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Searched...nothing...Overheating with new everything

XJfire75

NAXJA Forum User
Location
Toonnerville, GA
Hey guys this is my first post on this site(I'm a member over on fullsizebronco.com so I know the forum rules and hate it as bad as yall when newbies dont search) Anyway, I just bought a 1989 XJ yesterday I was told that it had a new radiator, water pump, t-stat, radiator hoses. I just drove it around the yard and let it idle for a few mins. It ran about 210 for a while then went up to around 230 so I cut it off(noticed a little leakage around the tank cap and fittings on the tank). It started boiling over and leaking worse and worse til it lost enough pressure to cool off. I found some helpful threads on "burping" and drilling holes in the thermostat. but what do you guys think would be the best place to start? I'm thinking the tank and cap first then maybe the hoses coming off the tank. Need some opinions please.
 
89 is the closed system I think, not sure what year it changed, if it has the tank , or turtle, on the firewall it's a closed system, if so, step one, replace the turtle and the cap with a new one. www.quadratec.com or spend some $100 or so on a brass or steel one. Do a search on 'surge tanks' I posted a bunch of links on metal replacements a few months ago.
Rule of thumb, low speed overheat that goes away as soon as you start moving is usually a bad fan clutch, high speed over heat is usually a bad radiator.
 
Well, I had an overheating problem that I couldnt solve and I finally replaced the motor.
http://www.naxja.org/forum/showthread.php?t=915767
Turns out that my head gasket was more than likely blown in between the cylinders. I will know for sure when I tear it down. I had replaced the radiator, all hoses, thermostat, thermostat housing with a high flow one and a high flow water pump and it still overheated. Oh, and upon pulling the old engine out, the last 2 down pipes on the exhaust manifold were broken completely off.

Good luck.
 
Nice, easy to follow answer! Nice Post! X2 on the bottle (turttle) and cap. Also the fan clutch was not listed as already new in his post, so that makes it a likely suspect as well, but it should have kicked on the electric fan at about 210 to 215 F.

So when did the electric fan kick on, or did it?

Definately replace the bottle and cap. The cheap plastic one works fine for about as long as the hoses do, and you can visually see the coolant level in it, which I like. I am still using the clear plastic ones.

RichP said:
89 is the closed system I think, not sure what year it changed, if it has the tank , or turtle, on the firewall it's a closed system, if so, step one, replace the turtle and the cap with a new one. www.quadratec.com or spend some $100 or so on a brass or steel one. Do a search on 'surge tanks' I posted a bunch of links on metal replacements a few months ago.
Rule of thumb, low speed overheat that goes away as soon as you start moving is usually a bad fan clutch, high speed over heat is usually a bad radiator.
 
You mentioned the "tank cap" in your original post. The OEM radiator in an '89 did not have a cap on the radiator. If your radiator has a cap, it may have been updated to the open system. If so, the plastic expansion tank will have been removed. Or, maybe the radiator only was replaced with one that has a cap. That is what we are all trying to figure out for you.

If you have the plastic expansion tank, then, as mentioned, the tank and/or its cap are the prime suspects. Or, at least the easiest to fix of the suspects.

Oh, and if you get ambitious and replace the thermostat, save yourself some trouble and just get a stock 195 degree one from the stealership. Do a search for other opinions on that subject, LOL.Hasta

And welcome aboard.
 
...come to think of it, I bought a '90 about six months ago that the PO had replaced the radiator, T-Stat and water pump on because of overheating. That didn't fix the problem...until he replaced the plastic pressure tank and cap. By that time, he was piss@# off at it and I picked it up for $500.
 
it could either be a leaky cap on the bottle, or air in the system still.
 
if the sender was replaced with non-OE part it could be reading wrong. Get a temp gun and check the temp manually if nothing else fixes it.
 
Could be air in the system. When it's cold, pull the temp sender- driver's side, back of the head, I think it's a 9/16 deep socket. Reinstall after a steady stream of coolant comes out.
 
XJfire75 said:
I found some helpful threads on "burping" and drilling holes in the thermostat. but what do you guys think would be the best place to start? I'm thinking the tank and cap first then maybe the hoses coming off the tank. Need some opinions please.

The best place to start is the cheapest, so I'd suggest reasing those threads on burping and make sure you get all the air out of the system. This can be difficult to do sometimes, especially with the old closed system, so read those old threads and meticulously do all the things they suggest. For example, I may be remembering wrong, but didn't I read that you have to park those old closed system types on an incline to get the last little bit air out?

Another easy/cheap thing is to visually inspect the front of the radiator to see if you have a bunch of dead bugs/grass seeds/dust/misc junk clogging up the openings. Flush that stuff out from behind with water or compressed air.

As far as the overflow bottle and hoses, you should probably replace the pressurized cap on the bottle but otherwise, unless you see visible leaks, they would not be causing overheating even if they're bad. Replace them if they're old and worn to save future grief, but don't expect that to help with the overheating problem.

After that, I'd check the fans to be sure they come on when they're supposed to. I presume the closed system still had 2 fans like the newer models, with the electric fan coming on about 210 degrees.

I, too, was a little confused when you mentioned the tank cap, but I'm guessing you mean the overflow bottle cap. If there really is a cap on the radiator, you might want to compare your cooling system lay-out to either the manual or to another pre-92 XJ. Since you don't know the history, perhaps a prior owner started to convert to an open system but didn't finish, leaving you with a hybrid. I really don't know what would happen if you replaced a closed system radiator with an open system one, and left everything else the same - but I wouldn't be surprised if it didn't work right.

T-stat and water pump and radiator should be kind of a last resort, but let me clarify something you mentioned - about "drilling holes in the thermostat". The stock T-stat has a weep hole in it, but many auto parts stores will happily sell you one the same size without the weep hole and say it's the one for your truck. This happened to me when I was going through my over-heating problems, and I did have a modest improvement when I put the right one in - not much, but enough when combined with other things to fix the problem.

Like Kevin above, I'd recommend the stock 195 one from the stealership. I suppose it would work to drill a hole in an aftermarket one, if you knew exactly what size hole and where to drill and that everything else was the same, but it's probably safer just to buy the stock one.

On the water pump, if it's going bad you should notice a loss of fluid from it after warming up the engine. Even if it's not bad, you might get some improvement from a higher speed pump (or the one on it could be the wrong one), but this is getting into more expensive fixes now, and I'd guess the odds are 10-to-1 that the problem is one of the cheaper things mentioned above.

Good luck and keep us posted what you find - as you may noticed from your searches, overheating is a problem a lot of us have faced and it can be very frustrating to figure out how to fix it.
 
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