Yanmar 6LYA 370Hp - Clicking at idle

Good morning all,

I have a 370 with 500hrs, runs great etc - at low RPM, harbor cruising there is an audible clicking with about 1/4 second frequency (I will get a more accurate number if necessary) but is this a feature of this engine, or something to worry about? I searched the archives but did not find anything. Thanks, Ed

Ed,

Is this in gear only?
Will it do it in reverse?
All times or only once up to temp?
At what rpm? At what RPM does it begin and end?
All fluids are where they should be?
Any recent servicing or changes?
Have you hit bottom or nets in the recent past?
Where exactly is the noise coming from? Can you isolate it or get a general area?
Does it seem internal or possibly external to the engine?

You need to be in the engine room while this is going on, while someone at the controls makes it start and stop if possible.

Would be anxious to hear your answers. Bill

PS- Did this just begin or has it been this way for some time. If this is recent, you should not use the engine until you know what is going on. Noise=friction, friction=wear, wear=failure.

Older gas engines used to get a valve that would tap. It made a rather light metal click or tick that varied with engine rpm.

John

Have you checked to make sure nothing is loose? If this does this in idle, it could be the fuel injectors.

If in neutral which I assume it is, then if the noise is coming from the upper part of the engine, then valve lash or possibly injector. If it coming from the lower aft part then it could be a failing torsional damper- the round flat plate that connects the engine to the transmission and absorbs pulses.

Pull off the oil fill cap and see if the noise is coming from inside the rocker cover. That strongly suggests valve lash. If not and the noise is coming from the upper part put your ear down near the injection pump (starboard side in front of the after cooler) and listen.

Not sure of a specific test for damper plate but listen down there and see, well hear.

David

Wow - thanks all, she lives on a lift so no bottom damage. Will get her out this weekend and get specific answers - will try to get it run with me in the engine compartment and get a feel for where - may even shoot video ... it may just me normal engine noise.

Any attempt at some of the questions:
Believe in gear only (not sure about reverse) - about 900RPM for about 300 RPM ... maybe higher but would be hard to hear. No recent changes, and fluids are where they should be but will be verified at the weekend.

Again thanks, E

If in gear only, could very well be the transmission.

A clicking noise is not normal, but may not be a problem. I had two Yanmar 370s in two boats over a ten year period. Never heard a clicking noise.

David

On the now defunct Yahoo Mainship site a fellow complained of a metallic clink until he found the engine cover support arm's locking pin dangling free instead of in its stowed position. Ya never know...

Hi all.

So it’s about 1100 rpm (neutral and In gear) I crawled around the engine compartment and nothing obvious. Interestingly it’s more audible at the helm. It may well be normal diesel symphony. Uploaded a sound clip to youtube in case anybody cases to listen. https://youtu.be/S2eSNBOqXG0

Interested in your thoughts and feedback.

Thanks. Ed

If you dont have a stethoscope use a section of garden hose or similar to listen at various places to locate the source.

I am a little confused. You are now saying that the clicking noise is audible in gear or in neutral. In post #6 you said it was in gear, but i guess you didn't say anything about in neutral. Yes it matters.

I listened you your video and it sure sounds like valve lash. Did you try listening at the oil filler port like I suggested in post #5?

David

Hi David and all. I did the oil fill check on a different video which I can post - same sound. After posting the sound near the shifter .... I got to thinking, why would I hear more there than in the engine compartment .... went back down and found the culprit .... shifter cables that run along the engine and turn (unsupported) to starboard then up to the shifter and at 1100 rpm they resonate against the metal fuel tank .... two zip ties and no more noise. Thanks all who helped. Thank god it’s that simple.

Gotta love that solution. If it had not been the cable I was gonna comment that I surely would not like that sound coming from my 315 HP Yanmar.

Sometimes you just get lucky!!