My car has 230k on it, a 1991 300d. My mechanic said that's a long time for a water pump to be working and that I should consider replacing it. Seems like I asked before on this forum but I couldn't find the thread, how many miles on your car with the original water pump?

You are not saying what year you have.

On my year and model removing the Water Pump and or that plate behind the Water Pump results in broken off bolts. That can happen if you are changing the Water Pump before it leaks of after it leaks.
Changing it before it leaks allows you to plan for the possibility of broken bolts and or stripped allen heads.

On my own engine when I removed the Water Pump at about 250K I found it was made in Japan. I take that as an indication it had previously been replaced (and one bolt/screw broke off). Unless you have a bunch of complete records there is no way to know if yours had been previously replaced or not.

So what shortens water pump life? Over tightened belts stress the bearings. If your engine over heated that is hard on the grease in the bearings and the seal.

I don't know if when the coolant goes bad the lubricating ability on the pump seal also goes south.

Anything gritty inside of your coolant system is going to shorten the life of the seals.

In my case the good news was a brand new water pump is not expensive. Having a mechanic do the job is and it will be more expensive if bolts break off.

I can't remember which member or which engine but one of the member said he made a drill guide for the broken bolts/screws.

Note that if bolts/screws break off I don't think there is room to get in there and drill them out with out removing the Radiator and of course draining the coolant. That all going to be an added expense.

In my case I simply did not drill out the single broken bolt and it has been fine.

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84 300D, 82 Volvo 244Gl Diesel

Mine was went down after 29 years of use .This is on a one owner car 97,000 .
The Myle i fitted as been running for 2 years dont know how many years this will one will run for .

Don't get a GEBA brand pump. I bought one and was proud of the $$$ I saved... for approximately 3 months... then it started leaking. The shaft of the pump was off kilter (wobbly). I bought a genuine mercedes and haven't had an issue in 18 months (15k miles).

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1991 300D 2.5 "Rocinante"
2002 Golf TDI "Teen Spirit"
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1984 300D
1966 Mustang I6 3sp
1985 Mazda RX-7 GSLSE
1982 Toyota Supra
1977 Datsun 280z
1971 Datsun 240z

Took one off my partners e300d and it had been on there since new - 27 years.

The 60x pumps last a long time. The one on my 300SDL had an indicated 189K on the broken odometer, but likely significantly more than that and still had the original pump without any issues. It would have still been running it until it died except for having to remove the entire water pump to remove a very seized fan clutch bolt. My '91 350SD is also on its original pump.

Drive it until the bearings start growling or you start getting weeps/drips. Unless you live in the rust-belt, the bolts probably won't give much if any trouble either. When you do replace the pump, go with Laso or Graf. Laso was OE, you'll probably find their name on your MB star stamped one if you look close enough.

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Current stable:
1995 E320 149K (Nancy)
1983 500SL 120K (SLoL)

Black Sheep:
1985 524TD 167K (TotalDumpster™)

Gone but not forgotten:
1986 300SDL (RIP)
1991 350SD
1991 560SEL
1990 560SEL
1986 500SEL Euro (Rusted to nothing at 47K!)

I just edited my post to show year and model. Sorry about that.

It is really a crap shoot as to how long it will last. If the car has had the specified coolant used throughout its life, it will go along time. There should be a weep hole in the top of the pump that will start leaking prior to failure. I would drive it until it starts leaking if the car is used as a daily driver and not for long-distance travel. Make inspecting the weep hole part of your weekly ck. like oil level and tire pressure.

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-- Chris

'95 E300, 216k miles, Silver Surfer
'05 E320 CDI, 138k miles
'07 S550 4matic, 69k miles

Gone but not forgotten:

'76 300D, 350k miles?, SOLD in 1995
'75 240D, 300k miles, SOLD in 1991

Depends on the pump. Dealer supplied pumps last the longest - I just changed mine after 44 years

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Why I will never do business with "DieselKraut" again

http://www.peachparts.com/shopforum/mercedes-benz-used-parts-sale-wanted/378935-why-i-will-never-do-business-dieselkraut-again.html

Both pumps that I have had to change, one om603 and the other om606 started to squeal when engine started from cold with the noise vanishing after about a minute.
The belt slips on the pulley unable to turn the pump but once pump starts to turn then it quietens down as it gets some heat into it, You eventually discover its the pump after ruling out alternator and tensioner / idler wheels etc.
Neither of the two I changed leaked

It should give you some warning before leaving you by the road.

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Jim

The pump in my 190D (602 engine, same pump) had gone 456K miles when the car died. Still had the original pump. Do I get the prize?

You should! That's impressive!

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Current stable:
1995 E320 149K (Nancy)
1983 500SL 120K (SLoL)

Black Sheep:
1985 524TD 167K (TotalDumpster™)

Gone but not forgotten:
1986 300SDL (RIP)
1991 350SD
1991 560SEL
1990 560SEL
1986 500SEL Euro (Rusted to nothing at 47K!)

My 1994 E420 with M119 engine had a full maintenance history from new with no record of water pump replacement, although did have regular coolant changes at dealer. 1st owner drove over 100,000 miles in33 months, sold to 2nd owner who took 17 years to add another 100,000 then came me. Never had any indication of pump failure, fan clutch done several times over life of car. Don't remember mileage when sold, but was around 300,000. Best engine of any car I ever owned. When sold, still did not drip or burn oil and was eerily quiet at idle.

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John 5:25