spqr105

My 2004 525i has just reached 62k miles and I was wondering if I should be changing the Serpentine and AC belts when I get my car serviced next time in August? It squeals a bit upon startup in cold weather but goes away once I start driving it. Other than that, the car pretty much runs like a top. It only gets driven a few thousand miles a year as evidenced by the current mileage. I know the plugs don't call to be replaced until 100k miles but is there any other recommended maintenance? I read that the e60's have water pump issues and should be proactively replaced. I had all fluids flushed and replaced around 55k miles. Air and cabin filters have also been replaced.

I was also wondering how the CBS system knows the mileage until something needs changing. I know there are sensor based and internally calculated based items. I had my brake fluid flushed at the 55k mile mark but it's saying that I'm way overdue for it. Is this because the mechanic at my independent shop didn't reset it? I'm assuming the internally calculated items need to be manually reset after servicing while the sensor based items don't? Any insight to this matter would be greatly appreciated! Thanks for your help guys.

In an unrelated note, I have had some slight "fluid" sounding noise being emitted when I'm making turns. Is this an indication that my power steering pump is going bad? It's almost as if I can hear the power steering fluid going through the lines. Thanks again!

DavidF

I don't go by any set interval, but rather judge when they need changing by appearance (i.e. brittle and/or severe cracking). The A/C belt gets changed after it breaks (since it is standalone and a PITA to change...at least on my 545i with stretch belt).

BimmerFan52

Unfortunately the cooling system on many BMWs is an Achilles heel. Many of the components are plastic and the others (water pump, thermostat) tend to have a rather short life compared to other automobile brands. The plastic used in these parts grows brittle with age and the heating/cooling cycle.

The danger in having a coolant system failure is that if you are caught in a situation where you can't quickly pull over and turn the engine off, the all aluminum engine can experience severe expansion, which can damage the head gasket, and in the extreme can warp the heads and even seize the engine. At the very least overheating stresses many gaskets and you could be stranded on the roadside waiting for a tow.

The recommendation of most E60 owners is to do proactive maintenance on the cooling system, generally at 75,000 miles or 8 years, whichever is first. This is not something that you need to call today and make an appointment for, but begin planning for this critical preventive maintenance. And at the same time you do the water pump, thermostat, hoses, coolant expansion tank and vent tube, change both belts. (Tip: Ask the mechanic for your old belts and store them in the trunk in case you break one while out of town).

Most CBS maintenance is mileage based, with some time based. For oil it is a combination of mileage, driving habits and a wiz-bang sensor that is supposed to measure the dielectric constant of the oil to measure impurities. It is basically useless. It is recommended that you change your oil every 5,000 to 7,500 miles, depending upon driving habits, or in your case I would do it at least once per year, but better, twice a year in spring and fall.

Most people change their brake fluid every 2 years, although you could probably stretch to every three or even four years without an issue.

Plugs I would suggest you change at 80K miles, but it is up to you. If the engine is running fine you can stretch it to 100K.

I would definitely change your transmission fluid if you have an automatic transmission now. BMW says it is a lifetime fluid, don't believe it - like any other fluid it has a finite life. If you plan on keeping the car have the fluid drained and filled twice to turn over between 80-85% new fluid.

To reset the CBM system, follow the write up below to reset it yourself (disregard the part about pushing the start button, just turn the key to the on position (just before last position or cranking position).

Sorry, can't help you with the running water sound, it doesn't ring a bell with me.

spqr105

Thank you very much for the insight. Would you also replace the differential fluid? What do you figure it would cost for parts and labor to replace the cooling system? It's something I hadn't previously considered. I greatly appreciate your input.

spqr105

Is it possible to reset the cbs with a specific number? My brake fluid was changed 7k miles ago so I believe I have 23k miles left. If I reset it, it will go back to 30k.

BimmerFan52

I just addressed the items you mentioned plus the cooling system which is the most critical.

I did my cooling system myself, when I was in the engine taking care of a failing alternator. So many of the same things have to come off the engine to get to both that it just made sense, and besides the time had arrived when it was ripe.

RE Cooling system service cost - I would have a difficult time guessing off the top of my head as I bought most of the parts mail order. The labor prices vary greatly from dealer to independent mechanic, whether they use all BMW parts and whether they charge you list for those parts or discount them.

The dealers will always be more so I would shop independent BMW specialists in your area. Be specific about what you want replaced (water pump, thermostat, hoses, expansion tank, serpentine belt and vent tube) and ask them to give you an out-the-door price with tax.

The differential is a sealed system and fairly hardy, so most people wait until 100K. But given the age of your car it couldn't hurt.

Re resetting CBM -, no you can't enter a certain number of miles. You are just basically resetting the clock to the default count down built into the computer for that item.

I don't pay attention to the CBM at all, but instead keep a log book in a legal binder (holes punched at the top) with all records. The front pages are a chart with the major service such as oil changes, brakes, cabin filters, air filters, trans-fluid and other fluids. I maintain three family cars so I also have an oil change chart on the garage wall as a reminder. It also lists filter part numbers, socket sizes and torque specs for each car as reference.

spqr105

Thanks again! Would you say most people on this board have problems with the cooling system or just a handful of unlucky people?

Also, do you have any idea what that fluid like sound I'm having when turning could be? That I mentioned in the original post?

spqr105

Also, if you don't mind, would you possibly be able to provide me with the part numbers or links on eBay to the vent tube and necessary hoses? Thanks a lot!

BimmerFan52

Many have had cooling system problems and preventive maintenance of the cooling system is a common theme.

Hard to quantify or say you would be accurate in using the word "most". And obviously no forum captures the experiences of many owners who take their overheating cars to the dealer or mechanic, and those that have no problems, both of which may not record their experiences. Also, because the cooling system failure is age or mileage related, it typically doesn't show up in many new car reliability ratings which typically track the first 3 or 4 years of the car owner's experience.

Search this forum with the phrase "cooling system" or "overheating" to read what others have written. Again, it is not the only problem with the E60, but overheating has the potential to dramatically affect the health of the engine.

In the last sentence of post #3 I indicated that the running water sound is not a problem I have heard of.

Regarding part numbers there are variations in part numbers depending upon the month of manufacture of BMW vehicles for a given model, and identifying PNs can be misleading.

This is the best source for part numbers. Enter your VIN number.
RealOEM.com Online BMW Parts Catalog

I believe the vent tube (BMW calls it pipe) hasn't changed and is universal to all E60s but others do change. The vent tube is a common failure point, but generally does most of its job after the car is shut down.
Vent tube (pipe) - 17127519247

For other hoses I would wait until you have the work done and have the mechanic assess each hose, looking for softness or cracking to determine if they need to be replaced.

spqr105

Thanks again for of your help!