380sl Injector Seal Repair

[mbboy]

My car's been idling rough. So, I sprayed brake cleaner around the injectors, and the idle changed significantly when I sprayed the 3rd,4th, and 5th cylinders' injectors. Consequently, I assume that those seals are allowing air into their cylinders.

As I replaced all the injectors and seals about 5 years ago, I'm now wondering whether I should just replace the rubber sealing rings, or the insulating sleeves, too.

Also, I notice that the manual shows another O-ring, but I'm not sure whether that goes on the base of the rubber sealing ring, or on the tip of the injector. So any help would be appreciated.

Thanks very much in advance.

[Strife]

There is a rubber "doughnut" (a seal) at the top of the injector insulator, and then the insulator has a conventional O-ring on the outside of it. To the best of my knowledge, there are no other rubber parts. The insulators I used came with the O-rings but not the doughnuts. I did this recently, and I'd say that your chances of removing the insulators without breaking them are low (they get brittle quickly); I'd also recommend cleaning the pockets thoroughly before installing new parts, and to use Syl-glyde or other "rubber safe" lubricant when installing.

Even if your other parts (the air distributor tubes, fittings, etc) are newish, be very careful because they are also hard and brittle by now. Read cautions on this site concerning non-MB supplied air distributor tubes (they may fail nearly immediately).

[mbboy]

Thanks for the info, Strife. As I'm getting ready to order the parts, I was wondering if you thought that there was a significant difference in the MB vs aftermarket seals and insulators, like MTC and Woco? It's not that there's a big price difference, but I'm curious whether a big difference could exist in such simple things.

Also, do you really think that these things would have become brittle in only 5 yrs?

[nobby]

Originally Posted by mbboy

Also, do you really think that these things would have become brittle in only 5 yrs?

Yup. Many hot/cold cycles. Left undisturbed they can last a very long time....providing they were of decent quality to begin with.

Those parts are reasonably priced from MB.

[mbboy]

Thanks again for the usual, well-informed advice, guys. I will definitely heed it.