Toyota Matrix engine/transmission noise

I have a 2004 Toyota Matrix, 5 spd manual with 175,000 miles. It’s been a great car, but about 4 months ago I noticed more noise than usual from the engine compartment. It sounds like someone dropped a noisy diesel engine in there! The noise is most noticeable on the highway when the engine is under greater load (e.g. up hill). The dealer told me it’s the belt tensioner. I had that replaced, but the noise is still there, and it’s getting worse. I recently had the car completely serviced, full tune up, transmission fluid changed, etc… Again, that did not eliminate the noise. I’d appreciate your help!

One man’s “noisy diesel engine” might be described differently by somebody else. In other words, noises are hard to describe and to convey to others.

If the noise sounds like pebbles ratting around in a tin can, then it is likely that the problem is “pinging”, otherwise known as pre-ignition. This could be due to lax maintenance, but if a “full tune-up” (whatever that might mean) did not eliminate the noise, then lax maintenance can probably be crossed off the list.

However, if the EGR valve is stuck, or if the knock sensor is no longer functioning, then it is possible for the engine to be pinging. At 9 yrs/175k miles, either of these situations is certainly possible.

A problem in the cooling system, causing the engine to run hotter than usual, can also be a cause of pre-ignition. Has anyone looked at the radiator, the cooling fan(s), and the thermostat?

If the noise doesn’t sound like pebbles rattling around in a tin car, then it is possible that you are hearing exhaust noise. So, another angle to explore is the possibility of a cracked exhaust manifold, or a leak from the manifold.


Was the dealer aware of this bulletin?

You may laugh, but there are some dealer mechanics who are extremely computer challenged and barely know how to look for information . . .

If the belt was NOT replaced with the upated part, I will assume that this modification was not performed

Thank you for your suggestions. I don’t think the dealer changed the belt! I will check with them on that. An additional observation today: The noise goes away completely when I depress the clutch (I had not noticed this in the past). Now I’m worried that the transmission is going - there is online chatter about a problematic transmission bearing in this era Matrix.


Look on your invoice

If there are any issues, go back to the dealer, show them the bulletin and ask them why it was not performed

03-05 5-speed Corollas and Matrixes often have problems with transmission bearings.
Do a google search and you’ll find lots of complaints about the Toyota C59 transmission.
One of the bearings actually has a plastic ball bearing holder that eventually cracks.
I would take it to a good independent transmission shop and get it evaluated before it fails and sends metal shards throughout the tranny.

An alternative to a rebuild is to replace it with a 6-speed, which bolts right in.
Here is a transmission that keeps the economical top gear ratio:

p.s. this engine does no have an EGR system, it’s done with valve timing.

Thanks again to all of you. I’m going to have the tranny looked at this week and make a decision thereafter. A new 6 spd sounds like a viable alternative!

I have 2007 5 speed, manual, Matrix. A year ago I had same loud noise that would stop when I put clutch in. Had to have transmission rebuild. Thing is, the noise came back, am having second rebuild, luckily under warranty. Transmission guy said it was the bearings. Makes me wonder if I should trade car in, if I have a “lemon”. Wish I had known about getting the 6 speed.

Well, it is the transmission after all and the car is currently in the shop having a new transmission installed. The new tranny comes with a 100K warrantee, which should meet my needs. Clearly there is an inherent problem with this 5 spd manual. I find it disappointing that Toyota won’t acknowledge it and, at the very least, provide its customers with some credit towards a replacement. In my case, I can’t really complain as I got 175K out of it before it went. I know too that manual transmissions are not that popular any more; we had to order ours special. Still, Toyota should stand behind its products. Hopefully this new tranny will outlast the rest of the vehicle.