E24 BMW M6: What you need to know before you buy

Just five years ago, the best examples of the original BMW M6 cost close to $55,000. Today, prepare to add to that figure: According to Hagerty, No. 1 money now sits at $102,000. 

Why the recent interest in the M6? Perhaps because these coupes fill a unique space in the world of early BMW M-cars, one where everything is just right. Goldilocks would approve. 

At the top end of the market, you have the M1 supercar–and with it the prices associated with anything labeled a supercar. The M3, the brand’s touring car special, has been a value buy for years, but those days are have passed; top examples regularly fetch near six figures.

The original M5 sedan is a bit of a unicorn, as BMW only offered it to U.S. consumers for 1988. Further narrowing the field, it only came in black. 

Don’t think of the M6 as some sort of consolation prize, though. Call it what it is: One of the finest coupes ever offered–perhaps more luxurious than a 911, more comfortable than an E-type. It’s certainly more exclusive than either, as BMW sent just 1767 copies stateside. 

BMW based the M6 on the E24-chassis coupe, its 1976 follow-up to the famed 3.0 CSL and related machines. The E24 continued to deliver a roomy, airy cockpit plus that traditional long hood paired with a short trunk. 

The M6 variant finally appeared in 1983, with European customers getting first dibs; U.S. customers had to wait until 1987. The formula, though, remained constant: more power, stiffer suspension and that now-iconic front air dam. 

The original M6 ran through the 1989 model year, retailing for close to $60,000–about $140,000 in today’s money–making it a top-shelf purchase back then, too.

Why You Want One

• Makes a fine grand tourer that also works well around town thanks to a usable trunk, real bumpers and easy ingress.
• Classic lines and smooth power, an everlasting formula for success. Guaranteed to get one with a stick shift, too. 
• Strong support from clubs and shops.
• Racing pedigree thanks to the M6’s strong showings in ’80s touring car competition.
• Can’t swing an M6? A lot of that basic goodness can also be found in the more common 635CSi. Or if you’d like more luxury, seek out an L6–it’s automatic-only but comes with a leather headliner. 

BMW M6 Shopping Advice

Allen Patterson
Korman Autoworks

If you’re shopping for one of these cars, do a compression and leak-down test. The main expenses you will have will be under the hood.

Steer clear of early M6s with the M88 engine, which they shared with the E28 M5. These are all gray-market cars and had to be federalized. U.S.-market cars had an S38 engine under the hood. We’ve yet to find any two M88 cars that were brought up to U.S. standards the same way. The problems with these are not with the body or lighting but with the piggyback oxygen sensor systems. The high compression combined with our fuel and these generic systems inevitably leads to detonation, which in turn breaks the piston ring lands. Even the best-maintained cars eventually succumb to this.

It’s long been thought that the crank hubs on both the M88 and S38 engines were too soft and would eventually allow the crank nut to come loose, but we’ve never seen this happen when the crank nut was properly torqued.

You may be tempted to do away with the vane-type airflow meter in favor of an MAF conversion. We have fixed cars by removing these conversions, but never by putting them on.

Good used transmissions are almost impossible to find, and BMW doesn’t sell new or remanufactured units presently. If you do have a transmission problem, rebuilds are not cheap, but the boxes are very robust.

U.S. cars have dual air-conditioning systems, which are prone to problems. Often the valve that splits the refrigerant between front and rear fails, leaving you with only one part working. The car needs both to keep you cool; that’s why BMW added the rear unit–and its accompanying beverage cooler.

Most U.S. cars have had the rear load-leveling suspension deleted by now in favor of the conventional 635i-type suspension. This is not going to bring down the value of the car much, but we often find that not all the components were removed in the conversion. Do so for weight savings.

If you haven’t replaced all the rubber in the rear suspension, you need to.

U.S.-spec M6s rarely have rust issues unless the undercoating gets damaged, which can occur by jacking up the car.

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