rangermonroe

Oh.. and yes, the fan is turning in the correct direction. That was the first thing I checked.

dave1123

I realize the dynamics are hard to reason with but I base my opinion on the fact that my WJ only has an electric fan, but has the original shroud designed for the clutch fan and has only overheated once when the control module stopped working. I was quick enough to realize it and shut the engine off when the gauge topped 240*. The electric fan with the shroud is like a blowpipe in the middle of a venturi in that it gets the air surrounding it in motion as well. I WILL say, however, that the engine compartment needs more venting. All that air coming thru the radiator builds pressure around the engine with no place to escape, more so with a V8.

wingless

The tool I use to verify proper fan clutch operation is a strobe light w/ a manual variable speed control. This tool permits me to precisely measure the fan RPM and the clutch hub RPM to determine if it has locked or is slipping.

rangermonroe

I put the shroud back on, just for S&Gs. Maybe the venturi effect will help, we shall see.

Here is a bit of critical information that I inadvertently omitted: When I replaced the t-stat, I accidentally put in a 195 degree one. A Stant with the larger bore, FWIW.

I suppose that I could pull it entirely, just to observe any difference; however, as I ran my heater on the way home this morning, the heat seemed tepid and didn't effect the gauge temp reading in any appreciative way.

The A/C running made it warm up about 5 degrees. The air was as cold as it ever is.

I am leaning toward a faulty sensor. I should swap them out of my kids' cars and see if it makes a difference. LOL.

97grand4.0

Dont know what the factory stat for the v8 is, but the 6 is 195. Meaning it starts to open at 195. My stant runs just under 210 when going hard but does pop up to 212 or so. For OBD2 to go into closed loop and use O2 data to trim fuel, you must be over 200F with ANY obd2 engine. So, 225 does not really seem all that bad to me in the first, I could be wrong its happened once before. That said, moving the air across the radiator is the only thing that will cool it, you need to increase the air flow or the radiator.

dave1123

Hey Ranger! How about updating your profile so we know what it is you're driving?

rangermonroe

I have and drive 4 of them.

this one, is as stated in the OP , 1994 v8 AWD with the 231(IIRC) TC, and no front drive shaft at the moment. The ****ty TC that has all the problems.

rangermonroe

yeah. You are right.

It's either cooling, or it's not.

I am spending an inordinate amount of time trying to "diagnose" this, in public and on this forum, for reasons.

Mostly because I am **** and have been broke most of my life. I want this dang temp gauge to read "correctly", and I want to spend the least money that can be spent to achieve this goal.

I suspect that most folks who stumble in here are searching for the same information.

It would be easy enough to change out the remaining parts of the cooling system, en bloc, and I would be done. That would never tell anyone following what the issue was ultimately, just that it took money to fix...

I am going to sort this out a bit at a time: for both my entertainment and the edification of anyone who finds my Quixotic endeavor.

You guys are a fountain of information that I have quietly observed and benefited from over the years since I have been a member. Maybe this is the time I need to sort it out, with y'alls input, for the benefit of this board?

dave1123

If you want to get OCD about it, the t/case that's ****ty is the NP249 Quadratrac AWD. The NP231 is a manually selective 2wd-4wd t/case used mostly in the XJs and is rugged and dependable. The NP242 Selectrac is a manually selective t/case the same as the 231 except it has an additional 4wd range that's full time 4wd and is found in the ZJs and WJs, usually in the 4.0s. I've never heard of a Limited with a 231 unless someone swapped it in.

Just for grins, when was the last time the block was cleaned out? There's a drain plug on each bank just about the oil pan. Just about every time I've pulled them on a Chevy, they were so crapped up I had to bust the rust loose with a screwdriver. All kinds of loose junk came out then. That should help the coolant flow thru the engine. Also, I don't know Dodge well enough to know, but some engines have a steel diffuser tube that slides into the water pump ports to help spread out the coolant flow evenly thoughout the block. These can get crapped up and slow the flow. You wouldn't have seen these unless you took the water pump housing off the block.

rangermonroe

No, you are right. It's the 249.

As far as the block drains go, I have never heard of that, so of course I haven't gotten that far. Yet. Damn you.

The water pump was rather new, certainly in good condition,and the housing didn't have a lot of crud on it. I suspect that that is an indicator of the rest of the system, but will have a better idea after I get done draining my block.

ETA: I appreciate the help.

dave1123

Sorry to add work, but I wanted to touch all the bases to make sure we hadn't left anything out. About the diffuser tubes, I can't seem to get a definitive answer weither the 5.2 has them or not. The last time I saw them was in an old 392 Hemi. (circa 1958) I wouldn't pull it apart just to check.

rangermonroe

The black tube coming out of the water pump on the driver's side? I checked that already when I changed the water pump. I was clear.

If the shroud doesn't do anything, I am probably going to toss a new sending unit in it tomorrow.

Then do the flush thing.

I was actually going to do that today just to mess with you, but it was too hot and I have a couple other more pressing projects that demanded my time. (Wife is happy that I fixed the washing machine today.)

dave1123

No, what I was talking about are tubes that go into the block water jacket with holes in them to even out the coolant flow around the cylinder barrels. I guess they got rid of them in the 50s.

Yeah, going to the laundramat sucks. Happy wife, happy life!

Nofearxj

Hey I need help with my 99 Jeep Cherokee to I have put a new thermostat in 160 temp and new fans and new water pump still over heating at high way speeds

97grand4.0

Welcome to the forum, and you need to start another thread with the new topic I believe, but, do not put a 160 in, your pcm will not go into closed loop and run rich. You need a 195 Stant. That will have you run around 2o5 to 210F. You have to be above 200 for the obd2 to work.