Intermittent vibration

Hi all,

I have a 2008 Mazda3 (2.3L automatic, 34K miles), which has recently been annoying me… The problem started about 4 months ago, when I got new tires and a brake job (pads + rotor resurfacing). Ever since, it has been having intermittent vibrations. I feel the vibrations mostly on the floor, but sometimes also on the steering wheel. Here’s what I’ve done so far:

When the vibrations started, i thought it was a problem with the new tires. I had them re-balanced 3 times at two different places, with no improvement. I then took the car to the dealer, who replaced two of the three engine mounts (it appears these tend to break easily on this model). This seemed to improve the situation for about half a day, and then it went back to the same. I took it back to the dealer, who could not find anything wrong. Not being satisfied, I took it to a different dealer, who could also not find anything wrong.

So, I am now stuck with this vibration… It is not always there, and not always of the same magnitude… it seems to be more likely to happen in the morning after a colder night (well, as cold as it gets in Los Angeles). It is most likely to be felt at around 45-50mph, but you can also feel it at higher speed sometimes. A couple of times I could definitely feel it at around 25mph. Also, I’ve noticed that the engine vibrates when the car is stopped, at around 1500-1800rpm (e.g. when I first turn it on). The dealer claims that this is natural for a 4-cyl engine, but I had never felt a vibration before.

My gut feeling is that this is something related to the engine, but two different dealers could not find a problem… since this is intermittent, it is hard to nail down I guess. Any suggestions as to what this may be? Perhaps I could ask the dealer(s) to check specific things…

Thanks!

I am thinking out load but a good friend of mine has a 09 ford focus which shares a lot of commen parts w/mazda 3 he has a small shutter in his car’s torque conveter. or your mechanic that that the tires and the front brakes over torqued the lug nuts when he put the front tires back on the car. or did he cut the rotors or just clean them up? i would have someone check your front rotores for runout (warped) and retorque your wheels with a torque wrench( if you have alloy wheels)and not an impact gun.

This vibration issue is always a slippery slope. I just spent way too much money and wayyy to many head-aches over leaking parts just to find out my new tires were crap.

Do you have anyone in your family with a similar wheel/tire size? Maybe find out on Tirerack if the wheel pattern is the same and get someone to loan you their wheels and tires for a drive. It is a pain and a lot of work swapping 2 sets of tires back and forth but it will rule out those tires you bought. That is how I found the tires were bad on my car. I didn’t have to look any further than my wife’s Dodge wheels that fit on my Chevy Monte Calro.

Has anyone done a front to back rotation of the tires? You could have a bent rim.

You did two things to car at once. Tires and brakes. It seems you covered off tires mostly.

Maybe have another look at brakes. Our Subaru was exhibiting vibrations intermittently which turned out to be a seizing caliper. If you slam brakes does it go away?

My tires balanced out perfectly on the balance machine… They just weren’t round tires. Mine were Uniroyal, I talked with the original installer and he suggested I contact Uniroyal about my issue. One phone call, two trips to a more local installer (one for inspection of the tires and a second for installing a different set) and i have 4 new Michelins on my car for very little difference in my first purchase price. Mine were about 4 months old and had about 4Kmiles on them because my car had been in and out of other shops trying to chase down the vibrations.

I was concerned I had no recourse to tires I hated. It turns out we do.

The intermittent and variable nature of the vibration tends to point away from tires.

I’m leaning towards an engine issue as the vibration is reported when the vehicle is idling - AND engine lounts improved it.

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CapriRacer
You could be correct on that assumption. I was just implying that just because a shop got the tires to balance doesn’t mean they are always smooth riding afterward.

Thanks everyone for your input! I’ve had the tires rotated and unmounted/remounted several times, that did not seem to change anything. The shop also said they checked the tires and found them round… I’ve asked them a few times about the brakes, but they insist that nothing they did on the brakes could be causing this… plus I’ve been there so many times, that they are less than happy to see me at this point. Because of the intermittent nature of this, they have been unable (or unwilling?) to feel it, and told me I am ‘over-sensitive’ to vibrations… which of course is not true, since everything was fine until I had the work done.

If it is an intermittently seizing caliper, is that something that can be easily diagnosed?

Thanks again!

W30post: the idea of swapping wheels for a day also occurred to me, but I haven’t found anyone whose wheels match perfectly… so I was wondering, how dangerous is it to use wheels that are somewhat different?

Also, it does not seem to go away if I brake (gently) while it is vibrating… If I were to slam the brakes, it would go below 45mph quickly, at which point there is no vibration anyway…

I don’t think it is the brakes. You need to have someone put a dial indicator on the wheels, not the tires but on the lip of the rim and rotate the tire to see if the rim is bent. Rims can get bent during the unmounting of the old tires from them (not from removing the wheels from the car).

Another test that can be performed with a dial indicator is for wheel bearing play. If the dial indicator indicates that a rim is bent, before changing the rim, have the brake rotor removed and checked for trash or a rust buildup which can make a rim appear to be bent, even when it is not.

If the offset is slightly different, the total diameter is slightly bigger, those things will not matter. I looked up your car with some guesses and it has a large offset. Bolt pattern is key. You do not want to stress the lugs at all. rim diameter may be a consideration because of brake clearance.

If the shop does not have a dial indicator for this task, then they might just pull the wheels and the rotors and clean the surface of the hub and the inside of the rotor where they mate. Sometimes that’s all it takes.

The Mazda 3 has a common problem with the passenger side engine mount that can cause vibration. It’s not hard to remove and check it. The link below has more info.
http://www.mazda3forums.com/index.php?PHPSESSID=a0b3e8c23ea1879eb7867a18176881b1&topic=119411.0

My VW with many more miles at the time had intermittent vibration while traveling at freeway speeds. It was a CV joint going bad.

thanks all for your ideas! I just took the car to a newly paved road that’s almost perfectly flat, and was able to get the vibration at around 20-25mph. Not as intense, but definitely there (it would be nice to see if the vibration was at half the frequency as well, but could not tell). My guess is that at such low speeds the tires and rotors should not have enough moment to cause a vibration (correct?).

The next thing I am itching to try is to tape my camera phone under the hood, and record video of the engine as I drive… that would be cool in itself, but may also give me some evidence I can rub in the dealer’s face. Now

About the lugs: on the second-to-last time I took the car to the place where they mounted my tires, they said they made sure the wheels were torqued to factory spec. They also told me they checked the rims, and they looked fine…

My fear is that this will be a combination of things (e.g., a little off-round tires, a slightly warped rotor, a slightly defective engine mount) that all resonate to cause this…

I would caution strapping you Iphone under the hood. The engine heat may be too much and kill the display.

The vibration caused by my bad tires was also present at the low speeds, also present intermittently. The shop that said they were round, is it the same shop that installed them the first time?

Before I forget to comment on this, wheels that are slightly different may not fit. If they DO fit on the lugs, you may have issues with the speedometer misreading your actual speed, and you MAY have some small issues with a tranfer case. Now, these issues won’t be bad if you’re going for a quick spin around the block, but there’s just something telling me it’s not a good idea.

In any case, if you’re getting the vibration when you’re idling, forget the wheels and brakes entirely - unless you have 2 problems going on.

Check your spark plugs and injectors, maybe even spark plug coils. That’s my thought. Start at the repairs that are least expensive. If that doesn’t work, I’m just speculating, so come back and get another opinion! LoL

Good luck.