Severely overheated.. Now hard start, hesitation, and rough idle..

I searched for a couple of hours and didn't find what I was really looking for so here goes..

'98 Limited 4.0 Auto.. Now the back-story.. It was running hot but not overheating a bit over the past month.. New water pump and I flushed it several times and had just put some chemical flush in it last week.. After 2 days with the flush in it, no more hot running at all.. 210* around town and 40 mins on interstate twice a day.. Yay. Now, my girl takes the XJ Tuesday to run a few errands and on the way home about a 1/2 mile from home the truck starts losing all power and making a CLACK CLACK CLACK noise from the engine.. Instead of pulling over at the 1st sign of trouble, she decides she's close enough to home to make it.. She managed to get it 1/2 way up a very short driveway before it stalls and won't restart.. She comes and gets me..

As soon as I get to the truck, I turn the key to see the gauges and watch the temp needle smack the right wall of the gauge.. It won't start and now there's a real nice billow of smoke coming out from under the hood.. Whether it's oil being burnt off of the outside of the engine or the inside I don't know, but it seemed to be originating from just below spark plug level..

After letting it sit and cool a while, I went to see if I could start it fearing the worst.. It barely managed to fire up with my foot into the pedal quite a bit and had a hell of a time keeping it running.. All the while, that CLACK CLACK CLACK (loud, couldn't miss it if you tried) chiming in with the RPM's I cut it off and started checking things out..

Now, my girl swears up and down that the gauge read 210* as she was driving it back home.. But I discovered that the radiator had cracked and there was nothing in it.. When it drained I have no idea, gravel driveway and all.. Thus the overheating..

I've since replaced the radiator, and taken a couple of test drives.. There's definitely some hesitation on starting.. The CLACK that was there is now gone.. In park, it will rev no problem with no odd sounds whatsoever.. But trying to get it out of the driveway and down the road was quite difficult.. A lot of hesitation and near stalling.. A mile into the test drive, and things are got a little better but not right by a long way still.. Got her up to speed at around 65 a several times from a stop using WOT and tried to 'blow out' any junk.. Temp never went over 210* yay.

Took a second test drive just before writing this.. Still have a harder start, rough idle (park and in gear), and hesitation on acceleration from a stop. After a couple laps around the block and quite a few WOT takeoffs, the hesitation seems to have cleared up a lot. The rough idle is calming a bit and she re-started a bit easier after pulling back into the driveway.. No Check Engine Lights.. The oils burnt, but to early to say if it's gonna get milky..

My questions- What in God's name was that CLACK'ing? What should I do besides an oil change, spark plugs, and monitor the coolant and oil for a couple of weeks? I'm thinking some Sea-Foam to clean up any other junk that may have gotten cooked inside the cylinders.. What else do I need to look for as far as damage? ie- the head/gasket Anything else?

Funny thing about all this is that it's my jeep.. Hers is already mostly torn down next to it for a blown head gasket and incurable overheating.. That, and I took her radiator..

But seriously, I've never seen any vehicle overheat that badly and am worried about what damage my engine may have really sustained and what to look out for/check on..

yeah just change everything you can, its a pretty tough engine. maybe the clacking is due to the burnt oil not being able to properly coat the engine, so there is more metal to metal contact. And sea foam wouldn't hurt.

And im not just saying women make "poor decisions" but my friends OLDER sister did the exact same thing in his 94 grand cherokee. well it was hers for a couple months, but in that time she ran it with no coolant once and out of oil twice! but it was pretty much fine after some new coolant and oil.

these jeeps are VERY reliable, but once you hit the ten year mark you just need to replace stuff, or dont be surprised when it fails. stuff wears out, im just glad that are engines and transmissions dont!

I hope its not the case but be prepared: The last time I had an engine overheat albeit a different engine, I had the same symptoms: rough idle and clacking sound, the heads needed to be rebuilt.

Regarding women and cars, my ex-mother in-law drove a Buick Lesabre without ever adding coolant or oil or opening the hood for that matter and ended up with a cracked block with less than 30K on it. To make matters worse, she took $2000 for it as a trade-in on a new car from a dealership. I was ready to fly down there, pay her 2 times that much for it, shove a rebuilt engine into it and sell it at an amazing profit but it never happened.

Rent a coolant tester--you have to purchase the chemicals--and check the coolant for combustion gasses.

Then run a compression check--first cold, then hot.

Post up what you find.

austinaubinoe said:

yeah just change everything you can, its a pretty tough engine. maybe the clacking is due to the burnt oil not being able to properly coat the engine, so there is more metal to metal contact. And sea foam wouldn't hurt.

And im not just saying women make "poor decisions" but my friends OLDER sister did the exact same thing in his 94 grand cherokee. well it was hers for a couple months, but in that time she ran it with no coolant once and out of oil twice! but it was pretty much fine after some new coolant and oil.

these jeeps are VERY reliable, but once you hit the ten year mark you just need to replace stuff, or dont be surprised when it fails. stuff wears out, im just glad that are engines and transmissions dont!

Click to expand...

This friends sister didn't happen to live in Bel Air, Md did she?