P700m4 Top end engine noise

[Hunter801]

I have a 700 Pioneer. I have had it to the dealer multiple times with a what sounds like a top end engine noise with no repair results. It sounds like valve tap. When the engine is idling at cold the noise is not there. Once driving the machine for a half hour or so you can here what sounds like valve tap (Loose chain) at an idle. As soon as you increase the throttle ( just takes a slight increase in RPM) the sound disappears. The dealer has adjusted the valves multiple times. Last visit the installed a new camshaft. Problem is still there. I'm thinking it is a timing chain tension spring, that is getting hot and week after running awhile. If it was a valve or camshaft issue shouldn't the noise get worst with increased RPM???? Looking for some direction before going any further.

Thanks in advance for any help

 

[Admin]

 

[Hello_Darkness]

Timing chain tensioner will sound like a high pitched rod knock almost.

If you take the bolt out of the tensioner end and insert a small flat screwdriver ypu can turn it and make it tighter temporarily. The noise should stop, you can loosen it too and see if that's the noise your hearing.

It's very common on the 700 engine.

 

[Hunter801]

Timing chain tensioner will sound like a high pitched rod knock almost.

If you take the bolt out of the tensioner end and insert a small flat screwdriver ypu can turn it and make it tighter temporarily. The noise should stop, you can loosen it too and see if that's the noise your hearing.

It's very common on the 700 engine.

Thanks for the information. I will give that a try on my next days off and let you know how I make out.