I've been piecing this together little by little over the past few months in my spare time. I figured mind as well post it up. It's a work in progress. But we seem to have a decent amount of noobs around here lately, so hopefully it will help someone.
Should you buy an E36 M3?....
Let's first understand what the car is and where it came from. 3 simple points to make about the car...
-The E36 M3 was originally designed in the early 90s (as a bit of an afterthought, though that's beyond the scope of this thread) as a higher performance version of BMW's normal 3-series cars. With a price tag of around $40,000 or higher throughout its production period, the car had a target demographic that consisted of people that likely have/had more disposable income than you or I. They were able to afford taking it to the dealer for service and paying insane amounts of money to maintain the car. To put things into prospective, the previous owner of my car spent more money at the dealership service department than the amount of money I paid for the car when I bought it.
-Another fact about the car is that unlike a lot of automobiles on the road, the recommended service life of its components is not to be taken lightly. The original owner of the car likely drove it for 50-60K miles, or maybe 100K miles at most and unloaded it right around the time major cooling system components, suspension components and other things were at or past their recommended service life. This leaves you and me with a great car that probably happens to require a good amount of attention in the 2nd leg of its life if we intend to drive it without catastrophic failures.
-A third fact about the car (that will lead us to the point i'm trying to make here) is that it's a BMW. Parts are not cheap.
If we add these 3 things together, we can extrapolate one simple thing that will give you a bit of insight into E36 ownership: Despite the fact that these cars have become very cheap to buy, there were never designed to be cheap to own. A general rule to live by is that the lower the purchase price of the car, the more maintenance you have to catch up on after you buy it. The car will be very reliable if the maintenance is kept up to speed and you keep a proactive approach to maintenance by replacing things before they break. This requires one of 2 things: 1) Deep pockets to pay a shop to maintain the car for you. Or 2) A lot of knowledge to do it yourself.
THE E36 M3 YOU'VE SEEN ON AUTO TRADER/CRAIG'S LIST/ETC FOR A NICE PRICE WILL *NOT* BE AN EXCEPTION TO THE RULE.
Every noob that stumbles in the forum seems to be under the same delusion. Let go of the hope that you will not have to maintain the car like everyone else, right now. The car will cost money. You will have to replace parts, or they will break. You will have to learn the chassis pretty well, and stick around here to know exactly what failures you'll need to watch out for. If you're the type of buyer that's clicking "sort by cost: low to high" when you run AutoTrader searches...ask yourself if you honestly think the cars you'll be looking into will be a different ownership experience than every other car owned by every other person on the forums here. Plan on doing work on the car and spending money to keep it running. It comes with the territory. The E36 M3 is not a Honda or Toyota. It's a very very rewarding car to own and is a very reliable car *if* maintained properly. But at this point, it's basically a car to be owned by enthusiasts that don't have a problem wrenching on their own car, and don't have a problem owning a car that's a little more needy than average, in exchange for a more involving ownership experience than average.
There's a reason BMW's have such a dedicated following. But, there are prices to be paid for the positive aspects of the car that draw people to it. Nothing is all pros and no cons. You're here reading this to get an understanding of if that list of pros and cons is something you're willing to deal with.
Is the E36 M3 fast?
The E36 M3 imported to North America is stocked with a 240HP inline 6 that has a nice amount of torque. Coming from a Honda Civic, Acura Integra, or the like, the M3 will seem like an absolute monster. It's a reasonably powerful rear wheel drive sports car, and should be treated as such. It has enough power to get a driver into trouble if they're not intimately familiar with the handling dynamics of a rear wheel drive automobile. That being said, the E36 M3 is not a drag racing car. It wasn't built to race WRX's on the highway, or to stoplight race the new Civic Si. The car was designed around balance and overall driving experience. Power isn't *that* abundant, and extra power above stock numbers comes at a premium. GO fast mods generally yield paltry horsepower per dollar returns. If you've owned a fast car in the past, the E36 M3 will likely be fun to you, but it's far from powerful when compared to cars with *real* power.
We're not going to get into magazine racing here, but to put straight line performance into prospective:
-An 8th Gen Civic Si with a few bolt ons will give a stock M3 a run for it's money. A well modded 8th gen Si will pull away from a stock M3. If both cars are lightly modded, they're about even.
-A Stock WRX can't quite keep up with the E36. The M3 will pull away steadily. A Stage II WRX is a different story. Stage II WRX's will run neck and neck with a stock M3, or some protuned ones with extras like TGV deletes turbo inlet, etc will edge out a bit.
-A stock G35 will run about even with an E36, or pull away slightly depending on the year.
-A stock new Mustang GT will slowly and steadily pull away. One with even the slightest bolt on modifications will walk the E36.
Now, if you're more concerned than that, go watch some youtube vids. Enough said.
Do NOT buy an E36 M3 if you're in search of a fast car that will hold its own in a straight line when put up against modern sports cars, if you want a car that will respond well to modifications and will easily and cheaply gain horsepower over stock, or if you want a car whose strong point is straight line acceleration.
DO buy the E36 M3 if you're looking for a car that has wonderful balance, unflappable road manners, impeccable handling, and a chassis that's capable of amazing things with a little suspension know-how and some suspension tuning. Buy the car if you're more concerned with tearing up deserted back roads by yourself than cruising the nearest 4 lane road in search of cars you think you can beat to the next traffic light. Buy the car if tearing around highway off ramps puts a bigger smile on your face than seeing how many tenths you can drop off your 1/4 mile time by installing under drive pulleys and a 3.91 diff. Buy the car if you want something that has a perfect balance of performance, practicality, economy, comfort, and driving experience...wrapped up in an affordable package with timeless design that still has yet to look dated on the road next to modern cars.
So what's all this maintenance that you're talking about?
The following is a list of common items of concern for the E36 chassis. I'm not going to go over recommended service life of components. Just understand that if you buy a car that doesn't have any record of X part being replaced, you should be replacing it, some sooner than later.
--Rear shock mounts (RSMs)
The RSMs provide a means of fastening the rear shock shaft to the shock tower of the car. The rubber in these mounts tends to fail over time, which causes freeplay in the mount. Eventually this causes unwanted stress on the shock tower and sooner or later the shaft will pull away from the mount and wind up punching itself into the bottom of the tower when the car goes over elevation changes. The other scenario is that the metal will fatigue from the shock rebounding, and the entire mount will punch through the tower. Either scenario will leave you with completely destroyed shock towers, requiring new ones to be welded in. This is most likely not something you can do in your garage.
Replace the RSM's before they fail. The cost of a new pair of shock mounts runs anywhere from $40-$120 and installation can be done in under an hour with simple hand tools. When choosing mounts, understand that pretty much any aftermarket mounts out there will have a longer service life than the stock E36 mounts. Also understand that the longer service life is a consequence of a more robust design that usually transmits more force to the shock tower, and therefore you should have some sort of reinforcement on the tower to prevent stress cracks from forming...
In addition to replacing the mounts, there's a deficiency in the design that would behoove you to rectify. On the bottom of the tower the mount disperses the force of the shock pushing up into the tower. However, the top of the tower consists of the 2 mounting nuts for the mount. When the shock rebounds, this force is only dispersed over the area of these 2 small nuts. This isn't the best way to preserve the thin, weak sheet metal. There are reinforcement plates available that go on the top of the tower to disperse the force of the shock rebounding. There are no downsides to using these reinforcement plates, they should be on every E36 on the road. They are sold by every major vendor and are pretty cheap, at $25-50.
How common are problems with this? How long do the parts last?
The RSM's are a wear item. OEM RSM's have an approximate service life of 60K miles or so. Service life can be *drastically* reduced by environmental factors, modifications, or other factors. Shock tower failure is what i'd consider a moderate occurrence, high consequence issue.
--Rear Trailing arm bushings (RTABs)
The RTABs couple the front of the RTA to the chassis. The position of the RTA at this mounting point is what's responsible for the toe of the wheel. For this reason, when the RTABs wear out and become deformed, uneven tire wear can result due to the toe being out of whack. The car will chew up rear tires for breakfast if you let these bushings fail. There are 3 main options for replacement; Stock rubber, stock rubber with limiters, and Poly bushings.
Replace your RTAB's at regular intervals
OEM replacements have the most compliant ride, and least amount of NVH. They allow the most suspension travel under cornering load, which is arguably how the car was designed, but it's this travel that winds up wearing the bushing over time, making the rear end feel loose under hard cornering or acceleration. OEM is much more difficult to install than poly. The bushings need to be pressed in to very specific tolerances, and also need to be preloaded. The pre-load is specific to the ride height of the car and therefore if anything other than small ride height changes are made, it needs to be repeated at the new ride height (a concern for those with coil overs).
Limiters aka RTAB shims will limit the amount of travel under cornering load. These are only used with OEM RTABs. They will make the rear end feel a bit more taut at the limits and will extend the life of the RTAB a bit. But they arguably limit the range of travel that the RTAB was designed to permit, slightly. The issue with this is that if you're riding on stock shocks and springs, the tire's contact patch on the road can be theoretically reduced under hard cornering. However, if the reduction is only slight, and they provide a more assuring feel at the limits, are you really loosing anything? Like most mods, you give some to get some. I'm running this setup on my car and i'm happy with it.
Poly RTABs are much easier to install than OEM. They require no preload procedure. Ride quality diminishes a bit, as you can definitely feel the more rigid material when you're driving around. The car takes bumps harder, but provides a more taut feel when cornering and provides more resistance to bushing flex under hard acceleration while cornering. The harder material provides less flex than rubber and therefore is a more extreme version of the situation we described above with respect to reduced suspension travel. Think of it as a few more steps in that direction. Poly will squeak if not lubricated liberally. Poly allows the ride height of the car to be changed without re-preloading the bushing again (requiring the RTAB carrier to be dropped, and thus requiring an alignment).
Replacement RTABs cost $40-80 and installation takes roughly 3-7 hours, depending on a number of factors.
How common are problems with this? How long do the parts last?
The RTAB's are a wear item. OEM RTAB's have an approximate service life of 80-100K miles or so. Service life can vary due to environmental factors, modifications, or other factors. In the past, i'd consider RTAB failure a low occurrence, low consequence issue, as it tends to happen over time and the consequence is usually just uneven tire wear. However, something to note is that recently we've seen more and more failures of the sheet metal that the RTAB carriers bolt into. This is the section of the unibody where there are (3) threaded bungs welded in to hold the RTAB carrier (aka "console") in place. Letting the RTABs on your car get worn to the point where the rubber is torn and the trailing arm is slapping back and forth in the carrier will eventually result in failure of the sheet metal or the welds that hold the bungs in place. The RTAB can rip out of the unibody completely without any warning, and while the vehicle is in motion. I don't think I have to explain how dangerous this is. This is something to keep an eye on as the cars age, especially in areas where cars are prone to underbody rust.
See this thread for a closer look at what this failure looks like:
--Tie rods/Tie rod ends
This isn't so much a problem, as tie rods are a wear item on any car. Though, it's definitely worth mentioning. The tie rods are responsible for moving the front wheels based on input from the steering rack, and ultimately the steering wheel. They have an integrated ball joint designed to allow them to operate as the wheel/hub assembly moves about from elevation changes or other movement. This balljoint (and the boot holding in the grease) has a finite lifespan. When a tie rod end ball joint get worn, the alignment of the wheel (specifically the toe) gets thrown off. This will lead to uneven tire wear, and it may not be something you'd notice until the insides of the tire(s) is/are worn down to the belts.
Replace the tie ends or entire rods. OEM Lemforder replacement tie rod ends (the only way to go, stay away from Meyle and other cheap brands) run roughly $100 for both sides. Installation will take roughly 30 minutes, may require a ball joint puller and a torch to heat up the stock ends to break them free. An alignment will obviously be required after tie rod replacement.
How common are problems with this? How long do the parts last?
Tie rod ends are a wear item. This is a low occurrence, low consequence issue, as worn tie rod ends will just lead to uneven tire wear. Expect the OEM tie rod ends to last for roughly 80-100K miles, though service life can be drastically altered by environmental factors, driving style, or other factors.
--Other components to keep in mind
Front ball joints; they are integrated into the control arms so they must be replaced as a single unit. Worn ball joints can cause sloppy front end feel and possibly clunking sounds from the front end. Rear ball joints; These connect the rear trailing arm to the upper and lower control arms. They tend to wear over time, causing sloppy rear end feel. Shock absorbers; They tend to have a service life of 80k-100K miles and should be replaced accordingly.
Cooling system components:
The water pump is a direct drive component that has a mechanical cooling fan rigidly mounted to it. This means that the condition of the bearings in the pump is a VERY important thing to keep track of. When the pump fails, it causes an unbalance in the fan that will ultimately send shards of plastic flying all over the engine bay, severing the nearby coolant lines, and consequently overheating the car before you know what's happening. It doesn't care how attentive you are to the temperature gauge, there is thermal lag inherent in the gauge. Its all too easy to overheat the motor as a consequence of cooling system component failure.
--Mechanical fan and clutch
The fan should spin freely with a bit of resistance while the motor is cold and off. If it does not spin, or spins without any resistance, the clutch needs to be replaced. The fan itself goes through a lot of thermal cycling and should be checked periodically for any cracked or missing blades. This will start as a slight shaking noticeable from inside the cabin, and will soon destroy the water pump bearings leading to the death of the pump, the fan, and everything around them. Also, worn motor mounts can allow the fan blades to contact the fan shroud, making them more prone to breakage. Inspect the blades and shroud for signs of contact.
-Radiator, expansion tank, and hoses
These components should be checked periodically for cracks, breakage or leaks. The expansion tank has a high failure rate and shouldn't be trusted much beyond 80-100K miles of normal use.
This is a rubber flex disk that couples the drive shaft to the transmission. It has 6 large bolts going through it to connect these 2 parts. This item sees a lot of stress, heat cycling, etc. Fatigue starts as barely visible hairline cracks around the bolt holes. These can quickly spread, tearing the rubber apart which leads to unbalance in the driveshaft and can ultimately lead to driveshaft separation. Periodic visual inspection is a good idea.
--Motor and tranny mounts
Worn mounts should not be taken lightly, as they can make the car prone to mis-shifts (the infamous "money shift", which is not a club you want to be part of), can cause the cooling fan blades to contact the shroud (see the cooling system section above), and can even put undue stress on the power steering lines, which don't have a lot of slack in them.
--Diff mounts and mounting bolts
The rear differential mounts to the rear subframe at 3 mounting points. There are 2 rear mounts, and one front one. Worn bushings at these points can cause excessive freeplay in the diff. But the bigger issue is the fact that there is only *one* mount in the front. This mounting bolt (aka, front diff bolt) is prone to breakage under high torque situations. It can, and has broken in completely stock cars. When doing maintenance, it's a good idea to replace the bolt, which costs under $2 from the stealer and takes 60 seconds to swap out with a new one. Waiting for it to break will result in you having to drop the diff to either drill it out or use some other means of removing the sheared off remains from the rear subframe.
The power steering lines feeding the power steering fluid reservoir are VERY prone to leaking. It's not a matter of *if* they will leak, as much as *when* they will. Many many E36's have leaky PS lines. This should not be taken lightly, as running the PS pump or the PS rack low on fluid will damage them. It's a BMW...they're expensive.
The motor, transmission, and diff should be checked for leaks periodically, like any 10-15 year old car.
How common are fluid leaks?
I'd consider PS fluid leaks a very high occurrence, low risk issue. I'd consider all other fluid leaks low occurrence, low risk issues. Most leaks will take a while to get bad enough to deplete the fluids to the extent that damage will be done. The E36 is no different from any other car in this respect. Though, given the very high occurrence of PS fluid leaks at the reservoir, that's something you should give a quick look every time you're under the car doing an oil change (your view of the PS fluid reservoir is blocked from above by the stock air box).
Other mechanical issues:
--Oil pump nut
The S50 and S52 motors have a chain-driven oil pump that is driven by a single sprocket. This sprocket is secured to the oil pump by a single 19mm reverse-threaded nut. This nut has been known to back off, which causes the oil pump sprocket to fall off the shaft, resulting in the oil pump stopping immediately. You have a brief moment after the oil light illuminates to turn the ignition key and stop the motor before it seizes due to oil starvation. Basically, a single 19mm nut can destroy your motor in a matter of seconds.
Secure the nut with something other than good old fashioned torque. There are 4 main methods by which people secure the nut with more reliable means;
-Safety wire (buy a safety wired nut that can be secured with wire to the sprocket)
-Thread locker (must be high-temp, high-strength automotive grade Locktite or equivalent)
-Welding (put a small tack weld on it. NOTE: people have started fires doing this, be sure the sprocket is free of oil and/or degreaser first!)
-Stake the threads (use a punch or something similar to fold over the threads, so the nut can not back off)
You may use any of these, or any combination of these at your own discretion. There are obvious pros and cons to each method, but any of them (when done right) will alleviate the issue.
How common is this?
I'd consider oil pump nut failure a low occurrence, extremely high risk issue. There is NO correlation between vehicle mileage, driving style, environmental factors, production year, or any other factors with the failure of the nut. It's not a high occurrence issue, but it can happen to any E36, at any time.