Expansion Tank From Dealer Leaking

[bkgreene39]

I recently installed a new expansion tank that I have purchased from the dealer. Looks like I don't have the greatest luck with parts. This new expansion tank is leaking currently, and not from the cap. I have checked the cap it's dry around that area.

I have my old expansion tank in the trunk just in case something like this would occur. Couple of strange questions I will be throwing out here so bear with me. Before this happened I slightly tightened the hose clamps on the lower hose. Would this affect anything pressure wise? The remaining parts that I have not changed in the cooling system are the water pump, fan clutch, expansion tank cap.

I installed this new expansion tank at the end of September, and I have reused the old cap from the previous expansion tank. But again it does not appear to be leaking from the cap area. All has been fine until Nov 3, yesterday. Would any remaining parts that I have not changed affect the expansion tank? Or is this just a defective tank? I have looked around the water pump, appears dry. I will switch to the old expansion tank and see if that one leaks, but it will take me a couple of days since I don't have the time to work on the vehicle at the moment. Thanks for any replies.

Perhaps it is the cap, i will change it then update.

[larrym3711]

It's a good bet that if you got the tank from the dealer and did NOT use a new cap, the problem is the cap seal with the old cap on the new cap. I would start with a new cap and seal before blaming the tank itself.

larrym3711
2001 540iA Sport

[TriniSpeC]

where did you buy it from? life quality? I hate their parts dept.

[bkgreene39]

where did you buy it from? life quality? I hate their parts dept.

Life quality. Hating in what way as in the parts are not sufficient? or the personnel is not too your liking? Because the individual that I have dealt with there twice was very nice and signed me up for 10% discount. Every penny counts.


It's a good bet that if you got the tank from the dealer and did NOT use a new cap, the problem is the cap seal with the old cap on the new cap. I would start with a new cap and seal before blaming the tank itself.

larrym3711
2001 540iA Sport

I will install a new cap to start with as I mentioned in the post.

[TriniSpeC]

Life quality. Hating in what way as in the parts are not sufficient? or the personnel is not too your liking? Because the individual that I have dealt with there twice was very nice and signed me up for 10% discount. Every penny counts.



I will install a new cap to start with as I mentioned in the post.

Parts and help. I was given the wrong parts so many time its a shame.

[ViolinARC]

I reused my old cap, shouldn't be an issue. My first OE replacement (reliable indy) failed just after a year and the second aftermarket replacement (DIY) is way beyond that. $350 replacement from the shop vs. $75 DIY and 30 minutes of my time...:buttrock At the shop, they drained the entire cooling system and hit me up for the extra time and fresh fluid but when I DIY'd, I clamped off the hoses instead...

Take the old et back to the dealer and request a replacement. The worst that could happen is that they say no...:cool

[bkgreene39]

Parts and help. I was given the wrong parts so many time its a shame.

That is unfortunate. There the only game in town as far as bmw dealerships go, not including Manhattan. Did you give them the part # and the vin? If they still gave you wrong part then thats some incompetence right there.


I reused my old cap, shouldn't be an issue. My first OE replacement (reliable indy) failed just after a year and the second aftermarket replacement (DIY) is way beyond that. $350 replacement from the shop vs. $75 DIY...:eek:

Take the old et back to the dealer and request a replacement. The worst that could happen is that they say no...:cool

I hear ya. What failed the cap or the tank? 350 for the tank and labor??? Thats ridiculous. Took me barely anytime to swap the tank out. Remove fan clutch, fan shroud then your good to go. And that was my first time ever working on a car EVER. I understand mechanics need money for services but thats insane. I will change the cap first see what happens. Then if all else fails I will install my old one, which btw is the original 14 year old expansion tank which never gave me any issues. If it is indeed the expansion tank then the hell with preventative maintenance. If it ain't broke don't fix it will be my new slogan.

[ViolinARC]

The tank had failed near the bottom.

$350 was for doing the entire job including draining and refilling the entire cooling system. Their hourly labor was $110/hr. at the time vs. $150/hr. at the dealer. The "approved" fluid and retail prices are uber expensive, which is why I ordered my own part on the www and just clamped off the hoses without draining the whole damn system the second time around...DIY FTMFW! :checkered

[bkgreene39]

The tank had failed near the bottom.

$350 was for doing the entire job including draining and refilling the entire cooling system. Their hourly labor was $110/hr. at the time vs. $150/hr. at the dealer. The "approved" fluid and retail prices are uber expensive, which is why I ordered my own part on the www and just clamped off the hoses without draining the whole damn system the second time around...DIY FTMFW! :checkered

Good stuff, you saved yourself coolant as well. I might try that next time.

[ViolinARC]

Good stuff, you saved yourself coolant as well. I might try that next time.

I even captured the escaping fluid and put cotton balls into my funnel before adding it back to the system. I did the same thing when replacing the upper rad hose. Gotta save all those pennies for the next repair! :D

[bkgreene39]

I even captured the escaping fluid and put cotton balls into my funnel before adding it back to the system. I did the same thing when replacing the upper rad hose. Gotta save all those pennies for the next repair! :D

This is true, I like what I'm reading. :thumbup:

[bkgreene39]

Installed new cap. Not leaking anymore. Expansion tank from dealer is not to blame. You can see the original cap has some plastic that has broken off exposing the o-ring. Lesson learned, change your cap when changing the expansion tank.

[Aradaiel]

Even if the tank starts leaking later, there is a 2 year parts/labor warranty from the date of purchase on all BMW parts purchased from the dealer. Just save your reciept.