95 E300D heater flow valve and heater water pump - PeachParts Mercedes-Benz Forum

Texasgeezer · #1 02-13-2018, 12:38 AM

I've read a few other threads about this combo unit that seems to be unique for just a few years.

Most threads said it is not surprising for the plastic housing to crack and seep water.

Some threads said it was rebuildable, but in my searching I haven't found a repair kit.

As others have mentioned the new part goes from $500 to much higher.

Question:
Does anyone know what site might have a kit to rebuild.

Howto thread:

https://www.pelicanparts.com/techarticles/Mercedes-W124/15-WATER-Heater_Valve_Replacement/15-WATER-Heater_Valve_Replacement.htm

Part # I believe is: A0018304084

This seller on ebay has a new one for about $800 and a repair of your valve for $90.

https://www.ebay.com/itm/REPAIR-SERVICE-Mercedes-W124-1995-E300D-Diesel-Heater-valve-Monovalve/192438417778?epid=1422250545&hash=item2cce393972:g:y3MAAOSwImRYWPgi&vxp=mtr

oilslick · #2 02-13-2018, 06:45 AM

I’m gonna be watching this thread. I have a ‘93 300D with the same heater valve. This past summer I was clamping off hoses to keep the hot water from flowing. During the winter I have plenty of unregulated heat. I would LOVE to find some type of rebuild kit. I also own a ‘95 E300 with the same heater valve...but it works well.

Texasgeezer · #3 02-13-2018, 07:02 PM

Just adding picture of my W124 1995 E300D heater flow valve and pump assembly. I've about given up on finding a rebuild kit but plan to keep looking.
Will also try to contact person on ebay that says he will rebuild them.

Scary even to order a new one, one poster said he went through about 4 new ones from Mercedes that developed leaks during warranty.

I did find a few kits for Mercedes heater flow valves on ebay europe from the Ukraine. Haven't determined if any fit.

KrustyKustom · #4 02-13-2018, 10:35 PM

In this same discussion I want to replace those behind the firewall heater hoses but cannot find part numbers in the EPC. I wonder if that heater pump and valve shares part numbers with any other models?

Mine is a 95, just about to roll 300k, runs like new but all the old fittings make me nervous. My mono valve looks like a type of resin or even bake light?

Maxbumpo · #5 02-14-2018, 04:11 PM

Subscribed. My '95 E300 is fine, but my '87 300TD may have a faulty monovalve. It looks as if the monovalve / pump from 124 cars with the OM602 engine can be modified to fit into the E300, probably at a significant cost savings, but there is no kit for rebuilding the internals of the monovalve part that I am aware of. Would be nice to find one for my '87 wagon.

torsionbar · #6 02-14-2018, 08:15 PM

Quote:

Originally Posted by Texasgeezer

Just adding picture of my W124 1995 E300D heater flow valve and pump assembly.

Looks like you're missing the rubber seal strip that goes along the top of the metal engine bay partition.

Texasgeezer · #7 02-15-2018, 07:41 PM

I've pulled quite a few things off so I can replace a few things that might fail in the next couple of years. Today I finished cleaning my heater core & evaporator and taking an excessive time to put the plastic lower fan plenum back in place ( I tore it up during removal ).

On my monovalve & pump, it appears from my searching that Bosch used the same or similar solenoids & pumps for BMW's & other brands. Some sites list the rubber parts to fit some models of Mercedes plus BMW's. Most seem to come out of the Ukraine. I'll probably order one of those kits that contain two rubber diaphrams, seats, and brass flow plungers. If it fits then I would still have one set left over for the future. On the flow motor and solenoid, I plan to hook up a synchroscope to see if there is a straight 12 volts or if it fluctuates to get different flow volumes.

If it is a straight 12volts 'on', then there are quite a few 12v pumps that could be put in-line to get flow, some of those are brushless with a quoted 20-30,000 hour expected life.

sgnimj96 · #8 02-15-2018, 09:39 PM

this is the simplified solution for some w123 owners...
https://www.amazon.com/gp/offer-listing/B00MA9DQ50/ref=dp_olp_new_mbc?ie=UTF8&condition=new

oilslick · #9 02-16-2018, 02:15 PM

Quote:

Originally Posted by sgnimj96

this is the simplified solution for some w123 owners...
https://www.amazon.com/gp/offer-listing/B00MA9DQ50/ref=dp_olp_new_mbc?ie=UTF8&condition=new

It’s a three hose fitting job, IIRC.

Texasgeezer · #10 02-20-2018, 05:15 PM

I've exchanged msgs with two ebay sellers for monovalve components.

One offers repair service that turns out to be $99 for new valve parts installed. Extra charges if solenoid or motor is defective. If those are replaced they will be used parts.

Other seller has kits for valve parts. For my W124 E300D they are about $36. I've ordered that & should be here the 1st week of March. I'm still guessing one of the BMW dual valve kits would provide two repairs for about $8 more, but seller wouldn't answer question about diameters or applicability. I have found a few comments on the internet that a few of those for BMW's & other vehicles will work in Mercedes.

I also found comments that the MTD brand diaphragms failed because some were pinched when assembled new. Don't know if that is true or not.

I plan to take the motor off also for cleaning, lube, and brush replacement.

KrustyKustom · #11 02-20-2018, 10:06 PM

Keep us posted on this rebuild. As I mentioned earlier the body of the valve appears to be a bake light material which may be perilously brittle?

Did you happen to measure voltage on this yet?

carl177 · #12 02-21-2018, 11:06 AM

You may want to give this guy a shot, a few years back I purchased from him an intake maniforld switch over lever metal plate for an M272 and the product was top notch; The transaction went smoothly.

He also has a few other iteresting things up on his website.

Regards,

BENZ W124 E300 E420 E320CDI Heater control Valve Repair Kit-04 - Hong Mei Trading Co., Ltd

Texasgeezer · #13 06-26-2018, 03:25 PM

I was wondering when the motor was turned on by the controls so I Mickey Moused an led on the voltage plug.

It turns on immediately when the defrost button is pressed.

It turns on with a delay after the temperture dial is turned from blue to red & also the air flow inside switches from the dash vents to the windshield at what appears to be the same time the led light turns on.

The motor voltage does not seem to be applied ( led not lit ) if only in air conditioning mode.

I planned to put another L E D on the solenoid plug but didn't know which side was 12volt & didn't have a volt meter & also didn't want to short out anything with my flimsy connection method.

andrewjtx · #14 06-26-2018, 03:53 PM

I can't help with flow directions, but I can help with rebuilding the valve.

My electromagnetic plunger gave up a while back and was dumping hot water into the core 24/7. After going round & round with Bosch trying to get replacement parts, I finally found another Bosch valve that uses the same dual-cone plunger. Works perfectly.

P/N 1147412049

This won't help with the housing, but if you need just the coil & plunger setup with the seals, this new valve works perfectly.

andrewjtx · #15 06-26-2018, 03:55 PM

If you spent more time than I did, you could probably find a way to mount that housing and add in a boost water pump as well. Mine was working fine with no leaks though.