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still overheating at 103 same old heating prob.

Tony G

NAXJA Forum User
Orange county
Ok I have a new radiator( 3months old ) new water pump ( 3 weeks) new hoses ( 3 months ) new t-stat and housing ( 4 days) new bottel and cap ( 1 week )new fan clutch ( 3 weeks not oem ). When driving around temp is 210.When I stop it goes up depending on how long I'm stopped for. Today in so.cal it's 103 to 107 and I'm driving to go off roading and befor I even get there the temp starts to ries. I stop and turn off the engine and it starts to boil over. I let it cool down and go to take the cap off and its not as tight as when I first put it on. By the way I had my electric fan on the hole time( axu switch ). This temp rising up and down happens weather its 60 or 107 degrees.Any help befor I take it to the dealer. 89 xj....
Did you burp it ?? On the lower hose, did you move the old spring from inside the hose to the new one or did the new one already have one ??
Inside the lower radiator hose is a big spring, it keeps the lower, suction, hose from collapsing. An aftermarket hose may not have one, easy to check, just squeeze the hose, you will feel it.
As for the burping, it's almost a required art form for the XJ LOL, most don't know how to really do it and it takes about 45 min to do.
One thing, ONE overheat will destroy a thermostat, if it overheated that badly then the stat is probably shot already.
I'm assuming you have the closed system as you mention the pressure cap and bottle. I'm more familiar with the open ones. From my understanding of the closed ones you park it facing down hill and remove the rear temp sending unit on the back of the head and allow the air to escape from there as you add coolant. Also if the thermostat that was used did not have the small 1/8" vent hole in the flange and that vent hole was not put into the 12 O'Clock position you will never get all the air out.
Ill check the lower hose. I did run into the red today so the t-stat may be junk but it did have that hole with a little ball in it and I put it in the 12 o-clock postion.I"ll try to burp it with it parked on a hill.
What is the ball for ??? All the OEM's I use just have a little hole in it, no ball, does it move ?? Great, high tech moves to thermostats, wonder where that ball goes if it falls out..... :D
The ball was in a little holder and it did move.Also my lower rad hose dose not have a spring in it and I can squeez it together pretty easy it is new.
The 4.0L water pump is considered a reverse rotation pump because it's the opposite rotation from the water pumps on the older engines with V belts. I once read that the ones for the 4.0L will have a big 'R' somewhere on the casting, but I've never looked for it so I cannot verify that.

The spring in the suction hose is, as Rich said, intended to prevent collapse when the pump is really working. If the spring is missing, it usually shows up as overheating on the highway, not heating up when idling in traffic.

Is your non-OEM fan cluct a heavy-duty, thermostaticically operated one, or a standard duty with no lockup?
I just picked up a new water pump. It has REV. cast into the casting. It also has a R on the impeller.
I put a new pump in on Saturday. The "R" was a tiny stamp on the impeller. Apparently, the impeller is the "official" place to put the stamp.
The REV. is on the pump itself, not on the pully. I don't know if it is visible with the pully on or not. I will check on my nest break.
Just checked its not visible with the pully on. If you pull that and its there you will be able to see it.
Well I took it to the jeep dealer this morning. I know it well coast more but at lease it well be fixed.I tryed to fix it my self but I'm not the mech. I thought I was.Thank everybody for your help.... Untill the next break keep wheelin...........