1986 560sel, had badly fouled plugs, changed to fresh and now get a billowing cloud when idling in traffic. (haven't been driving it much since I changed the plugs)

Burned/used oil substantially previously and still does

Puff of smoke upon cold start and no smoke (begins to get slightly noticeable as car warms up... 60c onward) until operating temperature where it is visible from space.

Once warm, smokes at idle and under acceleration from idle for a few seconds... the longer the idle, the longer it takes to stop billowing afterward (within a 5 - 10 second band)

Doesn't appear to smoke at road speeds once undeway (possibly due to rapid dissipation)

Freeway driving fine except under hard acceleration (possibly due to even more rapid dissipation)

Any suggestions on how diagnose/troubleshoot to narrow things down further without pulling it apart would be appreciated with thanks in advance.

Patrick

hi, there are a few things i have seen cause this, the most common one that i have found is the oiler tube for the cam on the drivers side cylinder head.
what happens is the oiler tube comes disconnected at the rear bearing and sprays oil into the breather chamber that is in the top of the valve cover, the rubber hose that connects to the valve cover on the drivers side has vacuum present and these two combined will draw oil into the intake causing this problem. one way to check it is to park the car on a down hill slope, pull the hose off with the engine warm and idling and see if you see oil in the hole where the hose was connected. another way more direct is to remove the valve cover for the drivers side and actually see if the oiler tube is broken. let me know what you find.
Ray

1984 300d Turbo
Replace Valve Stem Seals Diy

Hi Ray

Pulled the hose off the driver's side valve cover at the top of the valve cover and saw that there was a significant amount of crud in it. Also while running, the smoke seemed to abate to a small degree while this hose was off, but was still fairly significant. Upon reattaching, it resumed the job of interstellar signal marker.

Is there any special handling required to pull the hose from the engine side? It does appear to be pretty cramped where it attaches to the intake.

Also, would it cause a problem to try a short, or for that matter longer highway drive with the hose detached from the engine side? should the opening be plugged or left to breathe?

Thanks again in advance,

Patrick

Unfortunately, I don't have the facilities or the skill level to pull off that DIY.

Someday.... (sigh)

Thanks very much though,

Patrick

Most smoking on the m117 is attibuted to 2 things: 1) Oil getting into the intake, or 2) Bad valve stem seals. To produce extreme smoke like you're describing would probably mean your stem seals are in pieces, or you're sucking in a fair amount of oil.

Disconnect all the breather hoses from the intake. Plug the intake to avoid getting crud in there, do NOT plug the breather hoses coming from the engine - doing so will create positive pressure in the engine which usually escapes through the simplest exit (such as your dipstick tube, which means you'll be pushing oil out the engine). Leaving them unplugged but not fed into your intake will produce a noticable smell if your engine is idling for a prolonged period, or working hard (say going up a hill quickly) that is noticable inside the cabin. If oil SPOTS are noticeable or spray is visible coming out these hoses, you have a major leak inside the engine.

I would definetly examine the oiler tubes. The valve covers are held on with 4 bolts per side and are very easy to take off (although you may need to work them around some hoses). If the oiler tube IS off your cam will be starved for oil and you'll burn up the bearings and lobes of the cam and cam towers, as well as your rocker arms.

__________________
Current:
2021 Charger Scat Pack Widebody "Sinabee"
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1972 280SE 4.5
2018 Durango R/T, 2014 Jeep Grand Cherokee Limited "Hefe", 1992 Jeep Cherokee Laredo "Jeepy", 2006 Charger R/T "Hemi"
1999 Chrysler 300M - RIP @ 221k

I trust that I would need to acquire valve cover gaskets then? to be applied upon reassembly?

Thanks in advance,

Patrick

I took a gamble and had the Stem seals and oiler tubes done... smoke problem was never totally gone but very much reduced for about 800 miles/1200km before returning. Lost that bet but at least it snuck in at just under $1/mile. Now biting the bullet and going in for the head job (not the bragging kind ).

While the seals were being done, one of the guides was observed to be bad so it was a long shot at that point for the seals to be an effective fix. (pays yer money, takes yer chances)

While the mechanic is doing the heads and timing chain, what other small stuff can easily be done concurrently?

Thanks to date and in advance,

Patrick

THANK YOU

That completely explains the problem with mine (I thought it was timing) I know the oiler tube is busted on the right side, but I didnt have the parts when I pulled the valve cover last time.

__________________
-1983 VW Rabbit LS Diesel (5speed, VNT/Giles build)

throtlle valve replacement is the answer to your problem.cheerios...

Would that be directed at me, or Monomer?

TIA

(Advice pertaining to ancilliary maintenance while heads are off, still gratefully accepted)

Patrick

If you have an oiler tube popped out, don't try to put it back in - my experience is that the plastic fittings are too brittle when old to hold and then you have a broken piece of plastic floating around. These are very inexpensive even at full list at a dealer. Also, they are kind of tricky to install - you should definitely feel a click. It takes a little more than hand pressure but much less than a hammer to acheive this. Leaving them "sort of on" is VERY bad.

__________________
86 560SL
With homebrew first gear start!
85 380SL
Daily Driver Project

http://juliepalooza.8m.com/sl/mercedes.htm

It's "sort of" not conected at all right now.


The cars not driveable at the moment anyways - I broke a hard brakeline yesterday. Before tha I put a few hundered miles on her wih the oiler broke.

The kit's in the mail still, it's installed first thing when I get it.

__________________
-1983 VW Rabbit LS Diesel (5speed, VNT/Giles build)

A bit of an update:


The Cam oiler repair kits has been installed. NO black smoke anymore. Can runs like it's never had before. Idle is flawless (shifts to 1100RPM in park, though)


I recomend that anyone having problems like this change them out. I had to pick some of the cracked peices with a pair of needlenose pliars. New ones installed with a gentle tap from a tacking-hammer. Be sure they're seated fully, they sit at an angle so it may look like they're seated when they're not.

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-1983 VW Rabbit LS Diesel (5speed, VNT/Giles build)