KR1

Hi All,

This will be my first post after browsing through the forum for information regarding repairs on the GL 500 (550). I own a first production, 2006 GL 500 (550) daily driven and currently has 70.000 miles. the car still looks great and the engine running strong, we plan to keep it for another 2-3 years should the car does not cause too much problem. Before i continue, i would like to say that this forum has been quiet helpful in providing information on repairs specifically regarding the Airmatic issues.Thank you all

In two weeks time, i will have a 1000 miles road trip for business purposes. Not only that, i will be doing light to mild off-roading (sand and mud). Right now, im preparing the car for this road trip and would like to ask advice on what needs additional attention. During the last 6 months these are the list of items that have been changed:

Suspension:
- New valve block (Airmatic Compressor was changed two years ago)
- New airmatic suspensions on both front and rear

Engine:
- Water pump and hoses
- Fuel Pump and filter
- Regular oil & filter change, plugs and air filter

Please kindly advice on other list of items that needs to be changed or paid attention. I do not want to be stranded due to a breakdown, or at this mileage which engine parts/sensors that are prone to failing? The engine No is 273963 30 051553 , which is the early model 273 model. Im concerned on the Timing Chain/Gear balance shaft issue. Any information regarding this issue on the GL?

The car also has the 21 inch wheels with Pirelli 295/40/21 tires, with a fairly 'OK' amount of tread left. How do these tires hold up when used in light to moderate off-roading, not speaking of traction but more on strength of the tires itself. Are the Continental CSC5 better tires when it comes to strength?

Thank you all...

BlownV8

The 21's are really an on road type of tire. If you want off-road, you will need to go down to 20" rims or less. Not sure if the 550's rotors will work with 18" wheels. As far as the engine, it's not even half way broken in. You are good there. It's a very robust engine that has been used by MB for a long time across many models.

KR1

Thanks for your reply. What about transmission, is there anythng i need to be worried about? I agree on the 21 inch not suitable for off-road. However it will not be heavy off road.. i will need to go on dirt/sand that is not deep with a little bit of mud. I will try to find a 19 inch replacement though..

BlownV8

Make sure they clear the rotors. On the tranny, have you had your transmission valve body changed? Not sure if that was an issue with your year but was with mine. It failed around 70k miles if I'm not mistaken.

KR1

Noted, thanks for the info. Have not changed the valve body, but i will flush the transmission oil and put in fresh ones with new filter as well.

alx

for any offroading you want 19" or 18" tires... 21" and 20" wheels are grossly inadequate for any off roading.

carry a portable compressor and before medium or worse offroading deflate tires to whatever psi drops the tire height 75% from the stock pressure. when done- reinflate back.

carry a spare compressor relay- very cheap, but they do go when compressor is used aggressively.

carry some extra oil- when your particular engine is tilted a lot during offroading it might burn a bit more oil.

carry a tire plug kit. most punctures you can plug without even removing the wheel from the axle.

was the transmission flushed at 40k miles? if yes- leave it alone. if no- flush the tranny. make sure they also drain the torque converter.

BlownV8

Will 18's clear the 550's rotors?

I had the tranny flushed on mine at 40k miles but my turbine speed sensor went out regardless.

KR1

Thanks for the replies.

Finally came back from the trip. It was overall an great trip with a two day delay due to a blown front left airmatic. Luckily it happened when we arrived and received new parts in two days time. Luckily the off road track we had to go through was not as heavy as expected therefore usng the 21 inch wheels and tires was not a problem and going through sand was still manageable. I also took a ffew pics of my car during the trip.