I own a 1984 300GD which is a little smokey at idle especially when cold. The motor has done 260,000 km (162,000miles) so it may just be getting tired but I'm thinking it could be leaking oil through the valves.

How difficult is it to replace valve guide seals on this motor?
Are the parts expensive?
Whilst doing this job, is there anything in particular I need to pay attention to?

Oli

Have a tech that knows these engines well check it out. These are great engines and rarely need a valve job this early.

(Very good model (GD)

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Benzmac:
Donnie Drummonds
300E
ASE CERTIFIED MASTER AUTO TECHNICIAN
SERVICE MANAGER FOR 14 BAY FACILITY
MERCEDES SPECIALIST 8 YRS
PARTNER IN MERCEDESSHOP.COM

Diesels really don't care about burning oil. They do it well, not seeing it as any different than other fuels. In other words burning oil doesn't cause the smoke of gas motors.

Most times the problem with smoke is either timing, mixture, or combustion related. Poor combustion takes place due to timing and fuel but also compression and injector spray pattern/prechamber performance.

Benzmac,

Mercedes diesel techs are fairly thin on the ground out here. Will a regular diesel mechanic do? Do these motors require specific knowledge? You mentioned 260,000kms as early in the engines life. What should I expect to get keeping in mind it probably works harder than in a merc sedan?
P.S The motor is turbo charged.
Also, how do I do a compression test and what are normal results?

Oli

Oli,

Is the engine using oil. As Steve said smoking is another situation. The valve seals are typically replaced to curb excessive oil usage.

Good luck,

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Larry Bible
'84 Euro 240D, 523K miles
'88 300E 5 Speed
'81 300D Daughter's Car
Over 800,000 miles in
Mercedes automobiles