OM603: Vacuum pump explosion, bearing intact! Injection Pump Timing device wrecked - PeachParts Mercedes-Benz Forum

ashedd · #1 05-21-2009, 08:37 PM

Ok I just ran into this thread. Now I am scared poopless about my pump failing in the 603.

Let me know if this plan of action is a good/bad idea.

My 87 300D has about 160k indicated but the odometer does not work. I have no history on the car. I think I should pull the vac pump and look for a date code. I should also inspect it the best I can. I want to start the car without the pump installed to see if a "lifter" noise goes away.

As long as the pump is not original AND it looks ok I will reinstall it. I understand a new pump is about $300 so I will stash some money away for a new one soon.

sound good?

compress ignite · #2 05-21-2009, 11:40 PM

The mess (OIL) it makes WILL BE the least of your problems !

gsxr · #3 05-22-2009, 12:26 PM

Quote:

Originally Posted by ashedd

Ok I just ran into this thread. Now I am scared poopless about my pump failing in the 603.

No need to be that worried, you just need to educate yourself about the pump on your car now, and the potential effects of failure (i.e., if it does fail, DO NOT drive the car home - don't re-start the engine until it's fixed).

Quote:

Originally Posted by ashedd

My 87 300D has about 160k indicated but the odometer does not work. I have no history on the car. I think I should pull the vac pump and look for a date code. I should also inspect it the best I can.

No need to pull the pump to look at the date code. The first inspection is for the four Torx-head screws on the pump cover. If there are no screws, the pump is original, and should be replaced as soon as you can afford it. If there are Torx-head screws, that's better - indicates the pump was replaced at some point. Then you look for the date code, which is on the front / bottom of the pump, but may take some effort to clean up & see. You may have to pull the fan, clutch, and serpentine off to clearly see the date code. BTW, you can get your odo fixed for ~$125 or so from a VDO shop... or, just swap in a different speedo from a later W124 with the same 2.65 gears. It's not hard to adjust the mileage on the new odo to match the old (or, estimate what you think is actually on the car).

Quote:

Originally Posted by ashedd

I want to start the car without the pump installed to see if a "lifter" noise goes away.

As mentioned above, it's probably a lifter, not the pump. Try Mobil-1 (15W-50 or 5W-40 only) and see if that cures the lifter noise. It can take a couple thousand miles sometimes. If not, you probably have a collapsed lifter or two... they're only about $20 each, but are a PITA to replace. I changed all of 'em on my '87 and '93 and they have been silent ever since.

Quote:

Originally Posted by ashedd

As long as the pump is not original AND it looks ok I will reinstall it. I understand a new pump is about $300 so I will stash some money away for a new one soon.

The important part is if the pump has the open-cage bearings or not. Some early pumps with the 4 screws have the open bearings, I think from the early 90's. I believe my pump with the good, "closed" bearing was dated 1995, so anything newer than that is probably OK. But I don't know the year (or date code) in the early 90's when they changed to the improved style bearing. It's not likely you'll run into this scenario, most likely your pump is either original, or post-1995....