JGC2000

Hello All,

Quick question about how my 4.0 on my 2000 WJ is running temp wise. From past experience with a '01 XJ with the exact same powertrain, I know that it should be running smack in the middle of the temp gauge at 210. My WJ seems to run much cooler, usually somewhere in the 2nd quarter of the gauge (between 170-190 at cruise). It only seems to get into the 210 area if I idle in traffic or at the drive through (fan kicks on works properly). I'm not overly concerned, but this seems off to me. The coolant is clean & green, it had a new water pump, thermostat, belt, bypass hoses, upper & lower radiator hose, and most of all,a new radiator in the last 20K. Any suggestions? I have heard that there are two thermostat temp ranges that are used in the 4.0, a 195 and a 180. I don't tow, and don't haul anything more than my bicycles or people. Thanks for reading!

Bustedback

It sounds like you have a 180 degree t-stat in there. Don't be worried, your temp is fine.

JGC2000

I appreciate that, I am so used to my other vehicles running in the middle of the temp range and thought running that cool would be harmful for my older engine, especially going into the winter here in the NE. Thank you!!!

JGC2000

Get this, I failed NYS inspection because the low temp readings triggered a check engine code. When I took it in this morning, it just refused to get much above the 150 mark and it was chilly outside Lukewarm air (at best) blowing through the vents. Turns out that the thermostat WAS/IS sticking and it threw out the code. Had the code cleared. Off to the parts store, will change it out and take it back Monday, no biggie. 1st time I have ever failed a state inspection since I have been driving. (30 plus years)

Bustedback

Well, if the check engine light is going to come on it will be right before or during the emissions testing. Sorry I steered you wrong.

dave1123

I have a 195* 'stat in my '00 WJ 4.0 and, like you said, my temp gauge runs in the center all the time. Last winter, when the air temp was below zero, it liked to run around 180* on the road but warmed up in traffic. I noticed a lack of heat in the cabin at times and thought something was wrong, but as soon as the outside air returned to something near normal, it was fine. What I figured out was the outside air wasn't getting warmed enough by the heater to actually feel hot enough. I changed the air flow to recirculate and the temp inside the cabin went way up. Nice and toasty. I live in the Syracuse Metro area BTW.

JGC2000

No worries, that morning, it just wouldn't warm up.....Replacing it today, will let you know how that turns out. I am hoping this is not a bigger issue, like a heater core plugged up. More to come.

JGC2000

I get the fluctuation in the outside temp can affect the temp of the motor. When I got this in the summer (mid August) we were having some hot weather and I was like, " Nice, even with the AC blasting and sitting still its right in the middle!" This issue popped up with the recent string of mornings in the low to mid 40s here in SE NY. Sat. morning, it just refused to get above 1/4 on the gauge and was blowing lukewarm air (and that's being kind). Gonna change it out and flush the system (even though the coolant looks great and it has many new components (including water pump & radiator). Sucks that this all went down for what amounts to a $12 part. More to come.

dave1123

I just bought a Stant Superstat on rockauto.com for $4.35, with shipping it was $7.00 and I got it in 3 days. I'm getting ready to do my biannual system flush and fill and replace all the hoses.

JGC2000

That's what I used....old one was not a Stant and I got it locally for $12 at a good parts store.

JGC2000

Old stuck one on the left...Jammed open so bad I couldn't unstick it




Housing on the bench, cleaned up




Block without the housing




Engine without shroud..which my brother and I removed for easier access. What a PITA!




Fan shroud after removal.

dave1123

Just an idea I'd like to share. You could cut the shroud in half on the sides and use sheet metal screws and plastic plates to rejoin it. That way you could remove the top half leaving the bottom half mounted for the next time you have to do this. Use hex head screws because there isn't enough room for a screwdriver. 1/4 ratchet works the cat's.

The fan shroud on my Chevy truck was 2 pieces stapled together on the sides. The PO had removed the staples and used sheet metal screws. I thought that was a fantastic idea when I had to replace my water pump. I had all kinds of room to remove the fan bolts, hoses, and other stuff. When I did this on my ZJ, I had to remove the bolts and slide the shroud back over the pump to get room to remove the fan bolts and lift both out together. I cut mine before putting it back together. I'll probably do it on my WJ from the looks of yours.

How is the fan mounted?

JGC2000

The fan on my WJ was mounted with the factory 4 bolts/screws. When my brother owned it he actually cut the wire for the fan to disconnect (we had to do that again), and then did not replace the two bottom screws, instead wedging it in tightly in the existing slots (it works!). I never thought of cutting the shroud. I know that on the new Wranglers it is a two piece shroud, so that makes complete sense. I love this suggestion and if the need arises, I will see if it works. The only thing I would be concerned about it securing the bottom, but I guess we can find a way with the hex heads. Let me tell you, it took us 45 minutes for 2 of us to shimmy it out. Thanks for looking out!

bigbadon

Don't trust your gauge as being accurate. My gauge reads left of center (about190) but a scan tool reads dead nuts 210.

JGC2000

Since the change out...it is right up the middle where it should be. What a relief!