Im copying a post I set up over at G20.net, hoping to get some action/feedback...
Hey everyone, Im trying to see if the engine lurch when I rev is more than normal. Please take a look at this video I shot:
http://www.youtube.com/watch?v=FH-4eppoPNI
Sorry for the crappy cell phone vid. Please take a look at the engine movement when I rev and tell me if you think its excessive. Maybe 2" max, probably less.
Im getting kind of a rattling sound when the engine is cold and idling in park - around 1100rpm, that sounds like something is rattling/tapping intermittently against the drivers side front subframe. When the engine is warmer, or idling at a lower speed (~900rpm in gear), the rattle goes away. At one point, I had an exhaust hanger fail, and it allowed my exhaust to droop to the point it was rattling on the rear crossmember. This sound is similar, but since I replaced all the hangers, the exhaust snugs up tight to the car, so I dont think its that. I was worried that I had a failing engine mount, but I dont think its that either after reviewing this video. Not sure what is going on, but the sound is definitely something tapping on something structural on the chassis - the sound is being transmitted into the cabin, and its pretty loud, not something internal to the engine. I am out of ideas. I guess Im gonna have to drop the cash to take her in to the shop and have them check it out.
Anyone think the motion is excessive, or have some other way to find/diagnose this issue...Ive been trying for DAYS, and have nothing at all, I cant find anything. And of course, I only hear the sound in the mornings when Im trying to leave for work. In the afternoons when I have time to investigate, I cant get the rattle to come back...and Im going nuts!!!!
Applying my usual complete lack of specific knowledge... I think it's interesting that it happens in the mornings but not in the afternoons. Presumably the engine is just as "cold" (i.e., un-warmed up) both times, so I'm wondering if the whole car is significantly colder in the mornings and/or warmer in the afternoons. Does it spend its days in heated or semi-heated underground parking? If so, now you're looking for something that expands with heat to the point where it doesn't rattle. That means they won't be able to find it in their nice warm shop, either. Yay. You may have to bite the bullet and get up at your usual work time on Saturday to crawl underneath.
well, oddly enough, the car is in my garage overnight, so its a reasonable ~50° in the morning, when the noise happens, and it also happens in the afternoon when I start my car to leave. After the drive home, the engine/trans/accompanying areas are all way up in temp, and the sound is gone. I agree, the rattling is happening when things are cold, and things (like rubber mounts and such) are contracted, and goes away when things warm up and expand. I just wish I knew why now? What changed in the last month to cause this to happen? WHat needs replaced? Im really guessing its something having to do with my trans/motor mounts...maybe a swaybar mount? I just dont have the garage for that kind of work attached to my house...sigh...never like opening my wallet and not having a faster car for the effort
More than once I've worked on cars for friends, and found a bad motor mount, even after they said they just recently had a shop replace a broken one. Check ALL the motor mounts. FWD cars are hard on motor mounts, and if they are heavy or high powered they are even harder still. Also, depending on the design of the mount, a failed mount might not be obvious.
In reply to 4cylndrfury:
I just reread your last post. You don't usually need a great garage or special tools to change motor mounts. Ramps, jack stands, a floor jack, and regular hand tools will do it for most. I just replaced the rear M MT on a friends MITSU a few weeks ago, I picked up a really long 3/8" drive extension from hf to make it easier, but it could've been done without it. And I did the job in the driveway.
Maybe its a Rattlesnake?
http://forums.pelicanparts.com/porsche-924-944-968-technical-forum/657608-rattlesnake-my-924-a.html
Ok, so lets say idecided to try to replace a busted mount thats tucked in somewhere I cant even see...whats turnaround on something like that, working by yourself, with a jack and stands, without many powered tools, having not done this before? if the answer is longer than 48 hours, then the checkbooks gonna come out to pay a shop to do it in a day, cuz shes my dd, and pappas gotta bring home da bacon...no car = no mulla
