Good morning everyone
I've just bought a W208 1999 CLK430 with ONLY 9660Km! (that's less than 6000 miles for you folks!) it still smells like dealership.
The car sat in a garage for many years, only service @ Mercedes was done in 2010 (oil and battery change).
I have changed differential oil, engine oil and filter, battery. reset the transmission, wiper blade.
Car passed Aircare inspection (Canada) and runs extremely well, I had the fuel gauge not working well and a code P0450 (Evap sensor) that pops up and I hope is the fuel cap and the fact that has been sitting so long!

Any suggestion from the experts? transmission fluid seems to be good, no leaks, I was thinking about changing the brake fluid.

Ill post pictures soon since really this car is unique! and I love it.

 

I would definitely change the brake fluid as it can absorb moisture and: change the coolant a.s.a.p. Antifreeze (I am told) that sits in an engine for a long time without change can become quite acidic and very detrimental to an aluminium water jacket.

the following is a copy/paste: Vehicles using Extended Life antifreezes should be changed in about 50,000 miles or 4 years to prevent system damage and radiators and heater cores from plugging up.

WATER CONCENTRATION/ANTIFREEZE CONCENTRATION SHOULD BE AT LEAST 50%
The modern antifreeze, however, does much more. It provides year-round protection of the cooling system: It prevents freeze up in winter and boilover in summer (especially in cars with air conditioning). It provides protection from rust and corrosion and does not harm rubber hoses and plastics.
A desirable antifreeze should not corrode metal parts, attack rubber, become viscous at low temperatures, or evaporate readily at the ordinary engine operating temperature. It should be chemically stable, a good conductor of heat, and a poor conductor of electricity (which causes electrolysis).

The performance requirements of automobile antifreeze became more severe during the 1980's. The reduction of the overall mass of vehicles to improve fuel economy entailed extensive use of light materials such as aluminum and plastics for the construction of engine and cooling system parts.

The volume of antifreeze used was also drastically reduced to further reduce weight, subjecting the antifreeze to high rates of flow, high temperatures and significant metal-to-coolant heat fluxes. Today's smaller, efficient and powerful engines dissipate more heat, requiring that the antifreeze keep the heat exchange surfaces in clean condition. In addition, corrosion, which in itself is of concern, can also result in heavy corrosion deposits that impedes heat transfer.


What is Electrolysis?
As the additives in your coolant that keep it neutralized become depleted over time the coolant actually develops an electric charge from passing over dissimilar metals. You can even measure this voltage with a voltmeter! This small electric current removes metal from engine surfaces leaving large pits or holes and can eventually eat entirely through a component. It can also weld bolts and fittings to the engine and components.
This can be caused by coolant that is too old or antifreeze mixtures that are not close to 50%.

A Digital Multi-meter can be used to test for this.

Attach the DMM ground probe to the negative battery post.
Insert the tip of the positive probe into the coolant and observe the reading.
OK - less than .10 volts.
Bad - anything above .20 volts.

Electrolysis destroyed this headgasket. (picture) It started leaking from a coolant passage to the outside of the engine after the material was eaten away.

 

Sitting long periods is not always kind to a car. If your still rolling on 14yr old oem rubber, I'd swap in a new set of shoes before you learn the term DRY ROT at highway speed. Last thing you want is a tire to come apart on the freeway and have bad things happen very very fast! You wont always get the warning cracks and 10 years is bout max for tires to still be considered "safe".

 

I have to agree with everyone here. The worst thing for any vehicle is to sit,unused for extended periods of time. Change the coolant/antifreeze and brake fluid. Install new tires. Inspect all belts and hoses for any cracks or dry rot. If you can take it to your local MBZ dealer and have them do a PPI just for good measure. After all of that drive it under normal conditions to see how she behaves. If all is well after that,drive it like you stole it and put that permagrin on your face.