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What happened with your replacement expansion tank?

  • Genuine BMW tank - Easy to install, no problems, it's still working fine.

    Votes: 37 54.4%
  • Aftermarket tank - Easy to install, no problems, it's still working fine.

    Votes: 13 19.1%
  • Genuine BMW tank - Very difficult to install, worked out in the end.

    Votes: 0 0.0%
  • Aftermarket tank - Very difficult to install, worked out in the end.

    Votes: 5 7.4%
  • Genuine BMW tank - Catastrophic failure, cracked open or similar.

    Votes: 6 8.8%
  • Aftermarket tank - Catastrophic failure, cracked open or similar.

    Votes: 3 4.4%
  • Genuine BMW tank - Too difficult to install, went with aftermarket.

    Votes: 0 0.0%
  • Aftermarket tank - Too difficult to install, went with Genuine BMW.

    Votes: 0 0.0%
  • What's an expansion tank?

    Votes: 4 5.9%

How did your replacement expansion tank fail?

9K views 58 replies 24 participants last post by  genuity 
#1 · (Edited)
A lot of posts on here passionately state that the only acceptable expansion tank is the Genuine BMW or the "OEM" Modine/Cool Xpert tank with the emblem/roundel ground off. The second tank being, of course, exactly the same as the Genuine BMW.

I opted for the Meyle tank from FCP due to their lifetime warranty, the fact that I trust them to sell mostly quality parts, and the lack of strong evidence to support the claim that all aftermarket expansion tanks are bad. Many people seem to have trouble installing the replacement tank, and I feel like a lot of the aftermarket tanks are blamed when it's actually all tanks that are difficult to install.

My question:

If your replacement--NOT YOUR ORIGINAL--expansion tank failed, (1) how did it fail, (2) how long did it last, and (3) what brand was it? OR was the aftermarket tank too difficult to install, so you opted for the Genuine BMW tank?

(If you reply to the poll, please realize that the "OEM" Modine / Cool Xpert tank that has the roundel ground off IS EXACTLY THE SAME as the Genuine BMW tank. If this is what you purchased and installed, please reply with one of the Genuine BMW answers.)

ALSO- Please remember that this thread / poll only pertains to your replacement expansion tank. NOT the original.

***If you had to reseat the tank, if you had to use a jack to put pressure below the tank while installing it, if it leaked at all after you installed it, that would all fall under "difficult to install."***
 
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#2 · (Edited)
I ended up voting for " Genuine BMW tank - Easy to install, no problems, it's still working fine. " However, I have experience in the past where the old expansion tank was basically seized from coming out. I had to literally use a hydraulic jack to push it out, the second time I did it on a complete separate car it came out easy as pie.
 
#3 ·
No problem. For the poll, the only thing that should factor into installation difficulty is ease or difficulty of installing the replacement tank itself.

My original tank--noted as such by the production date on the sticker--was really difficult to remove. In the end, I think I somehow pried it up. It was less than a year ago, but I don't quite remember exactly how it finally came off.

The replacement tank--aftermarket/Meyle--leaked twice and finally sealed once I used a jack and a piece of wood to put pressure on the piece it mounts on, and put silicon on the o-rings. (My post about that: http://forum.e46fanatics.com/showpost.php?p=16952542&postcount=5 )
 
#5 ·
An important factor on the aftermarket ETs is how well the coolant level sensor works. Many cheap chinese ebay garbage ETs are so poorly designed that the level sensor doesn't work properly. The float magnet is too weak, incorrectly positioned, or falls off. It can either always show low coolant, never show low coolant, or intermittantly show low coolant.
 
#9 ·
One time bought URO Parts expansion tank for wife's car. Installed. Within one day, noticed leaks. Inspected. Inspected again closely. Merely tugging on the bottom of the tank induced large streams of coolant, WTF!!! Removed new tank, determined it was simply a poorly sized o-ring at the bottom connection that caused the problem. Immediately returned, put old perfectly functioning OE tank back in, zero problems. Ordered new OE tank, zero problems. New OE Tank going in my car soon, expect no problems.
 
#20 ·
Same experience here with the URO ET, install was smooth but leaks started after couple months and couple hundred miles of use. Took me a while to notice where the leak was coming from but it ended being poor orings on these aftermarket things. I took it out and replaced just the orings, no problems since.
 
#13 · (Edited)
This hasn't been up very long, but I'm not seeing many "difficult to install" responses here, which doesn't really match up with what I've found searching forums. Plenty of people have had difficulty installing these tanks. If you had to reseat the tank, that would fall under "difficult to install."
 
#23 ·
I replaced mine with an OEM BMW ET and it all went smooth as butter. Not really, installing the hoses to the ET was a pain in the butt and took a while. But seating the ET was actually quite easy.

I replaced the whole cooling system all at once with genuine BMW parts and haven't had any issues ever since. The coolant level hasn't moved since the next day after the bleeding when I had to add some.

For me the most difficult part was removing the old hoses and re-installing them again. But I didn't use any grease, otherwise it might have been easy.
 
#26 · (Edited)
Mango, I find it truly surprising the you opted for the Genuine BMW expansion tank. ;)

If I'm being completely honest here, I have to say that I probably would have gone with the OEM Cool Xpert/Modine ET--identical to Genuine BMW--had I bought it after my tank went bad. But I added the tank for my first order of parts so that I would have it in the garage if the tank went bad, which it inevitably did. If I'd bought the tank from anywhere but FCP I definitely would not have purchased the Meyle tank. But I do trust their judgement for the most part. And their warranty.

How apt that I have just spotted this thread after my original 1999 BMW tank cracked open the other day when I was in the middle of nowhere in Sutherland (Northern Scotland) 11 hours drive from home (London). 4 miles down a rough potholed track from the nearest tarmac road and 3 miles from any mobile phone signal (it was a good walk to call the recovery services!).
Annoying as this was the first time in 23 years of driving that I had ever broken down.......hey it was a beautiful spot for the car to decide to die! The tank had cracked with no warning, I started the car, drove it slowly for about four miles before i noticed the coolant gauge creeping towards the red so i immediately switched the engine off. Opened the bonnet and saw a liquid below the tank, I knew straight away what had happened (just disappointed it had happened in such a remote place). Went to a nearby bern (stream in Scotland) to get some water but sadly it leaked out of the tank as fast as I could pour it in.
After being recovered to a local garage (who's service was outstanding - Victoria Garage in Brora) they confirmed my suspicions and took my word for it over the phone and had ordered a new tank from BMW in Inverness which arrived about an hour or so after I arrived at the garage. The 17.5 year old tank had a 5-6" crack up one side!
Anyway that tank, the coolant hoses, the front shocks and all four springs are the only major serviceable items that have not been replaced on the car - I suppose I was unlucky with the tank.......but maybe I was pushing my luck due to its age?!!
That's exactly what usually happens to them. I can't even see the crack on my tank now that it's off, but I could barely sort of see it when the engine was up to temp. These guys on here freaked me out to the point that I was checking under the car every time I shut it off. I caught mine quite early.

For me the most difficult part was removing the old hoses and re-installing them again. But I didn't use any grease, otherwise it might have been easy.
This made a world of difference for me. After my thermostat went bad, which was a month or so after the expansion tank, I put dielectric silicon on: the new water pump o-ring, the old upper radiator hose o-rings, the new thermostat gasket, the new lower radiator hose o-rings, and the new fan switch o-ring.
 
#25 · (Edited)
How apt that I have just spotted this thread after my original 1999 BMW tank cracked open the other day when I was in the middle of nowhere in Sutherland (Northern Scotland) 11 hours drive from home (London). 4 miles down a rough potholed track from the nearest tarmac road and 3 miles from any mobile phone signal (it was a good walk to call the recovery services!).
Annoying as this was the first time in 23 years of driving that I had ever broken down.......hey it was a beautiful spot for the car to decide to die! The tank had cracked with no warning, I started the car, drove it slowly for about four miles before i noticed the coolant gauge creeping towards the red so i immediately switched the engine off. Opened the bonnet and saw a liquid below the tank, I knew straight away what had happened (just disappointed it had happened in such a remote place). Went to a nearby bern (stream in Scotland) to get some water but sadly it leaked out of the tank as fast as I could pour it in.
After being recovered to a local garage (who's service was outstanding - Victoria Garage in Brora) they confirmed my suspicions and took my word for it over the phone and had ordered a new tank from BMW in Inverness which arrived about an hour or so after I arrived at the garage. The 17.5 year old tank had a 5-6" crack up one side!
Anyway that tank, the coolant hoses, the front shocks and all four springs are the only major serviceable items that have not been replaced on the car - I suppose I was unlucky with the tank.......but maybe I was pushing my luck due to its age?!!
 
#27 ·
In my opinion lifetime warranties are worry it if from a local store. From online store - not so much. You have to remove the part, ship it, pay for shipping, wait for a new part to arrive, install it. It's like a week or more without a car. Who can afford it? Fcp is ok, but not my first choice.
 
#28 · (Edited)
You order the new part and install it. Ship the old one back within 90 days, and receive a refund for the new part. I receive parts from FCP the next day with ground shipping. You would probably have to pay for expedited shipping in MO. If you contact them and explain the nature of the failure, they might even expedite/ship the new part for free. They'll give you a prepaid label if the part fails quickly, or in a ridiculous manner. They have the best customer service of any company I've ever dealt with.

(Except for my last experience with New Balance, which was excellent. They gave me a coupon for any pair of shoes on their website because there was a manufacturing defect on a pair of shoes I wore for a week that I'd bought from Amazon. They only needed a photo of the defect.)

I don't have any connection at all to FCP. I'm just happy to promote a good company.
 
#36 · (Edited)
I would love it if the people who installed an aftermarket tank and aren't having any problems with it would chime in to mention which aftermarket they installed. Or, if you're one of the two--as of right now--who installed an aftermarket tank and had a catastrophic failure. That info would be helpful as well.

The rough number of miles on the tank is important, too.
 
#38 · (Edited)
Mine failed last night on a 2001 330i with 74K miles on a trip from San Diego to San Francisco...looked like it failed at the upper hose nipple and was leaking a few drops a minute... my coolant light came on, and I was hoping it was just low, but when I stopped and opened the hood, I could see it leaking.

Was staying at a hotel in Sunnyvale and walked over to European Auto and bought a CoolExpert tank for $92, and a gal of antifreeze for $25.... the guy told me it was premixed 50/50, Huh? F'n place unethically sells diluted antifreeze for regular price...

Anyway, did the job in the hotel parking lot with my emergency toolkit... I could not pull the f'n tank with my hands, also tried banging it out from the bottom, still would not come out... then I figured out an angle, if I put the cap back on, I could pry it out using the open end of a 19mm box wrench using the cross frame for leverage... that's the most f'd up design for a cooling tank... worked on many Toyotas and VWs in my life, but this one is the most FUBAR'd design I've ever seen.
 
#39 ·
Mine failed last night on a 2001 330i with 74K miles on a trip from San Diego to San Francisco...looked like it failed at the upper hose nipple and was leaking a few drops a minute... my coolant light came on, and I was hoping it was just low, but when I stopped and opened the hood, I could see it leaking.

Was staying at a hotel in Sunnyvale and walked over to European Auto and bought a CoolExpert tank for $92, and a gal of antifreeze for $25.... the guy told me it was premixed 50/50, Huh? F'n place unethically sells diluted antifreeze for regular price...

Anyway, did the job in the hotel parking lot with my emergency toolkit... the f'n tank would not come out... but I pried it out using the open end of a 19mm box wrench under the cap using the cross frame for leverage... that's the most f'd up design for a cooling tank... worked on many Toyotas and VWs in my life, but this one is the most FUBAR'd design I've ever seen.

What a bummer...... I just posted this a few days ago in the cooling thread mentioning how it was easier to unscrew the ET bracket and then get the tank off...

Qoute: "I elected to remove the ET retaining bracket as the tank wouldn't budge and I didn't want to do the jack trick from below. I used a little bit of PB to free up the connection along with a couple of very soft rubber hammer taps and it separated from the bracket. It seems that's a much easier method then trying to get it off the retainer. It went together perfectly and I did the bleed technique with the front end lifted etc. OBC temp 95 to 98 with no visible leaks after a test run. It's cooling now and tomorrow I'm expecting to either add a little or siphon some out".
That must've been a PITA in the parking lot. Glad you didn't ovehheat.
 
#45 ·
My original cooling system started leaking about a year ago so I replaced the ET with a Vaico from ECS, mainly because they were the closest to me and I had to get the car back on the road ASAP. The install wasn't too bad and the leak was fixed. There are no visible cracks in the old tank so I didn't throw it out. Now I've got the leak again but haven't been able to pin point the source yet. I'm thinking it's the O-rings but I'm not certain of the exact sizes. 4 x 38mm is the closest I can figure for the larger one and is available at O'Reilly Auto Parts and the smaller one I was able to match at work but is 1/8" instead of 4mm material. Anyone have the sizes and a source or should I just buy the OEM Coolxpert from FCP?
 
#46 ·
Do you remember if it had regular, rounded o-rings, or the squared o-rings that seem to come on the Behr tank?

My Meyle tank had normal, round o-rings. It's been on the car for about a year without any problems. The o-rings--which I'd covered in dielectric silicon grease--still looked new when I had it off to the replace the radiator a few weeks ago.
 
#49 ·
I'm going to get the O-rings and once my spare car is back I'll pull the tank and change them out. I'm just hoping the 11 month old transmission thermostat doesn't break when I wrestle the tank out. I just wish the bottom of the tank on an automatic was as accessible as a manual, the bottle jack method of removing it looks so much easier.
 
#50 · (Edited)
I'm just hoping the 11 month old transmission thermostat doesn't break when I wrestle the tank out.
That was my big concern when I had to pull the expansion tank again. But the nine-month-old thermostat didn't break. Hopefully yours makes it as well. I think it probably takes 5+ years for them to degrade. Or maybe that's wishful thinking.
 
#53 · (Edited)
My exp. tank failed by developing a micro crack, invisible, but apparent during the inspection. Especially, shortly shutting off the engine I could see a tiny streak of coolant coming from a wall of the tank.
Like I said the crack was invisible to the eye, so if you guys chase a coolant leak you really need to get under the car with the engine running and observe the place it is leaking from...
 
#54 · (Edited)
I think mine was like this... the leak was hidden on the driver side of the tank, and all I could see were drops of antifreeze falling down onto the bottom cover below... after I removed the tank, on inspection, I could not really see the crack... after replacing it, it does not leak, so I assume it was the original tank that was leaking.
 
#55 · (Edited)
Tried to get O-rings today, even though O'Reilly's website had the larger one listed the guy at the store couldn't find a place to order it from. I tried NAPA and they had a selection of metric O-rings but the largest was a 3.5mm cross section. I'm going to take the old originals over there tomorrow and see how close they actually are. I crawled under it today with it running and up to operating temp and after drying everything off with compressed air I couldn't find any leaks. I must have been under there for about 10 minutes and everything stayed dry. This f***ing thing is driving me nuts. Maybe if I can find some O-rings I can coat them with dielectric grease like lingon300k did and the tank will seal.

UPDATE, Just went back out to check the coolant level and add some coolant. Looked underneath and found a small puddle and the connection of the heater hose to radiator was dripping. I couldn't feel anything wet above it so I'm hoping this is my leak. I'm going to order the hose tonight, I'm sure it will need a new one eventually. The only thing I can think of is the connector expands and seals when the coolant gets hot and contracts as it cools allowing it to drip, at least I hope so.
 
#56 · (Edited)
Just came in from pulling the hose I'm gong to replace,the new heater return hose will be here Monday, what a PITA! Had pull the ET to access the clip on the hose and have enough room to get a grip on it. The level sensor seems to have come apart and I can't get the detached piece out, yet. The old one fits in there yet and actually fits tighter than what's left of the one that came with the tank. EDIT the sensors are just different, OEM is more fragile looking, as in thin wire like end and the one that came with the tank looks to be covered in a plastic sleeve. Now I remember reading on ECS Tuning's site that sheath needs to be removed,:facepalm:
Lingon300k, I pulled the O-rings out of the Vaico tank and they are more square than round in cross section. A little dielectric grease is going on all o-rings along with coolant to aid assembly.
 
#57 ·
I've replaced it using OEM part by my independent shop as a PM. What are some of the reasons for going non OEM to begin with? Is the OEM that much more expensive? The usual shop I go to won't even nstall aftermarket ETs but he would for others like regulators and even clutches etc. I waited for him to the entire job and everything went fine without a hitch. He kept talking to me the entire time while I watched.
 
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