kit, are those the kits that you splice into your hoses with? I'd prefer NOT to splice hoses and introduce new potential leak sources.

EDIT: Dealer quoting 195 degree t-stat as 9.85 and 1.50 for the gasket.

Is the OEM quality that much different than what I'd get at NAPA?
 
#14 ·
EDIT: Dealer quoting 195 degree t-stat as 9.85 and 1.50 for the gasket.

Is the OEM quality that much different than what I'd get at NAPA?
The NAPA thermostat is fine, and stick with the factory specified 195 degree thermostat as you mentioned. Going with anything cooler like a 185 degree thermostat (like was recommended above) won't help the engine get warm faster (it'll actually slow it) and it won't help it run cooler in hot weather either. :)
 
#15 ·
Jerry, I was thinking that too, and dealer specs call for 195 degree, so that is what I'll run in the TJ.

I noticed that my overflow bottle is VERY low (perhaps 3/4" of coolant left in it). I'll be picking up a coolant tester since I lost my last one and see where it is at and add either distilled water or coolant as needed to top that off.

Would a low overflow be a potential reason why it wouldn't warm up properly?
 
#20 ·
Rich good idea to have a hose setup for just the flushing. I didn't like the idea of cutting a good hose and driving with it. Hadn't thought of that part of it.

I DID top off the overflow and the temps were better, but it was still only at the first hash mark. I have a new t-stat and gasket from the dealer ready to install. I just need to pick up that flush kit and some more coolant and find the time to do it.
 
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