replacing thermostat

Many have a minimum labor charge, plus they are likely to tell you that your coolant is bad so plan on new coolant and a "liquid waste disposal fee". After twelve years those upper radiator and heater hoses are likely to crack when disturbed, thermstat is going to cost retail. I shudder to think about it.

Earle

How difficult is this to do yourself?

Not difficult at all. Here is a ref.

Personally I think the used way too much RTV on the gasket. I tend not to use any unless the gasket calls for it, and then just a very thin coat. A torque wrench is also handy. The bolts go to about 16ft.lbs and make a note of where the longer bolt goes. You need to allow time for everything to seal up and check after it idles for a while and gets hot.

"If you have to ask, yes..."

No, not for most of us with mechanical experience.

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Thanks for the link. Any tricks to getting the bolt near the serpentine belt out? It looks pretty tight.

I live Permatex Hi-Tac red for coolant applications. Whatever you use, make sure it says "for ethylene glycol" on the label. Otherwise you're going to have a leak.

Earle

Depends on where you live and what type of garage you go to.

It is a fairly simple job, you will want a new thermostat of the correct temperature plus a gasket and something that can be used as a scraper to clean the mating surfaces.

You drain a good bit of coolant out of the radiator so it doesnt get all over the place. Keep it clean unless it looks gunjy, in which case replace the entire coolant.

Then pull the old thermostat. Clean the two mating surfaces carefully so you dont leave any scratches or old gasket material behind.

Some folks use a dab of permatex sealer, but if you do be very careful it doesnt get on the thermostat itself.

Make sure you point it the right way as you put in the new one.

Then, you will probably need to burp the system a bit as you add the coolant back, otherwise you can get an air bubble that messes with your temp sensor big time. Methods vary.

Or, find a local independent garage that when you pull in knows exactly what a TJ is and can tell from a glance if you have the 4.0 six, etc. Call around and ask if they know what a Jeep TJ is, and at that point they should ask you whether it is the six or four.

Just replaced the tstat in my 97 TJ. Seems like the engine is not warming up completely. It is staying around 180. I put a 195 tstat in. Also, It seems the heat is no longer working. could the tstat not be in all the way. I made sure I put it in correctly. Ideas? Thanks

When you put the heater hoses back on did you reverse them?

To check flow just squeeze(pinch) the upper radiator hose when the engine is hot and running. You will be able to feel the heat and hear/feel the rush of coolant.

You can (with a cold engine) remove the radiator cap, start the vehicle and wait for the thermostat to open and flow to start.

Maybe that is a defective "new" thermostat. I currently have one too that is keeping my engine too cool since I installed it. I have to change it out one day soon. ;-)

Your heat prob might be due to low coolant level. Gotta get that excess air out!

Stupid question, but was it by any chance one of the "failsafe" type? If so, you'll probably find when you pull it that it locked itself open.

If it's like my '95 there is a 3/4" heater hose and a 5/8" heater hose. It's really hard to do so, but dumbasses at the factory switched them. I know from this that having them reversed won't make the heater not work. The heater is likely to get an air bubble when you replace the thermostat though. One way to eliminate this is to hook up one heater hose first, then fill up the heater through the other hose using a funnel. This does sound like a defective thermostat or incorrect part.

Earle

I just slightly open the backflush tee for a moment on my flush-n-fill kit to let the air out of my system. It's right on top and next to the heater core and is a great place to purge the air after a coolant fill up. This also worked on a V8 Chevy.