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Unread 12-09-2012, 04:59 PM   #1
drog929
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99 4.7L coolant leak problem

I have a 99 Grand Cherokee Limited with 4.7L V8 with 345,000 kms (I'm in Canada). Jeep runs generally well but have recent problem with an intermittent coolant leak.

I am wondering if anyone has the same problem or can help diagnose or suggest a repair.

There is a threaded metal fitting (or return tube) acting as a return tube that connects hose from top of radiator to coolant bleed assembly. When coolant does leaks (usually in mornings), the coolant drips in a constant stream from this metal fitting/return tube. When I took Jeep to my local shop, he ran car for 20 minutes and there was NO leak.

I have tightened hose clamp but coolant still leaks. The metal fitting (return tube) seems to be pretty solid and when removed it looks fine.... could it have a micro-fracture?

I tried finding a replacment fitting but local dealerships here don't stock this fitting and will not even place order for this part since no shipping date is indicated. (The parts person at dealership gave me a part number as 6035961AA).

Is there another fitting that I can use? or do I have to check local salvage yards? Does anyone else have a similar problem? Any ideas/suggestions would be appreciated.

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Unread 12-10-2012, 04:50 AM   #2
shockracer
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Could you post a picture of it, what I search that part number it comes up as as chain cover.
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Unread 12-10-2012, 06:28 AM   #3
drog929
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Here is a side view picture of the rubber hose from rad connected to the coolant bleed assembly with a threaded metal fitting/tube. The coolant is leaking from bottom (where arrow is pointing). The rubber hose was changed thinking that was problem but coolant drip still occurs intermittently.
coolant-leak-fitting.jpg  
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Unread 12-10-2012, 06:54 AM   #4
shockracer
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I was finding them online for around $12 USD just by googling the part number. I would be vary careful when trying to unthread it, it may just crumble. Soaking it with a lot of penetrating fluid.

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Unread 12-10-2012, 07:06 AM   #5
jahcure
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If you plan on taking it off be sure to heat up the housing with a torch for a min or two and it should come out with no problems
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Unread 01-08-2013, 12:54 PM   #6
drog929
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Just posting a follow up to my leaking coolant problem.

The leak seemed to have disappeared for a while so I did not replace the threaded metal fitting. However yesterday morning it was cold and when I started up the car the coolant was dripping steadily from the top hose connection. I drove car a few blocks to the store and when I got back home the leaking had stopped. I let the engine run for about 10 minutes in driveway and no leaking at all. I turned engine off and restarted again and no leaking. It appears that after the car warms up and engine is turned off the leaking stops.

Same thing happened again this morning. Started car and coolant has a steady drip. Drove it a few blocks to the store and turned off engine. Came back to the car after 2 minutes and when I started the engine there was no leaking.

What could be causing this? Can anyone suggest a reason why the dripping coolant at the top hose would only happen when engine is cold at start up? I would think if the problem was the metal fitting, then the dripping would be constant (not just when cold). Any thoughts? Could problem be related to the thermostat?
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Unread 01-08-2013, 01:08 PM   #7
jahcure
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When it heats up it expands sealing the leak and when it cool well it leaks can you thigten the fitting?
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Unread 01-09-2013, 05:02 AM   #8
imaguy3
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Is the fitting aluminum like the housing it screws into? If not then my guess is you had a reaction b/t the two metals, causing corrosion, and both pieces will need replaced. Even if they're the same material, the threads still look corroded (or maybe that's just grime, hard to tell in pic.)

As others have said though as the metal piece heats up it expands slightly which seals the leak.
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Unread 01-10-2013, 05:21 AM   #9
drog929
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I believe the fitting is aluminum like the housing. Can't really tell with all the grime< but the leak is not coming from where the fitting connects to housing. The leaking is where the rubber hose and fitting connect. I have tried tightening clamp again and does not seem to work. I even installed a new second clamp beside old clamp and leaking still occurs. I have checked online for this part number and apparently it is "discontinued", so I am on the hunt for a salvage yard part or person parting out their Jeep.
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Unread 01-10-2013, 06:11 AM   #10
jahcure
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Is the rubber hose in good condition?
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Unread 01-11-2013, 09:38 AM   #11
drog929
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Yes. Rubber hose is new. This was the first think I replaced hoping that would solve leak problem. Unfortunately this did not help.
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Unread 01-19-2013, 03:12 PM   #12
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Update: coolant leak seems to have gone away. I suspected the hose clamp may have been the problem and possibly loosening up with vibration when driving car. I replaced one clamp with two brand new clamps and leak has dissappeared.
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Unread 01-25-2013, 07:09 AM   #13
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Original coolant leak has re-appeared (although not as bad as before. However, I now see that there is a leak coming from top of rad on passenger side. (see picture). The leak is a slow drip from the plastic cap (see red arrow). Can the plastic cap be tightened?? Is there a cheap fix (i.e. JBWeld) or does the radiator need to be replaced? I already had rad replaced just 3 years ago.

I have had this Jeep for about 6 years and it has served me well but I am am considering if it time to retire the Jeep. It does have 215,000 miles on it now.

Any advice or suggestions would be much appreciated.
rad-leak-top-passenger2.jpg  
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Unread 01-25-2013, 07:24 AM   #14
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The plastic cap appears to have a hex shaped hole? Can this plastic cap be tightened?
rad-leak-top-passenger-hex2.jpg  
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Unread 01-25-2013, 07:56 AM   #15
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Only one way to find out, do it doooo it
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