AlanB

Hi all,

first post on the forum and just wanted to get some info/opinions on a fault that I've had today with my 2004 Mazda3 GT Sport.

I was driving along the road and start hearing this vibrating/rattling sound when traveling at certain speeds. It becoming increasingly noticeable as I pulled away from a set of traffic lights - then, a sharp clunck, and a noise that sounded like something snapping in the engine bay. After this, vibration noise was gone and everything sounded as normal. Car also drove normally. On the dash however, battery light came on, and the temp sensor needle went straight up to 'High'. Quickly pulled off the road into a car part and switched off. Underneath the car, I could see the belt hanging down, shredded. When I opened the bonnet, I found this piece sitting to the left of the engine cover:




So it looks like this part (which was used to hold the belt) failed.. is this common? It's only plastic I guess.. the car has done 172000kms. What does this belt drive? is it just the alternator? I thought it was the timing belt but someone has mentioned that the 2.3 engine uses a chain?

Strobe Media

yes, i think ALL mazda 3's, correct me if i'm wrong use a timing chain, so you don't have to replace the timing belt.

mazurfer

Wow! Not good at all!

My daughters car isn't here right now, so I can't look, but it appears to be one of the tensioner pulleys. This is a pulley that is used to tighten the belts up. It's either that or the one right off the front of the water pump. My guess since you over-heated right away is that it must be the one on the water pump. Don't drive until you get this fixed!

AlanB

thanks for the info.

I pulled over fairly quickly and it was then towed to the garage - Because it's labor weekend, i'll give them a shout tomorrow morning to see what's what - but it sounds like that part was off the water pump section, as the needle went straight up, however when looking under the hood, the coolant seemed fine (normal op temp).

mazurfer

Yeah you had coolant, but it wasn't going anywhere(circulating) with that bad pulley and belt.

djs2571

maybe 2 years ago, shortly after I got my M3 I saw a similar post where the idle pulley broke. Just so you know it may be a warranty item if there's enough complaints.