Merc 3.0 still chirping

[Alpheus]

Re: Merc 3.0 still chirping

He is just saying that the head gasket wasn't showing any signs of leaking when you were doing a compression test, but when the engine was running the pressure from the combustion of the air/fuel mixture was much greater thus allowing your head gasket to leak.

I myself have never seen that happen. When a head gasket blows it stays blown, but you never know. Sounds like you got it fixed so run it and pay attention to your gauges and keep checking the oil...

 

[rcarden711]

Re: Merc 3.0 still chirping

Alpheus, Lightbulb just went off. Thanks for clarification.

Also, Thanks to your valve adjustment video, I got up enough courage to see if a loose rocker arm was causing noise...that is how I discovered bad head bolt. I never would have attemped it without that video. Thanks for putting it out!

 

[Bluestream]

Re: Merc 3.0 still chirping

Do you think the bad head bolt rusted out on its own, or as a result from someone striping the treads it in the past?

Are all head bolts under the valve cover on that motor, can't picture the layout right now. Very unusual to have the threads rust out.

Looks like you caught the gasket just in time before the block was damaged.

 

[rcarden711]

Re: Merc 3.0 still chirping

Bluestream,

I think either the bolt was stripped sometime in the past and allowed water to eat away at the sealant or the threads on the bolt never had thread sealant on it to begin with. All the other bolts clearly had sealant on the threads as well as on the shoulder part of the bolt.

This particular bolt went down into the water jacket directly behind the circulating pump so it was exposed to saltwater. Six of the ten bolts are under the valve cover...there are four corner bolts that are partly exposed but cant be removed without taking cover off.

Started noticing the chirping during a trip last month and stopped running it. Luckily no damage so far.

 

[fat fanny]

Re: Merc 3.0 still chirping

All it takes is one mechanic not using the thread sealer during assembly to cause this issue. lckily you got the threaded part of the bolt out. glad to hear you figured it out