W124 Engine Vacuum Pump replace before it breaks???

[lpozzo]

Hi All,

I have a 1990 W124 300D (2.5TD) that was manufactured in February 1990 and it currently has 170K miles. I heard that the engine vacuum pumps sometimes break and the bearings from the pump grenade into the engine causing engine damage.

Do you know if my vacuum pump is a sealed unit or will my model year grenade the bearings into the engine? Does it make sense to change before it breaks? If so, is it easy to change?

Thanks for your guidance and recommendations.

Best Regards,
Louis

[pawoSD]

You can usually tell by the outward appearance of the unit. Are you able to post a picture of the one installed on your engine?

I went the cautious route and replaced the pump on my OM601 engine with a modern new closed bearing one. Cost $340 or so...but now I have no worries. The original was the open bearing design and had 249k on it without failure, but I wasn't taking any chances. The new one has been smooth and great for over 5,000 miles so far.

[ah-kay]

Check picture on post #95. That is a new pump with screw heads on the outside cover.

W124 climate control vacuum pod replacement

[vstech]

Screw heads are NOT a guarantee of sealed bearings, but if you don't have them, it's a guarantee they are open, and prone to grenading into the timing chain.

[ah-kay]

Originally Posted by vstech

Screw heads are NOT a guarantee of sealed bearings, but if you don't have them, it's a guarantee they are open, and prone to grenading into the timing chain.

remove the darn thing and do a visual then.

[shertex]

An original pump from a 1990 will not have the screw heads.

[lpozzo]

It sounds from the comments that I should be safe and change the pump. Any recommendation on a brand? Also, is it easy to change the pump myself? Thanks.

[vstech]

changing the pump is not difficult, but you have to remove EVERYTHING from the front of the motor to do it...

fan clutch, belt tensioner, fan shroud, and while it's possible to change it with the radiator on, it's MUCH easier to do it with the radiator out of the way... (your knuckles will thank you)
after all that is removed, you gently remove all but two bolts, one top, and one bottom, then SLOWLY remove the top one, and if the pump pushes out with the bolt, rotate the motor SLOWLY until you can push the pump back by hand easily.

you can also, loosen the top bolt one turn, then the bottom bolt one turn, repeat until the pump is out... your call.

[Mxfrank]

Also, if you're using the (recommended) Pierburg pump, you will need to remove and discard the timing basket, if your car still has it in place. The reason is that the Pierburg pump comes with a special gasket that traps some oil against the front of the pump. I'm not sure why they do this, but the bolts for the timing basket will interfere.

[TheDon]

Originally Posted by Mxfrank

Also, if you're using the (recommended) Pierburg pump, you will need to remove and discard the timing basket, if your car still has it in place. The reason is that the Pierburg pump comes with a special gasket that traps some oil against the front of the pump. I'm not sure why they do this, but the bolts for the timing basket will interfere.

DO NOT DISCARD THE TIMING BASKET!!!

Have you priced one lately?! Leave it in place and pick up a gasket that will work with it in place. I did the VP on my 603, left the timing basket in place, used a gasket that didn't have the dam, and life is good.

[Mxfrank]

I think it's ok to set it aside and keep it safe. It serves no purpose other than as an assembly guide.

[pawoSD]

Either way, don't discard it. I think I discarded mine when I changed my pump They cost a fortune.

[lpozzo]

Hi All,

I checked my vacuum pump and it does have 4 bolts on the outside cover of the pump. Does that mean my pump is the newer pump that will not grenade into the engine?

It does have a part # that I can read off the pump. Would that help to determine if it is a sealed unit? Thanks for your help.

Best Regards,
Louis

[TheDon]

Originally Posted by Mxfrank

I think it's ok to set it aside and keep it safe. It serves no purpose other than as an assembly guide.

I would leave it in place. Some say that it helps contain the ball bearings when the original pump explodes.

The new style pumps may or may not use a ball bearing roller and instead use one that rolls on a finely machined dowel or something technical. Mine didn't look like a typical sealed bearing

[lpozzo]

Is there anyway to confirm from the part # if the pump I have is the new style that will not grenade bearings into the engine? Thanks.