SL Learning Series
Mastering the 107
OK, listen up! We’re seeing lots of interest in 560SLs lately so we thought some basic training would be in order for anyone who either has one or is thinking about buying one. You won’t get any fluff here, just the facts. And don’t blame me if after you read this article you find you bought a clunker. We could have shipped you a good one if you just picked up the phone!
This is SL boot camp so I’ll just yell the basics at you.
Body! Mercedes-Benz built these cars very precisely with careful attention to how every item fit in relation to another, particularly in the sheet metal and interior areas. All external body sheet metal should fit precisely with even gaps between any adjacent panels. If you could tip that car on its side and roll a ball bearing around the door perimeter gaps, that ball bearing should just cruise around without falling between panels. The same goes for hood and deck lid. Funky gaps mean DAMAGE or prior panel REMOVAL! Nice gaps were the reason my brother made so much money selling new SLs in the late 80’s. “Mr. Spencer, why does this SL cost $65 grand? Well sir our SLs have superb BUILD QUALITY! See, look at these wonderful, even gaps.”
Be SURE to confirm that the warning lights function on the instrument cluster!
Stand back and look at the car! Are the door to fender gaps nice and straight? Is the front bumper parallel to the side moldings which should be parallel to the rear bumper? Open the hood, doors and deck lid to find the body tags (1987-1989). Each panel has a tag affixed by the factory with that specific vehicle’s ID number. A missing tag means replacement panel, not the end of the world but reason to look more closely. Check the bumpers too as you will find body tags under both the front and rear. Missing tags usually mean DAMAGE.
Open the hood and check where the fenders are bolted to the inner aprons! Mercedes painted the cars AFTER attaching the front fenders/doors to the car so all the bolts should be body color and should be bonded with paint to the panels. As soon as a wrench is fitted and bolts loosened the paint bond is broken – a sure sign of repairs. With the hood open, look straight down and you should see a metal plate with stamped numbers screwed to the panel that the hood latch is bolted to. It also was affixed before the car was painted. You should see decals with various emissions/SRS information. If any of this stuff is missing, get your calculator out and deduct thousands of dollars from the seller’s price: THOUSANDS!
With the doors open check where each is bolted to the body of the car! Is the paint broken? There is no reason whatsoever for a door on an SL to be adjusted at the pillar area so broken paint or evidence the hinge no longer sits in its original position is a no-no. Get the calculator out again!
Check the deck lid bolts as well! The underside of the deck lid and fastening bolts are ALWAYS a matte grey. You can tell how the deck lids were painted because often the factory did not flow enough paint to cover the area in the shadow of the lid bolts or the back surfaces of the diagonal reinforcing panels. Hence you can sometimes see the body color bleeding through, a rare lapse in MBZ quality. Broken paint at the deck lid bolts mean the lid was either adjusted or off the car. Not a good sign.
Open the fuel filler door and have a look around! Most body shops absolutely ignore this area and you can find masking tape, overspray, incorrect bolts and just plain grunge if the car sat in a body shop for weeks or sometimes months. When you are poking around the trunk, flop down the carpeted panel that covers the battery on the right side wall of the trunk. Look into this area for bondo dust, color sanding residue and certainly metalworking repairs. It’s the nooks and crannies on these cars that help tell their true stories!
Interior! Aside from the obvious cosmetics that immediately meet the eye, look at the headliner. A 3 inch cut or burn technically means a new headliner, a HUGE job. You can pull the rear package panel up and out of the car. It is carpeted wood. Removing this exposes the unit body of the car, another nook that may reveal an SL’s past. Check ALL the switchgear, everything! Even if the owner says everything works, check them.
The owner may not have flipped the passengers visor down in 9 years! And no doubt, when you get the car home and your wife wants to freshen her lips, the lighted mirror will fall out and the plastic pin that secures the visor to the header panel will break. We’ve learned the hard way. What you overlook will come back and bite you! If you don’t know how things should work, get the owners manual out. The manual should be part of the original literature packet which should also contain the maintenance booklet, dealer directory, top removal instructions, service and warranty policy booklet, radio operation guide and the top removal tools.
Check the climate control system for proper functionality and be sure to cycle through all the vents throughout the temperature range. AC should come out the center vents as well as the left and right dash vents. No air out the center vents during AC mode can mean a massive repair. You would wince if you saw a 560SL with its heater box removed! The interior must be disassembled all the way to the firewall!
Every 560SL was equipped with an alarm from the factory. Many were disconnected and many simply don’t function. You can test the alarm by lowering the drivers window, closing and locking the door and waiting about 30 seconds to make sure the alarm has time to arm. You then reach inside the car and open the door from the inside. This should set the alarm off with horns blaring and headlights blinking. Rotating a master key counter-clockwise in the driver’s door lock shuts the alarm off. Keys with an oval head are referred to as “valet” keys and only operate the door and ignition.
Be SURE to confirm that the warning lights function on the instrument cluster! Turn the key to the 2nd detent without starting the car and note which warning lights come on. Here’s a possible scenario. The SRS (Supplemental Restraint System aka: the airbag) brain fails, triggering the SRS warning light on the dash. An SRS module replacement can be a $2,500 repair so rather than spending the money, owners / technicians sometimes remove the warning light bulb! Problem covered up for $75 instead of the proper repair! The same can occur with the ABS light. If you see a missing warning light, get out the calculator again!
Under the hood
Mechanical! 560SLs can be oil leakers. Valve cover gaskets, head gaskets, rear main oil seals; they all can leak. The 560 engines seem to have recurring problems with the left (drivers) head gasket leaking at the rear corner. Valve cover gaskets eventually get fried by exhaust manifold heat and become crispy letting oil pass from the camshaft area out onto the exhaust manifolds and down the rear of the engine block to drop on the crossover pipe. This means stinky oil smoke on occasion. Get on your knees and eyeball the under engine area! Blackened residue all over the crossover pipe means oil leaks. If you smell burning oil as the car idles at a stop, this means oil leaks.
Rubber items perish on these cars as a result from use and time with no use. The location of the subframe mounts is a little hard to describe. Check the Research Section “Basic Training” photo essay for the location. If there is a 3/4 inch gap between the subframe bolt/washer and the frame itself, this means the mounts have collapsed.
Collapsed mounts allow road resonance to be transferred directly to the unit body and directly to the seat of your pants. The same goes for engine mounts. While the 560 doesn’t generate much power, it does generate a fair amount of torque and is hard on engine mounts. We can get a read on engine mounts by just starting the car. If you feel in you fingertips a resonance as the car rumbles to life, chances are motor mounts are collapsed.
Now here this! Timing chains need to be checked on every 560SL from 60k miles forward! Unless you can see a repair order noting chain inspection / replacement within 10k miles or so, have a tech check the chain for you. Yes, these cars have the double width chain and no, they don’t last forever. If you hear a few seconds of metallic slap from the engine area during the first startup of the day, you need to pay attention. The tensioner might be dead and/or the chain may have stretched enough to rattle cold. This is a serious issue and you should have the chain/guides inspected. Chain failure while at speed means pistons reach the top of the cylinder chamber to be met with open valves. CLANG!
That’s all for now. Dismissed!
roy spencer/editor mercedesheritage