Injector replacement 1 by 1 and an oil question - PeachParts Mercedes-Benz Forum

katja · #1 08-20-2013, 10:22 PM

Some time ago I purchased some rebuilt injectors from a craigslist seller. Finally, I bought a socket to install them, some fuel return line and a set of heat shields, so I will be doing this job soon. (And for those who don't know me, I'm not very mechanically-inclined, and tend to over-think things ahead of time because I'm very adept at making a mess when I start wrenching).

I had been thinking about replacing one injector at a time, running the engine in between, for several reasons: 1) I don't have a pop tester and am really curious as to which of my old injectors is causing the nailing; 2) If one or more of the "new" injectors (of unknown origin) turns out to be defective, I would know which one it is, and 3) theoretically I could run the engine on 3 cylinders while it bleeds air out of the injector line I just replaced.

But....is this a wise idea? My concerns about doing it this way are damaging a metal injector line (they are connected together in pairs, so how easy is it to remove just one without damage?) and also the braided return line hoses will have to be removed again on one end when the next injector in the row gets replaced.

A second, unrelated question is the blow-by issue on this car and how to deal with it. It is pretty intense; if the oil fill cap is loosened, it will fly off (and it's a metal one!), and there is oil trying to seep out of every seal & gasket - oil cap, breather hose, valve cover gasket, air intake (all the gaskets were replaced about 5 years ago).

I had been using Mobil 1 Synthetic 15w-50 until it no longer was C-rated, and since then have been using Mobil's 5w-40 turbodiesel truck oil; my guess is that this is too thin for my engine in this condition. Would changing to 15w-40 Rotella help? Would there be a problem with switching back to a dino oil, or (not to make this an oil thread) would anyone have a recommendation of what oil to use?

And realizing that my engine is worn, it still starts & runs well, and the car looks good cosmetically so it's a keeper - I just want to do whatever I can to keep it going for as long as possible or until I find a good used engine. (BTW my 240D gets driven about 2 hours a week on average and isn't my primary car).

Zacharias · #2 08-20-2013, 10:32 PM

It isn't advisable to do the injectors one by one as you should only remove the metal injector lines as a unit, never singly. That would mean you would have to bleed air out of the system four times, at best a lot of trouble for nothing.

It also really isn't necessary. If you want to assess which injector is making the most noise, with the car at idle you can take your 17mm wrench and (slowly, carefully) crack the metal injector line connection at each injector and see how the car sounds and runs when each is taken out of the equation.

Just for future reference, one of our forum members, Greazzer, cleans and rebuilds injectors at a very good price. Craigslist would not be my first choice for finding such stuff... these are the correct injectors for a non-turbo?

Can't offer advice on the blowby issue.

Junkman · #3 08-20-2013, 10:39 PM

I would swap in a 617 which can be had for a few hundred. Replace all gaskets down to long block while you have it out of the car. Of course, don't mess with the head gasket. Do adjust valves and check timing chain stretch before install. Refrain from making a lot of changes to a good running engine. Only stop the leaks.

Alternatively, send your injectors off to be pop tested or make your own tester. Professor Google has lots of information. You can loosen the hard line at the injector while engine is running and see if the nailing becomes obvious.

Install all of the injectors at once after you know that they are good. There is no point in removing the valve cover 4 times to do an injector install. (Edit: I was thinking of the ram where you injectors are under the valve cover.)

cooljjay · #4 08-20-2013, 11:11 PM

Have you done a valve adjustment on this car? I would switch to dino 15w-40.....there is so need to use synthetic in these engines, leg alone such a thin oil....it will come out of ever hole the size of a human hair.....my recommendation....is to just put these mystery injectors in, with out new shields....send your OEM set to the member listed above, and then when you get them back install them with new shields and be done for the next 75k miles....sell your mystery ones as cores....

Diesel911 · #5 08-20-2013, 11:27 PM

You can do one Injector at a time You just need to either draw a picture or take a picture and save that of where the Line Clamps on the Fuel Injection Lines go so that you can remove them and put the Clamps back on where they came from.

Removing the Fuel Injection Line Clamps will allow you to remove one Fuel Injection Line at a time.

You can change one Injector at a time and still do that in one day. But, it will be time consuming as you need to test drive in between each Injector change to find out which one you think might be the bad Injector.

Make sure the Injector Heat Shields/Seals go in the correct direction. I found out that if you drop them in the hole they want to flip over. After that I stuck them on a Philips Screw Driver and stuck the Screw Driver in the Hole and let the Heat Shield slide down inside.
Followed by a visual verification with a good Flashlight.

katja · #6 08-20-2013, 11:52 PM

The injectors were for a 220D that someone was parting out (I got a lot of new parts from the seller) and appear to be rebuilt by Kent Bergsma of Mercedes Source though I don't know if they have Monark or Bosch nozzles. At least on the outside, they look like new.

I think I'll take a leap of faith & install them all at once with the new heat shields & return lines. Hopefully all will go well & there will be no issues. Otherwise, I will be posting for your help

I like the heat shield tip. And yes, I am due for a valve adjustment, at which time I will replace the valve cover gasket.

I do oil changes once a year, due to how little I drive. That was one of my reasons for using synthetic. I use synthetic in my other car and garden equipment too, but I noticed that I had oil leaks in everything after I switched. The leaks did improve somewhat after a while.

cooljjay · #7 08-21-2013, 01:47 AM

If they were rebuilt by msource, then they would be monark nozzles and pretty nice! Remember when you change the injectors, you will need a torque wrench and a deep socket....some fit, some don't....best thing to do is like I did was to take an injector into harbor freight if you have one and try on some sockets....another thing to keep in mind, is if the injectors are original one or two heat shields may be stuck in.....let's hope not, but just prepare yourself...

Synthetic is a good choice for a lot of stuff and I recommend it, but it is so thin and we all know how diesels natural leak oil and then the blow by....isn't worth it....I ran 5w-30 out of curiosity on a trip back to cali, I burnt and lost every drop of it.....so I won't be trying it again...

Get that valve adjustment done asap, that can help blow by a lot....if the valves are really tight and some loose....they may be carboned up pretty badly, mine never had a valve adjustment...this is my 6th one in about a year and less then 3k....this was the first adjustment where I actually had one valve to spec....because there was so much carbon and driving it was slowly beating it off the valves...

Govert · #8 08-21-2013, 04:45 AM

Once oil heats up, there is not much difference in viscosity between a 15W-40 and a 5W-40.

The 5W-30 oil can only be used up to temperatures of 10 degrees C/50 F.

sloride · #9 08-21-2013, 10:02 AM

Quote:

Originally Posted by cooljjay

If they were rebuilt by msource, then they would be monark nozzles and pretty nice! Remember when you change the injectors, you will need a torque wrench and a deep socket....some fit, some don't....best thing to do is like I did was to take an injector into harbor freight if you have one and try on some sockets....another thing to keep in mind, is if the injectors are original one or two heat shields may be stuck in.....let's hope not, but just prepare yourself...

Synthetic is a good choice for a lot of stuff and I recommend it, but it is so thin and we all know how diesels natural leak oil and then the blow by....isn't worth it....I ran 5w-30 out of curiosity on a trip back to cali, I burnt and lost every drop of it.....so I won't be trying it again...

Get that valve adjustment done asap, that can help blow by a lot....if the valves are really tight and some loose....they may be carboned up pretty badly, mine never had a valve adjustment...this is my 6th one in about a year and less then 3k....this was the first adjustment where I actually had one valve to spec....because there was so much carbon and driving it was slowly beating it off the valves...

I amy getting ready to do a valve adjustment, but do not think it has anything to with blowby (crankcase pressure). If the exhaust valve clearance is to tight that exhaust valve will not seat and seal loosing compression to the exhaust system. If an intakes valve is to tight it would loose compression into the intake manifold. Adjusting the valves allows the engine to build compression to the maximum that the engine is capable of producing without any replaced parts. If that is not correct please inform me how it helps blowby. I have read that a Marvel Mystery Oil soaking of the cylinders could loosen up stuck rings which is where most of the blowby is coming from.

katja · #10 08-21-2013, 11:00 AM

Maybe I should do the MMO soak while I have injectors out; I suppose it won't hurt, and might help with blow by.

The last valve adjustment honestly made no difference in performance, but the valves were pretty tight. I suspect they are again.

I'm still wondering if there may be any negative effects changing back to a conventional 15w-40 oil like Delo or Rotella. It doesn't get very cold where I live, and I do notice that only after climbing a hill or a freeway drive does my oil pressure gauge drop below "pegged" and even then, it's at 30 psi/above 2 bar.

ROLLGUY · #11 08-21-2013, 12:55 PM

I have done the MMO soak before, and have had positive results. Your blow-by issue is most assuredly caused by the use of synthetic, but should lessen with the use of 15-40 and the MMO soak.

Diesel911 · #12 08-21-2013, 09:48 PM

Quote:

Originally Posted by katja

Maybe I should do the MMO soak while I have injectors out; I suppose it won't hurt, and might help with blow by.

The last valve adjustment honestly made no difference in performance, but the valves were pretty tight. I suspect they are again.

I'm still wondering if there may be any negative effects changing back to a conventional 15w-40 oil like Delo or Rotella. It doesn't get very cold where I live, and I do notice that only after climbing a hill or a freeway drive does my oil pressure gauge drop below "pegged" and even then, it's at 30 psi/above 2 bar.

Members have claimed that using Synthetic Oil frees up the Piston Rings after several 100 Miles. If you still had the blow-by issue during the Synthetic Oil uses I doubt if the MM Oil soak would have any effect.

Replacing the Valve Stem Seals has helped a few with the blow-by. The Parts are cheap but the job is slightly labor intensive.

Neither the Valve Stem Seal replacement or the MM Oil soaked helped the blow-by issue on My Mercedes. But, mine blow-by is not as bad.

I have not read on any of the Forums that Synthetic Oil Caused blow-by???

I have read about Synthetic Oil leaking more than conventional Oil but that might be because of the Crankcase Pressure you are having and the Syn. Oil being thinner.

If you have not done it change the 2 little O-rings at the bottom of the Oil Filter Cap Tube. That sometimes restores some Oil Pressure if they were the cause of the Oil Pressure loss.

Do some more research on how your Oil Pressure is supposed to act.

eatont9999 · #13 08-21-2013, 11:02 PM

Use regular Dino 15W-40 and you will eliminate an oil viscosity issue. I use Chevron Delo and either I have two great engines with almost no blow-by or I am using a good oil.

Change the injectors all at one. If you really need to know which old one is bad, send them to me and I will pop test them for you. Just remember that if you have bad compression, injectors won't fix any of your problems.

katja · #14 09-05-2013, 10:37 PM

OK, so I still haven't changed my injectors or my oil. I entered a car show the weekend after this one and I want to work on detailing now, so I will change out the injectors later this month.

Looks like the consensus is that 15w-40 conventional oil would be the proper oil for my engine. Problem is, I have an unopened 5 quart bottle of expensive Mobil-1 5w-40 Turbo Diesel truck synthetic that's been sitting in my garage for half a year now. Anyone want to buy it?

Otherwise, I was thinking of using that up first, since I already have it....

In the meantime, I treated my tank with Star-Tron (fuel prefilter was black again), did a diesel purge (had two cans of that around, so why not), changed fuel filter, and haven't had any more random nailing under light acceleration. However, all is not well...there is a rhythmic, metallic "tapping" at hot idle after heavy acceleration. It goes away after about 5 seconds, so I can't locate its source. I hope it's just the bad injector and not something more ominous.

I replaced the injector return lines because 3 were leaking. I hope I can reuse them when I change the injectors. I changed coolant & brake fluid today also.

Valves were ALL tight. A new valve cover gasket fixed one oil leak. I hadn't gone 15,000 miles since the last valve adjustment, but I have read that sometimes if the valves hadn't been adjusted for a long time (like with the previous owner), they will go tight again in a short while after adjustment.

Now that valves are to spec, I'm wondering if the missing after a cold start will be gone now. I'll find out tomorrow, but I'm not holding my breath.

eatont9999 · #15 09-05-2013, 11:53 PM

Nailing injectors will make the engine sound like it is ready to detonate. Get your injectors replaced if you want more power, economy, and a smoother running engine.