Mercedes-Benz: 1991 190E 2.6 Aux Water Pump - Repair?

This pump helps to bring hot water quicker and more efficiently to heater core.  It does not participate in the engine cooling.  So, there is no damage to bypass this pump.

AFAIK, the whole pump is sold as a unit, no internal part is available (from dealer).  I am not sure if generic gasket/seal can be used for repair.  I chose replacement a few years ago when this pump was only about $80.  Not anymore, thanks to current Euro exchange rate.  Note that if the electric portion of this pump fails, it may draw too much current which will burn the push button control (PBC).  Therefore, buying new part also gives you this insurance.

The clicking sound behind grovebox comes from the switchover valves (which converts electric signals from PBC to full or no vacuum to control motors).  The clicking is normal when switching on or off the valve.  However, the rapid and continuous clicking when using heat on W201 usually means the potention meter on the blender door is failing so PBC cannot determine the opening angle of this door.  Unfortunately it is a many-hour work to replace this sensor which is deep inside dash.  Many people choose to live with it.

glgxg wrote: Aux water pump on my 1991 190E 2.6 has started leaking (Borch APG 12V 0
130 002 070) from the black plastic housing.  The pump appears to be
still working & I still get full cabin heat etc., but I do get some
clicking noises from the passenger side glove box.  Also, the leak is
not major at this point, just spots on the ground when the car is parked.

Three questions:

1.  Rather than going out and buying a new part (approx. $130-140) or
searching the junkyards for a used part, is it possible that this unit
can simply be removed and perhaps be repaired with new gaskets, seals etc?

2.  If I do remove the unit for inspection/repair, would I do any damage
by temporarily rerouting the hose from the water pump going to the unit
directly to the black metal tubing going to the heater core (effectively
bypassing the aux water pump altogether) and driving for short distances?

3.  If it is possible to simply repair the unit by replacing
gaskets/seals, does anyone know of someplace that stocks the parts the
repair?

I'd hate to spend $130 plus on a new unit if it is possible to repair
with a few dollars in gasket parts.

Wan-ning Tan wrote: 

Thanks for the info -- I will plan on buying a new one.

New pumps are available for a lot less than $130...

Ron
http://germanstar.net

Just replace it. I got one for 91 dollars locally here in san diego and
changed it in 15 minutes. Lol. you really want to fix it? If you are a
really cheap bastard, put a piece of pipe in between where the pump was and
throw the bad pump away. Zip tie the wires out of the way somewhere they
wont short, it will be fine.
KH

"glgxg" <com.invalid> wrote in message
news:com.invalid... 

Kevin in San Diego wrote:
 
Interesting comments from someone that tore his dash apart to find a
cold solder joint rather than taking his car to the dealer. ;-)

As I said in my first post; the aux water pump is working just fine, it
just had a small leak from the black plastic housing. I removed the
unit, cleaned it, put in a new rubber gasket, sealed it back up,
lok-tightend all of the screws, and re-installed. I've now driven the
car for a little over 180 miles in stop & go traffic (w/heater on just
to be sure), and haven't lost a drop of coolant since.

Total time to repair: approx 30 min, total cost: $2.60 for 24" of spare
heater hose to put in the trunk for by-passing the pump later on -- just
in case I'm not as smart as I think I am.

So, call me what you want, but sometimes it pays to be a "really cheap
bastard"...

I did take it to a repair shop a few years ago. They never found it and
offered to replace the whole instrument cluster for tons of money. So I
guess you are right, I am a cheap bastard too But seriously, for 91
bucks Fix it yourself the right way.
KH

"glgxg" <com.invalid> wrote in message
news:supernews.com... 
and 

Kevin in San Diego wrote:
 

Sometimes I wonder if fixing something the "right way" (to remove &
replace with a brand new part) is really necessary -- I suppose time
will tell if the unit continues to work properly & w/out leaking in the
miles to come, or craps out. But if it does crap out sometime down the
road, then I now know enough about what the unit does (and does not do)
and can safely bypass the temporarily if necessary until I can replace
with a new part.

In my case, it appears that 97K miles of road vibration may have just
loosened the casing screws and allowed the unit to leak from the plastic
propeller housing. The two screws at the base of the metal housing were
loose, allowing the top portion of the unit to move just slightly. The
screws at the top of the black plastic housing for the pump propeller
(the coolant chamber?) where the hoses connect were slightly loose as
well. I only replaced the rubber gasket in the coolant chamber housing
as a precaution -- the original wasn't cracked, broken, or dry -- and
used one that fit perfectly from a grab bag that I had on hand.

Upon closer inspection of the unit, it seems to me that the unit is
nothing more than an afterthought add-on part from MBZ -- it's not even
a real pump actually; it's simply a 12V activated type of device that
turns a propeller in the unit's fluid chamber to assist in pushing
coolant up into the heater core while the car is at idle. I suppose that
there is a reason MBZ added the part (perhaps poor engineering on the
190E 2.6 to begin with, customer complaints that the cabin heating
wasn't fast enough or staying hot at idle, or a deal with Bosch & MBZ
manufacturing), but the whole unit seems to me to be like a gall bladder
-- it's ok to leave it in as long as it's working and not leaking or
causing harm, but also ok to cut it out and forget about it if necessary.

For now the $91 - $130 (or $109 per Ron w/German Star -- thanks Ron for
the info & link, nice site) can be used elsewhere.

Perhaps now someone with a similar aux water pump leak problem might be
inclined to take a closer look at their unit to see if the unit leak can
be repaired individually by simply cleaning and tightening the
screws/seals on the unit, or if the unit really needs to be replaced
outright.

Interestingly enough, my brand new bosch one (14 months old) was still
working without a leak but decided to intermittently draw too many amps and
cause my entire climate control system to shut down. It was a nightmare to
troubleshoot and the only way to fix it this time was to just replace it.
This time with an aftermarket one that is probably better lol. the original
one failed by leaking the replacement failed by shorting internally or
something. What a piece of crap.
KH

"glgxg" <com.invalid> wrote in message
news:supernews.com...