Water Pump and Thermostat Replacement

[nswillin]

Hey everybody,
I am currently replacing the waterpump and Tstat in my 2006 325i. I am almost finished except for a few things.

The two hoses that go to the Tstat with the clips on them, I cannot get these back on to save my life. They are the only two I cant get on right now.

Also, the electrical plug that goes into the water pump does not want to go on all the way. The plug looks fine. Shouldn't it just clip back on easily?

I finally gave up for tonight because I was getting frustrated. Any tips on these things?

Thanks

[huntermanmt]

the front two hoses take some finesse. I tried many times before I got them locked in. Just try and keep pushing and wiggling them in as far as they can go and get them right over the grooves so the jubilee clip slides in and locks. It's a PITA I was about to give up but I just kept trying. Be sure to double check that they are locked in solid otherwise they will pop off and you lose all your coolant driving down the road. It happened to me.

[White94RX]

Spray the thermostat with some WD-40 or some silicone lube and they'll slide right on and lock in.

As far as the electrical connector, I've never had one not slide right on and lock in place.

[floydr]

Hey everybody,
I am currently replacing the waterpump and Tstat in my 2006 325i.

I'm curious on why you're replacing them. Did the water pump fail or are you replacing them for preventative purposes? The parts are around $500, aren't they?

[90turbo1]

Spray the thermostat with some WD-40 or some silicone lube and they'll slide right on and lock in.

As far as the electrical connector, I've never had one not slide right on and lock in place.


the electrical connector has a rubber seal inside it, spray it with some lube (wd40 eats rubber) so use silicone but dont spray the pins in the connector, use the straw thing. same for the coolant hoses, spray the plastic connector on the t-stat and spray the oring in the hose and it will slide on like butter. REMBER those hoses have a locating slot on them if for some reason the hose is not lined up it will not push on.

[02325]

I'm curious on why you're replacing them. Did the water pump fail or are you replacing them for preventative purposes? The parts are around $500, aren't they?


most dont last much past 75k miles.

[floydr]

most dont last much past 75k miles.

I very much doubt that that is true.
1) On my '01 330xi, the original was still there at 145K when I traded it.
2) The N-series of engines have a radically different water pump than the M54 engines which you have in your 2002 325i, and I had in my 330xi.
3) The ECUs for the E9x N-engines go into limp mode if the cooling system fails, unlike the E46, to help save the engine.

It's a lot different, replacing a pump and thermostat on an M54 for about $200 parts, than replacing a perfectly fine water pump that costs $600 parts.

[nswillin]

Thanks for the replies everybody. I went back out today and popped both hoses on on like 10 mins. I guess last night I was just tired and frustrated.

I'm still worried about the connector going to the water pump though. I got it to go on there pretty good but I still don't think it clicked in all the way. I'll try to lube thing tomorrow.

Also, I bought a new temp sensor but could not get the old one out. I can get the top wire clip off but the senor will not budge to come out.

To the person who asked why I am doing this. My water pump failed so I replaced it and the T stat.

[floydr]

To the person who asked why I am doing this. My water pump failed so I replaced it and the T stat.

Thanks. Thought it would be that. How many miles?

[White94RX]

I very much doubt that that is true.
1) On my '01 330xi, the original was still there at 145K when I traded it.
2) The N-series of engines have a radically different water pump than the M54 engines which you have in your 2002 325i, and I had in my 330xi.
3) The ECUs for the E9x N-engines go into limp mode if the cooling system fails, unlike the E46, to help save the engine.

It's a lot different, replacing a pump and thermostat on an M54 for about $200 parts, than replacing a perfectly fine water pump that costs $600 parts.


Actually it is VERY true. The electric water pump basically can fail at any time. It's very different from a mechanical pump that will usually only fail when the bearings wear out. I have replaced them as early as 35k, and as late as 100k. I replaced the one on my E60 at 118k. It didn't completely fail, but I started getting "speed deviation" fault codes, and I knew it was on it's way out. I have replaced TONS of them between 60-80k. That's probably the average mileage.

[floydr]

Actually it is VERY true. The electric water pump basically can fail at any time. It's very different from a mechanical pump that will usually only fail when the bearings wear out. I have replaced them as early as 35k, and as late as 100k. I replaced the one on my E60 at 118k. It didn't completely fail, but I started getting "speed deviation" fault codes, and I knew it was on it's way out. I have replaced TONS of them between 60-80k. That's probably the average mileage.

Interesting datapoint. What percentage of cars have they failed on?

[90turbo1]

I would say we have a 25 percent failure rate on those suckers here. that being said for 100 cars we sold we probably seen 25 back for a water pump replacement. It is less on the 335's because they have different water pumps that seem more robust. but yeah they are failing.

if you have a lift they really are not hard to put in. on a jack and drive way i feel for ya.

[02325]

I very much doubt that that is true.
1) On my '01 330xi, the original was still there at 145K when I traded it.
2) The N-series of engines have a radically different water pump than the M54 engines which you have in your 2002 325i, and I had in my 330xi.
3) The ECUs for the E9x N-engines go into limp mode if the cooling system fails, unlike the E46, to help save the engine.

It's a lot different, replacing a pump and thermostat on an M54 for about $200 parts, than replacing a perfectly fine water pump that costs $600 parts.


And i worked for BMW for 8.5 yrs as a tech and replaced many pumps and t-stats on the N-engine. So i know. I ahve seen M54 pumps go 200k miles. I have never seen a N-eng pump go 200k miles. Just saying.

[mryakan]

And i worked for BMW for 8.5 yrs as a tech and replaced many pumps and t-stats on the N-engine. So i know. I ahve seen M54 pumps go 200k miles. I have never seen a N-eng pump go 200k miles. Just saying.
How may cars with the Nxx engine have you serviced that have 200K? Don't most people typically do repairs outside the dealer when the miles hit above 100K! I would guess it would be hard for a dealer to estimate failures for cars not serviced by them.

[White94RX]

Interesting datapoint. What percentage of cars have they failed on?


That's really hard to say actually. So many of the cars we never see again when they're out of warranty. But if a car has CPO up to 100k, there's a good chance we will put a water pump on it before the warranty is up.

I would say that 100% of cars will need the electric water pump replaced at some point. I really don't think I've ever seen an original go past 120k, but I'm sure they may be out there.

[Awayne123]

My 06 325i just hit 127,000 miles and the pump finally went out. I guess I am lucky that it lasted so long I was just unaware that they are a known problem. The thermostat from the dealer was 126 with a discount 150 regular price, water pump 426 with discount 480 regular, and 2 gallons of coolant for 40 with discount 55 regular. I took the parts to a mechanic thats a buddy of mine and he charged me for 2.5 hours of labor, he said it normally would of been about 4.5 hours of labor. That cost me 250.00 so in all with a hook up I spent around 800

[SunzOut]

Just replaced the pump on my 335xi - really was a pain. The On-line DIY's I foudn are non-turbo and or 2 wheel drive. There was a lot more in the way on the 335xi to get the pump and thermostat. Did it on Axel stands, remove the metal sump guard, the pastic under tray. The small metal shield over the drive shaft as well. just woked my way around each of the clips and disconnected.

Helped to disconnect the line at the base of the expansion tank to allow me to pull some of the lines out of the way. Also had several extra line and brackets to remove before I could even drop the sway bar.

Overall about 5 or 6 hours. Going back together was a lot easier.