The Mercedes SLS AMG Coupe Takes Off Its Top

The Mercedes SLS AMG Coupe Takes Off Its Top

The Mercedes-Benz SLS AMG coupe debuted this year at the Frankfurt Motor Show, scheduled to go on sale as early as next year. For those of you who have seen this beauty, the concept of a convertible version makes perfect sense. Yes the Mercedes SLS AMG convertible version has been leaked onto the internet, spurring rapid-fire rumors of its existence. The rumors, photos and videos have only served to amp-up anticipation for this exotic beauty. So let's compare the Mercedes coupe and the convertible. The notable disparity is that the convertible version spied lacks the suave Gullwing doors featured on its coupe predecessor, replaced by standard doors. It may be less James Bondish, but it is ideal for warm weather destinations. We are thinking that it would make a stellar addition to any fleet of exotic rental cars, adding an understated and sporty option to appeal to the masses. If the rumors are true, the door marks the only difference between the SLS AMG coupe and the SLS AMG convertible. Both are said to feature the same 6.2-liter V8 engine capable of 563 horsepower and 650 Nm of torque. As for the 0-60 test, the Mercedes SLS AMG coupe version hits it in an impressive 3.8 seconds, and that leaves us to assume that the topless version will lag somewhat behind, likely at an even 4 seconds. It is always a welcome addition when a great supercar paves the way to a "convertible" or often named "roadster" version of itself. The market for exotic convertibles and exotic rental convertibles will certainly have room for one more!

For some reason, Mercedes-Benz decided to use a single row timing chain in the M271 engine while its predecessors, the M111 and the even older M102, had double row timing chains, which were very reliable. The timing chain should be watched in the M271. If it starts showing any symptoms of stretch, it should be replaced. It鈥檚 difficult to estimate precisely how long the chain will last. There have been cases of chain failures at 80k miles, and there are cars that go far past 100k without any problems. In my opinion, you should treat the chain as a 100k miles service item if you want to be really safe. 1. Avoid the M271 engine entirely. 2. Get one that already had the chain and chain tensioner replaced. The replacement chain should be good for another 100k miles. 3. Buy the car, and plan to get the timing chain replaced at some point.

The timing sprockets may need replacing as well if they are worn. A typical symptom of a stretched timing chain is a chain rattle that lasts a couple of seconds after a cold start. In severe cases, the engine may be difficult to start as well. Usually, the 鈥淐heck Engine鈥?light won鈥檛 come on. Click here to learn more about timing chains and how to check them. The M271 engine is equipped with Variable Valve Timing (VVT). Mercedes-Benz employed VVT in most petrol engines from that time. The VVT system is operated using two camshaft solenoids attached to the front of the engine. The solenoids occasionally develop minor leaks, which would normally be completely harmless. What happens is that oil, leaking out of the camshaft solenoids, can enter the wiring harness and embark on a great journey through the wiring to the oxygen sensor, mass airflow sensor (MAF) and finally the Electronic Control Unit (ECU). A pretty ridiculous problem, don鈥檛 you think? This is possible because of capillary action - the ability of a liquid (engine oil in this case) to flow through narrow spaces (wire strands) without the assistance of any external forces.

If this sounds astonishing, think about how difficult it is to predict such behaviour. Don鈥檛 be too hard on Mercedes-Benz engineers. If oil gets into the wiring harness, most of it will end up at the oxygen sensor, which usually fails first. If the oil isn鈥檛 stopped, it may reach the MAF, and lastly the ECU. The solution is simple - fix any leaks from the camshaft solenoids, and fit short extension cables (pigtails) so that the capillary action is interrupted at the pigtail. With the pigtails fitted, the oil cannot travel further to the actual wiring loom, which is plugged into the pigtail. If you鈥檙e going to buy a car with the M271, I advise you to check the plugs on the cam solenoids for any oil. They are on the front of the engine and easy to get to. If the oil has already contaminated the wiring loom, then it will need to be cleaned or replaced.