I just bought my first MBZ, an '82 300D automatic with 142K miles. It looks and feels great on the highway. No burning oil or anything that screams "take care of this first".

My only experience with diesels is limited to an Audi 5000 years ago, which I really liked (5-speed), and my tractor. So the question is how sluggish should I expect my 300D to be? It downshifts fine, although a little jerky, but does not seem to be sufficiently responsive from 0 to 35mph, let's say. How do I know if the turbo is working, and should the turbo be helping out with this?

I've seen a number of messages about adjusting the valves. Could this be it?

Thanks for your input,

Welcome. Assuming the car has been neglected, a few things I would do: 1) Get a Haynes manual, 2) Change the inline and main fuel filters and air filter, 2) remove and clean the banjo fitting at the back of the intake manifold, 3) get a valve adjustment done. I can usually "feel" my turbo kicking in at around 2500 rpm. 0-60 in this car should be around 13 seconds. You could use a pressure guage to check your boost, do a search for "boost check" and you will find lots of info. Good luck.

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2001 Dodge Ram 2500 Cummins Turbo Diesel - 4x4, auto, 3.54 gears, long bed
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'92 300D 2.5 Turbodiesel - sold
'83 300D Turbodiesel - 4 speed manual/2.88 diff - sold
'87 300D Turbodiesel - sold
'82 300D Turbodiesel - sold

That's a great checklist. I'll get started on it right away. I've found that the 300D is a great car to work on and mine looks really super. Absolutely no rust.

Thank you

SW has some good suggestions. In addition to these, I would make certain that the various linkage--from the accelerator to the injector--is nice and tight. When I got my 300D turbo, it was dreadfully sluggish, quite unlike what a turbocharged 5-cylinder should be. I adjusted the linkage, changed filters, cleaned the banjo fittings, etc., and now she does a respectable 13.5 from 0-60.

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Matt
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1995 E300 Diesel (Die Blau Frau)

Whats a banjo fitting? Where is it located on a 83 300d? What adjustments are needed, or cleaning requirements? Does it ever get replaced? I've never heard of this banjo thing, and I thought I had a fairly good (DIY) knowledge about these cars. Obviously not.

The banjo fitting is only outfitted on the turbo models. Some of the compressed air that is forced into the intake is routed through this fitting, then over to the switchover valve, and on to the aneroid compensator, where it signals the injector pump to feed the engine more fuel. A turbocharger makes little sense if this mechanism isn't working properly. It's easy enough to remove and clean(it sits at the firewall end of the intake manifold), but be careful not to overtighten when reinstalling. Furthermore, if this fitting is badly clogged, it's a safe bet that the switchover valve is similarly clogged. When cleaned, it will make a world of difference.

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Matt
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1995 E300 Diesel (Die Blau Frau)

kenwc21,

Is your car a turbodiesel? The '82-'85 US spec 300D's were tubodiesels. However, there are a few euro '77-'85 (non turbos) on the road. If yours is a non turbo, it probably does not have this fitting. The banjo fitting I referred to was the one that is threaded into the back of the intake manifold, you will need a 12mm wrench to loosen it. It is a hollow bolt that allows pressure from the intake to get to a valve (follow the line to the valve). The valve sends the boost signal to the fuel pump for more fuel and also sends a signal of some sort to the transmission. The turbo's have an exhaust gas recycling valve. Over time, soot from the egr will plug the bore of the bolt and eventually restrict boost from reaching the fuel pump. You can clean it with wd40 or brake parts cleaner.

__________________
2001 Dodge Ram 2500 Cummins Turbo Diesel - 4x4, auto, 3.54 gears, long bed
-------------------------------------
'92 300D 2.5 Turbodiesel - sold
'83 300D Turbodiesel - 4 speed manual/2.88 diff - sold
'87 300D Turbodiesel - sold
'82 300D Turbodiesel - sold

Thanks Matt and SW. I do have a turbo, thought all 83-85 d's where so I forgot to mention it. Tanks again, I'll check out the banjo this weekend.

One last point and Matt alluded to it. When your done cleaning the banjo fitting disconnect the tube at the injector pump end and make sure you can blow trough the line at the banjo end and air comes out at the pump end. If boost pressure is unable to reach the pump you will have no enrichment and no additional power from the turbo.

Bob D.

run it on the road today after getting the brakes in good working order. Now I have a turbo boost question. I disconnected the (now clean) banjo fitting and hooked a 0-30 psi test gauge up to the line coming off of the fitting, revved the car and the pressure actually went slightly negative. Next I removed the waste gate housing from in front of the turbo and checked to make sure that all of the ports were clean/clear. I even started the car up with the waste gate removed and observed the turbo spinning but I never got any positive pressure from the waste gate "port" although I more did not let it run up very much. I did notice that on the turbo side of the diaphragm there was a little "ridge" which could possibly be preventing the diaphram from sealing off. The diaphrahm looks original (215k miles on car). Can a turbo "wear" out where the clearances get so large that it stops providing boost? Can the wastegate spring wear/weaken to the point that it allows the boost to go to the exh manifold instead of to the intake manifold? I did notice that after reassembling the waste gate section and driving the car I could hear what I perceive to be "turbo whine" starting at around 2000 rpm and then the whine goes away at around 2500 rpm. Any thoughts/ideas etc.
thanks,
Jim
'95 E320
'97 CRV
'85 300D turbo

You will not observe boost reving the engine in neutral. tee into the line from the intake to the alda and run a piece of line between the hood and the windsheild. Install your gauge and tape it to a spot on the windsheild. Run the car under load above 3500rpm to observe boost.

Bob D.