What's wrong with my car?!
September 1, 2011 9:02 AM   Subscribe

'03 Toyota Matrix makes terrible noise when even slightly lugging engine. What's wrong?

So this has been going on for a while to some degree. When I am going up a hill and the engine is working hard, it makes a sort of winding sound, hard to describe. It's kind of like high-pitched groaning. If I down-shift this tends to go away.

Well last night driving home on a long gradual up-hill it got much worse sounding. Once in a while when I stepped on the gas it would sound like a spinning saw-blade. I took the thing home and I'm afraid to drive it now.

The car is an '03 Toyota Matrix. It has a timing chain, which is what my mechanic suspected was the problem. He thought the tension might have been poor. Any thoughts?
posted by cman to Grab Bag (4 answers total)
Never lug your engine. It's always bad.

I don't think it's the timing chain. There's no real load on it, and it doesn't work harder
when the engine is working harder. When was the last time your timing chain was
replaced? Do you have about 90K miles on it? Timing chains generally outlast timing belts,
so I'm suspicious of the diagnosis.

What's the engine temperature doing when you are hearing the sound? I suspect the
fan, fan clutch or fan motor. I've had experiences with fan clutches that sounded to my
inexperienced ears like the transmission was going to explode any second.

Do you feel any loss of power when the noise manifests?

When you downshift, the engine RPM goes up, the engine is cooled more effectively by
the fan, and the fan clutch (if it's thermostatically operated) can disengage, which fits
your "tends to go away" to some degree.

Another thing that can make noise is a plastic part that has come loose, and leans into
a moving part when the engine is tilted uphill, or downhill. Open up the hood when the
engine is cold and look for loose plastic parts that might vibrate or rub when the engine
is vibrating because you are lugging it.
posted by the Real Dan at 10:00 AM on September 1, 2011

By lugging it I mean going 60mph in 5th gear.

Reading around a bit, the timing chain should apparently last as long as the whole car. I currently have 120k miles. I should clarify that he suspected the tensioner of the timing chain because it is controlled by the oil pressure, but with this new sound he is now more suspicious of the VVTI.

There was no noticeable loss of power. I only noticed this problem from the noise. In fact, despite this my mileage has been consistent at 33mpg.

What sorts of things can I look at to help with the diagnosis?
posted by cman at 11:46 AM on September 1, 2011

What you're describing sounds like clutch failure.

If it's a standard, you can check your clutch by putting it in 2nd or 3rd gear, while the car is running mind you, and with one foot FIRMLY on the brake slowly release the clutch. If the car shudders and stalls out then it's probably not your clutch.

If that's the case then it's probably an accessory belt for power steering or A/C. You can test those by spraying them with some kind of "belt treatment" spray that you can find at your local auto parts store. If the sound goes away temporarily, while freshly sprayed then you need to adjust one of the tensioners or replace the belt.

If it's none of those, take it to a different mechanic, because there is no way that this is a problem with your timing chain.

(former mechanic here...Good Luck!)
posted by snsranch at 6:56 PM on September 1, 2011

The clutch is definitely OK. No slipping whatsoever.

The accessory belt WAS going bad and was squeaking and my guy just replaced it. Squeaking went away.
posted by cman at 6:59 PM on September 1, 2011

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