300 SD smoking, not a lot of miles on the car - PeachParts Mercedes-Benz Forum

bcsawyer · #1 10-20-2011, 09:51 PM

I just bought an 81 300 SD that has been sitting up a while.
The odometer shows 159,000 miles.

The car isn't the best cosmetically, but the cost was just a little more than scrap price.

It runs good, starts very easily and the transmission shifts fine, but it smokes quite a bit.

I'm a farmer and I've had quite a bit of experience with naturally aspirated diesel motors, but we've only had one tractor with a turbocharged motor (a 354 Perkins in an 1105 MF) and it smokes a lot because the seals in the turbo are gone.

This car has some blow-by and the smoke smells strongly of fuel.

The air cleaner is oily and the intake side of the turbo is too.

Does anyone have any suggestions about where to start looking?

I hope it's not a case of worn out rings or something like that.
If that's the case, I guess I'll part it out and junk the rest.

whunter · #2 10-21-2011, 12:32 PM

barry123400 · #3 10-21-2011, 12:35 PM

Obstructed air filter will cause some symptoms. Pull the air filter out for a few minutes and check your exhaust. For the nominal cost involved a quick checking of the injectors might be considered.

Even if the engine was worn I would not think you would smell fuel in the exhaust. Although there might be some wear senarios where you might.Some of these older diesels have had basically nothing done for a very long time engine wise.

Biodiesel300TD · #4 10-21-2011, 03:11 PM

Welcome to the forum firstly!

Since it's been sitting, a few things can happen. Your fuel system can have build up and sediments, or a gummed up the IP and/or Injectors. And the piston rings can also get stuck. I'd change the oil, oil filter, and the air filter. Run diesel purge through the system, then change the fuel filters. Put fresh fuel in the tank, and do a valve adjustment. See if that takes car of the smoke. If not then you've still got a few options. Have the injectors tested for pop pressure and spray pattern, and try the Marvel Mystery Oil or Brake fluid in the cylinders trick to break the piston rings loose. I've used this trick several times with good luck.

Is the smoke there always, or does it go away once the car is warm?

bcsawyer · #5 10-21-2011, 03:27 PM

I'll try the suggestions listed. Thank you very much for the advice. I am accustomed to working on British and American diesels, so I am eager to learn about the German ones. When you speak of diesel purge, is that an additive or are you talking about just a good fuel system cleaning? If the fuel system cleaning and valve adjustment doesn't work, I'll pull out the injectors and try the Marvel Mystery Oil trick. I'll also run a compression test if I pull the injectors. I'm sure it's long overdue for a valve adjustment. Someone added a clear inline filter in before the transfer pump and the fuel looks rough. We have had algae problems in tractors before and it clogged up filters quickly. I was chopping silage one day with a MF 1105 and had put in some inline filters with cleanable elements and was cleaning them every hour or so. I have a small pump that attaches to a drill and I'm thinking about pumping all of the fuel out of the tank and starting over with fresh fuel and filters. The smoke does not go away and increases steadily with higher rpm. I am planning on converting the car to WVO if the motor turns out to be in good shape, but I'm going to get all the kinks out first. My main concern is not putting a lot of money into a motor if it is simply worn out, but from what I have read, these engines hold up a very, very long time so I'm optimistic. I'm used to bleeding Perkins and Case engines with CAV and Roosa Master pumps. If I get all the fuel out of the system, does the MB fuel system have any quirks when I go to bleed it?

Biodiesel300TD · #6 10-21-2011, 03:50 PM

Diesel Purge is a product made by Lubro Moly. And is fuel system cleaner. It can be added to the tank as preventative cleaner, or run directly to clean the system.

I think your idea of running the car and learning it before running WVO is a good idea. I suggest this to everyone I talk to about running WVO. Lets you learn the kinks of a 30year old diesel, so you can know when problems are WVO related or jsut car related.

kerry · #7 10-21-2011, 07:44 PM

Not sure about the 81, but the 79SD had a vacuum pump that vented into the intake manifold/air filter. If yours does too, check to make sure there is no oil in that vent line. If there is, you have a holed vacuum pump diaphragm and are sucking engine oil into the engine. Also the 79SD vented the PCV hose directly into the u-tube going to the turbo without an oil separator. If yours is like that and you have a lot of blow by, you could be sucking oil thru the PCV tube and into the turbo and engine.

bcsawyer · #8 10-22-2011, 01:33 AM

Thank you for the advice, gentlemen. I'm going to pick up a valve cover gasket and some other things tomorrow after I go to a junkyard to look for some interior stuff. Hopefully I can get the valves adjusted this weekend. The biggest thing after getting the fuel system straight will be some electrical issues. I don't have wipers or right turn signals and the right signal lights burn solid when the headlights are on. I guess I'll have to start chasing wires and you may see me show up in another section.

whunter · #9 10-22-2011, 08:12 AM

Quote:

Originally Posted by Biodiesel300TD

Diesel Purge is a product made by Lubro Moly. And is fuel system cleaner. It can be added to the tank as preventative cleaner, or run directly to clean the system.

I think your idea of running the car and learning it before running WVO is a good idea. I suggest this to everyone I talk to about running WVO. Lets you learn the kinks of a 30year old diesel, so you can know when problems are WVO related or jsut car related.

http://www.peachparts.com/shopforum/mercedes-parts-reference-library/180990-lm2005-liqui-moly-diesel-purge.html

whunter · #10 10-22-2011, 08:14 AM

Quote:

Originally Posted by bcsawyer

Someone added a clear inline filter in before the transfer pump and the fuel looks rough. We have had algae problems in tractors before and it clogged up filters quickly. I was chopping silage one day with a MF 1105 and had put in some inline filters with cleanable elements and was cleaning them every hour or so. I have a small pump that attaches to a drill and I'm thinking about pumping all of the fuel out of the tank and starting over with fresh fuel and filters.

Algae/Fungus fixation...
Algae/Fungus fixation... - PeachParts Mercedes ShopForum

Biobor, what is it, why do I need it???
Biobor, what is it, why do I need it??? - PeachParts Mercedes ShopForum

Filters, Fungus, Biocide, etc.
Filters, Fungus, Biocide, etc. - PeachParts Mercedes ShopForum

Algae Clogged Filter Pic StarTron WORKS !
Algae Clogged Filter Pic StarTron WORKS ! - PeachParts Mercedes ShopForum

tyl604 · #11 10-22-2011, 10:22 AM

As a purist I would not run WVO. Diesel works just fine and even with the high fuel prices today at 20+mpg your cost per mile should be acceptable. Take a look at all the posts that talk about the negatives of WVO.

scottmcphee · #12 10-22-2011, 10:31 AM

Also take a look at the forum here dedicated to running WVO, lot's of help and suggestions on that:

Alternative Fuels - PeachParts Mercedes ShopForum

But ya, sort the engine out first because any marginal issues with compression or injection or clean burning will amplify with WVO, creating shorter maintenance intervals and possible damage that running diesel you might squeak by with (e.g. rings).

bcsawyer · #13 01-16-2012, 08:04 PM

Due to an illness in the family and a lot of stuff on the farm that had to be done, I haven't had time to work on the car since before Thanksgiving until the last few days. I've got the basics done to get it inspected and on the road, but still have to do a few minor things like a window regulator, dash lights, and some interior stuff. After letting it run quite a bit and putting in fresh fuel with new filters, I have noticed a lot of noise from the front of the motor that sounds like a really slack timing chain. I haven't been able to do a valve adjustment yet, but I'm thinking that I need to go ahead and replace the timing chain when I do. Is it a terribly expensive or time consuming task? This is the first Mercedes I've dealt with and I've been impressed with how simple it is to work on. From what I've read here and other places, it sounds like some valvetrain work would certainly help the smoking issue.

whunter · #14 01-16-2012, 09:08 PM

Quote:

Originally Posted by bcsawyer

Due to an illness in the family and a lot of stuff on the farm that had to be done, I haven't had time to work on the car since before Thanksgiving until the last few days. I've got the basics done to get it inspected and on the road, but still have to do a few minor things like a window regulator, dash lights, and some interior stuff. After letting it run quite a bit and putting in fresh fuel with new filters, I have noticed a lot of noise from the front of the motor that sounds like a really slack timing chain. I haven't been able to do a valve adjustment yet, but I'm thinking that I need to go ahead and replace the timing chain when I do. Is it a terribly expensive or time consuming task? This is the first Mercedes I've dealt with and I've been impressed with how simple it is to work on. From what I've read here and other places, it sounds like some valvetrain work would certainly help the smoking issue.

Just some thoughts on how and what to look at.

A common horrible rattling noise is a loose A/C belt, A/C compressor and/or clutch failure.

The hydrostatic engine cooling fan clutch can make extreme noise before catastrophic failure.

Can banging sound at front of engine.....what could it be?
http://www.peachparts.com/shopforum/diesel-discussion/228061-can-banging-sound-front-engine-what-could.html

* I would also inspect the front lower ear of the alternator bracket is not broken, cocking it out of alignment.

http://www.peachparts.com/shopforum/diesel-discussion/303373-joy-replacing-alternator-bracket.html

* It would be wise to inspect the water pump.

Water pump question (OM617)
http://www.peachparts.com/shopforum/diesel-discussion/264945-water-pump-question-om617.html

* If you are unlucky the harmonic balancer dowel pins may have sheared, or the pulley bolts are partly sheared.

Diesel Harmonic Balancer threads
Diesel Harmonic Balancer threads - PeachParts Mercedes ShopForum

Main seal front/rear and harmonic balancer + Pulley
Main seal front/rear and harmonic balancer + Pulley - PeachParts Mercedes ShopForum

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bcsawyer · #15 01-16-2012, 09:51 PM

thanks for the info. just went outside to check and the fan clutch is loose. water pump is not leaking, felt tight, alt. bracket is good, harmonic balancer looked fine, ac clutch is fine, but belt is a little loose. I used a piece of wood to listen since I don't have a stethoscope, but it seems like the only noise maker is the fan clutch. I guess the next step is to replace that and adjust the valves. I also forgot to mention that the car may not be as low mileage as I thought. The odometer/speedometer doesn't work so who knows when it quit. this is going to be a beater car anyway so it really doesn't matter. If I can get the smoking to a manageable level, it will be fine for a farm/drive to work car.