I've got a 1985 300td at 211K in need of a new turbocharger. I'm told if I can find one with lower mileage, I'll get much better mileage (currently around 22mpg on a good day) and noticeably more oomph.

I have a couple questions I'm hoping someone who knows w123s can help me with:

1) I'm told that the turbocharger for '85 123s mounts differently than previous year models, so I really can only get one from another '85.

2) I've also heard that w123s sold in California were required to have a different turbocharger (presumably for pollution reasons) than those sold in the other 49 states. So I need to find one from a 1985 w123 sold in CA. Is this correct?

3) If I'm right about these points, anyone have any suggestions for where I might look for a replacement part, other than ebay? I've heard VERY bad things about the chinese-made replacement turbochargers, anyone hear differently?

Thanks in advance for any suggestions.

 

Can't answer the specific turbo questions but the I believe your CA model has a Trap Oxadizer on it.

As part of a recall the Trap Oxadizer is supposed to be replaced for free. Also problems with the Trap Oxidizer have been know to ruin Turbo Chargers. If the Turbo is damaged by the Trap Oxidizer it may also get replaced for free.

I do not know how to identify if your Trap Oxidizer had been fixed already. If it were my Car I would go to the nearest dealer and find out if it had been prevously fixed or not.

There is a bunch of factors that conspire to cause poor milage.
Right now the Winter Diesel Fuel will not give the same milage as summer Diesel Fuel Will.
After that there is Valve Adjustment, Fuel Injection Pump timing, Camshaft Timing (this has to do with Timing Chain/Gear wear), Injectors not atomizing the Fuel well so it burns well and Compression in the Cylinders.
Low Tire inflation and dragging Brakes (jack up the Wheel so it can be spun. Have someone step on the Brake and release the Brake Pedal. Spin the Wheel. If the Wheel dose not spin freely you Brake Caliper Pistons are sticking and causing the Pads to drag on the Rotor.)

 

You won't. There is no difference between a turbo with 3 miles and one with 300k miles.

Any turbo from the same model engine will work if you rotate the housings to match.

No. There is zero benefit to using one of them. Installing one without the bypass valve on the compressor will increase fuel mileage and power.

The best option is to completely convert the engine to federal emissions standards. You will need; Intake manifold, exhaust manifold, oil supply line, oil drain upper tube, exhaust down pipe, air filter assembly and the gasket kit. Toal cost should be less than $250.