W124 E300TD Gunge in inlet ports

[The Big E]

Hi Guys & Gals.
I'm new to all this, my first posting!
Anyway I've had my 1994 estate for just over two years now, with 182K on the clock but what a great vehicle. Had to change a glow plug recently and having removed the inlet manifold found some ports were lined with black sticky gunge. I know that some deposits are normal but on mine with two inlet ports per cylinder, some cylinders had one dry port and one very sticky!
Has anybody experenced this and could it be where previous removal of the manifold has let debris fall in fouling the valve seat, letting gasses and fuel back out? Does this means a top overhaul
Still getting 30+ mpg

 

[Bolide]

E300 Diesel black gunge

Welcome to black gunge world! Thanks to the EGR system on the multivalve - designed to save the whale, make trees grow, etc - the inlet manifold, butterflies, tracts, EGR & everything else get coated in sticky gunge. I am told that diesel fuel is a good solvent for it - it's certainly not easy to remove

At any one time there will be valves open so trying to clean the inlet tracts should be done with caution. I don't know the "official" way of doing it so won't suggest one. But I have heard reports that cleaning the whole intake system gives a benefit to MPG. Please let us know

BTW, when you reassemble it all, some of the black EGR T-pieces will self-destruct & need replacing. While you're in there I'd replace all the O-rings in the fuel system as well. They're a source of non-stop fun when they allow air into the system and they always seem to do so after they've been disturbed

Nick Froome
www.w124.co.uk

 

[The Big E]

Hi Nick
Thanks for the quick response. It's all been back together for some time now but still running as well as ever. The plastic ventilation manifold along with the regulator valve were all renewed. The lower butterfly was in pieces on removal and was replaced. The manifold was degreased. My concern is whether the explosion gasses are getting back past the valves.
I used to recondition a few engines in my youth, cars from the 50's. Having bought this, my first Merc, I quite enjoy working on it. I do all my own maintenance so how difficult do you think it would it be to strip and regrind the valves.
I found your site after I bought my car, shame!

 

[Bolide]

Top end

No, I wouldn't even think of doing the top end at that mileage. It's EGR crud, not valve blow-by, otherwise the car would be running like a dog. They run a pretty high CR and any lack of valve sealing will result in spectacular effects

The best maintenance with these engines is regular oil changes and fuel filter & pre-filter replacements. Spend the rest of your time stopping the front wings from rusting (a W124 speciality) and keeping track of dodgy suspension bushes, balljoints and coil springs. I'd also very strongly recommend replacing the autobox fluid & filter - it tends to get ignored by non-franchise dealers

I think if you have a 2-year programme of maintenance when you first get one of these cars you reap the rewards over the next decade. I hope I get 10 years out of my "new" W124 like I did out of the old one. That'd be an achievement!

I drove two "potential" W124s today, one with 90-odd K, the other with 165k. I'm sure there are lots of brand new cars on sale that'd love to drive half as well as either of them


Nick Froome
www.w124.co.uk

 

[The Big E]

Cheers Nick
I'll leave well enough alone.
By the way, I'v done the box 3 times so far, a couple of bushesat the rear along with the diff bushes. Also had one rear spring and bearing go, let the experts deal with them! As for servicing, I think I may have over serviced it if thats possible. I'm doing around 20K per a year, it's my everyday vehicle and I love it! The wife can keep her Accord!!
Thanks again
:grin: :grin: :grin: