[brad s1]

2007 supercharged USA

drivers side I see it dripping off the drive shaft boot, it blew quite a bit out. From the top of the car the heads look good and see no evidence of where it could be coming from... it seems to be dripping from around the area or just below the ABS module. Any ideas? Hoses in that area or components I should checkout? Coolant looks clean

TIA

 

[brad s1]

I took the air box etc out, not an easy to spot leak... Finally found it, multiplug fit to this thing, seems to leak from the body... auxiliary water pump? What the hell?!?!?!? Anyone deal with this bit before? I'm about to try to pull it, not alot of room to deal with the quick connect hoses on it... seems it comes apart, maybe I can throw another gasket in it before ordering a replacement.

 

[brad s1]

So believe this is the issue (aux water pump widely available)

I found the bottom of this pump to be wet... It's sort of a pain to remove, located below the abs valve block and behind a heat shield under a bunch of hoses between the inner wheel well and the engines valve cover. It has those horrific BMW quick release hoses which are not easy to remove given the limited access. It's also held in there with a rubber grommet fit onto the car by a torx screw. I cut the hoses off to expedite removal, figured it only makes sense to replace the hoses while it's all apart so no harm. Upon pressure testing the pump I found the outlet of the pump where it meets the body to be hair line cracked so I'm confident this is the issue. The other ends of the hoses are clamped on, so they're easily enough removed from the car side of things. Seem this is most likely the leak, especially since I did find damage, unless I did that during removal. What a stupid thing this is... why wouldn't the hose feeding this pump just feed the heater core? LOL

 

[brad s1]

this is how it failed

I broke the barb off and you can see the plastic has degraded

 

[03rangiemark]

Hey Brad-
I saw those on Rock Auto when I was poking around for prospective parts availability for prospective new-to-me RRs.
I was wondering what that pump was for.
Prices don't look too bad for a Gates anyway.
The also have a GMB (not familiar with them) for like $340.
Big price range.

 

[03rangiemark]

It seems to me that any plastic out of Europe has shorter life than U.S.-made plastics, maybe environmental laws and limitations.

 

[brad s1]

I replaced with gates... hopefully this area doesn't become an issue again because without removing additional heater core parts it's a really annoying area of the car to work on.

 

[MarkinMaine]

The pump is necessary to helps push coolant thru the the heater core at idle/low rpm to maintain heat at very cold ambient temps like we have in Northern USA.

 

[brad s1]

The pump is necessary to helps push coolant thru the the heater core at idle/low rpm to maintain heat at very cold ambient temps like we have in Northern USA.

Yeah... BMW over engineering. haha

 

[MarkinMaine]

Many mfg's use this pump system, especially with big aluminum V8's. My Jag SV8 has it too. Usually the brushes go before they leak. My Jag and l322 are Ford era.

 

[brad s1]

Many mfg's use this pump system, especially with big aluminum V8's. My Jag SV8 has it too.

Yeah, I realize that. We got along just fine before with just a line splicing off the coolant pump circulating straight to the heater core and back for decades upon decades though. On cold start the main pump would circulate coolant around the engine and heater core until up to temp, then the t-stat would open and loop in the radiator. Size of the engine has no baring on this. I get the logic of why it's there (mainly to account for over complicated coolant routing) but really it's unnecessary. I also tested the pump itself and it wouldn't run, whether that had to do with the way it cracked I still had plenty of heat despite the pump serving as just a coolant path vs a coolant driver. I'd be willing to bet had I just cut both ends of the quick connect hoses off and spliced them together deleting the pump I'd never notice a difference short of maybe a background trouble code. Seems like where the heater core loop is there probably isn't a lot of pressure which is why they run this pump. Over engineering at it's finest. Why route some hoses efficiently when you can create a rats next of hose PLUS a pump. Haha

If anything it's probably to accommodate the large cabin heating/over-sized core, tho again... I hadn't noticed an issue with the pump not working. either way new pump fit and it's at least not leaking now.