Trying to understand why I have seeping coolant


4BY4ADV

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Oceanside, CA
Recently had a heater hose blow on me making a huge mess. I replaced that hose and in the process, I had to loosen the adjacent hose running to the top of the radiator. Next day, that hose started leaking at the engine, so easy enough fix, I replaced that hose too, refilled with coolant, and other than getting to smell some of the excess coolant burning off, everything was fine.

Two weeks later(yesterday), I pull up to a lunch meeting and I have coolant dripping down. Pop the hood and find that it *appears to be seeping out from that newly replaced hose at the connection to the radiator. I'd tighten the hose... except that I went 2 weeks without it leaking and it is already pretty snug. I don't want to crack/deform the plastic neck, so I leave it.

After the lunch meeting I return to the office and peer under... nothing leaking. After work, still no additional leaks and when I pop the radiator cap, the fluid level is great. My overflow reservoir however is low. I didn't have any coolant or distilled water, so I just headed home watching the temps with my digital gauge.

Everything was great on the drive home. And again this morning and today at lunch. So I'm looking at what might have been an isolated event, but trying to understand why it would leak at that hose/fitting. My assumption is that any additional pressure should pop out the radiator cap and into the overflow right? Only other factors that might be playing into this, the lunch meeting was only a few blocks away from the office.

Is it possible that I drove too short a distance that the temp didn't raise enough to pop the thermostat and allowed a buildup of pressure that for some reason the cap didn't handle?
 

MountaineerTom

LJ Enthusiast, Retired USAF Weapons Loader
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You said you tightened the hose, so I’m assuming you have worn drive clamps. I had multiple leaks when I had some on mine. Especially when temps changed in the spring and fall. I went back to the OEM constant tension clamps in Nov 2019 and haven’t had a leak since.
 
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4BY4ADV

4BY4ADV

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Brand new hose clamp. I didn't tighten it because it was plenty tight enough and I was worried of cracking the plastic connection. Same tension prior to and after leak.

Only thing that makes sense to me is that there was excess pressure and the radiator cap didn't allow it to release... so it found another path. I'm going to replace the radiator cap as a cheap precaution and keep my eye on the temps and ground for leaks. I just hate not knowing what caused an issue.
 

Moglocker

TJ Enthusiast
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Mar 19, 2021
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Missouri
Brand new hose clamp. I didn't tighten it because it was plenty tight enough and I was worried of cracking the plastic connection. Same tension prior to and after leak.

Only thing that makes sense to me is that there was excess pressure and the radiator cap didn't allow it to release... so it found another path. I'm going to replace the radiator cap as a cheap precaution and keep my eye on the temps and ground for leaks. I just hate not knowing what caused an issue.
Cap is a good start,get a good one
 
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