60K Mile Coolant Service Thoughts

[kayger12]

Just got done doing some preventative maintenance: belts, pulleys, thermostat, and water pump.

First cooling system work I've done to the ZHP. Easy as pie thanks to the fact that I've opted to go with the Old School Maint schedule and put the expansion tank and hoses off for a while.

There's always been a lot of discussion about how much of the preventative maintenance on these cars (especially the coolant system) is necessary, and how much is the result of the marketing fear factor.

Here are my thoughts based on what I changed out today at 57,498 miles:

SERPENTINE BELT


Decent amount of splitting and cracking, so definitely was ready to be changed out.

AC BELT


This belt was in much better shape, and showed no cracking or wear which would make me think it was in imminent risk of failure any time soon.

PULLEYS

I tried to get a video of this, but it didn't work out resolution-wise. The idler and tensioner pulley for the serp belt were pretty much free spinning. In addition, if you gave them a shake, you could hear that the bearings were worn. Definitely glad that they are now changed out.

With respect to the water pump pulley, it was seized on the water pump slightly, and when I gave just the slightest bit of pressure with a screw driver to attempt to pry it off, here's what I got:

See the cracked off plastic around the back edge of the pulley? Pretty damn brittle. Glad I replaced this, but not glad that I couldn't get my hands on a stock-size aluminum one.

WATER PUMP:


The water pump looked to be in good shape. The impeller looked strong with no cracks nor abnormal/unusual wear. It seemed to be "tight" with respect to any play in the pump. I would think that this pump would have lasted a pretty good amount of time longer.

THERMOSTAT
The thermostat had some built up, dried out coolant in the area outside the seal, but other than that looked good. No cracks or anything abnormal that I noticed in the housing.

The only hang up I had with the whole project was that I ordered the wrong tensioner pulley for the AC belt, so I have to get my hands on the right one and throw that in.

So all in all, most of what I changed out preventatively seemed to be warranted, while some (such as the water pump and thermostat) I feel were more of an insurance thing.

Now we'll see if my expansion tank and coolant hoses make it to 90k...

[telijah]

I think 70k is right around where most tanks began to fail. However, I would at least go ahead and buy the tank, as just about everyone one of them seems to fail sooner or later.

[kayger12]

I think 70k is right around where most tanks began to fail. However, I would at least go ahead and buy the tank, as just about everyone one of them seems to fail sooner or later.

Good advice. I'll order one up when I order the pulley I need and then keep my fingers crossed and try to make 90k.

[Marcus-SanDiego]

I agree on the expansion tank. That's historically been one of the weakest things on my BMWs (7 of them). Something about those expansion tanks. It's typically a hairline fracture that does it in.

[ranger]

I did a full cooling upgrade on my former 2005 BMW 325 EXCEPT the expansion tank at 100k. Expansion tank failed a month later. I would definitely change the expansion tank at the first opportunity.

[BCS_ZHP]

Kayger,
Was told this by a BMW tech -- on the expansion tank, when the coolant level "thermometer" changes color it's getting ready to fail. That level indicator is normally dark red but will fade to a medium or light red and even a pink, must change it at that point.

[kayger12]

Kayger,
Was told this by a BMW tech -- on the expansion tank, when the coolant level "thermometer" changes color it's getting ready to fail. That level indicator is normally dark red but will fade to a medium or light red and even a pink, must change it at that point.

Good info, Bruce.

Thanks!

Droid X. Tapatalk. Use it.

[aurelius]

For your shopping pleasure, ECS Tuning sells a Meyle tank for $50 and the Genuine BMW version for $76.

You might also consider the updated coolant level sensor, part number for which is 17137553919. The update (redesign?) happened 2 years ago and applies to current BMW & Mini models, as well as past models back to E39. Draw your own conclusions but I bet BMW had a few pricey warranty claims related to this.

Some recommend also buying the clip for the level sensor, which often breaks when removing the original.

[danewilson77]

Good lookin out.

HTC Thunderbolt+TT

[kayger12]

For your shopping pleasure, ECS Tuning sells a Meyle tank for $50 and the Genuine BMW version for $76.

You might also consider the updated coolant level sensor, part number for which is 17137553919. The update (redesign?) happened 2 years ago and applies to current BMW & Mini models, as well as past models back to E39. Draw your own conclusions but I bet BMW had a few pricey warranty claims related to this.

Some recommend also buying the clip for the level sensor, which often breaks when removing the original.

That's great info.

Appreciate it.

Droid X. Tapatalk. Use it.