[E91 Hoarder]

Need you advice guys.

So my 2007 335i is approaching 60K mark and I took it for the annual inspection at a local BMW indy shop. One of their suggestions was to flush and replace the cooling fluid and put a new tank.

"Replace expansion tank, drain and refill coolant, pressure test and inspect for leakage, read out engine control module fault memory, bleed cooling system following BMW procedures for vehicles with electric water pumps."

Total quote was for $415, including parts and labor.

There is no any problem with it currently, but at this age, they say, it may be contaminated and should be done as a preventative maintenance.

What are you thoughts on this?
To do or not to do?
If it ain't broken, should I fix it?
Can I DIY it?

Thanks!

[Efthreeoh]

My coolant tank is 7 years old with 228,000 miles on it. I did replace the coolant cap a few months ago, but that's it. It is a rotational or blow-molded plastic tank; not much to go wrong with it.

[BKV122]

You can DIY. Id pass on the tank replacement unless it shows signs of wear. There should be a DIY about draining fluid and bleeding the system. If you want to flush he system than that's a little more work but a simple drain, refill, bleed is fine IMO

[123Britt]

It is definitely a DIY project --- however, my suggestion is to save the money to buy a new WP & Thermostat when you get 80k. Unless you have a leaking system now -- I would not replace tank until you do the bigger job.
.
I have 90k and just did the WP/THERMO a while back. The coolant change is easy but I did have to drop the IC (10 min job). Search is you friend. YOU CAN DO IT.

[Efthreeoh]

The coolant in these cars is good for 100K. I doubt the tank is "contaminated". If it was, than the rest of the system would be too and you'd have overheating issues (i.e. the radiator tubes would be clogged). Just drain and refill the coolant. There are DIYs for both the and N52 and N54 in the DIY section. The coolant drain and refill is very easy on the E90.

[Chriztofor]

Replace coolant tank? Never go back to that shop again......never.

[F32Fleet]

Pre-E90 they were prone to splitting. So the shop isn't wrong per se, but the E90 cooling system seems to be more robust than those of the past.

[E91 Hoarder]

Thanks everybody for the input. My take is that the tank is more durable than in E46 gen, and most likely doesn't need the replacement. However the flush is a good thing to do.

Any suggestions on the coolant type and amount needed?

[F32Fleet]

Originally Posted by BMWTF?

Thanks everybody for the input. My take is that the tank is more durable than in E46 gen, and most likely doesn't need the replacement. However the flush is a good thing to do.

Any suggestions on the coolant type and amount needed?

OEM. Cheap and easy to get.

[Efthreeoh]

Originally Posted by Socom

OEM. Cheap and easy to get.

+1. 1 gallon.

[Wongway]

Good to know.

I'm coming into an E90 from the X3 (E83) so much of what I'm used to is probably very similar to the E46 and my coolant tank split open a little after 100k miles. Not knowing any different, I probably would have had my coolant tank replaced, along with the water pump and thermostat around 90k miles to be sure.

(of course, doing this preventative maintenance is never a bad thing either)