Injector cleaning - PeachParts Mercedes-Benz Forum

Diesel Dan · #1 09-20-2007, 03:40 PM

I am getting ready to pull my injectors and get them tested. Before taking them to be tested, I want to attempt to clean them as best I can, so if they fail the test, then I'll know for sure I need new nozzles.

I've read up on some other threads, and saw where people have used biodiesel, Marvel Mystery Oil, and Acetone to soak the injectors. Has anyone had success with anything else? What about that chemical dip stuff? Like Berryman Chem-Dip? Is that too harsh? Are there any parts inside the injector that would be damaged?

I've never seen an MB injector, but I assume there must be a rubber o-ring or two that could be easily replaced. If so, are there biodiesel-resistant viton versions available somewhere? And I believe there is a washer that also needs replacing any time you remove an injector, correct?

chasinthesun · #2 09-20-2007, 03:58 PM

Im pretty sure their is no rubber in the injectors ,those pieces get real hot under driving conditions.The mechanic I was using had spun some apart but youll need some elbow grease along with a good work bench vise and helper bar .They really are put together .I wouldnt spend the time taking them apart without buying another set of nozzels ,you can save some money by just buying the lower part of the injector ,I would suggest if you do this to take time to make sure you study how all the parts are put together ,getting everything back correctly would be critical on these pieces..There is a right up on it if you do a search here.

TMAllison · #3 09-20-2007, 04:26 PM

The shims/washer do not need to be replaced except to adjust the pop pressure. Be certain not to mix them up during disassembly OR you will mess them up. Also dont touch nozzles or contaminate them with lint, etc.

rs899 · #4 09-20-2007, 07:31 PM

I have used the Berryman dip and found that it worked well. There are no metal pieces - it is all steel. Be careful assembling- there is a cone-shaped piece in there that wants to go sideways and if you tighten it that way, you have ruined your nozzle.

TMAllison · #5 09-20-2007, 09:35 PM

If you take them apart, this post will help you.

http://www.peachparts.com/shopforum/showthread.php?t=155294

Diesel Dan · #6 10-10-2007, 10:56 AM

I ended up using Berryman's B12 chem dip. I soaked the injectors overnight, and it worked like magic! The one thing I wish I had done would have been to partially unscrew the two halves of the injector body to release the tension on the spring. The conical surface of the nozzle plunger end still has just a bit of discoloration or gunk on it, and I think the reason is that it was compressed against the nozzle body, and didn't get the benefit of the solvent. Live and learn... always the hard way it seems. I don't have the patience to do the soaking and cleaning all over again, so I'm just going to take them to the shop as planned today, and get them tested. I suspect they are the original injectors and nozzles with 200K on them.

rs899 · #7 10-10-2007, 12:57 PM

you didn't take them apart?? You missed all the fun ( and benefits)

TTCummins · #8 10-10-2007, 01:39 PM

Diesel Dan, please post back with the condition of your injectors. I have a 1986 300D with 218K on it and I am wondering if it would also benefit from this service.

Thanks

Kurt Kiefer

winmutt · #9 10-10-2007, 02:28 PM

I disassembled soaked and used a brass brush. It would be swell to have the kit specified in the FSM.

Diesel Dan · #10 10-10-2007, 03:16 PM

Quote:

Originally Posted by rs899

you didn't take them apart?? You missed all the fun ( and benefits)

I did disassemble them, just not till after the chem dip.

I just got back from getting them tested. 4 of the 6 injectors had bad spray patterns. 1 was too wide, 2 were off to the side, 1 was just a stream. It probably would have been worse before I cleaned them, because each injector nozzle had a layer of baked-on carbon. The pop pressures were all in-spec though, so I assume my springs and shims are all still good to go. So I'm going to just replace all the nozzles, and the heat shields, of course. Looks like it will run me about $260 plus tax for 6 new Bosch nozzles and shields.

I hope to install them this weekend, but I have a list of other jobs to do while I've got things apart. I'll try to remember to report back about how the car is running once I'm done.

TTCummins · #11 10-11-2007, 08:00 AM

Alright, thanks for the info man, sounds like new injector time for me too. Look forward to hearing the final results.

TwitchKitty · #12 10-11-2007, 11:57 AM

This thread is a study in how not to clean your injectors.

Read the factory shop manual. The thread that is linked in the post above is a good start.