Coolant puddle
11-12-2017, 02:53 PM
#1
JK Enthusiast
Thread Starter
Coolant puddle
My 08 JKU hasn't moved since wednesday(3 days). It has had a small occasional drop on the lower driver side of the radiator for several months but I've never pinpointed the exact location of the leak. I've watched over the last couple days as the wet spot underneath has grown. I understand that things expand and contract with varying temps and it has gotten substantially cooler this week along with not running the jeep at all. Today I had a few moments took inspect under the hood. I noticed moisture under the thermostat housing and a bit of moisture on the front of the block under the intake. The water pump area as well as the manifold gasket areas are very dry. So I can identify that the thermostat needs replaced. But what about the drip under the rad? The hoses feel dry. I can barely see any moisture along the edges of the tank and fins about 2 inches up. I know these plastic meets aluminum rads are prone to separate but I guess I'm wondering if the failed thermostat could possibly cause a drip at the radiator...i intend to change the thermostat and pressure test on Tuesday. Just looking for some forum fore sight until then. Thanks.
11-12-2017, 04:59 PM
#3
JK Enthusiast
Thread Starter
11-13-2017, 04:17 PM
#4
Super Moderator
The only way to be certain where your leaks are coming from is to use a pressure tester.
I purchased the HF pressure tester and it was well worth the $75 I spent, since I spent months guessing.
These are the adapters you would use for our JKs.
I purchased the HF pressure tester and it was well worth the $75 I spent, since I spent months guessing.
These are the adapters you would use for our JKs.
11-14-2017, 06:02 AM
#5
JK Enthusiast
Thread Starter
P.S. Not a single drop came out of the thermostat housing while under pressure. Yet it was soaked while sitting idle for 3 days. 🤔
11-14-2017, 10:48 PM
#6
JK Jedi Master
After installing a new radiator (no problem with the OEM one at 180K miles, but was headed above Arctic Circle and didn't want to learn up there I needed a new radiator!), I had an occasional problem with coolant ending up on the radiator fans. Making a long troubleshooting story short, it turned out to be the seal on the new thermostat was slightly curled out of correct position, and when driving the leaking coolant got whipped over to the radiator fins. Recommend fix the thermostat first and see if that takes care of things. If your radiator is approaching 200K miles, recommend replace it before going on any trips above the Arctic Circle. ;-)
11-15-2017, 05:28 AM
#7
Super Moderator
Same here regarding the guessing game...I pressure tested it today and laughed my ass off at the downpour coming from the radiator. I mean it was spraying out. The leak is on the top, front driver's side. Under the dust cover. I'll be replacing the rad next week. Ha.
P.S. Not a single drop came out of the thermostat housing while under pressure. Yet it was soaked while sitting idle for 3 days. 🤔
P.S. Not a single drop came out of the thermostat housing while under pressure. Yet it was soaked while sitting idle for 3 days. 🤔
It was a mystery for awhile where I noticed my coolant kept getting low over time, where I ended up having a lower intake manifold gasket leak as well. I was not able to find this leak using the pressure tester. My thought on this, is that while pressure testing the engine is cold and therefore things weren't expanded and therefore no leak but as the engine warmed up, then things expanded and then that's when it would leak.
Just something to keep your eye on, so you can learn from my experience. I eventually found my lower intake manifold gasket leak when one day I was driving and coolant was pooring from the side of the engine but the signs were there previously, if I had just known where to look.
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11-19-2017, 08:26 AM
#8
JK Enthusiast
Thread Starter
Something I learned because I actually had 2 separate leaks. I had the same radiator end cap leak as you, found using pressure tester. It took me 120K miles for me to get there, so no complaints.
The
It was a mystery for awhile where I noticed my coolant kept getting low over time, where I ended up having a lower intake manifold gasket leak as well. I was not able to find this leak using the pressure tester. My thought on this, is that while pressure testing the engine is cold and therefore things weren't expanded and therefore no leak but as the engine warmed up, then things expanded and then that's when it would leak.
Just something to keep your eye on, so you can learn from my experience. I eventually found my lower intake manifold gasket leak when one day I was driving and coolant was pooring from the side of the engine but the signs were there previously, if I had just known where to look.
The
It was a mystery for awhile where I noticed my coolant kept getting low over time, where I ended up having a lower intake manifold gasket leak as well. I was not able to find this leak using the pressure tester. My thought on this, is that while pressure testing the engine is cold and therefore things weren't expanded and therefore no leak but as the engine warmed up, then things expanded and then that's when it would leak.
Just something to keep your eye on, so you can learn from my experience. I eventually found my lower intake manifold gasket leak when one day I was driving and coolant was pooring from the side of the engine but the signs were there previously, if I had just known where to look.
Outs never ending in a Jeep. Keeps me entertained I guess. Thanks for all the input!