I've searched! No heat, Overheating

Well let me start out w/ yesterdays experience,99 XJ 4.0. She was running a little hot 210-215* (normally 190-195*), so I was keeping track of my gauge, going down the highway, 65-70mph, next thing I notice antifreeze coming out of the hood on the front driver side corner. So I make it home and just as I pull into my drive way it pegged out.

I just had the waterpump, all hoses, and thermostat, replaced the radiator cap. Took it on a small trip today, first thing I notice is that it is taking forever to heat up,and it was kind of stutering when I stopped in gear, so I stop to get a coffe keep truck running come back out and the temp. gauge is moving, good, but I wait and it stops at 210-215* and the heat wasn't getting hot. Damn so instead of heading back to my house (2 min.) I decided it should be ok.

Well I drove 5 min and notice the gauge was going up so I get of an exit and decide I'll park it and let it cool down, as I was exiting the gauge goes back down so I decide I'll head right home. Wrong decision, I get of my exit and the gauge starts to peg, Its alright I live like 2 min. away now. The gauge is going up-down, up-down, and when I get to a red light the thing is diesling hard, starts knocking and wants too stall. I just drove it the rest of the way home parked it in the garage and there it sits. I opened up the hood and smoke is coming from everywhere, and it don't smell like just antifreeze anymore

Did I damage anything? Checked oil and it looks good. If I just replace the radiator should it be ok? Do you folks think that the heater core crapped the bed to? Is the heater core something I can do my self? I am fairly mechanical. Did I f'up my XJ?

Sorry for the long post but thank you for reading and thanks for any info. and PLEASE help me to help my dieing, or DEAD XJ.

When you say you noticed antifreeze coming out of the hood in the front driver's side corner, do you mean steam, or actual antifreeze spray? Did you replace the parts yourself, or did someone else do it?

It was green antifreeze figured it was coming out the cap, had the work done.

I'm new to jeeps and the 2.5L and 4.0L, but in the Chrysler 2.2L/2.5L & 2.0L/2.4L motors I've owned, this was common after draining the cooling system, as well as other cars now-a-days. Air gets in the system and has to work its way out, till then you risk overheating, because the air pockets aren't doing any cooling.

Some motors you can burp the system, it usually involves a plug at the highest point of the cooling system or near the thermostat, that you open and close as the system runs. I've always just let the air work out in the driveway after completing the job. Make sure you coolant recover system is working correctly, then just warm up the motor and let it cool off, repeat several times. The expansion and contraction of the coolant will force the air out and suck fluid back in its place using the coolant recover system. The change of fluid level in the coolant recovery tank/reservour is an indication the air is working out.

What happens doesn't sound good, warped head and headgasket leaks would probably be the most likely aftermath. Just check out the motor and look for problems, most likely you'll be OK though.

It's been 2 weeks or so since I got the work done, wouldn't this have happened before now?

raypla said:

It's been 2 weeks or so since I got the work done, wouldn't this have happened before now?

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If by 2 weeks you mean 14 or close to it, warm-ups and cool downs, then yes, I agree, the air should have worked its way out by now. If your coolant recover system was not working (fairly common) it would not work the air out.

Have you been pulling the pressure cap (WHEN THE SYSTEM IS COLD) and checking the coolant level under the pressure cap? If the coolant recover system is working right, when you pull the pressure cap, when the system is cold, the fluid level will be right at the top of the neck at the cap.

No heat out of the heater core, overheating, after the system was drained, all are symptoms of air in the cooling system.

Its possible for brand new thermostats to go bad and stick shut, especially if they are cheapo models, and often when you pay someone to do the job, they'll use the cheapest parts available. But, you would not have a problem with the heat coming from the heater core, if the thermostat was sticking closed.

You might want to take my advice with a grain a salt, since I have almost no experience with the Jeep 4.0L, but your symptoms really sound like air in the cooling system like I've seen in other engines. If your coolant recover system is not working, the air will not work its way out.

Just guessing, but it sounds like a coolant leak. I've had to re tighten my clamps a couple of weeks or so after a service.
In normal operation (open system),the system pushes the extra coolant (from expansion, engine hot) into the recovery bottle and when the system cools (when the motor is stopped for awhile) and contracts, it sucks it back into the system from the *recovery* bottle/canister (normal cycle).
If there is a leak, it can suck air (usually near the top of the system) into the system instead of sufficient coolant from the recovery bottle. A few cycles of coolant out and air in can mess you up.
Or after a system service, the trapped air is pushed into the recovery bottle. During the cool down period (after stopping the motor) the system sucks coolant back from the recovery bottle. A few cycles of air into the bottle and coolant out can drain it and then the system sucks air, form the recovery bottle.
A small leak can do the same thing, coolant out the leak (usually a leak lower in the system), is replaced by the recovery bottle, which eventually runs dry.
Or a combination of all of the above.
Double check your cap, the cap for the open system is different, than some other systems. It is valved to let the system suck coolant from the recovery bottle. Other types of caps just vent.
Two or three times now, I've seen guys put the thermostat in backwords. I've seen reverse rotation water pumps, that fit the 4.0. The bottom hose needs a coil in it to keep it from sucking closed. You can often see the buildup that closes off part of the radiator, looking in the bottom outlet.
But often, it's a leak and/or insufficient coolant in the recovery bottle.

Well I bought everything at napa. So it wasn't junk, and placed the old bottom hose spring in the new hose.
I'll pull my cap in a couple of minutes, do I just make sure the Rad. is topped of?

Like mentioned, if you pull the cap on a cold motor, the coolant should be very near the top. Mine actually overflows a bit on occasion. If it's very low that is an indication that the system is sucking air someplace. Top it off at the radiator cap, make sure the recovery bottle is filled to the full line. Wash your motor off (carefully! use search). Check for coolant leaks and seeps. They can be hard to find. The bottom radiator hose at the water pump, often seeps and is hard to see.
Rare, but if your motor takes a very long time to heat up and the gage swings dramatically, this is often a sign the thermostat is hanging (or installed backwords). A little too much RTV on the thermostat gasket can also cause problems. As can a plugged up heater valve. The heater valve has another function, it bypasses the thermostat (either through the heater or back through the valve) and is necessary to help the thermostat function properly (this can also cause radical temperature swings).

raypla said:

Well I bought everything at napa. So it wasn't junk, and placed the old bottom hose spring in the new hose.
I'll pull my cap in a couple of minutes, do I just make sure the Rad. is topped of?

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Yes, that will help, but won't remove all air from the system, air can still be trapped elsewhere in the system. Like 8Mud explained, the engine warm-up and cooling down works the air out of the system, the coolant recovery system working right, to allow coolant to be sucked back in when the coolant contracts is the key to getting all the air out, otherwise it just sucks air back in and you never get all the air out.

8Mud also mentioned a leak, its possible a leak can let air get sucked back into the system during cool down, as well, a leak can let pressure drop and let the coolant flash into steam.

Check your coolant recover system. Make sure the tube is connected to the neck for the pressure cap, trace it back to the coolant recover tank. Make sure the tube or tank are not cracked or leaking. Final check, pull the tube at the neck and suck on it and make sure you get coolant coming thru the tube from the recover tank and not air or a mixture of air and coolant. Obviously, spit out any coolant that gets in your mouth, DON'T SWALLOW IT.

my 2000 will only take the factory thermostats (they have a little gas valve on them). Any other stats i have used results in build up of gas to the point where no coolent is in contact with the temp sensor. Then some hits it and the gauges light up.

Use a factory thermostat.

Well I just went and messed w/it. Heres my findings:
1) Cap wasn't completely tight (was hopin that was the issue)
2) I poured antifreeze straight into the Rad. and it pretty much took a whole gallon. WOW
3) Put the cap on all the way tight.
4) Let it idle 2 min, after I did all that no movement of the temp gauge.
5) Took it around the block, first couple hundred yards gauge started creeping up, then by the end of the block it started to go way up again.

I looked under the truck when I first went out and there was nothing on the floor at all, and checked all the hoses w/ a headlamp on and no LEAKS.

F**CK please help, Do you think if I just put in a rad. it might be the cureall?

raypla said:

Well I just went and messed w/it. Heres my findings:
1) Cap wasn't completely tight (was hopin that was the issue)
2) I poured antifreeze straight into the Rad. and it pretty much took a whole gallon. WOW
3) Put the cap on all the way tight.
4) Let it idle 2 min, after I did all that no movement of the temp gauge.
5) Took it around the block, first couple hundred yards gauge started creeping up, then by the end of the block it started to go way up again.

I looked under the truck when I first went out and there was nothing on the floor at all, and checked all the hoses w/ a headlamp on and no LEAKS.

F**CK please help, Do you think if I just put in a rad. it might be the cureall?

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It sounds like you have air trapped in the system still.

Did the NAPA thermostat you installed have an air bleed hole and/or valve in the perimeter of the flange? If not, you can create on by drilling a 1/8" hole in the 'stat flange before installing, and make sure you install the 'stat with this hole at the TOP of the 'stat housing.

I believe it had 1, is there anything else?

raypla said:

I believe it had 1, is there anything else?

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Did you orient it so it's at the TOP of the 'stat flange when installed?

Take the thermostat out and run without it, this will eliminate stuck closed, option. You have to determine if it is overheating due to Tstat.

Do I have to get a knew gasket? I just had the t-stat repalced along w/the waterpump, hoses 3 weeks ago.
I had it installed so I don't know where he installed it.

Yes, get a new gasket. Get a dealer supplied t-stat, or a Prestone brand part #330-195. Should be available at Checker/Kragen/Schucks...Don't know which you have out east.

It's an easy job...just two bolts and a little leaked coolant. If the hoses are all new, you shouldn't even have to disconnect them...they will flex enough to rotate the housing away from the block. Scrape off all the old gasket material (stuff a rag in the coolant passage to keep gunk out of the block), and set the new t-stat in place. The prestone one has a air relief hole in it also. It's not on the flange, so you have to look, but it's there.

Use a small amount of gasket dressing (permatex, Indian Head, etc...) on both sides of gasket, and put it on the t-stat housing, with the bolts pushed through to keep it in place. Tighten the bolts up snug, but not too tight...all that metal is aluminum. It's better to have to cinch them down later if you have a leak, as opposed to cracking the housing.

Top up the coolant as explained before, and watch it for a few days. One way to purge air is to leave your coolant temp sending unit loose (all the way back on the engine, on the driver's side) and warm up the motor. Some coolant will leak out, but that's the highest point in your cooling system, so the air should squeeze out there.

Get a service manual (if you plan on keeping this Jeep for a while)...It will pay for itself the first time you use it.

Steve

Well I got a new T-stat, gasket and a tube of RTV. What is this hole I hear everybody talking about? I'm going to be installing this shortly, already got everything clean and what not. Is there anything special to do once I refill w/antifreeze, and loosen this sending unit thingy (what does it look like?).

raypla said:

Well I got a new T-stat, gasket and a tube of RTV. What is this hole I hear everybody talking about? I'm going to be installing this shortly, already got everything clean and what not. Is there anything special to do once I refill w/antifreeze, and loosen this sending unit thingy (what does it look like?).

Click to expand...

On flange of an OEM thermostat, near the perimeter, is a small check valve vent that is designed to let air bubbles pass out of the head even when the 'stat is closed. Many of the aftermarket 'stats don't have this checkvalve, and installation of them without modification WILL result in air bubbles trapped in the head, with attendant problems.

Fortunately, the aftermarket 'stat can be modified easily. Drill a 1/8" hole in the 'stat flange near it's perimeter, and be sure to orient the 'stat in the housing with this hole at the top edge when installing. Problem fixed.