QuestionHi, I have a 67 Volvo 122S wagon that has suddenly developed this nasty
clunking and accompanying noisy vibration. My mechanic says it might be
motor mounts. I can see the two in front, and one does indeed appear to be
degraded. Is (are) there another (others) at the rear of the engine? And does
the fact that the car is an automatic call for different mounts? I live on an
island, and you have to do a lot of the ground work yourself, and my
mechanic can't see me til July 9th. I'm leery about driving the car, and I think
the problem gets worse when I do. Thanks again.
AnswerSorry: didn't get the original experts email...
If the onset is sudden, I rather doubt it is the engine mounts; although if they look beaten up, certainly replace them (1 each side in the front, and one in the back, at the rear of the transmission, whether manual or auto). BTW, the rear mount is subject to much less stress, and may well be OK. It may be a different mount for an auto transmission, yes, but I doubt it. I expect you can find an exploded drawing and parts numbers on the web.
Anyway, I would more suspect a universal joint in the drive shaft (2 of them, front and back). When they give out they clunk and vibrate.
I'm not quite sure how to tell you check, but I suggest taking the car to a gentle hill, putting it in neutral and letting it roll down a ways, listening carefully out the window. The slightest clunking noise will indicate a UJ problem, and definitely not an engine mount problem. Conversely, engine mounts are only stressed when you put your foot on the gas when you're moving.
Regarding replacement... if you can get underneath (car up on ramps or stands), the UJs are moderately easy, a few hours. But when you (or your mechanic) disconnect the drive shaft to do the job, make sure to mark the mating flanges before taking them apart so that you get them back together in the same orientation. Otherwise you will have a new vibration to contend with when it's all back together!
For the engine mounts, I don't know the car well enough. If they are easily visible, a 2x4 and jack under the engine block (just behind the sump) to take the weight might allow you to change the front two yourself. The rear one will be more difficult, although the principle is the same: support the transmission with a jack while you take the mount out.
On your final question...if it's a UJ, and getting bad fast, I would not drive it far. But a bad engine mount should last for a bit.
