Does coolant flow through 3.7L intake manifold?

My wife's 170K mile 3.7l KJ Liberty is leaking coolant and there is steady, although faint steam from exhaust. I pulled the plugs and there was one that looked steam cleaned (coolant in combustion chamber), but the compression check was consistent across all cylinders. If it were a head/head gasket, I would expect 1 or more cylinders' pressure to be different.

So were is the coolant coming from? Is there coolant in the intake manifold? That's the only other possibility I can think of.

Thanks!

See the responses to your other thread...

Bob

This diagram shows a coolant temp sensor (item 3), which leads me to believe that there is coolant somewhere in there.

Manifolds, Intake and Exhaust, 3.7L [EKG]. Fits: 2002 JEEP LIBERTY | FACTORY CHRYSLER PARTS

I looked at my FSM, and don't believe there is coolant in the manifold. From what I could tell from the pic in the FSM, it looks like the temp sensor installs right in front of the manifold. I would verify this by looking directly, but our KJ is in the body shop right now.

i will answer for sure. there is no coolant at all going through the manifold. i got 2 sitting in my garage right now

Other engines do have coolant flowing through the intake (the Ford 3.8, 4.6 & 5.4 come to mind - ask me how I know) but the 3.7 does not.

Pretty much any engine with a plastic intake manifold does not have coolant running through it.

04Liberty said:

Pretty much any engine with a plastic intake manifold does not have coolant running through it.

Click to expand...

Not true,GENII/III GM 3.8 V6 is 1 example,has a plastic upper plenum that coolant does run through.

tjkj2002 said:

Not true,GENII/III GM 3.8 V6 is 1 example,has a plastic upper plenum that coolant does run through.

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It's just not a good idea to have a plastic intake with coolant running through it - as Ford learned with their 4.6 V8 engine.

04Liberty said:

Pretty much any engine with a plastic intake manifold does not have coolant running through it.

Click to expand...

tjkj2002 said:

Not true,GENII/III GM 3.8 V6 is 1 example,has a plastic upper plenum that coolant does run through.

Click to expand...

I did say pretty much lol. It definitely isn't a good idea and most (if not all) newer engines lately do not.

04Liberty said:

I did say pretty much lol. It definitely isn't a good idea and most (if not all) newer engines lately do not.

Click to expand...

You weren't wrong really. The (3.8 referenced) aluminum part that attaches to the heads is the lower intake manifold. The upper plastic part that attaches to the manifold is the intake plenum.