Doobie1369

1st, please bare with me, I'm not mechanically inclined. My '96 Jeep Cherokee Sport likes to stall out when the temperature gauge reaches about 210 to 230 degrees. It goes though it's initial cycle with the temperature going down & remaining steady if I'm driving on the freeway or am in continuous motion, but when it's an exceptionally hot day, I'm in stop & go traffic, or have been driving it for an extended period of time, the needle makes it's way back up & the engine just goes off. It will either do it as I'm coming to the stop or as I go to accelerate from the stop. When this happens, I'll get it started back up usually on the first shot to get it to a parking lot to let it cool down. Sometimes it doesn't want to turn back over right away. I'm taking it over to a mechanic friend this evening to have him look at it, but I'd like to go to him with a couple of places for him to start.
Please help, if you can...

qldit

Good Morning Doobie1369, I am not familiar with that vehicle but it sounds like it is running exceptionally hot!

Generally the water circulation through the radiator, (which goes in the top and out the bottom) is cooled by heat transfer in the radiator using ordinary airflow.

Generally at the bottom of the radiator you should see some thermal switches, these usually operate in the area of 185 degs and operate the electric fan and that should maintain the temperature lower, then switch off, when ordinary airflow is insufficient.

(I am assuming your machine uses the electric fan system)

The 210-230 degree area sounds quite worrying and needs urgent attention from my point of view.

It is a wonder you haven't been bursting hoses and having a steaming mess!

Things that can reduce cooling effect are the fan system not operating properly, bad hoses that suck inwards and limit water flow, (especially the bottom hose) coolant gelling, (where the coolant turns into jelly especially in the bottom area of the radiator) radiator with a flow problem or blocked, water pump not circulating coolant for some odd reason, (on rare occasions the actual pump impeller can become adrift) and faulty thermostat limiting flow, often placing airflow obstructions like driving lights and other accessories can affect intake airflow and thus cooling.

Engine efficiency and headgasket leakage where high pressure cylinder gases displace coolant also cam promote overheating, this kind of thing usually follows a series of repeated overheat and significant boiling event cycles.

It is not uncommon for overheated engines to cease operation, actually they can even sieze in some circumstances. Very ungood!

Others will have different ideas.

Cheers, qldit.

Doobie1369

Hi there qldit...= )...

Good morning (as it's just past midnight your time)...The 230 degrees was an extreme & it only happened once, it may not have even been that hot & I just had a fit over it, but I digress. Ok, my mechanic friend changed out the thermostat last night because it was stuck closed. It appeared to be working fine as we ran it around last night & when I started out this morning. The temp gauge is registering fine, but after being on the roads for about an hour, I came to a stoplight, & it stalled out again. I managed to get it started & into a parking lot & after letting it sit for about 2- to 30 minutes, I made it the last few miles to work. I want to rule out the water pump because we just replaced it within the last 3 months. My uncle suggested it might also be the fuel pump possibly going out & not getting enough gas through the system & creating a vapor lock. I will definitely pass all this on.

Thanks for your help!
Doobie1369

qldit

Good Morning Doobie1369, is that a normally aspirated non-efi type engine?

Some Jeeps are very hard to properly fill the coolant system and need to use special procedure to fill.

Apart from that, it kind of sounds like an engine mounted component may be involved, and you might be losing spark, does that machine have a distributor?

The easiest way to test this is to tie an unused sparkplug in a suitable easily visible area to the motor, so that you can remove a spark-plug lead and connect it to the remote plug, this allows you to observe if any spark is present during cranking without damaging anything when the problem happens.

Sorry to sound so vague.

Cheers, qldit.

Billygtr

I have a 97 Jeep GC with the 4.0L inline 6 cyl engine that had a very similar problem. On a hot day, while sitting in traffic, it would sometimes stall. I usually could restart it with no problem, but the wait times got longer and longer until after one stall it would not start and I had to call a tow.

Towing it to a (formerly trusted) repair facility initially yielded the diagnosis of a MAP sensor out of range, so I spent about $100 on a dealer MAP sensor because it was the only one available. That did NOT fix the problem.

I ruled out the coil, since I had replaced it about 2 months earlier for a similar stalling problem, but the second diagnosis was a bad coil. Fortunately, the replacement coil was still under warranty, and replacing it solved the stalling problem.

Stalling under high heat conditions is a classic symptom of coil malfunction, so if you're still having a problem THIS summer, you might want to look there.

Past performance is not indicative of future results; your mileage may vary...

BillyGtr

SABL

The coil going bad is a very real possibility due to the age of your Jeep. Have your coil tested at your local auto parts store.

Regardless of your outcome please post your findings back to the forum so others may be informed of your progress and perhaps the solution. This forum is for sharing information for the benefit of the members.

Thanks
SABL