shakes when it's hot (outside) - PeachParts Mercedes-Benz Forum

linguica · #1 03-05-2006, 09:36 PM

I have significant engine shake when the air temp. is high (75F+). Engine temp stays steady at about 90 when up to temp. When it is 40 out, the shake is barely noticeable. I am idling at about 750 and going up a little higher does not help. Here's what's been done so far:

Rack damper pin/bolt
mounts and shocks
tank cleaned
tank screen and both fuel filters

Bad mounts that go soft in heat?? Any suggestions?

linguica · #2 03-06-2006, 08:31 PM

anyone?

Larry Delor · #3 03-06-2006, 09:54 PM

do a search for "rack dampener".

linguica · #4 03-06-2006, 10:02 PM

Quote:

Originally Posted by linguica

Here's what's been done so far:

Rack damper pin/bolt
mounts and shocks
tank cleaned
tank screen and both fuel filters

Bad mounts that go soft in heat?? Any suggestions?

It has been replaced and adjusted....still no improvement.

Hatterasguy · #5 03-06-2006, 10:23 PM

How are the engine mounts?

NateVentura · #6 03-06-2006, 11:06 PM

For some reason, every 617-engined car I've ever driven seemed to shake a little worse when good and hot (especially when I've just gotten off the freeway after pushing it hard). I've just assumed that "they all do that"...

linguica · #7 03-07-2006, 12:39 PM

Quote:

Originally Posted by Hatterasguy

How are the engine mounts?

I had the mounts (and shocks) replaced by a local indy last fall(about 2k miles ago). At a glance, they look ok. Is there a specific thickness for the mount that"

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linguica · #8 03-07-2006, 12:41 PM

Quote:

Originally Posted by NateVentura

For some reason, every 617-engined car I've ever driven seemed to shake a little worse when good and hot (especially when I've just gotten off the freeway after pushing it hard). I've just assumed that "they all do that"...

It only shakes badly when the weather is good and hot. I can get off the hwy. when it is 40f outside, and the shaking is not bad.

#9 03-07-2006, 02:20 PM

Have been there and done that one. Turned out to be a couple of badly worn injectors.
First use diesels purge to clean them.
If that don't clear it up, remove the injectors and find someplace to have them pop tested. That will tell whether they are releasing the fuel spray at the right pressure. Also have the test check the spray pattern.
I still have questions on the pop test, as the injector failure usually occurs when they get hot, but the test is done a room temps? Dont't know if that really makes any difference.

Brian Carlton · #10 03-07-2006, 08:20 PM

I have noticed the SD get a bit rough in the idle when it comes down off an 80 mph run and stops at a traffic light. It's definitely not the injectors because they were checked for proper pattern and pop pressure. One injector was NG and was replaced.

The idle clears up after a few minutes.

Only exhibits this when very hot and it's relatively subtle.

Hatterasguy · #11 03-07-2006, 09:43 PM

I was paying attention today and noticed it as well. But only after I get on it pretty good and really heat it up.

Maybe its normal?

linguica · #12 03-07-2006, 11:09 PM

It's a wierd thing...I can run down the hwy. w/ it, and if it is 35f out...minimal shaking when I stop. If it is 80 out, I am shaking pretty well by the time I get to work (4 miles)! I think I will try the diesel purge(thanks old deis!). That is one thing that I have not done. Any suggestions on which to use, where to get. I also put some Startron in the 1st tank full after I put it back together to keep the black plague away!

240Demon · #13 03-08-2006, 01:26 AM

I suppose the ambient temperature could affect the hardness of the rubber...

Just a thought...

linguica · #14 03-08-2006, 08:37 AM

Quote:

Originally Posted by 240Demon

I suppose the ambient temperature could affect the hardness of the rubber...

Just a thought...

I am going to check w/ the indy that did the mounts to see what brand they were. I am also going to try the diesel purge,

linguica · #15 03-20-2006, 09:41 PM

Ran 2 cans of Lubro Moly. Instantly got quieter. The first time I got up to speed and took my foot off the pedal, I thought the engine had cut out b/c it was that much quieter(OK, my front wheel bearings are pretty rowdy at 60 so maybe that had something to do w/ it.). Nothing discolored ever came out. Not sure about the shaking...have to wait for some hot weather.