Still Overheating. EVERYTHING changed.

[kc_eiland]

Probably not relevant, or maybe misunderstood on my part.
IIRC the coolant needs some breathing room and shouldn't be filled to the top, just the FULL level.

Hope you get it figured out soon,
Mike

It maintains the full level in the overflow reservoir. Whenever the Jeep does boil over, its out of the radiator cap/fill neck of the radiator. I just fill the radiator back up after it cools. Should I not be doing this? Thanks.

 

[kc_eiland]

I like old_man's suggestion for cat, but no comment about power problem...

I like old_man's suggestion about running lean & MAP, too..

Otherwise I'm back to fault parts or an incomplete diagnosis on the head/head gasket.

If exhaust gases are leaking into the coolant... does your upper radiator hose stay pressurized overnight?

The power seems average, same as before it started overheating. There is no noticeable difference in power as far as I can tell.

Having the MAP checked is on my list for the mechanic. I thought about just replacing it anyway. I'm not sure how else to fully diagnose the head/head gasket as it is not leaking anywhere or anything externally, there is no oil in my coolant or coolant in my oil, and no exhaust in my coolant or coolant in my exhaust. It had good compression, doesn't tick or knock, etc... mechanic (who is fully aware of the 0331 head problems as a TJ owner himself) gave it a thumbs up. He also put some crazy looking contraption in the fill neck of the radiator to test for exhaust in my coolant system. It was a clear tube with blue liquid and had a hand pump on it. He said the check passed with flying colors.

And I have no idea if my upper radiator hose stays pressurized over night. I'll check tomorrow morning and get back with you. Thanks

 

[ehall]

It maintains the full level in the overflow reservoir. Whenever the Jeep does boil over, its out of the radiator cap/fill neck of the radiator. I just fill the radiator back up after it cools. Should I not be doing this? Thanks.

It should overflow into the bottle then draw back into the radiator as the engine cools. Maybe a cheap cap is your problem. NAPA has 16 lb Stant caps, they work great

http://www.napaonline.com/Catalog/C...tor-Cap-Safety-Type/_/R-BK_7031702_0443751064

 

[kc_eiland]

Do you still have the radiator you replaced? On my previous jeep, it would cool great when driving, but not so great when at a stop. I replaced the radiator and it cooled well for a month or two, then the same issue. I ended up cutting the tanks off the old radiator and discovered the fins were clogged with some thick sludge. I flushed and flushed the system until things were much better.

I second the comment about not needing the e-fans. Your stock engine fan moves a large amount of air. Also, with three fans how many amps are your requiring to power them?

I don't still have my original radiator. It cracked on the driver side from the top to the bottom. I just tossed it when I replaced it. I've flushed my coolant system twice since the start of this summer (the first time when I replaced my radiator, hoses, thermostat, thermostat housing, radiator cap, and coolant temp sensor, and the second time when I replaced my fan clutch and water pump). Nothing nasty looking or abnormal came out. Not even rust. It was all just coolant and the water from my hose during the flush.

As for the e-fans, they arrived yesterday. I'm staring at them and they're stating right back at me. I'm going to hold off on installing them for now.

 

[ehall]

If it works fine on the highway, then you have a really basic problem

 

[kc_eiland]

Maybe I missed it but does your XJ have the California emissions with the two precats?

Not sure, Its got the 2 cats in that single "Y" piece connected to the exhaust manifold. Is that CA emissions? Man.... I'm going to go look now.

 

[kc_eiland]

It should overflow into the bottle then draw back into the radiator as the engine cools. Maybe a cheap cap is your problem. NAPA has 16 lb Stant caps, they work great

http://www.napaonline.com/Catalog/C...tor-Cap-Safety-Type/_/R-BK_7031702_0443751064

I just bought that new radiator cap from Autozone a couple days ago after I first posted this. I'm totally down with trying another radiator cap tho as they don't cost too much.

And btw... I took your advise about revving up when it started to heat up. I was in the driveway after my drive home from work today and it totally worked. I let it creep to 220*, then held 1,800rpm for a couple of minutes and watched the temp drop about 7-8 degrees. Any other time, the temp would have kept creeping.

So WITHOUT driving but higher than idle RPMs, the temp was going back down. Its definitely an air and/or coolant flow problem.

 

[kc_eiland]

Not sure, Its got the 2 cats in that single "Y" piece connected to the exhaust manifold. Is that CA emissions? Man.... I'm going to go look now.

It definitely has only the 2 cats on that "Y" pipe coming off the exhaust manifold.

 

[kc_eiland]

I just checked my upper radiator hose and it has no pressure. And its still warm as I just drove it 2 hours ago.

 

[kc_eiland]

IMHO, this is the best option on the market for a radiator right now -

http://www.summitracing.com/parts/sum-382012/overview/year/1999/make/jeep/model/cherokee

I base this on this was the ONLY radiator that we have found that will keep the temps in line on our desert racer. We tried all the big $$ aluminum, 2 row, 3 row, blah, blah. I guarantee we push our cooling system WAY harder than anyone here - we are talking foot on the floor, 5000 rpm, 2nd gear, for 10 miles pulling uphill through a sand wash. The best aluminum would get us to 240 easily and we would usually have to ease up to get it to stabilize. The radiator I just linked to will keep us at 220 through that, and keeps us below 200 for just about everything else. And that is with 2 stock electric fans.

Facts - the 3 row has tubes that are too small - not enough tube surface area. 2 bigger rows are better than 3 smaller. A lot of cheap chinese aftermarket aluminum radiators have the fins glued (epoxied) to the tubes, which essentially insulates the tubes from the fins. If you want aluminum, make sure the fins are furnace brazed to the tubes so you have the best heat transfer. Copper is a better heat conductor than aluminum. The problem is that cheap copper/brass radiators started getting their fins either glued or lead soldered to the tubes, which again kills the heat transfer. Again, find a good radiator where the fins are brazed to the tubes.

As for water pumps, Flowcooler work great at low RPM, such as trails. They suck everywhere else. The best we found is the Hesco for higher speeds/higher loads (i.e. freeway), and it works awesome at the low speed stuff as well.

I noticed the radiator was for a 99... is there any difference between 99 and 00 in terms of fitment? Also, would a radiator be the difference maker in cooling between moving and standing still? I'm really asking because I genuinely don't know and am willing to take all the help/advise I can get. Thanks for the input and thanks in advance to your reply.

 

[Ian Christiansen]

So yours has three cats and cali emissions. From your posts it sounds like the radiator cap isn't functioning or the hose that runs from the radiator neck to the overflow is clogged. Get a good Stant brand cap.

 

[DieselSJ]

I just checked my upper radiator hose and it has no pressure. And its still warm as I just drove it 2 hours ago.

Hmmm....it should still have pressure if it is still warm. Next test is to see if it has pressure when it is hot. If it does have pressure, next is to see how long it takes to lose pressure after you shut it off.

Also, you might see if you can get one of the kits that tests for combustion gasses in your coolant.

I noticed the radiator was for a 99... is there any difference between 99 and 00 in terms of fitment? Also, would a radiator be the difference maker in cooling between moving and standing still? I'm really asking because I genuinely don't know and am willing to take all the help/advise I can get. Thanks for the input and thanks in advance to your reply.

I don't believe there is a difference. But you can follow the link and it will tell you all years that it fits. Yes, a radiator can make a difference between moving and standing still due to the amount of air flowing through it. Don't spend the $$ yet...check what I posted above and report back.

Do you lose any coolant? Do you need to refill your overflow on a regular basis?

 

[DieselSJ]

It maintains the full level in the overflow reservoir. Whenever the Jeep does boil over, its out of the radiator cap/fill neck of the radiator. I just fill the radiator back up after it cools. Should I not be doing this? Thanks.

Wait, I just read this. So it isn't pushing it into the overflow? Nothing should ever come from around the cap if the cap is installed correctly.

 

[thanasi85]

It maintains the full level in the overflow reservoir. Whenever the Jeep does boil over, its out of the radiator cap/fill neck of the radiator. I just fill the radiator back up after it cools. Should I not be doing this? Thanks.

Just a thought because I have done it before. New radiators normally come with little black rubber covers over all the ports. Any chance you left the nipple cover on the port that comes off the radiator and goes to the coolant bottle and just installed the rubber hose over it. Might explain why trapped air/pressure is coming out the cap.

 

[kc_eiland]

Hmmm....it should still have pressure if it is still warm. Next test is to see if it has pressure when it is hot. If it does have pressure, next is to see how long it takes to lose pressure after you shut it off.

Also, you might see if you can get one of the kits that tests for combustion gasses in your coolant.

The Jeep had been sitting for a couple of hours when I squeezed the upper radiator hose and was definitely NOT hot, but just barely warm. The hose does pressurize when the engine is running and gets to the 200* range. I'm not sure how long it would take to lose the pressure in that hose after I shut the engine off but I'll check it tonight and post my results.

As for the kit to test for combustion gasses in the coolant, my mechanic tested for that (clear beacon looking contraption with dark blue liquid in it with a hand pump squeezer that WOULD change liquid color if gasses are detected?) He did that and it passed.

 

[kc_eiland]

I just wanted to thank everyone who has offered any help/suggestions to me on this. This forum and it's members are awesome!!

 

[kc_eiland]

Just a thought because I have done it before. New radiators normally come with little black rubber covers over all the ports. Any chance you left the nipple cover on the port that comes off the radiator and goes to the coolant bottle and just installed the rubber hose over it. Might explain why trapped air/pressure is coming out the cap.

I'll check that out.... but I don't think so as the coolant level in the overflow bottle does change slightly.

 

[kc_eiland]

Wait, I just read this. So it isn't pushing it into the overflow? Nothing should ever come from around the cap if the cap is installed correctly.

I'm starting to think that my radiator fill neck (where the cap screws on) may be messed up and causing air to come in/coolant to boil over. That's where the mechanic hooked up another tool to test for coolant system leaks. Either that or my cap is really crappy (even though its only 3 days old). :dunno:

 

[md21722]

What you are reporting with the radiator cap & upper radiator hose temperature is not correct operation. The cap should release around 16 psi & push fluid into the coolant reservoir. When the system cools down, pressure is replaced by vacuum which pulls the coolant back in. Radiator caps are cheap, I think I paid $5 for one from NAPA. If it doesn't seal well then I'd say your radiator neck is jacked up and you should take it back using the lifetime warranty. No changes between 1997-2001 XJ's for radiators, I have both and have the same Spectra Premium in each. If there is air in the system that may explain the upper radiator hose problem, usually they are very hot to the touch.

 

[PhotographerMike]

Try blowing some air from the overflow tube (under the rad. cap) and see if it bubbles in the overflow tank.

Mike