Hi Everyone,
I've been using these methods for years. And I'm not the only one either. Please check them out and please do add your own tips and tricks you've learned over time as well to this thread, if they have not been included thus far.
1A. Diesel engine flush.
Method : Add 1 quart of diesel to your crankcase when you're about to change the oil. Run the engine at idle for 15 minutes. Drain fully and fill up with new oil and change the filter. Any trace remnants of diesel will naturally vaporise and get vented via the crankcase ventilation system during normal driving. Do this at every oil change.
Benefits : Diesel is an organic solvent. This is essentially what those off the shelf engine flushes are. For around 25% the price of one of those bottles, you get 1 quart instead of 16 oz. The more solvent you have, the more cleaning you get. And this is easily obtainable at your local gas station without problems. Which means you can do this every oil change. Which means you're going to have a squeaky clean engine all the time.
ALternatives : Kerosene in very small quantities as its really too thin. Gasoline will not work for the same reason. Stick to diesel. Or pay too much to get too little cleaning with the off the shelf stuff.
Been doing this for : 4 years. No problems.
1B. Diesel engine flush 2
Method : Drain your old oil. Put in a new filter. Fill up with cheap mineral oil (5 quarts). Add 1-2 quarts of diesel. Run the engine at idle for 20 minutes. Drain, and note the colour of the oil that comes out compared to what went it. Then repeat this with a fresh batch of cheap mineral oil and 1-2 quarts of diesel. Reuse the same filter. Run the engine at idle for another 20 minutes. Drain and note the colour of the oil.
Now you can do this one more time, but my experience has been that the colour of the new oil that comes out the 3rd time will be the same as the oil that went in (the first drain should be black, the second would be brown, and the third should be gold), and so its probably a waste of time and money. So do this twice, then change the oil filter and put in your regular fully synthetic engine oil and you're done with a thorough flush. After that, just add 1 quart of diesel to the crankcase at each oil change, run at idle for 15 minutes, and then drain and change the oil and filter as per normal. Do this for as long as you own the car.
Benefits etc : refer to 1A. But doing this at one go cleans out your engine immediately, instead of in stages over a few oil changes. Not critical imo to do this but hey some like it hot so let me put it here.
2. Diesel fuel system flush
Method : Add 2-4 quarts of diesel to a nearly empty fuel tank (you're at nearly zero), and then IMMEDIATELY do a full fillup with regular gasoline. Just switch to the next fuThis will ensure thorough mixing of both fuels and you'll have no drivability issues. Do not use more than 4 quarts on a full tank. Do this at every oil change. If this is the first time you're doing this to your car, do this during three consecutive fillups.
Benefits : Diesel is an organic solvent. This is essentially what those off the shelf fuel system flushes are. For less than the price of one of those bottles, you get 4 quarts instead of 16 oz. The more solvent you have, the more cleaning you get. And this is easily obtainable at your local gas station without problems. Which means you can do this every oil change. Which means you're going to have a squeaky fuel system all the time.
Alternatives : Kerosene, ethanol and rubbing alcohol. These are more expensive and harder to find than diesel, but do not require mixing in the tank. You can pour them in at anytime.
Been doing this for : 3 years. No problems.
3. Italian tuneup
Method : Drive the car at 5k rpm, for at least 15 minutes consecutively, on a highway during a time when traffic is light and road conditions are good (i.e. no rain or snow etc). Best done together together with the diesel fuel system flush.
5k rpm will take you beyond legal (and safe) speeds in most countries, so you'll have to switch your transmission to 3rd gear artificially and keep it there...you should be doing 60-70mph on third gear. Enjoy the engine's roar. Oh yeah, switch to sports mode (probably not significant but hey why not). Ideally, do this after every oil change, but I generally do this whenever I feel the need for speed like it
I've run my car at 6k rpm consecutively for 15 minutes at 3rd gear with no problems to the engine and transmission, no overheating, nothing. IOW, this is normal for a BMW that's working as designed. Groovy.
Benefits : This will do some minor decarbonising of your conbustion chamber and associated areas, helps to clean out your fuel injectors and will give your engine a real workout (we are talking about an e34 here). A thoroughbred must be treated like one from time to time, in order for its essential character to be maintain. People have reported a smoother engine and better fuel economy after doing this.
Alternatives : Well there's seafoam, water decarbonising, et al...but hey nothing beats the fun factor of this thing. You'll step away feeling alot more confident.
Been doing this for : 4 years. No problems.
Note : If you're running an E34 with a timing belt i.e. an 1988-1990 model with the M20 engine, make sure your timing belt is not too old before you do this. Italian tuneups place added stress on a timing belt which is risky when said belt is due for replacement. That being said, if your belt is good, then no issues. Its a BMW.
Note 2 : Only do this on a multi-lane highway with good visibility. Not safe to do this on winding single-lane country roads or the like. You will be too concerned about safety to enjoy the ride.
4. Fuel filter rinsing with water.
Method : Remove your fuel filter. Pour out everything from both ends. Then immerse it in a basin of clean water, and then pour out from both ends again. Repeat this until clear water runs out from both ends at least twice consecutively. Then drip dry and reinstall in the car. Rinse out your filter once a year to coincide with some regular servicing (assuming you would change it to a new one once every 2 years). Change to a new filter once every five years.
The actual rinsing itself should not take more than 7 minutes at most. Any water left in the fuel filter will get expelled through the combustion chambers naturally without causing starting problems. There's always a little water and condensation in the fuel system anyway, and the engine constantly breathes moisture from the environment - so there are no problems. Just switch the key to #2 for 30 seconds after reinstalling the filter to repressurise the fuel system, then start the car.
Benefits : The fuel filter is an impermeable non-chemically reactive media. Its just a strainer made of cellulose, and it traps solid particles. As such it can be cleaned safely with water. Cleaning it regularly keeps your fuel system cleaner and suppresses problems. When you see the gunk that comes out when you first empty the filter, you would be glad to do this more often rather than less. Switch to a new one every 5 years, just for the heck of it. You'll thus end up saving money over the long term. Although the real point here is that your fuel system stays cleaner, longer.
Even if you only wish to do this once every 2 years when you'd change the filter, well, just rinse it out instead thoroughly. You would eliminate 95%+ of the gunk that way...so why not?
Alternatives : Change to a new fuel filter. Its cheap but hey...every dime that you save is going to go back to your car in some way anyways trust me, you're not going to disneyland with your savings, so why not save that dime? And this method enables you to keep your fuel system cleaner more often as well, which is always a good thing.
Been doing this for : 1.5 years. No problems.
5. Air filter washing with laundry detergent
Method : Remove your air filter. Rinse it in running water to get most of the dust out. Then immerse it in a pail full of water with one full cup of laundry detergent. Lather it up good. Leave it for 2 hours or overnight. Remove and rinse with running water. If the water left behind in the pail was really black, repeat the detergent immersion for another 2 hours or overnight. Remove and rinse thoroughly with running water. Gently squeeze and drip dry. Then reinstall in the car. It doesn't matter if the air filter is very damp. The incoming air will dry it out within 30 minutes of normal driving. As mentioned earlier, moisture is constantly entering the engine all the time and that's designed for. There are zero hydrolocking risks with this. No difference in engine performance with a damp filter in there either.
Do this at every oil change or earlier. If you want to make this even better, pour hot water into the detergent bath. It will not damage the filter not to worry.
Since this takes awhile, it may be more practical to have 2 filters at the ready. Install the clean one when removing the dirty one, and wash it out offline and store for later use.
Benefits : The air filter is also a non-chemical solid particle strainer. Remove the solid particles, and you have a clean filter. That's all there is to the physics of non-reactive filters. Since the filter is made of cellulose, its best not to expose it to caustic chemicals such as degreasers and organic reagents. So water and laundry detergent will be fine and works fabulously. This procedure enables you to keep using clean filters as often as you like.
With this method, you can clean your filter more often, and you don't have to keep buying new filters. I would say....get a new air filter once every 3 years. So there, more money saved that you won't be using to goto disneyland trust me.
Alternatives : New air filters, or expensive washable metal filters.
Been doing this for : 1.5 years. No problems.
Note : Some sports air filters have oil in them. The oil will come out when immersed in water. I've been using my KNN with the oil out for the past 1.5 years. I've washed it dozens of times. I've not observed any differences worth a damn with or without the oil. I believe the oil in these filters is just a way for these guys to keep selling something to you, but that's just my opinion.
6. Engine bay washing out with direct water, degreaser, soap and simple green.
Method : Wait till your engine has cooled down - at least 20 minutes after recent driving. Wash it out thoroughly with a hose. Spray the hose everywhere. ANything electrically sensitive is either covered or sealed with multiple layers, so not to worry. After a first rinse, use an entire can of degreaser on all the visible metal parts of the engine and radiator. Spray on the oil sump area from under the front of the car as well. THis is safe for plastic parts (carburetor cleaner and caustic chemicals are safe too but will discolour plastic stuff which is icky). Leave for 5 minutes. Then hose off thoroughly everwhere.
Then use soap and generous lather and get that everywhere on your engine bay. Use a sponge and directly clean if you can reach it. Drip lather onto unreachable areas. Leave for 10 minutes, then hose off once again.
The engine bay can be left wet and the car can be driven off immediately. You DO NOT need to wait for it to dry. You'll have a very slight squeaking sound from wet belts drying off, but that will fade within 30 seconds. The engine bay will dry naturally within 30-60 minutes of driving.
This whole thing will take you anywhere from 15 minutes to 1.5 hours, depending on what you do and how well you do it. But, once you look at that clean engine bay......groovy.
Benefits : A clean engine bay, which is a thing of beauty unto itself. Furthermore, you'll clean out all the old oil stains and you'll be able to spot new oil leaks more easily in future, should they occur. This is important. If you've just bought your car, I strongly recommend that you get an undercarriage wash for this reason. Some professional car washes offer this service.
Alternatives : Pay BMW or some professionals $150 to do this for you, and they won't be using simple green to detail your engine bay either.
Been doing this for : 3 years. No problems to electricals or anything.
Check out what Rick does (he's the resident expert on engine detailing here) :
http://www.bimmerfest.com/forums/showthread.php?p=5978398
And here's what some other people do too:
http://www.youtube.com/watch?v=rPXuU55aeHs&feature=related
http://www.youtube.com/watch?feature=player_embedded&v=30w99uP3uzg
cheers,
Roberto
p.s. I invite comment and controversy over these methods. Please contribute your thoughts.