What would cause a Sprinter to vibrate while idling?

joderek77 · Nov 19, 2014

Always get good advice from this forum so I'll try again. My 2003 Sprinter with 250,000 miles is vibrating while idling. When I get up to speed I don't notice the vibration anymore, and it doesn't vibrate as bad during idling after it has been running a bit.

The first thing I thought was the harmonic balancer, but had it looked at and it's on tight and not going bad. Also thought about the alternator pulley but it's not that either.

Tech that looked at it said it could be a compression issue (I hope not) or a valve misfiring. I am going to drive home to my mechanic in the morning to have him look at it.

Have had the turbo and the EGR valve replaced in the last month by the way.

*Edit* forgot to mention no check engine light and it's not throwing out any codes.

greasytshirt · Nov 20, 2014

A weak cylinder could cause the symptoms you're describing. Pronounced vibration at idle, smooths out as engine rpm increases.

Is it down on power?
Has oil consumption increased?
Is the crankcase under excessive pressure? Like, if you take the oil cap off while it's running, does air rush out, or nothing dramatic?
Any injector nailing or black smoke? Blue smoke? Any recent overheat events?

T270_Dreamin · Nov 20, 2014

Bad fuel. Start with a good injector cleaner from Napa. Liqui Moly Purge is a good one.

joderek77 · Nov 20, 2014

greasytshirt said:
A weak cylinder could cause the symptoms you're describing. Pronounced vibration at idle, smooths out as engine rpm increases.

Is it down on power?
Has oil consumption increased?
Is the crankcase under excessive pressure? Like, if you take the oil cap off while it's running, does air rush out, or nothing dramatic?
Any injector nailing or black smoke? Blue smoke? Any recent overheat events?

Greasytshirt no overheating at all, no real loss of power, and no smoke. I do notice a couple time there is a little hesitation in the acceleration going uphill, like it cuts in and out, but then it stops. How bad of a repair is a weak cylinder?

joderek77 · Nov 20, 2014

T270_Dreamin said:
Bad fuel. Start with a good injector cleaner from Napa. Liqui Moly Purge is a good one.

It would be nice if that is what it is. Can you use those injector cleaners in a Sprinter? I've heard a few horror stories.

greasytshirt · Nov 20, 2014

joderek77 said:
Greasytshirt no overheating at all, no real loss of power, and no smoke. I do notice a couple time there is a little hesitation in the acceleration going uphill, like it cuts in and out, but then it stops. How bad of a repair is a weak cylinder?

If it's a problem that can be narrowed down to a single cylinder, the injector could be the culprit. Replacing an injector is easy enough, but they aren't inexpensive.

If it's a mechanical problem, e.g. liner scuff, burnt valve, whatever, then it will be nightmarish.

Your symptoms don't point to a scuffed piston or liner, thankfully. That's often followed with a spy hunter smoke screen.

Do the cheap stuff first. I know they make an injector cleaner for common rail engines. I have not used it, or even know what it's called offhand. It was definitely european in manufacture.

Most injector cleaners I've used have had no affect at all. One diesel fuel system cleaner I used caused an injector to leak much worse, causing horrible nailing. I've used Redline diesel fuel catalyst with good results.

If the problem persists, I'd recommend getting an actual diagnosis. Since the injectors aren't pocket change, I'd do a compression test first. If I had access to actual Sprinter diagnostic software, I'd do a cylinder balance test. In any case, when the weak cylinder is located, I'd test the compression in that hole and compare it to spec. If it's in spec, it's probably the injector. If it's not, a leakdown test can be done to see where the loss of compression is occurring. Generally it'll be a burnt valve or piston/liner damage. Hopefully not the latter. Well, hopefully neither.

T270_Dreamin · Nov 20, 2014

joderek77 said:
It would be nice if that is what it is. Can you use those injector cleaners in a Sprinter? I've heard a few horror stories.

Yes you can use those, they're made in Germany and tested on Mercedes engines and other german cars. You can get it at napa or online if you have time for mail order.

Check the link for product details

LIQUI MOLY - Motor Oils, Additives, Car Care - Products - Diesel Purge

One can of each and you'd be good to go.

LIQUI MOLY - Motor Oils, Additives, Car Care - Products - Pro-Line Diesel Cleaner

joderek77 · Nov 20, 2014

Thank you so much gresytshirt, you always give such great info. And thank you T270_Dreamin, I'm gonna find a Napa first thing in the morning and buy a bottle to try it out!

T270_Dreamin · Nov 20, 2014

joderek77 said:
Thank you so much gresytshirt, you always give such great info. And thank you T270_Dreamin, I'm gonna find a Napa first thing in the morning and buy a bottle to try it out!

No problem... If you get the purge just mix it with a couple gallons when you tank is near empty. If you get the fuel system cleaner you can fill the tank up when you fuel. Let us know how it goes!