Expansion Tank Conditions

[ersanto]

2004 325i, 97k miles.

Due to a small collision I recently had to fix the front, including replacement of radiator, vent, expansion tank.
The body shop did a good job, in my opinion, but to keep cost lower they used a "pre-owned" expansion tank.

My mechanic just declared the new old tank a pending disaster and is begging me to replace it.
He especially mentions the brown color of the top hose as a sign of degraded state.
I'm not expert enough to judge. If he had not said anything, I would not have been questioning the part

I'm enclosing a link to a picture.
http://i64.tinypic.com/j9sf7r.jpg

He's asking ~$700 for the job, including $320 of parts.
Dunno, ECS sells a complete kit for less than $150 and even just the $42.48 for a gallon of coolant seem way high.

I'd be grateful to anyone who wanted to weigh in on the hose/tank conditions and the cost of replacement.
I know this is a weak spot of the E46. Would keeping a close high to water temperature be enough to diagnose a failure before car is damaged ? The needle has never gone past midway, so I naively imagine that shutting off the engine as soon as it does would be good enough.

TIA

[legobumb]

That brown you see, is not part of the expansion tank. I think it's the return hose? It brings back excess coolant to the expansion tank. (Part #1 on this diagram: https://www.realoem.com/bmw/enUS/sho...diagId=17_0215) However, since most of the cooling system on these cars are plastic, you should definitely look into replacing that bit at the very least. It's something anyone can do because of the easy clip-on nature of that hose. No mechanic needed for that.

Shame on you for getting a "used" expansion tank, though. They're relatively inexpensive on their own, so there isn't really a need to go used. If I ever need a mechanic to do work for me on my car, I usually try to buy the parts myself because the garages will absolutely annihilate your wallet on overnight shipping costs and such. I also don't see how replacing the expansion tank and return hose would cost more than 1 hour in labor. Find a different mechanic.

[ersanto]

Thank you.
Yes, I had in mind to at least change the hose myself.


Agree on the fact that it would have made more sense to use new parts.
It was out of my control. Body shop got some used parts to fix extensive front damage after collision and, although they got new radiator and fan, decided to use that expansion tank assembly (I imagine from the same junk that generated the front bumper and lights).

I found a comprehensive video step by step of the entire tank replacement on youtube. It looks like an hour job and I'm going to get a second opinion from another mechanic.

[jclausen]

Brown is not good New is black

[Critter7r]

$700 had better include a new t-stat and waterpump too.

[yinzerinmass]

If you research this job enough you will find alot of recommendations to replace all the cooling system components while you are at it. This is sound advice, especially if you are paying a shop to take care of this type of thing. Personally I chipped away at it, and regret that decision. Basically each summer over the past few years i replaced the thermostat, water pump, radiator, several hoses in turn drain and fill each time. With the info out there this is definitely something that can be done at home.

I'm not really good at estimating shop fees but $40 for coolant is about a 2x markup on that alone. FCPeuro offers free shipping over $50 and, believe it or not, will take back any failed part that you buy for them for any reason with no hassle at all.

Good Luck

[ersanto]

$700 had better include a new t-stat and waterpump too.

Doesn't include squat: just tank, upper hose, coolant refill.
I'm getting estimates from others this week. Based on those I may only replace the upper hose myself (hopefully without having to remove the air box), or do the entire system.
Thank you all for the advice.
i

[Raddee]

Don't forget to replace the cap on the expansion tank aswell

[MarcoZandrini]

OP, try www.bimrs.org to find a reputable indie shop that specializes in bimmers. $700 to replace the tank and the upper hose plus coolant is a ripoff, even for The City.

[jclausen]

Only use the factory expansion tank, mounting plate and hardware, not china made crap