Recently, I had my first ever “Oh my god, Am I going home today in a tow truck?” moment with my 1996 BMW E36. I was at an autocross event that day, and everything started well. The car felt great all morning, it was a Test & Tune event, so I was mostly there just to throw the car around and have some fun. Towards the end of the morning, I had gotten the hang of the course layout and was starting to give a couple people ride-alongs. However, my runs were numbered, I just didn’t know it yet.
Here’s the thing. If you aren’t familiar with BMWs, let me fill you in. I’m personally most familiar with E36s (the 1992-1999 3-series generation), and while they are absolutely fantastic cars, they are notorious for cooling system failure. Typically from what I’ve seen, the main culprit for this is the fan driven by the water pump. It isn’t necessarily that the fan just blows up, but usually it's that the fan shroud comes into contact with the fan at some point for a variety of different reasons. But whatever the reason is, the odds of the fan shredding some or all of its blades are pretty much guaranteed.
I’m going to clarify something real fast, I just want to say that I got off extremely lucky in my situation. Normally when the clutch fan decides to blow up, it’ll destroy the fan shrouds, rip the coolant bleed line, and I’ve even seen it puncture the radiator before. Most of the time when this happens, it isn’t pretty and your E36 is more than likely going home on the back of a tow truck. I can only speculate on what happened and why I was so lucky in the first place, but let me tell you my theory about what happened. On the layout we were driving, there was one corner in particular after a high speed slalom where mostly everyone was topping out 2nd gear coming into the braking zone. The hard braking combined with throwing the car into the corner likely popped the fan shroud out of place or shifted it ever so slightly to the point where the fan came into contact with it. The fan shroud got pulled over the top of the fan and with it came the bleeder hose, dumping coolant literally everywhere.
The part where I got extremely lucky comes in with the fact that after pulling the fan shroud back over the fan and inspecting the damage, I found that only a SINGLE blade had been ripped off the fan - I still have no clue how the rest didn’t go with it. The fact is that this spared nearly everything in the vicinity of the fan, minus some mounting points for the bleeder hose on the fan shroud, and well, the fan itself. So needless to say, I was done for the day. I patched up what I could and zip-tied everything away from the fan, because I knew I wasn’t going to be so lucky next time if it was going to happen again. Before I get asked why I didn’t just take the fan off since it was broken and now totally unbalanced, I tried but I didn’t have the right tools with me and at some point I said screw it, I’m buying a new water pump anyways. So the plan was to just get the thing home one way or another without shedding any more blades. But stupid me forgot to think about one last thing, and it was the fact that I had just dumped at least a gallon of coolant everywhere.
Making Things Work
From the autocross course, I had a nice and stressful 50 mile drive home on nothing but country freeway. It was pretty naive of me to think that the drive home would be fairly smooth, I just had to try and keep my RPM low to keep my clutch fan from shredding itself. Probably no more than a minute or two after I passed the only gas station in a 10 mile radius, I looked down and noticed the coolant temperature needle start climbing rapidly from optimal temperature. So long story short, I called my brother who was thankfully only a couple minutes down the road in the opposite direction. Since there was no distilled water to be found and I didn’t really want to take a chance at mixing coolants either, we ended up settling on using bottled water to fill up and bleed my cooling system. Not really the best idea, but hey, you have to work with what you got. I drained and flushed out my cooling system with distilled water pretty much as soon as I got back in an attempt to clean out any minerals that could cause rust to build up.
Don’t Neglect your Cooling System
If there’s absolutely anything to take away from the experience that I had, it's that you absolutely should never neglect your cooling system. I’m not saying that you should go out and completely overhaul your cooling system like I’m doing now, but it is definitely so crucial to be aware of anything that may be an issue or could present itself to you as an issue sometime down the road. I personally advocate for dealing with that potential issue outright, especially if it’s a sort of situation where your cooling system is generally the system most prone to failure, like with many BMWs, both old and new. Obviously that’s much easier said than done, though, considering how it can be fairly easy to rack up a big bill on even just parts for this stuff.
Even with taking a budget-friendly approach towards maintenance, there are plenty of ways in which you can be proactive towards making sure that the components in your cooling system last as long as possible. For starters, keeping track and performing maintenance on time according to your car’s maintenance schedule will do a lot in terms of making sure you get the most life out of each system.
How to Stay Ahead of the Game
One of the best and easiest things you can do to stay on top of any cooling system issues that might arise is to just check your coolant level and make sure that there are no leaks at least semi-regularly. Keeping tabs on your coolant is very important, because noticing a change in its level can be indicative of some potentially serious problems looming.
If your coolant level has decreased over time and you can find a leak, then odds are that patching that leak will keep your car from running low and starting to overheat.
Coolant level changes with no leaks present is often a telling sign that there are potential head gasket problems, which should be addressed as quickly as possible.
Another good way to keep cooling issues at bay is to make sure that you are using the correct type of coolant for the climate that you live in. Generally, coolant is a 50/50 mixture of both antifreeze and distilled water. The antifreeze can come in a variety of different colors, and the colors typically have different properties. Because of this, it is often best to use what your car’s manufacturer recommends as guidance when deciding what type of coolant you are going to use. Also, mixing coolants is not really a good idea either, even if on the surface it seems like mixing different colors together will let you reap the benefits in a “best of both worlds” type scenario. Mixing coolants gives you results that at best decrease the effective lifespan of the coolant. At worst, given the right combination, mixing can cause the coolant to gel which will result in blocked passageways and reduced or no coolant flow. This is something that can obviously be catastrophic for any engine.
On top of the two aforementioned ways of staying ahead of the curve when it comes to your cooling system, the third thing that should be done is just making sure that you’re staying on track with your vehicle’s coolant flush schedule. As with anything else, the interval at which you should be flushing your coolant is going to vary depending on your vehicle’s manufacturer, so the best thing to do would be to consult your owner’s manual to figure out what that might be. The general rule of thumb is generally that you should flush your coolant every 30,000 miles or 2 years, whichever comes first.