Cooling issues/ possible head gasket?

Heres the specs: 99 XJ, 2wd, 2.5/ax5 115K

The water pump went out a few months back. I replaced that and the tstat and all was fine. The water looked a little brown and murky but not over heating... 190-210. After the flush, the freeze plug went out (behind the belhousing). Replaced, flushed and good for a bit. Now the tep goes between 210-220. It hasnt over heated but this still isnt good. took it to a shop to have it flushed and checked (presure, ect...ect...) all was good but it still hangs in the 210-220. Both fans do work.
This was les than a week or so ago. Now, the water is a bit stained again and tep still higher than normal (210-220). After driving a bit, I notice the over flow tank is bubling... and, you can see where fluid has been ejected from the overflow.

I pulled two plugs as I was told I may see a green tint if there was a head gasket problem. Nada. The exhaust doesnt smell "sweet" nor does it when I crank the heat. Even with the heat cranked, the temp really doesnt dip.

I am going to have a compresion test done but if a cylinder is low, it could be rings, vaulve issues or a head gasket. Wont tell me all that much.
At any speed there isnt hesitation from say colant or water getting in the cylinder... not yet.

Would swaping a 165(current 195) degree stat help? Radiator clogged? (forgot to mention when I flushed it after the pump was replaces, it was gunky dicoloored fluid (mud) coming out then turned clear) Bad temp sensor? Head gasket?

Where to start and what to look for is all I am asking, any and all opinons are welcome and appreciated. Thank you much in advance.

Marc

I HAVE READ ON HERE ABOUT SOME WATER PUMPS HAVINGTHE IMPELLER RUNNING THE WRONG WAY IN OTHER WORDS COUNTER ROTATING I CANT REMEMBER WHY THEY MAKE A PUMP THAT WOULD BE SET UP THAT WAY BUT I REMEMBER READING ABOUT IT what about the rad cap not holding press

As long as the water pump looked identicle to the one you removed, it will be fine....

AKA, the impellers pointing the same direction, etc.

I had a cooling problem. Temp would stay warm and would skyrocket into the red zone. It took me months to diagnose.

Turned out my year old AutoZone radiator apparently had a pressure leak. Not a coolant leak, but rather pressure. I never boiled over but the temp sure got hot!!

An all metal CSF 3 core radiator solved the problem. Really, any radiator would have fixed the problem. I just don't like radiators with plastic tanks anymore. Especially ones that aren't built to last, or come from AutoZone.

Also what brand/type of thermostat are you using? My heat always sucked when I used the AutoZone thermostat. Another piece of crap to add to my AutoZone hate list.

Jeep OEM thermostats work well. As do Stant thermostats.

Didnt look cloosely at the pump. cant tell you. As for the tstat... Standard el cheapo from Advance. 195 degree flavor. Thinking of taking it today for a complete diagnoistic (sp) check for $100.... if a compresion check is needed, then its included in the price.

Marc

Just woke up, maybe I missed it when reading. Have you changed the radiator cap? Is it the correct PSI?

As soon as I get my tcase problem fixed I am getting a 3 core radiator and I should be done with my cooling system problems.

I put in a hi-flow 180 degree thermostat and a hi-flow thermostat housing. Temp used to run at 210, now is around 190, but will climb to 210 after driving 80+ on the freeway. It hasn't been really hot here yet though.

If 3 core radiator doesn't do everything I want, then I'll go with a hi-flow water pump.

For the coolant turning dirty in the overflow bottle, I wouldn't be too concerned with it. For some reason the coolant gets dirty in the overflow bottles, even though there's no problem. When I did a drain and refill last year, the amount of gunk in the bottom of the bottle made me think I had a seriously bad head gasket/cracked head problem. It got dirty again fairly soon after changing the coolant, however every thing else is fine.

Unless your engine oil is looking like a milkshake, or you're loosing coolant in ways other than it being blown out of the top of the overflow bottle, I wouldn't worry about a head gasket or other head issues.

It wouldn't hurt a thing to do a pressure test on the cooling system (not a compression test on the cylinders). This would tell you if you've got a leak from another area.

Yes, my overflow bottle always gets dirty inside! While the rest of the system has bright green coolant in it.

x2 on the radiator cap as well, it should be a 16psi cap. The stores will sell you a 13psi cap. I boiled over twice or three times for no reason with the 13psi cap until I realized that it was the problem!!

What is the history of cooling system maintenance on this engine? At 115k, cooling system maintenance should have been done at least 3 times. I would flush run for a while and repeat until fluid stays green. You don't mention anything about having to add coolant. Assuming you haven't??

As far as the temp, you're really not that far off. Mine runs at 205 hot, has since new. I would want to verify accuracy of your temperature before getting too concerned. Sure, gauges can go bad but sending units are the cause of inaccurate readings way more often. They're not too expensive; may want to pop for one and find out. Could try a point and shoot infrared thermometer I suppose too and see what you get with that.

As for thermostats, there isn't much that I buy directly from Jeep but a thermostat is one of those items. I do know a few guys that have had good luck with Stant as well. I'd stay away from el-cheapo. I have had horrible luck with cheap no-name thermostats. And I would not recommend you changing the temp of your thermostat, stay with the OEM 195. If your engine is truly running warm, it will still run warm with a lower temp stat, the stat will just open sooner.

Let us know the results of the diagnostics. If you do suspect a head gasket problem, the cooling system pressure check and the leakdown tests are valuable there.

Good Luck!

Ok, for good mesure today I got a 16 lbs cap and a new temp sensor. refilled the coolant and such and it held at and under 210 +/-. To night coming home, it spiked to 215 and sta there. Got home, the coolant overflow tank was going over again. Heres the odd thing or I just have know idea.... I dipped my finger into the coolant overflow tank and the water wasnt warm... warm at best. As soon as I flipped the little release on the new radiator cap, the coolant started pouring out of the overflow.... literally...
I then put distilled water back in and coolant 50/50. I am waiting a few to drive it again and see if the same thing happens.

There were no shops open today so monday is the first time I'll have anyone be able to look at it. I'll repost and let you know what a shop says if something pops up. Thanks for the info.

Marc

Don't use the flipper type cap - I'm told it doesn't allow coolant to be sucked back into the rad. Your experience indicates that is what is happening.

I was using the lever cap and changed it to the regular type - my overheating went away. It's a cheap fix.

Now if i can find out why the tank goes empty every week, I'd be happy . . .

The lever style caps operate normally. The entire purpose of the lever is to quickly depressurize the cooling system safely. When the lever is down the caps functions like a normal cap.

Check the oil color or drain it. If there is coolant/water in the oil the head gasket might be an issue.