Jeep 4.0 radiator gurgling into overflow

[alexb]

I went through this a few weeks ago and thought I'd share. Definitely my cheapest repair to date.

I came to a stop and got out of the Jeep and heard a gurgling, like very distant thunder, sound from the engine. Opened up the hood and there was coolant bubbling (I don't think it was actually boiling) into the overflow container.

Fix was a new radiator cap for $4. Reading various forums, it is apparently a common failure point. I also did a flush because it was due and I've had no trouble since.

This is a 2005 LJ with the 4.0L I6.

[Patrolman]

You can also do a pressure test on the radiator caps. They are supposed to hold a certain PSI. If they don't have enough PSI then the coolant will come out more than it should (some is natural). If the PSI is too much, bad things could potentially happen as well, such as blown radiator hoses. The PSI range has to match the engine specs.

[alexb]

You can also do a pressure test on the radiator caps.

Because the cost was so low, I figured I would just replace it and see if it fixed it. In my case, that was true. :)

[Patrolman]

Glad it was an easy fix!

[06HokieTJ]

I think that's on my list for this weekend. I have a new cap that I'll put on when doing a flush. I also have a new t-stat and water pump that I'm thinking of installing while the engine is drained. The WP is barely weeping, but it and a t-stat was less than $35 at Advanced Auto parts, so I figure what the hey.