Coolant leak

[richard1]

I have a very slow and small coolant leak that come from under the engine on the intake manifold side when the car is parked in the garage after a couple of days. The freeze plugs are dry.

Could it come from the intake manifold hoses? I cannot see any of them leaking but I tighten up the hoses that seem to deliver coolant to the manifold. They were not loose but needed some turns of the screwdriver.

[Nissanman]

I need something from you...

What type of car are you talking about??

On the 240Z for example there is a coolant passage that runs between the two pairs of inlet manifolds.

This is a rigid metal pipe sealed by two screw in bosses.

The flexible hoses connect to the extreme front [cyl #1]and rear [cyl #6] of the manifold to two screw in pipe nipples.

Any of these 4 connections may be leaking.

See circled bits in the attached diag.

The factory wire clamps are a bit tough on rubber hoses, the rubber tends to flow away from the wire over time resulting in a loose pipe.

Re tensioning the clamp often does the trick.

If the rubber pipe or metal nipple are old and crusty, it may very well crush them both and create a bigger problem:tapemouth

It is possible, depending on your climate, to temporarily disconnect the coolant feed to the inlet manifold and leave it that way.

Just make sure you seal the feed pipe that connects to the front nipple and seal off the return pipe from the rear nipple.

[Zs-ondabrain]

I need something from you...

What type of car are you talking about??

He owns a 72' 240Z w/ a stock motor.

(on his profile page)