Contour Enthusiasts Group Archives Forums General Troubleshooting Timing chain rattle -- ALL the time

There's a rattle that seems to be coming from the cam gear area on the rear bank of the 2.5L HO on my '98 CSVT. Lately it's developed a little bucking noticeable up to about 2500RPM.

I had the codes read last week, and it showed that 1 and 3 were misfiring some. CEL was on, but it's been that way for a long time due to slightly out-of-spec cat. CEL is not on now.

I replaced wires on 1 and 3 (doing the rest when convenient) to see no significant improvement. Is the timing chain worn out? cam bearing shot? Chain tensioner loose? Engine has very high miles, but it's been bulletproof reliable to date. I've run full synthetic 5W-30 since second oil change. Car was built June 1997 as an early '98; I bought it new.

Sideline -- From reading other posts, I think the secondaries are not opening all the way, but that's been the case for over a year.

You may have a couple separate issues going on. For the rattle, there was a TSB for the idler pulley where the bearings would wear and you'd hear a scraping/rattling sound. I had this on my SVT, and I also thought it was chain related. Take off the drive belt and start the car; if the rattle goes away its one of the pulleys, with the idler being the probable cause. Its a cheap part and an easy fix. For the misfire, when's the last time the plugs were changed?

I could be way off here, but I though I'd offer it in the hopes that you don't have something serious.

Thanks for the quick reply. I suspect multiple issues as well, particulaly for the misfiring. Bosch platinum plugs looked OK -- no carbon tracking (mechanic who pulled the codes said to look for that), good gap measure, and white or grey color with a tinge of brown in places.

I have not worked on the engine myself except for simple things like plugs & wires, filters, etc. The sound really seems to be inside the cam gear housing -- I'll confirm this evening with another listen.

If it's the cam gears/timing chain, I guess that means replacement of all that, right?

Thanks,

I heard that the Duratec does not like Bosck Platinum plugs. I would recommend switching to Autolite Double plats.

I've heard and read that a few places now. I'll take your advice and switch the plugs when I finish the wires.

As for the timing chain, the rattling is not from anything hitting the cam gear housing, as it sounds from outside. By the "screwdriver to the ear" method, both cam gear housings sound the same. I hope Hetfeld was right in pointing to the drive belt idler. I'll find out asap.

Mark

You're right on both! Ditched the Bosch plugs for some new Autolites (most expensive plugs I ever bought - they better last 100k miles like the originals did) and the misfire disappeared. I'm now sure the rattle is the drive belt idler. I'll replace as soon as it's convenient.

Thanks for your help -- it saved me a bundle.

Mark

Instead of purching the complete idler, you can purchase just the bearing for 5 dollars. You can press out the old and insert the new with a socket. Better than spending 70 dollars or so........

Bob

$70 for the idler? Remember, there are two "idler" pulleys, the stand-alone idler and the tensioner pulley. The stand-alone (which has a Ford TSB) is really cheap, even from the dealer. That's probably the one making the noise.