[reinventthewheel]

Ok, so my last car was a gas VW Jetta and when I got it, it had an incredibly dirty intake manifold. I did a few seafoam treatments through the vacuum lines and it worked miracles.

I just got a '79 300td (non-turbo) and there's been a lot of blow-by. The air filter and housing is full of dark oil, and the car smokes much more than it should.
My thought was that since I was dealing with a similar problem, I would turn to a similar solution. I sucked a half a can of seafoam through the thin vacuum line coming off of the thick one that leads to the brake booster.

Since the big cloud of smoke didn't come out afterwards I just started to look up Seafoam treatments on these vehicles and found all this scary stuff about hydro-lock. Yikes.

I've only driven about 1/2 mile since doing the treatment, but I'm supposed to be driving almost 300 miles tomorrow (hence the desire to clean out the intake before getting on the road).
SO! Did I fuck things up? What do I do to fix it?
Also, how can I clean out the intake manifold? Will seafoam in the fuel do the trick?

Thanks

 

[Kajtek1]

when gasoline engines use intake as a source for vacuum -diesels have mechanical pumps for it.
sounds like your pump is very clean by now?
Those engines have engine ventilation going into the air filter housing, so oily intake is perfectly natural. High blow by is not. How bad is it? Will it blow oil cap off?
There is Moly brand diesel purge that does a wonder on older engines. Start with that.

 

[reinventthewheel]

So is my engine gonna be ok? Do I need to do anything to get the seafoam out?

Or is it just going through the vacuum pump and into the intake and probably not making it into the crankcase?
There was some seafoam dripping from a point at the back of the air box.

The oil was all over the air filter, are you saying that's ok?
Blow the oil cap off? Never heard of such a phenomenon.

 

[Kajtek1]

I don't remember where the vacuum pump blows the air out, but what is done is done. I can only hope the SF being petroleum will not dissolve the pump diaphragm.
Blowby can be roughly measured by lifting force of gases at the oil fill. My diesels will not blow a paper towel lay down on the hole, than you can put a piece of cardboard and see if it will stay, in extreme blowby the reversed cap will get blown off.
Now the oil all over the filter is not really precise description. I used to have turbo version and I can only assume your engine is having similar system. The crankase gases go inside the air fuel box where there is oil separator with wire filter in it. The excessive oil should drip at the separator and special tubing takes it back to the cranckase.
The system needs to be clean and well connected. I still remember that assembling the air box and making sure the drip tubings go into right place was quite a trick and have seen lot of cars with that tubing dangling loose under the filter. Also orings replacement on the tubing is often neglected.

 

[reinventthewheel]

Was out of town for a little bit.
Thanks for the info.

There is quite a bit of blowby. It will rattle the cap if I loosen it.
The oil was extremely filthy when I got this car, and was immediately black right after its first oil change. It also smokes a bit while idling.
I plan on taking it to someone with more experience for an engine check, but I'd like to do what I can to remove the carbon and lessen the smoke and blowby before doing that, though.
Suggestions?

 

[reinventthewheel]

I should say:

My current plan is to do another oil change, and to do a Moly Diesel Purge.
Any suggestions on synthetic vs dino?
Should I change the filter again even though it's only been about 600 miles?

I'm wondering if doing some sort of oil flush before changing the oil, or an oil additive, may be a good idea?

 

[Kajtek1]

Start with diesel purge and take it slowly. If the engine was neglected in the past, some things might be irreversible, so don't expect miracle in the bottle.
Your engine was design to run on dino oils. I do oil testing for last few years and shell Rotella seems to be the best on the market. It comes in dino and synthetic version. My Ford diesel loves T6 synthetic and I will switch my Mercedes diesels to it as well.
All the oil flushes have been proven more or less to be a kerosene mixed in different proportions. Same is Sea Foam. Just do earlier oil change if you feel it is necessary.
Filters are oversize on those cars, so unless you see lot of sludge, don't worry about replacing it before oil change.

 

[reinventthewheel]

Great, thanks.
O'Reilly has their diesel oil on sale so I think I'll do one change with that and then change it again to something better after another 500-1000 miles.

What do you mean by, "take it slowly"?
You mean take it easy driving with the engine, or??

 

[flyboyike]

What do you mean by, "take it slowly"?
You mean take it easy driving with the engine, or??

No, he means push the car uphill with the engine off real slowly.

 

[reinventthewheel]

thanks, that's incredibly not helpful.

didn't know if you meant something about the diesel purge process, haven't done it before

 

[Kajtek1]

get used to fly. You should see what he did to his real plane, that was on the background of his old signature picture
By taking slow I mean don't expect the car to start burning the rubber after the purge, or oil change.

 

[reinventthewheel]

Thanks. I'm just wanting to head up to southern Oregon in a week and a half and am trying to decide if I should drive her up there.
I just went up to Mt. Shasta and back (from the bay), which went fine on the way up but she was gettin tired on the way back. I think I'm gonna see how it goes after the oil change and diesel purge and if the blowby is any better. The Siskiyou Pass can be tough on the old ones.

 

[nrkmann]

My 2 cents is use Mobil 1 synthetic 0W-40 (MB uses this in almost all of its engine). Use Seafoam or Diesel Purge in the fuel (videos on YouTube) and change fuel filters and change them again any time you feel that "she aint pulling the hill very well" feeling. Use the Seafoam in the crank case for about one hour and change the oil & filter. Unless there is physical damage to the motor you will feel a difference.

Also have the valves adjusted. This can make a huge difference on diesels with mechanical lifters. Mercedes Diesel Valve Adjustment Procedure

A good test to determine if you have had results is the 40-60 mph test. Time 40-60 several times so you have a good average. After doing the diesel purge or seafoam test again. I gained about 1-2 sec on my 300sdl.

You can use diesel purge or seafoam for this...

Diesel Purge Mercedes diesel maintenance tips
Diesel Purge Injection System Cleaner kit with Instructions | MercedesSource.com
300SD Mercedes-Benz Heaven: Performing diesel purge

 

[reinventthewheel]

Supposedly the valves were adjusted shortly before I bought it, not that it doesn't need another valve adjustment...
I did a diesel purge and the smoke went down a little bit, but the blow-by isn't any better.
I actually put up another post trying to fix my blow-by:
http://www.benzworld.org/forums/w123-e-ce-d-cd-td/1617371-blow-stuck-piston-rings.html

I soaked the piston rings in MMO for three days and now have driven about 1000 miles with royal purple synthetic in there, blow-by isn't much better still.

I definitely want to do something to remove all the carbon build-up but don't want to damage things further.
Someone was suggesting using gasoline in the crankcase, as in the thread above.