My wife's '04 Mazda 3 recently started making an intermittent noise that sounds like marbles in a wooden box. A mechanic friend told her "it's a bad piston". Another friend said possibly the timing chain is the problem. She has put a ton of miles on in the last year with a new job. 95K miles and the timing belt or chain has never been changed. I'd be grateful for any information on this.
Mazda 3 Engine noise / timing chain replacement
- Thread starter denno
- Start date
GTXT23
LightFoot
VERY Doubtful its the timing chain ---1st off it has an automatic tensioner ---which when I say automatic ,it's just a spring forced pressure situation , then when it reaches max it can no longer take up the slack , THEN you may consider changing it . BUT ! The only way you could possibly have strectched that suckker out at that mileage it with REPEATED and BRUTAL sudden heavy load's forced upon the engine , aka...Flooring the thing in attempts to drag race the car froma dead stop --worst thing in the world for a timing chain --sudden poundage from a dead stop and if its a cold engine ...well you get the idea .
Here's how you know 100% if you chain is stretched without yanking the valve cover and more ... get the car up to either 2nd or 3rd gear and slowly rev it up to the 5K area ...then drop your foot off the petal and let it return to idle ....If the car bucks fore and aft like theres a strong headwind thats a spot on sign its stretched out , why because the timing is being thrown ever so slightly off as the slack area catches up to the engines supposed smooth reduction in RPM and speed. the test is one that you can do in a straight line or check it with 2nd, 3rd, 4th gears all going up to high rpm and then dropping off the power . Chances are after you read this you will already know if the car is doing this upon decelleration , if its not theres a 99% chance at the mileage it aint the chain my friend .
Here's how you know 100% if you chain is stretched without yanking the valve cover and more ... get the car up to either 2nd or 3rd gear and slowly rev it up to the 5K area ...then drop your foot off the petal and let it return to idle ....If the car bucks fore and aft like theres a strong headwind thats a spot on sign its stretched out , why because the timing is being thrown ever so slightly off as the slack area catches up to the engines supposed smooth reduction in RPM and speed. the test is one that you can do in a straight line or check it with 2nd, 3rd, 4th gears all going up to high rpm and then dropping off the power . Chances are after you read this you will already know if the car is doing this upon decelleration , if its not theres a 99% chance at the mileage it aint the chain my friend .
GTXT23
LightFoot
+ A timing chain replacment is not fun for the wallet if you pay as the timing chain , like on motorcycles has no master link ! Its machined into the most precise and perfectly weighted oval it can be then put over the spockets at the factory , so basically the same needs to be done in reverse unless you want a weakend chain in one spot --some people say ..oh yeah I can knock a link out and put it right back as good as new....NOT .....not if you want it to run for another 200 K you wont ! the whole head needs removal , tilting and then you can throw it over the cams ,,,lotta work for an inexpensive part !
"some people say ..oh yeah I can knock a link out and put it right back as good as new"
And it will probably destroy the engine, it will definitly stop it from running.
If the number of links in the chain is changed the valve timing would be continuously
changing. By design the number of teeth on the chain-wheels and links in the timing
chain are selected so the crankshaft rotates exactly two revolutions for each
revolution of the camshafts. Changing the number of teeth on the chain-wheels or
links in the timing chain will destroy the valve timing.
Normally a timing chain will last until the engine needs rebuilding. It's very unusual
for one to need replacing in less than 100 k miles.
I would suggest getting a good repair shop check the car. You haven't provided enough
information to help us suggest what may be the problem. For example, can you more
accurately explain intermittent? Does it happen at different engine speeds? Does it
happen with only a cold or hot engine? Has the engine ever overheated or run with the
oil level very low?
If you can duplicate the noise you can use a long screwdriver or metal rod with one end
at different locations on the engine and the other end near your ear to locate what part of
the engine the noise is loudest. Be careful, you can injure an ear or your head. It's best to
buy a cheap mechanics stethoscope for this test.
Clifton
And it will probably destroy the engine, it will definitly stop it from running.
If the number of links in the chain is changed the valve timing would be continuously
changing. By design the number of teeth on the chain-wheels and links in the timing
chain are selected so the crankshaft rotates exactly two revolutions for each
revolution of the camshafts. Changing the number of teeth on the chain-wheels or
links in the timing chain will destroy the valve timing.
Normally a timing chain will last until the engine needs rebuilding. It's very unusual
for one to need replacing in less than 100 k miles.
I would suggest getting a good repair shop check the car. You haven't provided enough
information to help us suggest what may be the problem. For example, can you more
accurately explain intermittent? Does it happen at different engine speeds? Does it
happen with only a cold or hot engine? Has the engine ever overheated or run with the
oil level very low?
If you can duplicate the noise you can use a long screwdriver or metal rod with one end
at different locations on the engine and the other end near your ear to locate what part of
the engine the noise is loudest. Be careful, you can injure an ear or your head. It's best to
buy a cheap mechanics stethoscope for this test.
Clifton
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I have a similar problem that just began tonight - 2007 Mazda 3 manual. I was backing into a parking space, and a loud rattling/marbles noise began immediately. What worried me was that I felt I might not have been completely in gear (my R is very troublesome), but the car was able to move. Wondering if this did something to the transmission.
Hoping for an update from Denno.
Safe to drive to the mechanic with this?
Hoping for an update from Denno.
Safe to drive to the mechanic with this?
