4.0 WJ Mysterious Coolant Leak

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08-12-2019, 01:19 PM

#16

Hunter_

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Location: Orlando, FL.

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Year: 2003

Model: Grand Cherokee (WJ)

Engine: 4.0L

Quote:

Originally Posted by Noah911

Coolant was never noticed boiling over in the resevoir before was it? Maybe that happening while parked on a slope could cause coolant to overflow, and be lost out the resevoir?

No but I have noticed that after I shut the engine off that the reservoir immediately fills up quite a bit before sinking back down moments later. I still am in the proses of "burping" the system because of the t-stat being replaced could this be part of the issue?

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08-12-2019, 08:59 PM

#17

Noah911

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Year: 2004

Model: Grand Cherokee (WJ)

Engine: 4.0

Yes. Any air in the cooling system is considered detrimental! It may result in causing steam, and hot-spots to form on metal parts in the engine. This may result in cavitation. Having microbursts of air bubbles attacking the engine and the lining of interior parts, at pressures as high as 60,000 psi. The result is pitting and erosion. The air needs to come out. It can cause all kinds of bad issues. It can cause steam and boil-over to happen in the resevoir, or out the radiator cap too.