IP noise -- starting to regret buying the car - PeachParts Mercedes-Benz Forum

16vjohn · #1 01-31-2015, 03:47 PM

A few weeks ago, I posted a video about some noise coming from the top of the engine. The details of that can be found here. I replaced the lifters and cam and got rid of the ticking noise. I was so excited about fixing that issue, that I completely ignored the rattle. Suffice it to say, my declaration of victory was premature.

I did some more poking around and I've determined the rattle to be coming from the IP. It only does it at a certain RPM and can be clearly heard here. I've already replaced the vacuum pump, cracked injector lines one by one, removed serp belt to rule out all those things. Anybody have any idea what could be going on inside that pump?

My only question to the forum is, when do I get out of the storm with this car? This has been the most expensive and least reliable car I've ever owned. I've had gas 124's, dozens of volkswagens, lots of diesels. I'm just want to know when do I start getting to enjoy this fine machine instead of dealing with egregious design flaws and the catastrophic failures the come with them? Starting to regret purchasing the car.

On that note, anybody want to buy a 300D?

Skippy · #2 01-31-2015, 04:26 PM

Maybe my ears are going, but it sounds fine to me.

16vjohn · #3 01-31-2015, 05:20 PM

Quote:

Originally Posted by Skippy

Maybe my ears are going, but it sounds fine to me.

You can hear at starting at 0:10 going to 0:15. On and off again at 0:18, 0:20, 0:23. It's right at around 1800-2000 rpm, under load or not. I'll take a new video tonight and get the mic closer to the pump.

Regardless, what would a RPM specific rattle like that coming from the pump mean?

oilslick · #4 01-31-2015, 06:12 PM

I bought an '87 SDL a few weeks ago. On the 5 hour trip home it had a terrible rattle. It wasn't diesel rattle. When I got it home I was able to isolate it to cylinder #2 by opening the nut on the top of the #2 injector. Every time I opened it the rattle went away. This was a very loud rattle so you could tell when it dropped out. I then removed the injector and the heat shield. I saw nothing out of the ordinary in there. Thinking that the engine probably was for the most part expired (bought it for the right fender and the hood, etc.) I put the heat shield and the injector back in and fired it up. Rattle was gone and hasn't shown back up. Runs quietly. I attribute it to extreme vibration in #2 injector line or the demon crawled out when I pulled the injector

. It only made the noise at various rpms.

16vjohn · #5 01-31-2015, 06:52 PM

Thanks oilslick. Would you say the rattle sounded similar to mine? I'm more than willing to try cracking injector lines again.

Zacharias · #6 01-31-2015, 07:11 PM

I can hear what you are talking about (mostly/best at around 00:20) but it doesn't sound like a rattle to my ears (and I am listening to it through a decent set of speakers).

If I heard that I would be looking for something related to a pulley or maybe the water pump.

Take this for FWIW, but I would not be worried unduly about something transitory in an rpm band. That is just my $0.02.

Mercedes diesels of that era make noises, I am an OM617 guy and that motor of yours sounds pretty good to me.

sixto · #7 01-31-2015, 09:25 PM

How are the injector line clips?

Sixto
MB-less

mattwestm · #8 01-31-2015, 09:53 PM

Here's what I've started to do with these old cars...

Does it drive safely? If yes, keep driving it. If no, fix it.

That being said, I do hear the noise.

2.5Turbo · #9 02-01-2015, 03:01 AM

My 602 makes the same noise and always has. I've owned it for about 80k miles.

Stretch · #10 02-01-2015, 03:32 AM

Quote:

Originally Posted by 16vjohn

You can hear at starting at 0:10 going to 0:15. On and off again at 0:18, 0:20, 0:23. It's right at around 1800-2000 rpm, under load or not. I'll take a new video tonight and get the mic closer to the pump.

Regardless, what would a RPM specific rattle like that coming from the pump mean?

I too can hear what you mean. On my laptop speakers it sounds a bit like a vibration out of balance problem - may be the injectors are now just that little bit out of balance...

...1800-2000rpm is the time when the timing device starts to change the point of delivery

Maxbumpo · #11 02-02-2015, 11:54 AM

On the same engine, a fellow with an odd noise cured it with new o-rings on the oil filter stem. I can't explain that, he was about to condemn the engine, but $1 worth of o-rings and a little wrench-time and the problem was solved.

As more than a couple have said, diesel engines make far more noise than gassers. If the noise doesn't get worse and the engine is running smoothly with no smoke, keep driving. Any serious noise (like a bearing) will quickly get worse and progress to terminal in short order.

You might consider a fresh oil and filter change, using a high quality synthetic like Mobil 1 5w-40 or Amsoil.

rob300SD · #12 02-02-2015, 12:17 PM

Sounds fine. My engine had this terrible knocking when I bought it, but it just turned out to be the old injectors and the low cetane diesel fuel I was using. Make sure you use a cetane boost and lubricant additive (for the IP). I use Power Service white bottle (because it's winter here) I use double the amount recommended to get the full 4 point cetane increase. I'm getting my diesel from Shell now too. Just the regular stuff and not the V-Power diesel (since I'm adding my own additives). I was using Esso (Exxon) diesel before and it was awful, awful, awful.

Drive it until the pump fails. Get a new pump from junkyard and bolt it on. Keep driving. I doubt your pump is going to fail any time soon though.

16vjohn · #13 02-02-2015, 05:36 PM

Quote:

Originally Posted by Maxbumpo

On the same engine, a fellow with an odd noise cured it with new o-rings on the oil filter stem. I can't explain that, he was about to condemn the engine, but $1 worth of o-rings and a little wrench-time and the problem was solved.

As more than a couple have said, diesel engines make far more noise than gassers. If the noise doesn't get worse and the engine is running smoothly with no smoke, keep driving. Any serious noise (like a bearing) will quickly get worse and progress to terminal in short order.

You might consider a fresh oil and filter change, using a high quality synthetic like Mobil 1 5w-40 or Amsoil.

It's very interesting you say that about the o rings. Now that I think about it, the sound started around th time of the last oil change. I use Shell 5/40 and German Hengst filters. I'll change the oil and have a look at the filter o rings.

By the way, why does this filter come with two copper gaskets? I can only assume this filter is used in other engines with different config.

Other than that, I'm going to borrow a pop tester.

Thanks all for the advice. We will see what happens.

vstech · #14 02-02-2015, 06:10 PM

Yup. Only the large copper ring is used. On the oil drain plug.

16vjohn · #15 02-04-2015, 02:02 PM

For what it's worth, I got back under there with the stethoscope. The noise is definitely coming from the IP and the IP only. It sounds real bad in there. It can be heard very well when the scope is on any part of the IP, but it it the loudest and clearest when on the vacuum control device or ALDA. I've studied diagrams and it's coming right from the area of the governor. Seriously, should I be concerned? The sound in the scope is horrific.

At this point, I am just going to drive the car and look for a spare pump to have on hand.