My Custom 1980 W116 300SD Project - PeachParts Mercedes-Benz Forum

suginami · #1 01-21-2013, 11:53 AM

As always, I love reading your updates.

Keep up the good work. Maybe one day you'll clear a million miles like Doktor Bert.

Squiggle Dog · #2 01-21-2013, 07:04 PM

This morning I decided to try out the "tea kettle" blowby test. The oil cap didn't fly off, so that's good. It actually just sat there on the valve cover. When I removed the cap, I couldn't see any smoke coming out at all.

I did the test with the engine cold. Is this the proper way to do it, or should I have done the test with the engine hot? Also, does the engine sound like it idles fine? No injector nailing or anything? The engine has over 315,000 miles. I use Amsoil Synthetic 15W40 Heavy Duty Diesel & Marine Oil and B99 biodiesel year-round (thankfully, it's cheaper than diesel).

Here is the video: 300sdblowby - YouTube

Squiggle Dog · #3 02-09-2013, 11:15 PM

I've been enjoying the lovely Arizona winter weather. Since I worry about what the heat might do to my car (and since my air conditioning needs a complete overhaul) I decided to start counteractive measures; I bought an Eclipse sunshade for the front windshield.

It mounts on the sides of the glass with 3M adhesive and closes in the center with Velcro.

Pulling the tabs apart releases the Velcro and the shade retracts on its own. It doesn't obstruct vision much.

It's much more convenient than struggling with the conventional sunshades!

As mentioned in earlier posts, I had a dead battery and decided to check the voltage regulator on the back of the alternator. It's a good thing I did, because I found the brushes were extremely worn and starting to fail. The old one was part number 1 197 311 009. The new part was 1 197 311 028. They are identical (long brush style, same specs) other than the new one does not have a resistor. Voltage regulator specs are here (page 15 and 18--thanks to JasonP for showing me): http://www.regitar.com/FlyerPDF/cs.pdf

Squiggle Dog · #4 02-09-2013, 11:17 PM

I cannot stand oil leaks! My front crank seal leak has been gradually getting worse, now leaving a spot of oil in the garage.

Since I have free time and the parts are cheap, I decided to try replacing it myself. First, the alternator bolts are loosened so the belts can be removed (17mm for mounting bolts, 13mm for tension nut).

Then remove the 10mm fan bolts and remove the fan and pulley. There is a high risk of rounding them. It is best to use a box wrench with the outer edge ground down so it will slip over them. I did not have one and yes, I rounded them. One was so bad I had to use clamping pliers to remove it.

The 8mm bolts on top of the fan shroud come out next.

Then the fan shroud comes out. Yes, it will come out, but you have to turn it on its side as pictured.

Squiggle Dog · #5 02-09-2013, 11:18 PM

Now the power steering pump is loosened (all 13mm nuts and bolts) and the belt removed.

Despite what others have told me, I did not believe it was necessary to remove the radiator. I would also have had to remove the condenser and oil cooler with it. I found that I was right; there was plenty enough free space and having it out wouldn't have done one bit of good. I didn't even come close to damaging it.

As a safety precaution, I flattened out a small cardboard box to act as a shield. I found it isn't necessary if you are reasonably careful.

I held onto the crank bolt with a 27mm socket while I loosened the 6mm hex key pulley screws (make sure the heads are clean or the socket won't fit in all the way and it can round them).

This became awkward, so instead I took a socket extension, wrapped it in a paper towel as a cushion, and wedged it between the cutout on the harmonic balancer and the air conditioning compressor to keep the crank from turning backward.

Squiggle Dog · #6 02-09-2013, 11:20 PM

Once the six pulley screws are out, the pulley and balancing disc will come off, so it is important to hold them to prevent them from falling and causing damage to anything or themselves. I don't know if it's necessary, but I marked the original position of the pulleys, balancing disc, and harmonic balancer to each other with punch marks. As you can see, once the pulleys are off, there is plenty of space to work around in.

No need for the extra headache to drain fluids and remove the radiator and oil cooler.

The 27mm crank bolt is torqued to at least 270nm (200 ft-lbs), so breaking it free after many years is very difficult. I did it the easy way--make sure nothing is blocking the crank from turning (remember the socket extension that was wedged in to keep it from turning?--remove it). Then I positioned a breaker bar wrapped in cloth against the frame rail and bumped the starter. Make sure the socket is fully seated on the bolt. This breaks the bolt loose with minimal effort. The breaker bar did fall back and rest on top of one of the transmission cooler hoses, but it didn't cause any damage.

Here is what the harmonic balancer looks like with the fixing pins. Make sure to mark the position of the balancer on the crank with punch marks on each. If it is installed 180 degrees off, the engine will be out of balance. If the old balancer is damaged, the replacement must be match balanced to the old one.

I didn't have a harmonic balancer puller, so I rented one for free from my local auto parts store. I used a generic one and it worked great. There was plenty of room to use it. The balancer came off slowly but smoothly. Make sure it doesn't fall to the ground.

Squiggle Dog · #7 02-09-2013, 11:22 PM

Excuse the blurry photo; I forgot I had my camera under the car when I hosed off the engine! The crank seal is now visible.

A seal puller is supposed to work well, but I used a screwdriver to pry out the seal--just make sure to not score any machined surfaces.

There is a spacer ring that rides between the crank and seal. It is a replaceable wear item and should be replaced every time the seal is replaced. I have heard that these should come off with your fingers. This did not work. I also tried prying from each side simultaneously with a screwdriver. This also didn't work. I had to resort to drastic measures and remove the upper seal cover. I split the seal ring apart from the sprocket by hammering a screwdriver between them, then rotating the crank and prying around circumference with larger and larger screwdrivers until it came off. It was a struggle the entire way.

My spacer ring had a deep groove cut into it from the crank seal. It wouldn't have sealed well even with a brand new seal in place; too much material was missing.

I protected the inside of the engine from debris by placing a plastic bag in the opening as I cleaned the mounting surface. Changing the oil is not necessary if you are very careful, but planning this right before a scheduled oil change is a good idea.