Odd Coolant Leak

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1979bettywhite
Posts: 547
Joined: Tue Jul 25, 2017 8:14 am

Odd Coolant Leak

Post by 1979bettywhite »

A few days ago after driving the Chief to work, I noticed a decent little puddle underneath it when I came back out to it at lunch. Turned out to be coolant. Opened the hood and looked around. Only place I could see coolant was around the cap area and on the little shelf that runs around the bottom of the top tank, where coolant might stand in place if it was leaking from above.

So I thought maybe it might be the overflow tube leaking a bit. Came home that night, removed the clip off the tube on the overflow nipple, inspected and slid the tube on a little further, reinstalled retaining clip. Seems ok, doesn't move when twisted etc. Opened up the radiator cap. She is full, all the way up to the overflow tube.

Drove to work yesterday, no issues. Came back out, no leaks. Drove home, no leaks I could see when I got home. Woke up this morning and went out there, small puddle again (but a little less). Opened up the hood and checked things out. Noticed a little coolant dripping off the underside of the fan shroud, onto the fan, onto the transmission cooler line, onto the ground. Really not much though. Opened the radiator back up, still full to the overflow tube.

Any thoughts on what might be causing it to leak after shutting down/overnight? Only thing I can think is maybe the cap is leaking a bit with the pressure? It's a fairly new standard 16lb cap (no release lever).

I don't think it is leaking while driving/running, but I may try to get it up to temp today and see if I can see anything leaking. Maybe drive around a bit and come back and monitor.

Any thoughts?
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freehold
Posts: 105
Joined: Wed Nov 20, 2019 7:52 am
Location: Cackalack

Re: Odd Coolant Leak

Post by freehold »

Must be something in the air. I just posted a similar issue (different space, but still a "coolant is coming out of nowhere" post) yesterday.
1987 GW, 202k miles, AMC 360 engine rebuilt 62k ago, all more or less bone stock
1997 Grand Cherokee ZJ, 244k and still going
When it rains, I drive an MDX

letank
Posts: 4010
Joined: Wed Oct 03, 2012 9:16 pm
Location: SF bay area

Re: Odd Coolant Leak

Post by letank »

good point on the cap seal... this one baffled me for over a year... on my older civic... temp would shoot up after exiting the freeway and waiting at a light... then back to normal... I pressure tested the cooling system .... no leaks... (of course the cap is removed), so I thought about the thermostat... yes, it is the thermostat, wrong temperature range... but no, temp going up as traffic slows after freeway run... retest and recheck, and yes I was loosing some coolant, but no dripping in the driveway or parking lot... then when I look at the cap the gasket was in very poor shape, a new cap... and all is good.
Michel
74 wag (349 Kmiles... parked, next step is a rust free body)
85 Gwag (229 Kmiles... the running test lab)
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66stepside
Posts: 3793
Joined: Sat Oct 13, 2012 9:59 pm
Location: Spokane Valley, WA.

Re: Odd Coolant Leak

Post by 66stepside »

I had the same, or similar issue in the M715; the cap was the culprit despite it being relatively new.


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candymancan
Posts: 3652
Joined: Tue Mar 22, 2016 11:32 pm

Re: Odd Coolant Leak

Post by candymancan »

Try a new cap. Tighten the clamps on the hoses all over if yours have clamps that tighten anyway. Otherwise im going to say your radiator is leaking.

Or maybe the water pump is leaking splattering on the fan and so forth. Youre just going to have keep digging to find it. We cant help much without being there and looking
1998 Jeep Grand Cherokee 5.9L Limited 219k
1998 Jeep Grand Cherokee 4.0 I6 laredo 430k
1990 Jeep Grand Wagoneer 155k
1976 Jeep J10.. 85k(repaired)

Topic author
1979bettywhite
Posts: 547
Joined: Tue Jul 25, 2017 8:14 am

Re: Odd Coolant Leak

Post by 1979bettywhite »

I think I am going to try a new cap first. I think that may be the culprit, but we will see.
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