[Blue Streak]

Originally Posted by hassmaschine

I don't think you can replace aluminum bolts with steel. They are still aluminum.

BMW has replaced (or upgraded) the water pump twice since my car was manufactured. The previous versions did require the use of aluminum bolts. The latest part number for the pump is 11 51 7 632 426. It is designed to be used with steel bolts, which are shorter because there aren't rubber grommets like in the previous part. The part number for the bolts is 11 51 7 602 123. I don't know why they use so many aluminum bolts on our cars anyway.

[hassmaschine]

That part number is aluminum, not steel.

The bolts are aluminum for two resons - weight, and the block is magnesium. Steel causes galvanic corrosion. The waterpump has nothing to do with it.

[Blue Streak]

The block on the N54 isn't magnesium though. The N52 and N55 are. N54 is aluminum with cast iron cylinder liners. I torqued the bolts down to specs, but I don't think it's going to do any damage. Making the car more light weight with some fairly small aluminum bolts is kind of silly though.

[hassmaschine]

Well, you posted in the N52 section, so i assumed. That part # is still aluminum though.

You'd be surprised how much it adds up, plus the E9x is a heavy pig of a car, it needs all the help it can get!

[Blue Streak]

Oh, I dint notice this was in the N52 section. I had so many tabs open that I was using for my research and DIY guides. Lol! I'm glad it all worked out though. I remember reading they had switched to using steel bolts there... I bought my parts from my local dealership parts store and they said that's what they have switched to for water pumps. I bet they do a lot of water pump replacements... Although I do know that the aluminum bolts are about 3 times the cost of the steel ones.

Another reason it would be nice to have an N52 instead of N54/55 is draining the coolant completely and from the bottom of the radiator wouldn't be such a pain in the ass... by removing the intercooler to get to it.

[Three_thirty_I]

Originally Posted by hassmaschine

That part number is aluminum, not steel.

The bolts are aluminum for two resons - weight, and the block is magnesium. Steel causes galvanic corrosion. The waterpump has nothing to do with it.

Yep, everything attached to the engine block has to be secured with aluminium bolts to prevent corrosion. But I often think about this, surely there are iron or steel materials as part of the construction of items that are attached to the engine block, so makes you sort of doubt or question this. At the end of the day, I won't risk it, I would just use the aluminium bolts and trust that it is for a good reason!

[hassmaschine]

I'm pretty sure there aren't any steel parts touching magnesium. steel touching aluminum is fine though, so there are some steel bolts on the head etc.

I've been looking around for some sort of thread inserts that could be used with steel bolts/magnesium but I haven't really found anything. I think it would have to be a plastic insulator material, and very hard - maybe UHMW. I doubt anyone makes thread inserts out of materials like that though.

[Three_thirty_I]

Originally Posted by hassmaschine

I'm pretty sure there aren't any steel parts touching magnesium. steel touching aluminum is fine though, so there are some steel bolts on the head etc.

I've been looking around for some sort of thread inserts that could be used with steel bolts/magnesium but I haven't really found anything. I think it would have to be a plastic insulator material, and very hard - maybe UHMW. I doubt anyone makes thread inserts out of materials like that though.

If I understand correctly, the block is magnesium and the head is aluminium? So it's then mostly the block that has to be carefully treated and no steel makes contact with it? For example, the Vanos solenoids have bolts that I am not sure are aluminium or steel, but the bracket that clamps the solenoid against the head is most certainly normal tin and not aluminium, but that's again mounted to the head, not the block.

[hassmaschine]

the outside of the block is magnesium. the inside is aluminum - it's a composite block. the head is aluminum.

[Three_thirty_I]

Originally Posted by hassmaschine

the outside of the block is magnesium. the inside is aluminum - it's a composite block. the head is aluminum.

That's right, forgot about that. Trust BMW to come up with something like this... Then the head gasket has to carefully separate/insulate the head from the block from what I have read and seen. Anyway, they tried to reinvent the wheel with this engine!

[Reesurfn.330i]

Just to fill you guys in on my situation. I had my local indy shop replace the water pump and thermo for $875

[PureE92]

Well I got a stuck open thermostat sigh. Going to ride it until the waterpump fails I guess.

[BeeMuh]

FBO 73k failed today. Romped it hard on the freeway and got an amber water temp icon then red then coasted to the shoulder of the freeway. I should've stepped out and have someone just rear end the shit out of my car so I can get a new car lol. Anyways, started up after 20 minute cool down and pulled into an indy shop. Quoted 750-800. Merry Xmas to me.

[areone]

I called fremont BMW and mountain view BMW in San Francisco Bay Area, both quoted $1700 for water pump replacement and an additional $800 for thermostat. That is just insane. I'm going to look for reputable indy shop in the area.

[Eagle1oh7]

Originally Posted by areone

I called fremont BMW and mountain view BMW in San Francisco Bay Area, both quoted $1700 for water pump replacement and an additional $800 for thermostat. That is just insane. I'm going to look for reputable indy shop in the area.

[Sydasupafly]

Originally Posted by Cir14

My 2 cents / recent experience:
2007 328xi
~76,000 miles
Coolant light appeared a few months ago causing me to check the coolant reservoir which very low, well duh the light came on. Took it to the dealer and they topped it off no problem. I had a feeling that the water pump was approaching the end of its life.

Fast forward ~3 months, Friday 6:00PM, very congested area in rush hour Friday traffic. Yellow coolant, immediately following by a Red warning light then limp mode. Managed to get it into a nearby strip mall, don’t ask me how but it wouldn’t go above ~1-2K RPM's. It’s a manual transmission so after trying to start it (even though you're not supposed to) it would stall (1st restart). Waited a minute or two (freaking out the entire time) then started again revved it to like 2K and it moved <5mph off the road.

Got it towed to dealer, fixed for $53 under certified pre-owner warranty. They said that it would have been ~$1,100 to repair had it not been covered under the CPO.

OMG the exact same thing happen. Coolant light came on like about a month ago. Topped it off then today lo and behold water pump went out and car lost power

[Leo_e93]

That happened to me when I just got my 335. You will need to change the water pump and thermostat. It cost me about $600

[John 070]

Originally Posted by areone

I called fremont BMW and mountain view BMW in San Francisco Bay Area, both quoted $1700 for water pump replacement and an additional $800 for thermostat. That is just insane. I'm going to look for reputable indy shop in the area.

Wonder how they arrived at this figure, even if you add up the list prices of the components.....coolant, pump, thermostat, bolts....I think you're in the $745.93 territory. So they want about $1,754.07 labor? I don't think this number can be right, OR, this dealer charges over list for parts (that does exist)....

[justpete]

Originally Posted by John 070

Wonder how they arrived at this figure, even if you add up the list prices of the components.....coolant, pump, thermostat, bolts....I think you're in the $745.93 territory. So they want about $1,754.07 labor? I don't think this number can be right, OR, this dealer charges over list for parts (that does exist)....

Sounds like 5.5-6 book hours, plus fees.

[Verte335i]

2008 335i with oil cooler, manual transmission. Radiator fans were running like crazy. Took it to Bert's in Santa Ana, CA. Cost me $941 for water pump only. It worries me a bit that he didn't replace the thermostat since after the work was done I researched that the water pump comes off then the thermostat. Other repairs: high pressure fuel pump (three times); low pressure fuel sensor; oil filter housing gasket. I am original owner and baby the car. What's next?

[F22_Raptor]

Well my fan is running pretty. loud all the time. Im gonna buy the N52 waterpump kit from eEuroparts.
https://www.eeuroparts.com/Parts/685...FRSPfgodi7cIuQ

I'm also gonna replace the OFHG while im at it.
$430 for parts. Im gonna hit up my local mechanic and see how much he will charge me in labor.

[GoRomeo]

Originally Posted by F22_Raptor

Well my fan is running pretty. loud all the time. Im gonna buy the N52 waterpump kit from eEuroparts.
https://www.eeuroparts.com/Parts/685...FRSPfgodi7cIuQ

I'm also gonna replace the OFHG while im at it.
$430 for parts. Im gonna hit up my local mechanic and see how much he will charge me in labor.

Thats a reasonable price for parts. how many miles?

Hope you get a good price for labor...