4.0 SOHC engine rattle.

[Mike65]

Our 99 Sport 4.0 SOHC had the engine "death rattle" on cold start up so I purchased 2 new hydraulic chain tensioners. I installed the r/s rear one & it was a little better, after I replaced the l/s front one the noise now seems worse & the rattle is now noticeable at idle also, WTF. I replaced the original ones with ones made by Cloyes. Would my next course of action be to tear the front of the engine apart, or should I just put the original one back in the l/s front?. If I run the engine with the oil filler cap off the noise sounds louder. If I use a flash light & look in the oil fill cap hole all I can see is the chain. HELP me please.

 

[2000XPL]

From my experience with the 4.0 SOHC is the jack shaft tensioner is the main culprit.

I had to strip my front down 'for the front' and remove the engine to get to the back timing chain set. Only replacing the screw in tensioners will not fix the problem.

It is a pain in the ARSE to do.

I had no jack shaft tensioner at all ... it sounded like a rattle in the exhaust but in the engine.

And from what you are describing it will be a complete engine pull and replace all timing componants.

 

[Flash]

Somebody on this forum says that the new tensioners are often not even as good as the worn out old ones but I would have thought you'd be ok with Cloyes.

Put the old tensioner back to see if it makes a difference.
If it doesn't rattle you're ok.

If it still rattles then you're up for a jack shaft tensioner which is was in my case.
The chain was rattling on the pivot of the non existent tensioner.

Here's a thought: are you installing the tensioner correctly?

 

[Mike65]

Here's a thought: are you installing the tensioner correctly?

I soaked it in oil prior to installing it, unscrewed the old one & screwed the new one in to the proper torque.

 

[Tech By Trade]

Pop the valve covers and see if you have any guides left. My guess is they are sitting in the bottom of the oil pan.