Tag: reservoir

Mercedes CLS55 AMG W219, New Coolant Expansion Reservoir

Also took the liberty to replace the old coolant expansion reservoir/tank with a fresh new one. The new reservoir was including a new coolant cap and coolant level sensor.

I have no idea when it was last replaced. Also it was leaking from the cap, even though I tried a new cap (see my previous post: https://www.ducked.nl/mercedes-cls55-amg-w219/mercedes-cls55-amg-w219-new-coolant-expansion-reservoir-cap-oil-filler-cap/ )




Mercedes CLS55 AMG W219, Replacing The Power Steering Reservoir & Fluid

The power steering reservoir on the W211 & W219 platform have a filter built in. This filter is not serviceable, meaning that you need to replace the reservoir if you also want to replace the filter.

I took the liberty to replace the reservoir/filter and also flush the complete system and put fresh new synthetic oil in.

I used a vacuumpump to get most of the old red mineral fluid out. Then replaced the reservoir and used the “lock-to-lock” steering motion to pump all the old fluid out. Temporarily cap off the return line on the new reservoir and extend the return line to any suitable container for the old fluid.

I used about 2 liters to flush the system and 1 liter to fill the system. Febi Bilstein CHF 11-S Nr. 06161 is the correct fluid for this system.

Steering goes noticeably lighter after this service!

Old fluid coming out
Almost done flushing (fluid is becoming more green/blue-ish)
Made this shot after removing the reservoir. It clearly shows why replacing the serpentine belt is a bit of a hassle there…



Mercedes CLS55 AMG W219, New Coolant Expansion Reservoir Cap & Oil Filler Cap

2 Items which are forgotten very easily in routine maintenance; the coolant expansion reservoir cap and the oil filler cap. The coolant cap is spring loaded cap (mechanical component (!)), which is usually set to 1.1 BAR, to allow the coolant to vent whenever the pressure is too high. But when it vents too fast (spring lost tension), the coolant system is not able to operate efficiently.

Therefore its a good habit of changing these out every now and then. For the couple of euros, it should not be forgotten.

I also swapped out the oil filler cap, as this was leaking/seeping out a little bit of oil.

All CLS55 AMG pictures here in my Google Photos album: https://photos.app.goo.gl/6SP5PFAUXCqanoSX9