The Labor Day weekend is a great time to do some simple tweaks to your car. This past weekend I did some M5 Labor Day jobs that didn’t warrant waiting for a club DIY event. I replaced a leaking intensive windshield wash reservoir, added a euro trunk cubby and replaced a chipped plenum badge.
When you own a car long-term there is usually a “I’ll get to it when I get to it” list of things to do. In my case one of those things was the intensive reservoir. What put it on my radar was repairing the main washer fluid reservoir recently, more precisely the hose that connects to it. That reservoir is behind the front passenger wheel well, while the intensive reservoir is easy to access in the engine bay. For some reason, BMW decided two separate windshield washer systems were necessary for the E39 M5.
For years, I never thought about having an empty intensive reservoir. You don’t need it, the regular washer fluid system works fine. But after fixing the hose, I figured why not have all systems prepped as designed? I probably should have guessed why I got the car with an empty reservoir – when I filled it there was a leak. So I ordered a new one and waited for it to be delivered. But on installation, I found out that wasn’t the source of the leak – it was the pump that inserts into the reservoir that was leaking.
It was a great reminder to look more carefully before diagnosing a problem. Through dumb luck I had a replacement – the pump I replaced prophylacticly at the last DIY. The same exact part is used in both locations by BMW. Even though it was old, it worked and didn’t leak. Score one for never throwing old parts out!
Next up was the euro trunk cubby. Sometimes it’s called a battery cover, because on other E39s (not M5s) the battery is on the passenger side of the trunk. It’s a small plastic container built into the fabric door. This provides a small storage place, where many owners like to put a quart of oil.
Not the most impactful tweak but it’s as easy as replacing three plastic push rivets. It’s officially listed as an E39 540i part, not M5, but fits perfectly. My plastic cubby was so authentic it seemed to come with 20 years of dust already in place.
Finally, repairing some engine bay bling. BMW made sure E39 M5 owners knew what they bought by putting a BMW MPower emblem on the engine cover, along with an M badge. My badge was looking worse for the wear with a chip missing in one corner. So I wedged the old badge out with a plastic pry tool and replaced it.
So that was my M5 Labor Day, a few easy DIY tweaks. (Hey – don’t judge!) I even had time to download and start to understand the software I need to make coding changes to both of my cars. That will make for a good post when I’ve got that figured out.
UPDATE 9/20/23
I should mention I had my rear vew mirror repaired, although it was before Labor Day weekend. It’s a common issue for the gel that powers the dimming function to leak. There is a full scale DIY procedure in which you purchase the replace glass and then repair the mirror yourself – video here with details.
That looked difficult, and buying an entire new assembly would cost over $700. So I decided instead to remove my mirror and send it to Radar Mirror for a reasonably priced repair. They did a nice job, though my car was off the road for about 10 days. I’d recommend them to fellow owners when this happens to your M5. Also – it’s counter clockwise twist to remove mirror, clockwise to put back on.
