Weird engine rocking/shaking?

[drevilkep]

So I've noticed my new-to-me 189,000 mile iS has a weird vibration when I'm revving the engine or accelerating. At about 1800, 2500, and 3100 RPMs, the engine shakes slightly, but enough to rock the car a little and move the shifter. It's more of a rocking, rather than an outright vibration (though the engine does vibrate too). I don't think it's driveshaft related because it occurs when standing still, in neutral, as well as when accelerating. I was thinking motor mounts, but I did the test where you set the E-brake, let the clutch out, and watch for engine movement. The engine doesn't seem to move much or at all, so I'm not sure about the mounts. They aren't leaking or cracked at all. The car does seem to vibrate more than I would expect all all speeds and at idle. Any ideas?

[tjts1]

Engine mounts don't have to be leaking or cracked in order to be worn out. Usually only the passenger side mount is worn. It takes most of the wear because of the direction of the crank and its exposed to exhaust heat while the driver's side mount isn't.
My worn out passenger side engine mount next to an new one.

[drevilkep]

Engine mounts don't have to be leaking or cracked in order to be worn out. Usually only the passenger side mount is worn. It takes most of the wear because of the direction of the crank and its exposed to exhaust heat while the driver's side mount isn't.
My worn out passenger side engine mount next to an new one.

Did you replace just the passenger side mount, or both? Did it make a difference? They are pricey so I don't want to blow $250 if it won't make a difference.

[txleadfoot]

wow, that's crazy. it's sagged down...what 1/2"?

[KenC]

IE Urethane mounts are like $50 each. Might want to check out your tranny mounts too... OEM ones are pretty cheap.

[ethirtydavid]

You don't need to spend 250 on engine mounts, you can get a good pair for much cheaper. If you replace one - replace them both.

[drevilkep]

You don't need to spend 250 on engine mounts, you can get a good pair for much cheaper. If you replace one - replace them both.

Where are you looking? Best I've been able to find is $119 each from BMA parts. I'd rather not do a solid mount as this is my daily driver and I'd like to avoid extra vibrations.

[tjts1]

Did you replace just the passenger side mount, or both? Did it make a difference? They are pricey so I don't want to blow $250 if it won't make a difference.

Just the passenger side mount. Check pelican parts. It was $90 when I got it. BMA is overpriced. Stay away from urathane mounts unless you enjoy noise, vibration and harshness. Before you buy a new mount make sure it isn't something else like vacuum leak, sticky injector or ignition problem.
cheers
Justin

[drevilkep]

Just the passenger side mount. Check pelican parts. It was $90 when I got it. BMA is overpriced. Stay away from urathane mounts unless you enjoy noise, vibration and harshness. Before you buy a new mount make sure it isn't something else like vacuum leak, sticky injector or ignition problem.
cheers
Justin

Yea, I just got done replacing every vacuum and coolant hose, along with both intake gaskets. The car run smoother now, for sure, but there is still a vibration that runs through the whole car at those RPM points. I checked the transmission mounts yesterday and they aren't torn or crushed, but they are soft so I ordered two. They are cheap and easy so I'll try those first. I was able to find OEM motor mounts at ECStuning.com for $93 each so maybe I'll buy one for the passenger side and see if that helps.

[ethirtydavid]

Here are some products you can take a look at:

http://www.rockauto.com/catalog/raframecatalog.php?carcode=1011373&parttype=5552&a=FRc1011373k1134045

http://www.autohausaz.com/search/product.aspx?gkw=BMW+318IS+Motor+Mount&gad=CPvVo5gCEgiM5kBgtQXq4Rjtn_T8AyCXvNMT&makeid=800003@BMW&modelid=1011373@318IS&year=1991&cid=20@Engine%20Parts,%20Seals%20%26%20Gaskets&gid=5552@Motor%20Mount

http://www.partsgeek.com/gbparts/1991/bmw/318is/engine_mount/oes_genuine.html?utm_source=google&utm_medium=ff&utm_term=1991+BMW+318is+Engine+Mount+-+OES+Genuine&utm_content=ymmbp_n&utm_campaign=PartsGeek+Google+Base

If it were me, I wouldn't get the cheapest ones but those from Autohaus Arizona seem like the best idea. IMO

good luck, beats spending 250 bucks for mounts that are not going to be raced. Those prices are insane..

[EN318isPDX]

I like my IE poly engine mounts, a lil stiffer but my car is quieter on the outside, shakes a lil on the inside but not enough to grind your teeth

[E30nate]

i had IE poly mounts on my m42. the only complaint i had was right at redline the accelerator pedal vibrated a little bit. other than that they were just as quiet as the stock ones, with minimal vibrations.

[twright]

Just so everyone knows: The engine mounts from RockAuto have a really good price ($20). However, they are not oil filled. They are solid rubber.

What this means is: 1.) If you're looking for inexpensive oil-filled engine mounts, don't go to RockAuto.
2.) If you're looking for solid rubber engine mounts, RockAuto has some with a good price on them.

[Mike@PureMS]

We've got a number of different mounts available.
Both E30 and E36 alternatives.
Feel free to email or call us for info.