If you still have worn out OEM motor mounts...change 'em!
I am guessing a lot of you have already found the benefits of changing your beat up motor mounts out, but I just thought I would share my experience for those of you who may not have touched them yet.
My Cherokee had 145k, and as far as I know original motor mounts. I discovered a crack in my exhaust manifold, and was told bad motor mounts can cause that. So, I decided to grab a pair of Brown Dog poly motor mounts.
I didn't really notice anything wrong my my existing mounts, but thought if I was going to repair my exhaust manifold it would be crazy to leave old motor mounts on there.
Brown Dog poly mounts cost somewhere around $85 after a cherokee forum discount. Brown Dog seems like a phenomenal company, by the way, as when I had a question the owner of the company answered the tech line within 2 rings and set me straight. He also suggested I pick up a transmission mount if I was going to go the trouble of changing motor mounts, as it helps limit vibrations. I got an Anchor mount for $26 at Advanced Auto, though they are way cheaper at places online.
Anyways, installing the mounts was pretty straight forward but it took some time to get everything lined up right with my jack and the through pin. I won't get too much into the instal, as there is lots of good write ups already. But, it sounds like most people take 2-3 hours for all 3 mounts (2 motor and 1 transmission). I took closer to 5 hours for all 3 but I'm a bit of a novice.
A couple bits of advice, on the passenger side just take off the bracket that holds the motor mount to the block. I also took out the battery but everything else stayed in place. On the drivers side I took out the old motor mount but left the bracket. I then struggled to get the through pin through both sides of the motor mount, but after loosening the bracket to the engine block I was able to finagle it into place.
Well, after I finished, I had lots of good and unexpected results. The throttle response is so much better, a clunk I had when coming to a stop and going over pot holes is gone, and it feels sportier when taking corners and on acceleration. Another result, though I think it must be coincidence as I am not sure how motor mounts can do this, is that my XJ is starting quicker on the first crank (almost instant compared to 1-2 seconds before). I have no idea how that may have happened, but I'll take it!
So, really long post just to say that if you haven't replaced your motor mounts and transmission mount, go for it! I am very happy with my result.
i need to do this... ive heard that the POLY mounts almost cause more vibes than stock OEM ones.
Yeah, they do cause some vibes. You use the poly ones because they last a really long time and keep your engine more secure. If you don't over-tighten the through bolt and you replace your transmission mount at the same time, the vibes aren't bad at all.
Great write up swervy. I installed my Brown Dogs last week and the process is super simple. Took about 2 hours for the motor mounts and just over an hour for the transmission mount. I didn't remove the through pin bolt until I had the mount out and on the floor. I removed the complete mount from the frame to the motor in one piece. The motor side bracket comes right off and the process is much easier. For reassembly, I put the new motor mount and bracket together in one piece, left the through pin bolt lose and pushed the complete assembly right into place. Align the motor bracket bolts and the thing will slip right into place.
One thing that really helped. I cut a 2x4 piece of wood about 24" long (my jeep has a slight lift) then used the piece of food and the floor jack to support the engine right at the oil pan rail. I was able to go up or down with the motor just when I needed to with the floor jack.
Performance of the mounts was much better than I expected. My old mounts were not really worn out but for sure my motor starts better, has better throttle response and in my rig there is no noticeable vibration back to the interior. I went with poly motor and transmission mounts. I can spin my big ag tires a full revolution now on the 1-2 shift.
I changed my mounts out while all my cooling system components were out from under the hood. I rebuilt the system after my fan chopped into the radiator.
With everything out of the way it was quite easy. As with AKIQ we used scrap 2x4 and jacks on the oil pan to manipulate the motor. Did the driverside then the passenger. Simply pulled the old mounts and installed the new. Took about an hour. Definitely a 2 person job - wouldn't wanna try it alone.
I went with BrownDog poly - huge difference from the old mounts. Like AK said, throttle response and startup/shutdown are improved. Yes it vibes more but this ain't my daily so all is good.
I got brown dog poly mounts because the autozone ultra-cheap-*** mounts would disintegrate after a couple months of driving..yes they give you another pair free under the limited-lifetime, but in the end its just bad news for anything connected to the drivetrain. The brown dogs are a good deal and very stout.