BimmerFest BMW Forum banner

1 - 8 of 8 Posts

·
Registered
Joined
·
3 Posts
Discussion Starter · #1 ·
Hi, I am new to the BMW world as I had traded my mustang cobra in for an e39. I absolutely love the car, best decision I ever made. However I am reading on the forums that the cooling system is a known problem. My car has 71k on it right now, I believe the major weakness is the water pump which has a plastic impeller instead of a metal one. My question for you is should I just change the water pump or do I really need to change the entire cooling system. That seems a bit extreme, and hard to believe since BMW makes such a high quality product. Thank you for your advice.
 

·
Registered
Joined
·
15,237 Posts
Actually it is not extreme at all.

An analogy is your garage door at home. Let's say it is 20 years old. And remember each part has its own lifespan. You replace the motor; 3 months later the chain breaks, 2 months later the spring breaks, 1 week later then the cable snapped, then the door rail fails. Then the bearings go. Then the door breaks. So it is better to change the whole thing than bits and pieces!!! Cheaper and more efficient this way. But if your budget is tight, you need to be mechanically inclined to handle it.

-----------
You should think about the cooling system as a "soccer team" with many players: missing one player, you are in trouble!!!

The problem is: some parts in the cooling system give you warning and some are "time-bombs". The plastic crack is classic, plastic becomes brittle with time and heat and the underhood environment is "perfect" for that.

SOME WARNING vs NO WARNING LIST

- WP leaking slowly or seized suddenly, taking the belts and fan blades with it....see recent post by "matt24"

- fan clutch usually failing slowly...so you may elect to wait a bit.
- fan blades can crack and fly off suddenly taking the underside of the hood with it.

- reservoir can crack slowly or suddenly
- Hoses can leak slowly or can blow suddenly
- Tensioners fail slowly causing belt squeal (not enough tension) and belts slip...so this item can wait a bit.
- Rollers fail slowly and make noise, giving warning. BUT......many of these components sit under the hood and when they make noise due to failure, the noise can be hard to notice.

- Thermostat housing is plastic and at 80K is overdue, it can crack suddenly and in 30 seconds, you have an overheated engine.

The bottom line is to replace the parts that fail suddenly because there is virtually no warning at all, leaving you stranded.

A Cooling Overhaul is not all that bad, Parts cost $550 and one full Saturday, your labor. You will be glad you do it. After all, this cost is minimal compared with the value of your car.

This is approx. lifespans for cooling system components. Take this with a "grain of salt":

RADIATOR:
540......40-60K
528i...... 80-100K

HOSES: 10y/80-100K
BELTS: 60-70K
FAN BLADES 10y/80-100K...Plastic degrades with time and heat, the underhood environment is "perfect" for this

FAN CLUTCH: 90-150K
THERMOSTAT: 60-70K
THERMOSTAT HOUSING: Plastic 80K max; aluminum 120K or so

RESERVOIR+CAP: 80-100K

WP: 80-120K (We have seen failure as early as 30K but this is rare)

So, figure it out, what has been replaced..keep them; what is overdue replace them. Do NOT wait for disater on the hwy (+ inconvenience to your family).

-------------
But if you are tight on budget (and provided that you are mechanically inclined and DIY; otherwise repeat trip to shop costs even more), then do the BASIC MINIMUM: Rad + Reservoir/cap + WP + Hoses + Tstat/Tstat Housing + Belts.

The tensioners fail slowly....so they can wait. The rollers (3 of them) can be repacked with grease and re-install.
(the tensioners x 2 are $95 for both, the rollers are $100 for 3 of them....so you save $190 or so, but you need to watch them every 3 months or so....listen for squeal and check the play in the rollers).

Yesterday I drove 450 miles in the middle of nowhere in Iowa in 110F heat, I will tell you having a overhauled cooling system gives you so much confidence that this car will not let me down. If you drive around town only, then do the basic minimum as above.

HTH
 

·
Registered
Joined
·
1,999 Posts
had a 98 e39 just traded it for e65,water pump failed @ 130k changed it , never had any other problems with cooling system, water pump only specially if it has this low miles
over all its up to you financial status
 

·
BMW Nuthead
Joined
·
2,388 Posts
agreed as well, if you leave anything out do the radiator at 90K but do everything else, I didnt replace my tesndioners and pulleys..but did everything else except for the radiator at 60K..I used Redline water wetter in my mixture and the car runs great
 

·
Registered
Joined
·
278 Posts
i am so lucky when i got my car
took it for a oil change for the first time, the guy told me, woww youe

change the entire cooling system
i didnt know it was changed so i thought ummmm (i am staring to like this car)


so far 99.xxxx miles just brake job

got it with 80k miles
 

·
Registered
Joined
·
439 Posts
agreed as well, if you leave anything out do the radiator at 90K but do everything else, I didnt replace my tesndioners and pulleys..but did everything else except for the radiator at 60K..I used Redline water wetter in my mixture and the car runs great
Our radiator started leaking at 91K, so we did a complete cooling system overhaul then. We didn't have any issues before, except for maybe some noisy pulleys and tensioners that were replaced under warranty. The six-cylinder components seem to last a bit longer.
 
1 - 8 of 8 Posts
Top