what is the purpose of aux water pump?is it to help cool engine or heat cabin? how do you know if its working?

From what I hear, it helps circulate coolant at idle so that you have heat. A lot of members on here find that it is somewhat useless, but I guess that's up to you.

Can't help you with the troubleshooting

__________________
Dan
2005 E320 CDI - 246k
1987 300SDL TD05-16g, Herlevi pump, Elbe manifold, 2.47 LSD - 213k
Past: 1987 300D - 264k

This link should have all the data you need.

Climate Control:
http://www.peachparts.com/shopforum/showthread.php?t=142408





Have a great day.

__________________
ASE Master Mechanic
asemastermechanic@juno.com

Prototype R&D/testing:
Thermal & Aerodynamic System Engineering (TASE) Senior vehicle instrumentation technician.
Noise Vibration and Harshness (NVH).
Dynamometer.
Heat exchanger durability.
HV-A/C Climate Control.
Vehicle build.
Fleet Durability
Technical Quality Auditor.
Automotive Technical Writer

1985 300SD
1983 300D
1984 190D
2003 Volvo V70
2002 Honda Civic

https://www.boldegoist.com/

it's used to keep circulating coolant through the heater core when the heat is on in the cabin. If you live in a more northern climate, You'll definitely know if it's not working while the car is idling and it's -35 outside.....

__________________
All it takes for evil to prevail is for good men to stand by and do nothing.

Too many people tip toe through life, never attempting or doing anything great, hoping to make it safely to death... Bob Proctor

'95 S320 LWB
'87 300SDL
'04 E500 wagon 4matic

'Burn out it's bearings and/or wear out it's brushes to be able to Pull more
Amps and burn out the CCU (Climate Control Unit) so the dealer can sell you
both!

UNLESS, You're savvy enough to install a 1 Amp inline fuse on the Aux pump's
Positive lead.(As close as possible to the Power Source.)

1 amp ATO/ATC fuse (BLADE TYPE)
Blue Sea Systems (In A "Package" of Two each.)
"Tin Plated Non-Corrosive Blades"
Blue Seas Part Number 5235
From West Marine (They'll probably have to Special Order them...3-4 days)
[Sorry I didn't save the receipt,So I don't have the WM part #]
(2) packs of fuses was about $5.00 USD

Inline type ATO/ATC fuse holder (Black Rubber with W.T. Cap)
ANCOR brand part # 607022
From the "soon-to-no-longer-be-in-business" Boater'sWorld
Two fuse holders $4.66 plus Taxation
[Whoa, these came from MARINCO their number 100208
(707) 226-9600 WWW.MARINCO.COM ]

Radio Shack part numbers for:

Inline Fuse Holder #270-1281 [$2.69 USD + Taxation]
(For Glass Buss type 1-1/4 X 1/4 ",rated 250VAC,10A fuses)

1/4 Amp,250 volt fuse #270-1002 (Pkg of Four) [$1.99USD + Taxation]

1 Amp,250 volt Fuse # 270-1005 (Pkg of Four)[$1.99USD + Taxation]

For connectors,
I really like ANCOR brand Heat Shrink,Adhesive Lined,Butt Connectors
(of the appropriate AWG gauge). 'Once your connectors have cooled,
a nice coating of Starbrite's Liquid Electrical Tape on the ends
(At the wires) provides An Obsessive's final Corrosion Protection.

1.I'm gonna start with an inline 1/4 Amp fuse for the Cabin Air Temp Sensor Fan.
('Cannot seem to find anything smaller ,Yet!)
2.1 Amp inline fuse on the positive side of the Auxiliary Water Pump.
(As close to the Power source as possible)(I'm gonna try a 3/4 amp inline first)
3.The Chassis was fitted with one of the Exterior (Of the Fuse-box) 30 Aluminum Strip Fuse holder for the Cabin Blower Fan.
[Anybody know if these fuses are Fast or Slow-Blow?]
(I think I'm gonna retrofit an ATO/ATC type fuse holder and go with a 25Amp fuse.)
(A healthy Blower Fan [Good Bearings and Brushes should draw less than 25 Amps.] )

The Auxiliary Electric Radiator Fans Relays, are another area of concern.
Even with the Aux Fans Resistor (Behind the LF headlight assembly)

The new K9 relay MB # 001 542 96 19 (Made in Hungary no Less!); I got
to replace the old one came with a Green 30 Amp ATO/ATC fuse installed.
In Reading K6JRF's "Page" http://www.k6jrf.com/MB_CTS.html
I note the Aux fans on HIGH will draw about 23 Amps.
So, I'm gonna swap the 30 Amp out for A 25 Amp.

The relay K10's High Power side is powered by fuse D in the fuse box
(16 Amps) AND K6JRF pegs Low fan operation @ 12.4 Amps...
Not much I can do there (Unless I can find a 13 Amp fuse to put inline
between Fuse D and K10...Too Much! I'll just have to trust the Resistor)

__________________
'84 300SD sold
124.128

Here is what COMPRESS IGNITE is talking about,

www.peachparts.com/shopforum/showthread.php?t=157591

www.peachparts.com/shopforum/showthread.php?t=241899

www.peachparts.com/shopforum/showthread.php?t=241913



I picked up a water proof fuse holder and 1 amp fuse at west marine.

Charlie

__________________
there were three HP ratings on the OM616...

1) Not much power
2) Even less power
3) Not nearly enough power!! 240D w/auto

Anyone that thinks a 240D is slow drives too fast.

80 240D Naturally Exasperated, 4-Spd 388k DD 150mph spedo 3:58 Diff

We are advised to NOT judge ALL Muslims by the actions of a few lunatics, but we are encouraged to judge ALL gun owners by the actions of a few lunatics. Funny how that works

These are fairly easy to "rebuid" When mine was locked up, I disassembled it and cleaned the hunk off, lubed with light grease, and put it back into service.

__________________
$60 OM617 Blank Exhaust Flanges
$110 OM606 Blank Exhaust Flanges
No merc at the moment

Thankfully the 86+ cars have short protection for this pump!

-Jason

__________________
1991 350SDL. 230,000 miles (new motor @ 150,000). Blown head gasket

Tesla Model 3. 205,000 miles. Been to 48 states!
Past: A fleet of VW TDIs.... including a V10,a Dieselgate Passat, and 2 ECOdiesels.
2014 Cadillac ELR
2013 Fiat 500E.