Bypass aux water pump- anyone have pics?

[EricV]

Hi guys. Over the weekend my aux water pump went out ('93 525 M50 vanos engine) and apparently the heater valve as well (I hear that often causes the pump to go south.) I usually use a shop an hour away in Richmond VA who I trust, but had to get it to the nearest shop here in Charlottesville.

The shop it's at wants 690 for the job....seems way high. My shop in R'mond wants 520...much better. The thing is, the tow alone eats up the savings.

I am thinking of bypassing it as I hear that works fine, but can't find very detailed instructions. Anyone have very detailed instructions? Ideally I'd love pics. As far as I can tell (from my roadside at a glance in the rain when this happened) is that there are 3 coolant hoses below the pump...not sure which to splice together.

Thanks!

Eric

[Tiger]

Why are you paying someone $400 to remove two clamps and an electrical plug to replace your aux electric water pump? It is so easy to change yourself.

[EricV]

Um, that's what I am trying to avoid.

As it stands now the car is stranded at the shop, so that's the pickle I am in. I am trying to get some detailed instructions on how to do a bypass (for now) and then I'll do the job myself later.

Thanks though.

[Tiger]

There is only two hoses... and you can pick up a splice connector at any auto parts store... pull the two hoses together into the splice and clamp it down.

[EricV]

Does the heater valve usually crap out w/ it? This shop is saying that's toast, which adds another 200 or so making my total 690...

Thanks!

[EricV]

Thanks fella- I do appreciate it. What about the heater valve...does it make sense that that would have crapped out? That's another 200 or so (of the 690) right there....

[Tiger]

Look, you got to do diagnostic first okay? Heater valve rarely crap out. If you don't have proper coolant flowing to the heater valves, then you are not going to get heat.

Find the leak first and fix it.

[EricV]

All reasonable. Here's the update:

I called the shop and they said "well, we really recommended the heater valve as a preventative thing, we'll do the pump for 390." Well, that kind of blew it for me- I'll do the bypass after work and order the pump from BMA (Patrick has always been great....and am assuming he still is. :)

SO (last Q, I promise) when I pull the aux pump to remove it and connect the two hoses, is the heater valve a part of that aux pump assembly- i.e. what should I be mindful/careful of?

Huge thanks guys, this place is the best.

[Tiger]

It is separate... just look at the BMA picture of that pump and you will understand what I am talking about.

[EricV]

Whew- glad you're out there...

In looking at it on the car the other day I was looking right at the heater valve thinking that was the aux pump...it's obviously not. I now see the pump is a bottle shaped thingy which I am assuming will be underneath the heater valve and that the heater valve must be dismounted first (though not disconnected necessarily) to get to it.

Sincere thanks fella. I know us novices can be annoying.

[632 Regal]

aux heater pump and valve comes as a single unit and is around 100 new. Just plug all 3 hoses and drive it where you can work on it. 690... sheesh my god there is NO WAY I would pay anything close to that. part # 64118391417
http://www.realoem.com/bmw/diagrams/e/d/17.png

[EricV]

Huge thanks! OK, don't shoot me here, but in looking at that diagram it appears to me the following:

1.) the aux pump I am after is #1, with two hoses on it.
2.) the heater valve is #15, w/ 3 hoses on it.

I thought my goal was to leave the heater valve on, and remove the aux pump (#1) and just connect those 2 aux pump coolant hoses together.

If the heater valve also comes off then I have 5 hoses and God knows what I connect to what then. :)

My real goal is to bypass the aux pump only so that I can drive it a few days (short distances, to get through the week until the parts come and until I can do the replacement over the weekend.)

[Rus]

Connect hose 3 to hose 23. That's it.

[EricV]

Connecting 3 to 2 wouldn't do it? Seems simpler. If 3 to 23 then that would in fact require a T connector.

Sorry guys- didn't realize this would get confusing.

[Rus]

No, plugging 3 and 23 won't require a T-connector.
Hose functions are as follows:
3 - Main coolant delivery hose to auxilary pump
2 - Hose connecting auxilary pump to distribution valve unit
21 - Right heater core coolant supply from valve
22 - Left heater core coolant supply from valve
23 - Unified coolant return hose for both cores.

Connecting 3 to 23 will make coolant completely bypass the auxilary pump and the valve unit. Connecting hose 3 to spigot for hose 2 on the valve unit or to hose 2 where it is disconnected on the pump end will bypass the pump. You can do it either way. HTH

[EricV]

Good deal. It sounds like the less fussy route may indeed be to connect 2 to 3 then and hope that gets me through the week. I only have to drive about 2 miles each way (to pick up my daughter after school) so I may be able to limp through the week this way.

I really appreciate the time you guys have taken.

[Rus]

No problem. I could take pics, but all my hoses are connected in a stock configuration so I doubt it'd help too much. What does help is popping off the plastic cover on the valve unit and looking at the hoses. The clips holding the cover can be rather stiff, so be careful if you decide to pull it off.

[bubba966]

Someone correct me if I'm wrong, but the Aux. pump is only to keep the coolant circulating when the car is shut off. Like if you're running the vent feature or just running the fan with the engine off.

Bypassing the aux. pump should then be of absolutely no problem at all to driving the car normally. Only reason the dead aux. pump is giving you a problem is because it's seized up and preventing any coolant to flow through. Bypass it though and that's no longer a problem. Only problem should then be lack of heat after a short while once the engine is turned off.

[Rus]

Actually, I believe the purpose of the pump is to improve the circulation of warm coolant from the thermostat housing to the heater. I also read somewhere that it helps warm up the interior quicker. Some e34 models did not have the pump and still worked fine, so its not an absolute necessity.

[russiankid]

Hose number 2 is actually in the shape of a U but with a slight angle. It would be tough to connect hose number 3 to it.

[EricV]

Well, after all my obsessing earlier (and I thank you for your patience for that...time was of the essence as I can't be car-less, single father and all...) I went to pick the car up and they'd done the bypass for me.

Now I'm not exactly jumping for joy as I am fearful of how tight the bypass is (as this place did, after all, start w/ a quote of 907, revised that to 690, and then went to 390 and change after I questioned the need to also do the heather valve.) The guy tried to explain the routing, but I never got a close enough look at the stock configuration to begin with- so it may be a bit of a challenge straightening this out myself, though the diagrams should get me through.

Now truth be told I only have a very short drive most days for my little one, and outside of that I don't drive it nearly as much as I used to (since moving to a place two blocks from my office.) I may bump along and see how it goes as it is. On my 4 mile round trip (some through town) the temp needle stayed steady and the heat worked fine...other than my paranoia about it leaking someplace the car worked as it should, drove just fine.

I wish it was hard to believe this BMW shop would have gladly soaked me for 907 had I not questioned them (and then, when they waffled, I simply pulled the plug.) So again thanks guys...I was worried about trying to get this worked out cost effectively, busy w/ work, etc. He*l of a day and w/out your guidance I'd have been scrambling to find the info to make informed choices. I'm sure I'll be back to pick your brains when I do the rest of the job.

It's tough- I like this car (I've had it 8 years, it now has 116K on it) but it's getting old. Overall it's been very reliable, but I have had to replace the transmission, the radiator 3 times, various smaller issues, and some niggling gremlins (actuators rightfully doing their safety thing when they go bad and unlocking the whole car, door panels starting to come loose, headliner starting to sag, and stuff like that.) It's been maintained very well though, and it still looks like new. I'm torn on selling it for a younger car.

Sorry to go long, thanks again.

Eric

[632 Regal]

Eric,

What did you take the car in for in the first place, the heater valve? Sorry if I didn't see it but i re-read and didnt see whats up besides aux water pump... SO bear with my stupidity here for a moment as I may just be reading too far into this.

You took the car in for Aux pump...why? Besides lower heat at an idle this is no reason for great concern unless sub zero temps with the little one in there.

You took the car in for a "leaking" aux water pump which happened to me luckily 2 miles away from home in which I would not have been able to drive the car without a bypass.

In either case even emergency situation 900 or 600 or even 300 is quite a lot in my eyes. I want to understand this as I am quite anal at times... at other times I can be a total prick and ban people for no obvious reason lol. :D

[632 Regal]

Wow mine has 215K and a long way to go before I consider it old and used up except a small spot of surface rust.
I've had it 8 years, it now has 116K on it) but it's getting old.

Eric

[Black540]

I cant believe they tried to rape you for 690. I just did this repair myself...took all in 10 minutes, and cost me $30 for the pump.

[Ross]

"well, we really recommended the heater valve as a preventative thing,
Translation: Umm, usually since we have to remove both parts to replace one we attempt to (over)charge you for both parts also.
An engine overhaul or a complete set of dentures would be a "preventative thing" too.
Glad to hear they didn't get you.

[EricV]

Hey there. I don't mind clarifying at all as it helps everyone. It must be said that I went to this local "BMW Psecialist shop" only because it was in limping distance of where this happened. I usually use this fantastic and trustworthy shop an hour away. Anyway, what happened....

I was driving back into town from the country and all of a sudden whiffed coolant. Thought "uh oh" and looked at the temp needle, which was just beginning to touch the start of the red section. Pulled over immediately (in the rain, of course) and popped the hood. Plumes of steam coming from under the heater valve, so I knew it was likely to be the aux pump or (hopefully) a split hose in that area. It still had coolant in the tank, so I let the engine cool and then shot on up the hill to the crest (about 1/4 mile) and coasted down the other side (at the base of the small mountain is this shop...thought I was lucky then. :) )

First they call late Mon morning to say 907 for new aux pump, heater valve, and replacement of frozen sway bar links. I told them let's take the links off the table straightaway as I had all suspension and components replaced a few thousand ago, so I'd investigate that another time. That took us to 690. You guys schooled me from there, so I called and pressed on the heater valve issue- they then said "oh, well, we really recommend that as a preventive measure." I said "so it's not shot, as you stated earlier?" "Well, we didn't exactly say it was shot." Yeah.... Anyway, during that convo they said "OK, we'll do the pump for 390." I politely said the whole thing hadn't inspired confidence and that I wanted to pick it up after work- so I did (and paid the 75 bucks to get it back...awesome. I'd have given the customer a "break" after getting caught trying to soak 'em to minimize bad press, but oh well.)

So that was it- a spewing coolant leak from the aux pump.

215K is impressive- glad to hear you're having a good run w/ yours. Mine hasn't been bad, mind you, but I am finding that it's having things go wrong w/ great frequency (and great cost- a manual transmission giving up at 108K is unacceptable, IMO, but I now know this box is known for that.) Of course it is getting old and these things are to be expected, I do get that (have always had older cars.) Though an entirely diff beast my 93 Civic has 165K on it and has had virtually no repairs- even has the original clutch. It's now sidelined w/ a bad axle/CV joint, but at 165K I sure can't complain. No matter- again they are diff beasts altogether.

Thanks again guys-

Eric

[E34-520iSE]

Here in the UK a lot of E34's were not fitted with the aux coolant pump as standard and have ran fine for tens of thousands of miles......

HTH,

Shaun M

[russiankid]

Here in the UK a lot of E34's were not fitted with the aux coolant pump as standard and have ran fine for tens of thousands of miles......

HTH,

Shaun M

They will run fine, you will just lack the extra coolant circulation through the heater core.

[caqueenslace]

Hi, ours is leaking coolant, so why would we connect 21 and 22 to and connect to 3 and leave 23 along?
Also if we do this by pass is there still risk of it leaking??

[mikell]

Wow mine has 215K and a long way to go before I consider it old and used up except a small spot of surface rust.

Mine's now at 270k miles and I have no plans for getting rid of it.
Maintenance is required, of course - we all hate paying for replacements, but the cost of that beats the hell out of monthly car payments.
The only non-routine wear part I have replaced more than one time (so far) is the fuel filler door hinge.
I love my E34.