4.0 overheating...WHY!

HouTexs · 06-13-2007, 06:27 PM

Ok, jeep overheated on the trail, blew head gasket. Head gasket replaced along with water pump, thermostat, valves and seals. Still overheating. Cooling system does not leak and has been pressure tested and blown out (nothing blocking). Actually overheating (boiling over and filling expansion tank). What could it possibly be!!!

Nothing specific assiociated with the overheating, just driving it. The repairs were done by "professionals" not myself. Does anyone have any ideas?

Another question, once all of this is resolved should I be considering selling the jeep and getting another, because all of this work has been done to it at 63k miles?

Thanks in advance for the help

HouTexs

FLATFENDER54 · 06-13-2007, 07:07 PM

cracked/warped head? timing? mud in radiator fins? Air in radiator system? Coolant checks out ok and not running pure water? Fan clutch working properly? Belt tight? Correct thermostat and working properly? You do have a fan shroud?

alvinl · 06-13-2007, 07:14 PM

Or maybe your radiator cap needs replace? Flatfender54 covered the rest of what I had thought of.

HouTexs · 06-13-2007, 07:22 PM

Quote:

Originally Posted by FLATFENDER54

cracked/warped head? timing? mud in radiator fins? Air in radiator system? Coolant checks out ok and not running pure water? Fan clutch working properly? Belt tight? Correct thermostat and working properly? You do have a fan shroud?

Head has been to the machine shop to be resurfaced, tested and cleaned. No mud in radiator. Air in system was addressed, coolant is correct mixture. Fan shroud in place, thermostat is new, belt is tight. I am assuming that the fan clutch has been looked at.

That is the worst part. What else could it possibly be? If the block was cracked there would be other symptoms. There seems to be no unsual strain on the engine when you are driving it. I am relying on the shop to figure it out but it seems like they can't figure it out either. Doesn't inspire a whole lot of confidence!!!

Thanks for the input!

HouTexs

Do you guys think I should unload it once it is fixed or what?

FLATFENDER54 · 06-13-2007, 07:29 PM

get that fan clutch checked out

oh and ive had several vehicles that the radiator didnt leak but a new radiator fixed the problem (they were a lot odler than a TJ though and could use a new radiator anyway with the HP increases they were getting)

dyna · 06-13-2007, 08:03 PM

The radiators in every 4.0 powered jeep product Ive owned has been short lived for various reasons. Did they actually flow tet the radiator wth water at the shop, or just say it looked good which isnt really gonna do the trick. The only 2 things you have left is the fan clutch which you should be able to hear roar to life when hot or upon startup for a bit. If its the factory radiator (alum and plastic) Id trash it and get an all metal one. I dont think a shop would even try to rod out a stocker.

crazyiven · 06-13-2007, 10:11 PM

How much coolant do you loose, or how fast does it fill the catch tank?

I had the same issue with it filling up the catch tank, and it was a bad cap. So i went and got another at the part store. Well they gave me the wrong one. So it would push the coolant to the tank but it would not flow back. make sure you have the right cap, the bottom of it coolant side shold be very very loose( the metal deal) sorry dont know the tec name for it. But it should be very loose. It solved my problem

Whats the actual temp? and when it runs hold the top hose and see if it gets hot when it heats up to temp. will tell you if its at least flowing. and if you wanted you can get a block tester from Napa for under 20$ and test for exhaust in the coolant system. That might be a cause

Unscathed · 06-13-2007, 11:30 PM

Quote:

Originally Posted by HouTexs

Ok, jeep overheated on the trail, blew head gasket. Head gasket replaced along with water pump, thermostat, valves and seals. Still overheating. Cooling system does not leak and has been pressure tested and blown out (nothing blocking). Actually overheating (boiling over and filling expansion tank). What could it possibly be!!!

Nothing specific assiociated with the overheating, just driving it. The repairs were done by "professionals" not myself. Does anyone have any ideas?

Another question, once all of this is resolved should I be considering selling the jeep and getting another, because all of this work has been done to it at 63k miles?

Thanks in advance for the help

HouTexs

I replaced my head at 53k... rebuilt it.. put new valves/springs/lifters/push rods/rockers/oil-pump/water pump/thermo/electric fan/ and she is ready to be beaten! (sad thing is the previous owner didn't take good care of er so I wasn't taking any chances!)

I wouldnt sell it.. but I will tell you that you can get another engine for between 1200-1800 bucks (4.0)

Unscathed · 06-13-2007, 11:32 PM

also.. if the repairs were done by professionals.. I suggest you take it back to them or get some money back and find other professionals..

I can't remember if you can put in a head gasket backwards on a 4.0...

jdragger · 06-13-2007, 11:38 PM

If it's running lean, timing is off or exhaust plugged it will run hot.

stuartgray · 06-13-2007, 11:46 PM

Stock radiator is a POS. As another poster said, every Jeep with a 4.0 needs to have it replaced early on in life. Mine went at 55K. Looked like swiss cheese.

Only thing that seems might have been neglected on your repairs.

Unscathed · 06-13-2007, 11:49 PM

well if he is going to upgrade his radiator.. what would you suggest? All Alluminum?

Wondering for myself eventually..

stuartgray · 06-14-2007, 12:26 AM

Quote:

Originally Posted by Unscathed

well if he is going to upgrade his radiator.. what would you suggest? All Alluminum?

Wondering for myself eventually..

That's what I did. I replaced my OEM at 55K like I said. At 105K now and everything looks fine.

**4.7stroker** · 06-14-2007, 01:06 AM

Silly Q however it is an easy mistake to make,
Is the water pump the correct one?
Pumps designed for a serp belt turn the opposite direction that pumps designed for V belts.
Is the t stat really opening? Even new stats can be bad.

Dwayne

06-13-2007, 07:07 PM	#2
FLATFENDER54 Registered User Join Date: Jun 2006 Location: OKLAHOMA Posts: 3,763 Profile Gallery Classifieds My Jeeps	cracked/warped head? timing? mud in radiator fins? Air in radiator system? Coolant checks out ok and not running pure water? Fan clutch working properly? Belt tight? Correct thermostat and working properly? You do have a fan shroud? __________________ 01 TJ Sahara 4"short arm/rear gas&tire carrier bumper/front winch bumper winch/detroitEzhttp://i73.photobucket.com/albums/i225/FLATFENDER54/Off%20raod%20trip%20to%20Colorado%20with%20son%20a nd%20dad/DSC01873.jpg 66 Chevelle(Not a good pic in shed 4 many years)http://i73.photobucket.com/albums/i225/FLATFENDER54/memeorystick512262.jpg 93 ford lighting-trick flow heads 6 psi supercharger http://i73.photobucket.com/albums/i225/FLATFENDER54/DSC01636.jpg 1954 WILLYS CJ3B (under construction) http://i73.photobucket.com/albums/i225/FLATFENDER54/DSC01301.jpg 99 escort zx-2 my favorite lil gas "sipper" (who cares)lol USMC "Semper Fidelis"

06-13-2007, 07:29 PM	#5
FLATFENDER54 Registered User Join Date: Jun 2006 Location: OKLAHOMA Posts: 3,763 Profile Gallery Classifieds My Jeeps	get that fan clutch checked out oh and ive had several vehicles that the radiator didnt leak but a new radiator fixed the problem (they were a lot odler than a TJ though and could use a new radiator anyway with the HP increases they were getting) __________________ 01 TJ Sahara 4"short arm/rear gas&tire carrier bumper/front winch bumper winch/detroitEzhttp://i73.photobucket.com/albums/i225/FLATFENDER54/Off%20raod%20trip%20to%20Colorado%20with%20son%20a nd%20dad/DSC01873.jpg 66 Chevelle(Not a good pic in shed 4 many years)http://i73.photobucket.com/albums/i225/FLATFENDER54/memeorystick512262.jpg 93 ford lighting-trick flow heads 6 psi supercharger http://i73.photobucket.com/albums/i225/FLATFENDER54/DSC01636.jpg 1954 WILLYS CJ3B (under construction) http://i73.photobucket.com/albums/i225/FLATFENDER54/DSC01301.jpg 99 escort zx-2 my favorite lil gas "sipper" (who cares)lol USMC "Semper Fidelis"

06-13-2007, 08:03 PM	#6
dyna Senior Member Join Date: Oct 2006 Location: Kalifornia Posts: 840 Profile Gallery Classifieds My Jeeps	The radiators in every 4.0 powered jeep product Ive owned has been short lived for various reasons. Did they actually flow tet the radiator wth water at the shop, or just say it looked good which isnt really gonna do the trick. The only 2 things you have left is the fan clutch which you should be able to hear roar to life when hot or upon startup for a bit. If its the factory radiator (alum and plastic) Id trash it and get an all metal one. I dont think a shop would even try to rod out a stocker.

06-13-2007, 10:11 PM	#7
crazyiven Registered User Join Date: Apr 2007 Location: Colorado Posts: 51 Profile Gallery Classifieds My Jeeps	How much coolant do you loose, or how fast does it fill the catch tank? I had the same issue with it filling up the catch tank, and it was a bad cap. So i went and got another at the part store. Well they gave me the wrong one. So it would push the coolant to the tank but it would not flow back. make sure you have the right cap, the bottom of it coolant side shold be very very loose( the metal deal) sorry dont know the tec name for it. But it should be very loose. It solved my problem Whats the actual temp? and when it runs hold the top hose and see if it gets hot when it heats up to temp. will tell you if its at least flowing. and if you wanted you can get a block tester from Napa for under 20$ and test for exhaust in the coolant system. That might be a cause

06-13-2007, 11:38 PM	#10
jdragger Registered User Join Date: Mar 2007 Location: Claremont, California Posts: 245 Profile Gallery Classifieds My Jeeps	If it's running lean, timing is off or exhaust plugged it will run hot.