exhaust leak - manifold? 84 300D - PeachParts Mercedes-Benz Forum

tobybul · #1 10-16-2006, 08:00 AM

84 300D - some diesel smoke coming out from below the air cleaner area around the exhaust manifold. can't tell exactly from where yet looking from the top. maybe exh pipe leak or a manifold leak.

anyone had similar situation? car has 240k and runs very well. thanks.

RAYMOND485 · #2 10-16-2006, 10:14 AM

1984 300d Turbo 140,000
Replace The Flex Down Pipe $140.00 Diy 2 Hrs, 2 Copper NUTS, At The End Of Flex Pipe And The Front Is Off The Turbo

SD Blue · #3 10-16-2006, 10:39 AM

the drain tube for the cyclonic oil separator has detached from the bottom of the air filter housing. This is usually caused by a broken air filter mount. Also, the nipple on the bottom of the separator needs o-rings.

(Appears as an exhaust leak but is actually oil vapor from the crankcase.)

tobybul · #4 10-16-2006, 11:18 AM

Quote:

Originally Posted by SD Blue

the drain tube for the cyclonic oil separator has detached from the bottom of the air filter housing. This is usually caused by a broken air filter mount. Also, the nipple on the bottom of the separator needs o-rings.

(Appears as an exhaust leak but is actually oil vapor from the crankcase.)

Are there specific part names for these if I have to look them up on line or are they all dealer items? I have not gotten in there yet and do any dismantling to check these suggestions. It'll probably be this weekend.

tobybul · #5 10-16-2006, 12:28 PM

Quote:

Originally Posted by SD Blue

the drain tube for the cyclonic oil separator has detached from the bottom of the air filter housing. This is usually caused by a broken air filter mount. Also, the nipple on the bottom of the separator needs o-rings.

(Appears as an exhaust leak but is actually oil vapor from the crankcase.)

another question... will this produce an exhaust or manifold leak sound?

pic shows turbo are without the air cleaner. I did start it up and smoke IS coming from down pipe.

SD Blue · #6 10-16-2006, 02:59 PM

The only aftermarket items would be the air filter housing mounting bracket with rubber shock mounts and heat deflectors. And of course the o-rings can be found any where.

No, it wouldn't give the exhaust sound. That would probably be either the flex downpipe or the junction of the downpipe and tailpipe.

The drain tube will produce a source of oil vapor when it comes disconnected. A telltale sign is the fine oil mist all over the fenderwell.

tobybul · #7 10-17-2006, 09:45 AM

Quote:

Originally Posted by SD Blue

The only aftermarket items would be the air filter housing mounting bracket with rubber shock mounts and heat deflectors. And of course the o-rings can be found any where.

No, it wouldn't give the exhaust sound. That would probably be either the flex downpipe or the junction of the downpipe and tailpipe.

The drain tube will produce a source of oil vapor when it comes disconnected. A telltale sign is the fine oil mist all over the fenderwell.

Checked a few things last night. Removed the air cleaner assembly revealing lots of stuff underneath not normally seen. Some items broken (aircleaner bracket and mount. Didn't see the heat shield. Wonder where it's mounted?

The drain tube appears to be intact. I did notice the turbo u-shaped plastic pipe was missing the clamp on the air cleaner end. Also wonder if thats available online or have to go to dealer. I realize I can get a stainless steel clamp anywhere.

Didn't get the opportunity to start the car with the air cleaner off which I am guessing will reveal the source of the exhaust smoke. I did see the flex pipe. I'll definitely be watching this area when I run the engine next time. Will post again later after I do more diagnosing.

JimZ · #8 10-17-2006, 11:19 AM

I have smoke coming from the same exact spot. When I brought my 300SD into the dealer shop for a checkup they found that the downpipe has a crack in it, so that is almost definitely the source of our smoke.

My question is: Does the downpipe need to be replaced, or can the crack be welded? The mechanic quoted me around $600 for MB parts and labor, which is way out of my price range. They said they wouldn't weld it there. I'm hoping I can take it to a regular old muffler shop and just have them weld the crack.

SD Blue · #9 10-17-2006, 11:46 AM

Quote:

Originally Posted by tobybul

............ Some items broken (aircleaner bracket and mount. Didn't see the heat shield. Wonder where it's mounted?
.......... the clamp on the air cleaner end. Also wonder if thats available online or have to go to dealer. I realize I can get a stainless steel clamp anywhere.............

The heat shields are small, cone-shaped, metal deflectors that fit on each of the rubber shock mounts for the air cleaner. They are important as they keep the rubber mounts from deteriating, so quickly, from the heat of the turbo.

I have seen the turbo seal rings, for the U-tube to flange joints, but not the clamps themselves. Check with the dealer. Sometimes they can pleasantly surprise you/ sometimes they can surprise you in other ways.

SD Blue · #10 10-17-2006, 11:58 AM

Quote:

Originally Posted by JimZ

......My question is: Does the downpipe need to be replaced, or can the crack be welded? The mechanic quoted me around $600 for MB parts and labor, which is way out of my price range. They said they wouldn't weld it there. I'm hoping I can take it to a regular old muffler shop and just have them weld the crack.

That is very hard to answer without knowing exactly where the crack is and how extensive. Sure, the regular old muffler shop may weld it, (Over and over and over again) if it is in a critical area. Why don't you just DIY? The header pipe is less than $200 http://catalog.eautopartscatalog.com/mercedesshop/sophio/quote.jsp?clientid=catalog.mercedesshop&cookieid=1WG0P2UAL1X80OUDGL&baseurl=http://catalog.peachparts.com/&partner=mercedesshop&year=1984&product=H2000-41355&application=000309189 Use lots of PB Blaster rust penetrant, get a new seal ring for the lower end and know that part is in good shape for another 20+.

tobybul · #11 10-17-2006, 01:24 PM

Quote:

Originally Posted by SD Blue

That is very hard to answer without knowing exactly where the crack is and how extensive. Sure, the regular old muffler shop may weld it, (Over and over and over again) if it is in a critical area. Why don't you just DIY? The header pipe is less than $200 http://catalog.eautopartscatalog.com/mercedesshop/sophio/quote.jsp?clientid=catalog.mercedesshop&cookieid=1WG0P2UAL1X80OUDGL&baseurl=http://catalog.peachparts.com/&partner=mercedesshop&year=1984&product=H2000-41355&application=000309189 Use lots of PB Blaster rust penetrant, get a new seal ring for the lower end and know that part is in good shape for another 20+.

Called the MB dealer in town and header pipe is $187+tax compared to $240 (less 20%off)+tax from Napa (Walker pipe). Both come with flex pipe. Bolts and seals are extra. Not sure if I want to DIY yet. Will be chkg with my mechanic to see how much.

BTW, although welding my be a good alternative, if the pipe wall has corroded this much, what tosay it won't poke another hole elsewhere. I think i'd rather put a new one.

JimZ · #12 10-17-2006, 02:00 PM

"if the pipe wall has corroded this much, what tosay it won't poke another hole elsewhere."

But I've never done a repair like this before. In fact, I don't know where to start...jack it up, needs to be on a lift...??

If I can do it myself, I will. Once I can see the problem, I'm pretty good at fixing it.

tobybul · #13 10-17-2006, 09:54 PM

Quote:

Originally Posted by JimZ

"if the pipe wall has corroded this much, what tosay it won't poke another hole elsewhere."

But I've never done a repair like this before. In fact, I don't know where to start...jack it up, needs to be on a lift...??

If I can do it myself, I will. Once I can see the problem, I'm pretty good at fixing it.

if i decide to diy, my plan is to use a ramp rather than jacking it up. this way I'll gain more clearance. these are times when i wish i had a pole barn equipped with a lift inside.

I don't think I ever mentioned it but the smoke/exhaust in the engine compartment was coming from a break on the lower end of the flex pipe in the down pipe.

tobybul · #14 10-27-2006, 09:26 PM

got all my exhaust parts today from alleuropeanautoparts.com. after shopping a few online places, they had the cheapest parts using Eberspaecher pipes and bosal muffler. The old header/down pipe was broken where the lower flex and the hard pipe come together. plus there were some holes on the center pipe. So I decided to replace the entire system.

I've removed the old down pipe. Fairly easy. Tomorrow, I'll tackle the center and tail pipes and slap the new system in. Right now, am working without the car elevated in anyway and so far so good.

I also decided to paint the new pipes with Duplicolor 1200 deg high temp paint (aluminum) to help preserve it. I light sanded the pipe (150) b4 painting. Looks pretty slick!!. Thank goodness my garage is heated.

JimZ · #15 10-28-2006, 11:26 AM

If you can, could you post a picture of the old, cracked flex pipe and the center pipe with the holes next to your new pipes so I can see what to look for on my car?

Man, it's nice you have a heated garage. I have no garage at all. Not even a driveway! And it has rained just about every weekend for the past month. Nice and dry while I'm at work all week, then when the weekend rolls around and I get to work on the car, here comes the rain.