New Radiator or...?

Hey All,

Today while I was trying to isolate a "pop" from my xj banghead: ), I noticed a small amount of steam rising up from my upper radiator area. The steam was about like a cigarette. It was near my fan on the passenger side. When I leaned over the steam, it had the faint smell of antifreeze, so I ran my finger along the top edge of the radiator (technically, I guess this is the bracket...) and when I removed my fingers, I saw a small amount of clear liquid on my finger tips. This liquid had no smell and had the consistency of water. It didnt "feel" like coolant, but the steam smelled like coolant.

The OP had replaced the radiator (and water pump, IIRC) with a new one just before he sold the xj to me, so the radiator itself isnt old at all. The "rail" of the radiator at the top seemed to be wet for about 3" or so and only my finger tips were wet. Im thinking a pinhole leak, but need some suggestions on what else it could be. I did check out the hoses running along the radiator and they were dry, so its definitely the top of the radiator. Sound like a new radiator to everyone?

Im adding this to my "spend more money" list :wave1:

Hard to say. I recently had a pinhole leak in a radiator hose that would only leak after about 30min on the freeway... double check your hoses, especially anywhere they sit on, or rub, other parts of the motor... ie the power steering lines. ASSUMING it is anything is a bad idea. I wouldnt replace it unless i SAW it spraying out of the radiator. Ive heard its pretty damn easy to repair a radiator via brazing, might want to seek out a local radiator shop if it's somewhat new, and you dont particularly feel like replacing it.

Thanks. Im going to stop by my local radiator shop today and talk to them about it. Im also planning to take the xj to my mechanic to give it a good inspection to get a proper list of "needs fixin' ".

I have my fingers crossed that its not a leaking head gasket or something because I talked to the PO last night and he told me that he had trouble overheating after the radiator replacement (the water pump and tstat were replaced at the same time). I have a ZJ fan clutch Im planning to install and also putting the shroud back on (guess whoever did the rad install chose not to re-install it...so I got one off ebay).

While its at the shop, Im going to have them do the test to make sure its not the head gasket. If it is.... :smsoap:

Jhumphrey said:

Thanks. Im going to stop by my local radiator shop today and talk to them about it. Im also planning to take the xj to my mechanic to give it a good inspection to get a proper list of "needs fixin' ".

I have my fingers crossed that its not a leaking head gasket or something because I talked to the PO last night and he told me that he had trouble overheating after the radiator replacement (the water pump and tstat were replaced at the same time). I have a ZJ fan clutch Im planning to install and also putting the shroud back on (guess whoever did the rad install chose not to re-install it...so I got one off ebay).

While its at the shop, Im going to have them do the test to make sure its not the head gasket. If it is.... :smsoap:

Click to expand...

lol bring some lube...

That needs fixing list is going to be epic. I remember being a tech a few years back and a loyal customer came back with his xj and asked for a quote for everything that needs attention. 1,900$ later i was hesitant handing him the estimate.

It was a pretty sound 99 xj also, just so many things were leaking etc.

ktwalker01 said:

lol bring some lube...

That needs fixing list is going to be epic. I remember being a tech a few years back and a loyal customer came back with his xj and asked for a quote for everything that needs attention. 1,900$ later i was hesitant handing him the estimate.

It was a pretty sound 99 xj also, just so many things were leaking etc.

Click to expand...

I totally understand. I had a YJ before the XJ and that thing was always giving me fits over something. It looks like the XJ is going to be the same way . The more I mess with it, the more I find...

But, Im taking it to my radiator shop to have it checked over in the morning. Then, Im off to figure out the mysterious front end pop (which I think is the drag link). It pops on the driver side at full drivers turn and feels like its under your feet on the other side of the floorboard. It only does it when its first started and stops after its been "worked" a few times. Has to be a bushing somewhere.

Dry steer it... have someone turn the wheel lock to lock with it running, in park. All while you are sitting under the jeep looking at the front end, it'll be semi obvious usually.

Pop on the drivers side, SCREAMS trackbar bracket to me.. allthough that wouldnt 'go away' per se.

My sway bar bushings and front passenger side U joint can be a drum set.

ktwalker01 said:

My sway bar bushings and front passenger side U joint can be a drum set.

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:roflmao:


So I took the xj for a pressure test. He pumped it up to 16lb. No leaks, but did lose pressure. I talked with him for about 30-40mins (wasnt really looking at the clock - hes a former co-worker so we were playing catch up), all the while it was "under pressure". It went down to about 12lbs, but did not leak. Im not losing any coolant and there are no other signs of a leaking head gasket, but the pressure has to be going somewhere. We also poured some distilled water into the radiator and reservoir to test the expansion system...which worked as it should.

Any suggestions? He said there could be seeping somewhere, but we couldnt find it. Should I just replace the head gasket (yes, I know thats a PITA) and go from there?

Btw, Im going to lift the jeep up later today and have someone turn the wheels while I watch. Ill see if that stops the pop and go from there.

So I did a compression test and found that the numbers were fairly equal, except cylinder #3. The numbers:

Cyl 1: 175
Cyl 2: 170
Cyl 3: 155
Cyl 4: 175
Cyl 5: 180 (between 175-180)
Cyl 6: 175

While I was out, I changed the cap and also put on the zj fan clutch as well as the fan shroud. About cyl 3, is that possibly a leaking exhaust valve (as the Internet says)? It a little over 10% difference. I've read that 10-15% is ok...

I doubt the head gasket is leaking.

You can do a "Cylinder leak down test" to check for valve problems, but comp. test shows good numbers.

How many miles on the 4.0?

Your radiator is probably plastic and where you felt water along the top is most likely leaking at the metal to plastic tank crimp points.

My ZJ had a crack in the plastic tank that only weeped a little for weeks and onlt when hot under full pressure.

I thought it was the drain **** valve o-ring and finally saw the crack after it split open and leaked ALOT.

Good luck

my2monkeys said:

I doubt the head gasket is leaking.

You can do a "Cylinder leak down test" to check for valve problems, but comp. test shows good numbers.

How many miles on the 4.0?

Your radiator is probably plastic and where you felt water along the top is most likely leaking at the metal to plastic tank crimp points.

My ZJ had a crack in the plastic tank that only weeped a little for weeks and onlt when hot under full pressure.

I thought it was the drain **** valve o-ring and finally saw the crack after it split open and leaked ALOT.

Good luck

Click to expand...

My xj has 164,000 miles on it. I have ran it a few times since changing out the fan clutch ("upgrade" zj) and put the shroud back on. Driving temps show a little under 210, at idle it gets to 210 but doesn't move beyond that (at least it hasn't). I also haven't had anymore leaks show up. I'm keeping an eye on everything and will report back if something changes.