yo_marc

I had two coolant leaks in my '07 3.8.

1) Water pump gasket. Not the pump shaft seal, but the gasket itself. This one was pretty obvious.

2) Intake Manifold - front and rear. I noticed the front weeping for some time. Honestly, about a year before it got bad enough for me to address it. The rear I did not know was leaking until I had the intake manifold off and in my hands.

From what I understand the intake manifold leak at the rear of the intake is the hardest to spot. Coolant travels a ways back (along the tranny) and can evaporate off before making itself known.

Knock on wood, I have yet to hear about a 3.8 needing a head gasket. I've heard of a LOT of 3.8's that need a water pump or intake manifold gasket.

Jiblet

Check inside the cap while it's cold. It'll probably be full if there is anything in the expansions bottle.

I'd suggest filling the bottle to just over the min mark.

50/50 HOAT is what you want. Or you can use water, distilled water is best, but if you plan to replace the old coolant soon then tap water will be ok. It'll be a pint or so.

Then use the jeep so it cycles hot and cold a couple times, in case there is a bubble to purge.
Then while the jeep is at operating temp, check the level. Should be well above the min level but at or below max.

If the coolant is still disappearing, I'd have the system pressure tested.

If it holds pressure fine, I'd just replace the 5year old coolant with fresh HOAT mix and pick up a new cap. I think it's an18 psi cap but confirm that.

ronjenx

yo_marc

One quick note -- I know it's common to be able to smell coolant leaks -- but I never noticed mine. And I drove with it leaking from various places for quite some time. This HOAT stuff doesn't really have much of a smell to it.

[The old green coolant is obvious - it smells like maple syrup.]

adampepper2012@gmail.com

Let's weigh our options here:

1 - drain your coolant refill with good coolant and pressure test for leaks. Labor costs and coolant

2 - replace water pump and intake. Labor and parts

3 - add small amount of liquid gasket seal. 10 dollar bottle of gasket seal , no labor

4 - just keep adding coolant until water pump fails or car has enough miles on it to warrant a new intake gasket.

5 - insert another option I'm probably forgetting


So many choices and so little time and money for most of us !

Jiblet

It's mostly the same stuff. Aside from the about 50% water, the coolant is nearly all ethylene glycol same as the green stuff. The inhibitor package is only a few % of total volume. I always thought the smell was the EG, not the add pack.

Maybe it's just the bigger leaks that smell noticeably.

Jiblet

I have a lifetime power train warranty covering my water pump, etc., so I'm not to keen on adding anything like gasket sealers.

adampepper2012@gmail.com

I always forget about the warranty thing because the dealerships are so cooperative , wink wink . Seriously though, take it in and see if they will help you out.

zstairlessone

They replaced my pump during the 5 year inspection under warranty because it had a super small leak.

Fireman-IV

I have a 07 and same issue, I found that I had a intake leak. Replaced the intake gasket and all has been well. Check the front of intake were it mounts to the block usually stands around the center head bolts!!