CGLockRacer
CGLockRacer Reader
7/26/09 12:28 p.m.

I have an '06 Mazda 3 w/ the 2.0L engine w/ 72k miles. It is making a very loud rattling noise coming from the timing chain side of the engine. I popped off the cam cover to just see if anything was obviously loose. The only thing I can see is the chain is drooping 3/8" between the pullies. The car has variable valve timing, so I don't know if this is normal or not. When I move the chain back and forth it sounds exactly like the noise I'm hearing when the car is idling (chain slap/rattle). The rattling noise changes with the engine speed.

Mileage and power do not seem to be affected, but the noise bothers me. It sounds like a diesel at idle and has gotten worse in the last few weeks.

It is not the throwout bearing; that side of the engine is quiet and the noise does not go away when depressing the clutch.

Any advice/suggestions? Thanks!

cwh
cwh Dork
7/26/09 12:54 p.m.

Sounds like a chain/ belt tensioner gone south. Had that on my Sentra, same symptoms.

Carrera30
Carrera30 New Reader
7/26/09 1:33 p.m.

^ That is indeed what is sounds like. Anyone know what kind of tensioner? Hydraulic? Mechanical?

CGLockRacer
CGLockRacer Reader
7/26/09 2:32 p.m.

Thanks! That's what I suspected too , I just wanted confirmation before I make an appt. for it. Hopefully this is covered under the extended powertrain warranty that came with the car.

Strizzo
Strizzo SuperDork
7/26/09 3:26 p.m.

Iirc, there was a tsb on the timing chain tensioner for those cars.

CGLockRacer
CGLockRacer Reader
7/29/09 2:04 p.m.

Update: The car is at the dealer. They've haven't found anything yet and now need to pull the cylinder head. UGH. This better be covered under the extended powertrain warranty or I'm screwed...

I need a cheap...reliable...E30...yeah, that's the ticket...

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