XJ AV8R
NAXJA Forum User
- Location
- Olympia, WA
'91 XJ, 4.0, AX15, NP231, D30, 29 spline 8.25, A/C if it matters.
Well, I'm a little baffled by this. Here's the background. About 4 months ago I replaced my clogged stock radiator with a CSF 3 core brass and copper. (Very nice upgrade, BTW. The system's cooling ability is drastically improved.) I also replaced the fan clutch, water pump, thermostat, serpentine belt, and various hoses/clamps.
After completing the install, I checked to make sure that clearances were good with the fatter radiator. All checked out good and the Jeep worked well until I took it to Naches in September. At the beginning of the trip I engaged 4-low. When I started to accelerate in a relatively flat area, I heard a ticking/scraping sound. I shut it down and looked under the hood but found nothing. I completed the trip, although whenever I was producing a little torque the ticking would become worse. On the way home my Jeep was making the sound in 2 wheel drive as well now. I could avoid it if I didn't try to accelerate quickly. Accelerating aggressively made the sound louder, and was definitely tied to engine speed.
After further investigation, it appeared that the fan was contacting the fan shroud under torque. I kept driving it and just didn't accelerate quickly due to a lack of time to correct the "minor" problem...until today.
I began smelling coolant this morning so decided to have a look. I figured I'd modify/reposition the fan shroud while I was tracking down the coolant smell. What I found was that in addition to the fan hitting the shroud, the fan clutch had contacted one of the support stringers on the radiator and had driven the stringer into the radiator causing a pinhole leak. ARGH! Although contact was obvious, there is currently a 1/2" gap between the fan clutch and where the stringer used to be. What the heck!?
Motor mounts and transmission mount were replaced about 1 1/2 years ago. There aren't any cracks in them and they look to be in good condition. There isn't any excessive movement when checking them with a long pry bar. Attachments to frame and crossmember are intact and tight. The radiator is securely fixed to the frame crossmember and doesn't wiggle even a little bit.
My long-winded explanation (sorry) leads to a few questions. How does the motor move forward that much!? I understand that the motor can rotate in the mounts a little bit under torque. I had no idea that it could move, or even be forced to move forward much at all, otherwise I may have been more concerned with tight clearances with the new radiator.
Is 1/2" enough space between fan clutch and radiator? Has anyone else had this happen? What am I missing about the motor being able to move forward in it's mounts?
BTW, I mounted the radiator using stock attachment locations and no other modifications.
The Jeep is driveable right now, but I don't want to put a repaired radiator in without researching something I may have missed in the install. I hope you guys can help shed some light on this.
Thanks.
Well, I'm a little baffled by this. Here's the background. About 4 months ago I replaced my clogged stock radiator with a CSF 3 core brass and copper. (Very nice upgrade, BTW. The system's cooling ability is drastically improved.) I also replaced the fan clutch, water pump, thermostat, serpentine belt, and various hoses/clamps.
After completing the install, I checked to make sure that clearances were good with the fatter radiator. All checked out good and the Jeep worked well until I took it to Naches in September. At the beginning of the trip I engaged 4-low. When I started to accelerate in a relatively flat area, I heard a ticking/scraping sound. I shut it down and looked under the hood but found nothing. I completed the trip, although whenever I was producing a little torque the ticking would become worse. On the way home my Jeep was making the sound in 2 wheel drive as well now. I could avoid it if I didn't try to accelerate quickly. Accelerating aggressively made the sound louder, and was definitely tied to engine speed.
After further investigation, it appeared that the fan was contacting the fan shroud under torque. I kept driving it and just didn't accelerate quickly due to a lack of time to correct the "minor" problem...until today.
I began smelling coolant this morning so decided to have a look. I figured I'd modify/reposition the fan shroud while I was tracking down the coolant smell. What I found was that in addition to the fan hitting the shroud, the fan clutch had contacted one of the support stringers on the radiator and had driven the stringer into the radiator causing a pinhole leak. ARGH! Although contact was obvious, there is currently a 1/2" gap between the fan clutch and where the stringer used to be. What the heck!?
Motor mounts and transmission mount were replaced about 1 1/2 years ago. There aren't any cracks in them and they look to be in good condition. There isn't any excessive movement when checking them with a long pry bar. Attachments to frame and crossmember are intact and tight. The radiator is securely fixed to the frame crossmember and doesn't wiggle even a little bit.
My long-winded explanation (sorry) leads to a few questions. How does the motor move forward that much!? I understand that the motor can rotate in the mounts a little bit under torque. I had no idea that it could move, or even be forced to move forward much at all, otherwise I may have been more concerned with tight clearances with the new radiator.
Is 1/2" enough space between fan clutch and radiator? Has anyone else had this happen? What am I missing about the motor being able to move forward in it's mounts?
BTW, I mounted the radiator using stock attachment locations and no other modifications.
The Jeep is driveable right now, but I don't want to put a repaired radiator in without researching something I may have missed in the install. I hope you guys can help shed some light on this.
Thanks.
