Mercedes-benz E320 CDI

Part two: We cover a full vehicle inspection and service.

There’s no effective way of telling whether a vehicle has been thoroughly maintained until it’s been raised on a two-post ramp. We finally had the opportunity to do this at Mer-tech of Hull. To our surprise, we didn’t find any worn suspension bushes or leaking dampers. We discovered the suspension consists of coilovers (coil springs and dampers) at the front, but air suspension units and telescopic dampers at the rear. Could the sometimes skittish handling at the front be caused by worn dampers and tired springs?

Elsewhere, we found a few nasty surprises. When we removed the two undertrays, we noticed the engine sump was coated in oil. Initially, we thought the sump gasket was leaking, but Luke at Mer-tech traced the oil leak further up the engine, explaining that the oil cooler’s seals are prone to leaking. Sadly, this is a time-consuming job, requiring most of the top of the engine to be stripped. Considering we had a trace of oil around the sump, but that none of that oil had dripped onto the main undertray, we cleaned the sump and will inspect it again in a few weeks to see if the leak is still there. Mer-tech finds that many customers live with the problem instead of forking our for roughly one-and-a-half days of labour to fix it.

Other problems will be easier to fix. While inspecting the rear suspension and brakes, Luke shone his torch between the inside of the rear tyres and the telescopic dampers to inspect the brake pipes. He explained that this is impossible to check during the MOT as the four-post ramp obstructs the view. He managed to inspect both rear brake pipes and showed us that deep corrosion had set in, so they’ll need renewing.

We also discovered a little play in the nearside front wheel bearing, but it may be possible to remove this by tightening the hub nut (it’s a tapered bearing). If not, Febi can supply new wheel bearings.

Forward planning

Some of the inspection jobs need a little more forward planning. We had planned to strip down all of the brakes for cleaning, despite the discs not being worn to the limit and the pads being only up to 20% worn. However, we were warned that the retaining pins for the front pads have usually seized and often break, so we will order a full set before proceeding.

So does our E320 appear to have been meticulously serviced? In most cases, yes. For instance, we were pleased to see the pollen filter had recently been changed, although we did find lots of leaves and debris inside one of the air filter housings. Overall, however, the servicing seems to have been completed to a good standard. All we need to do is keep it up.

2

There’s a little play in the nearside front wheel bearing. This is a tapered bearing, so the hub nut can be tightened, which usually removes the play. If not, Febi can supply new wheel bearings.

3

The lower front balljoint is known to wear, so we checked both sides with a pry bar and were surprised to find no problems with either. Even the rubber dust covers were in good condition.

4

The front brake pipes usually corrode, especially where they are routed through to the inner wheelarches. Our steel pipes were fine, so they were cleaned with abrasive paper and coated in grease. The rears were not so good and will have to be renewed.

5

The balljoint on the rear of the front caster arms can become worn, but ours was in good condition. This design of suspension arm is similar to those found on many Jaguars,and is prone to wear in the front bush.

6

The exhaust system mounts located near the rear driveshafts are prone to corroding and breaking off. Mer-tech can weld them back. Luckily, ours only have surface corrosion, although we can’t effectively rust-protect them as most paints will probably burn off.

7

The rear tyres are brand new, whereas the fronts are a little older, but still in good condition. We spin the wheels to look for uneven wear and buckling. Mer-tech recommends 30psi at the front and 32psi at the rear.

8

There are air suspension units with telescopic dampers at the rear. There were no visible leaks from the dampers and the air suspension wasn’t raising any faults. The rear suspension arms and bushes also appeared to be in good condition.

9

Finally, we checked the propshaft. Mer-tech rarely needs to renew the universal joints and coupling due to wear, but it is a problem on the Mercedes Sprinter, which probably receives more abuse than our E-class.