synergy58

So...ran my jeep (2001 Cherokee Sport, 4x4, automatic) down the road, doing about 65-70, in lots of traffic. Al of a sudden, the warning lights come on showing that I need to check my gages. I look and my temp gage pegs all the way to right, like in the 260 degree zone. It was 101 outside, AC running fast and cold, and I'm stuck in traffic with no where to go.

I finally get to an exit, of course I cut the AC off, and I get to a stopping point. Get out look under the hood and it's HOT under there. No signs of any damage, thankfully. I have 700 more miles to go before I get home too.

I let her cool for about 30 minutes, start her up and the gage pegs right again, then settles down at around 210-220, somewhere in between there. It ran fine for about an hour and stopped for a rest. Another start and she pegs right again, then after I start rolling, she begins to settle back down to the 210-220 range. This is repeated the rest of the trip, but one time when I started it after getting gas, she hesitated, ran ruff for a few seconds and then smoothed out.

About three months ago I put a new electric fan it, it has worked great. I'm guessing it still works but I can;t get it to come on, not sure how hot it has to get before it comes on by it self. Otherwise, I'm sure I need to get some things checked and replaced, but what?

I thought that maybe the was suck closed, but it must be open if its running around 210-220, right?

Anyway, any help would be greatly appreciated. I can get it all repaired but I don;t know what needs to be replaced.

Turbo X_J

Engine perhaps, do a compression test and see if the cooling system will hold pressure. Severe overheating is the kiss of death for any cylinder head and/or block.

BlueRidgeMark

After you got to the exit?

Bad move. Very bad move. When your vehicle is overheating, and you can't pull over immediately, you immediately kill the AC, open your windows, and turn on your heater full hot, full blast.

Yeah, heater. Full blast. In Arizona. That's right.

Your discomfort might be the difference between trashing an engine and saving an engine.



There can be plenty of damage that you can't see. The worst damage is where you can't see it.





That's probably due to an air pocket because you blew coolant out. You didn't add any after you let it cool?????

OR, it might be that your thermostat is sticking, then opening. More on that later.




Why would you be guessing it still works???? Test it, then you'll know. Give it 12v right to the connector. Then you'll know. Stop guessing. Test.


A lot less than 260! 218, IIRC, but maybe that varies a bit depending on the model year, but it won't be a LOT different.



Uh, that sentence doesn't make any sense. I think you some words out, maybe....

Do you mean to say, "maybe the thermostat was stuck closed"?

If so, well, maybe it's sticking and THEN opening late. It happens.



Well, first thing is what Turbo suggested. Get that compression test done. You need to know if you've trashed the engine before you start throwing parts at it.

The good news is, these engines are tough. I overheated briefly a couple of months ago (hit 260) and my compression is fine. No head issues. Nothing. I seem to have survived it. You might have, too. It all depends on how long you were at that temp.


If the engine checks out okay, I suggest a complete cooling system overhaul. Plenty of threads on that - many say it can ALL be done for around $200. That means radiator, t-stat, hoses, water pump, fan clutch - the works. I haven't priced it myself, but I plan to be doing that soon myself.

If you are doing all that, you also should replace your temp sensors, just to make sure. It's possible that's why your electric fan didn't kick on. Could also be a bad relay, or a blown fuse. Check it all.

One more thing - if the engine is okay, and you are going the full cooling system replacement route, try an old mechanic's trick first. Toss in a quarter cup of Amway SA8 laundry detergent. Run that way for a month or so. Then drain the system and replace your components. That stuff is great for cleaning out a cooling system. Won't harm anything in your engine, but really gets it clean. Search online for a dealer near you. No, I don't sell it.

Fred/N0AZZ

X2 till it gets to the bottom about the "Snake Oil" products don't know about soap.

toasterknight

You can do the same thing with straight dawn. it works much like those chem flush bottles but its cheaper.

synergy58

Hm? Okay....Well, I had a hard run for 1. hrs when all this occurred. I was stuck in the middle of bum *uck Cincinnati (my least favorite place, besides Dayton that I've ever been in my life!), on my way down to Florida (home). It was rush hour and there was not a *amn thing I could do. I did shut down the AC right away, but I did not know about the heat. I ran till 10pm and crashed in a campground. Hit the road at 7am and drove another 10 hrs to Florida. I had a couple of temp issues where the gage staged right into the max zone.
It lost NO coolant, not a drop.

I parked it and it sat till this morning. I checked it and it fired right up, ran fine, everything worked. I did not let it get up to complete operating temp as I only ran it for 5 minutes at the most.

So the electric fan is good, I checked it. I ran the battery straight to it and it came on and ran like crazy; I had replaced it 2-3 months ago. I never really heard it come on while driving. The only way that I know to make it come on is to run the engine until it reaches the temp that makes it come on, but I'd rather not do that right now. The oil is good, the radiator is full, the over flow is good, but both are old looking, like a dirty brownish green color. Yes, I'm sure it needs a service.

So, I'm guessing I need to replace...
1. radiator, OEM with a dual core unit
2. thermostate - what temp?
3. hoses - 2
4. sensor - is there only one?
5. coolant

Anything else? What brands?

AND YES, I forgot a lot of words...I was STRESSED OUT!!! Haven't you been stranded and running on limp mode not knowing whats going to happen in the middle of know *uc*ing where? I've been shot, bombed, beat up, stabbed, had 14 pieces of shrapnel removed from my body. I have two titanium rods in my back and a my 4th and 5th cervical vertebrae are fused, from getting blown up, and had my right arm nearly removed from my body. I have PTSD and TBI's and I get frustrated and STRESSED when ***** hits the fan!

Few...sorry, just had a moment there... , it's all good. Hooah!

Thanks.

synergy58

Alright, so I squeeze dawn in the radiator? How much? How long do I run it, a day, a week, a month? And what if I need to get all this work done right away? Can I just run it for an hour, will that work? Do I drive around for a while, what?

toasterknight

I added 2-3 seconds of squirting. Then ran it for 400 miles.

ehall

It sounds like your coolant temp sensor or the wiring is bad. Most of the sensors use resistance to ground. If you unplug the sensor at the connector, resistance is infinite and the gauge will drop to the floor. But if you short the sensor wires with a paperclip or something, no resistance, and the gauge will spike up. What you describe is like the sensor shorting internally periodically and then returning to normal

Simple test is get an IR temperature gun and point it at the thermostat housing next time.

Buy good quality sensors, either MOPAR or Standard brand, rockauto.com has them

Bocefus

Do a complete cooling system refresh.

New Radiator. (Advance Auto with discount code)
New Fan Clutch, Hayden standard duty (Advance Auto with discount code)
New Hoses (Advance Auto with discount code)
New Mopar Water pump (ebay)
New Mopar Thermostat (ebay)
New Mopar Radiator Cap (ebay)
Also a good time for a new Belt if its due, (Goodyear Gatorback on amazon)

If money is very tight, replace the radiator first. That is most likely the problem since you overheated on the highway, which indicates a flow problem. However, its not much money to just change it all, and its best to do when you have it all apart and coolant drained.

Bugout4x4

Thank you for your Service and Sacrifice for your Country! I'm not sure Mark realizes that helping someone learn by tying them to a whipping post and giving them 20 lashes in the public square to make an example of them can be both ineffective and unproductive. All it does is create animosity.

BlueRidgeMark

Cool! I hadn't heard about Dawn being used for that. That's good to know, as it's a lot easier to get than SA8. It's the detergent of choice for people doing oil-spill animal rescues. Gets the oil out better than any other.

If it cleans as well as the SA8, there's never any need for the chemical cleaners. I've used the SA8 on some pretty gunked up systems, and it leaves them thoroughly clean. The nice thing is, it can't hurt anything in your system. Toss it in and leave it all summer long - it won't hurt anything. Drain, rinse, and replace with coolant before freezing weather and you're good to go.



Yeah, since he didn't lose a drop of coolant, I'm thinking he didn't actually overheat, he got lied to by a flaky sensor. It's pretty hard to get that hot for that long and not lose a drop.



Maybe you should take some time to consider the significance of this thing known as a "smiley", especially this one -->

There's a reason those things are used.

rdr8887

Too me, this sounds like an incredible waste of money and an afternoon. Diagnose and use data to come up with a logical solution.

Turbo X_J

I guess we will be waiting for you then.

rdr8887

I wouldn't wait on me. I've already proven that I'm no good at diagnosing an issue. There has been a few good suggestions here already for checking the electric fan. Good place to start. I always start with a coolant pressure test when I'm overheating. See if anything is escaping. If not, flush the system and see what comes out.

I don't see the value of replacing the entire cooling system for a coolant issue. you never find the root cause and will never be able to give someone helpful advice in the future. You're definitely not expanding your trouble shooting knowledge base.

It's kind of like when people have a rough idle and the advice given is to do a full tune up and replace TPS, Cps, fpr, Fuel pump, fuel filter, MAP sensor, air filter, and the motor. That's a lot of things to replace each time you have an issue.