Maintenance

Most people will operate their DSM under one or more conditions deemed "severe" by the manufacturer. For severe (typical) operating conditions, oil changes are recommended each 3 months / 4800 km / 3000 miles.

Non-severe conditions: 
For 1G turbo models, oil changes are recommended each 6 months / 8000 km / 5000 miles. For 1G NT models, oil changes are recommended each 12 months / 12,000 km / 7500 miles. For 2G turbo models, oil changes are recommended each 6 months / 8000 km / 5000 miles. For 2G NT models, oil changes are recommended each 6 months / 12,000 km / 7500 miles.

The proper oil weight depends on the temperatures the car is driven in. For 1Gs, both NT and T models can use 10W-30 between -23 and +50 degrees C (-10 to +120 degF). 5W-30 can be used for lower temperatures. 1G cars hold 3.9L (1.8L engine) or 4.4L (2.0L NT and T engines); the oil filter holds about 0.4L, and the oil cooler (if present) 0.3L.

Some owners recommend you change the oil twice as often as required, or use synthetic oil and change at recommended intervals. There is no proof that this treatment extends service life.

The Last Word: Face it, the car is getting old. Unless you're a fanatic, the recommended intervals is probably fine.

By far the most important aspect of engine oil is to have the proper grade.

Update: Check this article (PDF) written by Forced Performance | Recommedations for Motor Oil

As is true for many automotive enthusiast groups, DSMers generally recommend fully synthetic oil for general use. Synthetic oils can withstand higher temperatures than mineral oils, and contain less wax, which theoretically leads to less residue building up in the engine.

However, some members stick with semi-synthetic or regular oils, and may or may not change them more often than recommended. A good case can be made for using either type of oil, so it usually comes down to the owner's personal preference.

Engine oil brand is even more debatable than oil type. There are dozens of brands on the market, each slightly different from the last. Fortunately, almost all of them will work just fine in all autmotive applications, including DSMs, allowing owners to pick whatever brand they have confidence in.

If you have deep pockets, these are talked about:  Brad Penn, Royal Purple (w/ Zinc. Not RP canadian Tire version) and Rotella

Some DSMs came equipped with a 'small' oil filter, and some with a 'big' oil filter - apparently a difference between Chrysler and Mitsubishi, as well as between different model years. Both filters appear to work the same, so owners generally don't sweat too much over which one to use.

A few owners with modified exhaust systems have found that the 'big' filter doesn't fit their car anymore. Changing to the small version seems to work fine for them as well.

As for brands, filters are like engine oils - it is nearly impossible to identify a 'best' oil filter. Many different oil filters seem to work equally well, and there is almost nothing to distinguish different brands from each other.

In a quest for knowledge, Russ Knize took a bunch of oil filters and cut them apart, to see how they compared internally. The results of his work have been written up on the Oil Filter Study page, which details the comparison of the different filter types. He also has a separate page detailing his personal recommendations on which oil filters should perform the best.

Final Word: Highly recommend to stick with Mitsubishi Filters

No, you don't. It is true that the original Mitsu/Chryco oil filters have a small check valve in them. The common belief is that this check valve helps maintain oil pressure, and keeps oil in the engine while the car isn't running. (Dealers often repeat this tidbit of DSM 'lore' in an effort to steer owners away from the popular oil-change companies.) Some suspect, however, that the valve is nothing more than a bypass valve that allows oil to circulate even if the oil filter becomes too clogged to operate properly.

In any event, the aftermarket oil filter manufacturers include the check valve in their own offerings for the DSM triplets. This makes perfect sense, as it is unlikely that either Mitsubishi or Chrysler manufacture their own oil filters. Those who prefer OEM parts may, of course, stick with what they are most comfortable with, but it is by no means mandatory.

Final Word: You should still stick with factory but do not need to.

   and other 'trick' products

This class of products generally includes those products which promise significant improvements in engine power, longevity, durability, economy, and emissions in one convenient package.  They either utilize proprietary formulae added to gasoline or oil, or provide some type of 'improvement' in the engine intake systems.

The pervading opinion on the Talon Digest, as well as on most other automotive mailing lists, is that these products provide few or none of the improvements they claim.  Few people have been able to verify these claims through real-world dyno or track testing.  Many of them cost as much or more than parts which have been shown to work, over and over, by the Club DSM membership and specialtyvendors, so you may wish to spend your money elsewhere.

As oil additives are generally the most pervasive "magic" product, they deserve special attention. Commercial engine oils are already formulated with several additives in them. The formulae are usually referred to as "synergistic" - that is, the combination of additives work together to produce greater effects than any single additive alone.

Engine oils are already manufacturered with great attention to detail. It is not likely that any separately formulated additive will greatly improve the oil characteristics. At best, the additive will have no effect; at worst, the additive might upset the chemical balance of the oil and actually degrate its performance.

Those who remain convinced these products do, in fact, provide significant benefit are generally unaware that the U.S. Federal Trade Comission has brought suit against dozens of companies selling these types of products, with a uniform result - the companies settle without contesting the charges. This means they do not have to admit any wrongdoing, but are prohibited from making further unsubstantiated claims about their product(s).

This type of federal action is a sure sign of a 'magic' product that even the manufacturer cannot prove to be genuine. Up until recently, this information was hard to come by, but the FTC website now provides a lot of useful information direct to the public - some of it is listed below. Among others, the FTC has taken action against the following brand names: Prolong , Valvoline, Slick 50 and STP.

While the manufacturer's information extolling the unparalleled virtue of these products is easily come by, there is also a lot of information available on the web that casts doubt on the claims of many of these products.  A quick search for trade names will often come up with as much bad information as good.

A few rebuttal links are

• a skeptical look at Slick 50
• the Slick 50 question from Miata Net
• a Federal Trade Commision summary of FTC vs. Quaker State / Slick 50, or the complete record.
• FTC vs. Blue Coral / Slick 50.
• a Federal Trade Commision cease and desist order against Blue Coral / Slick 50 (also PDF version.
• An FTC document describing actions against Ashland / Valvoline for their TM8 Teflon additive.
• Another FTC news release, this time against STP / First Brands for the XEP2 additive.
• Yet another FTC news release detailing how the makers of Dura Lube and Motor Up products were forced to discontinue their advertising. Dura Lube had to pay $2 million dollars in this case.
• The FTC search engine (try searching for "Slick 50" and/or "engine treatment" for more details on the above cases).

• Read the FTC's own words on gasoline additives and gasoline saver products.

• Try Fred Rau's article on Slick 50, originally from Road Rider.

• a search of the Club DSM archives for information on fraudulent ECU upgrades ('chips'), described below.
• if you can, check out the October 1998 Consumer Reports test on Prolong (subscription required).
• The Engine Oil Bible by Chris Longhurst.
• Finally, the Club DSM Fluids FAQ has some information on how to obtain some of the 'proof' claimed by certain additive manufacturers.

However, as with all things, you will have to make up your mind for yourself.  It's your car, and your money.

Those looking to restore their outlook on life after reading this information should visit the Kaleco Auto home page - I'm sure you'll find their products quite interesting. (Read carefully.)

Every 2 years or 48,000 km / 30,000 miles.

All DSMs should have their timing AND balance shaft belts changed every 60,000 miles (90,000 km). Many engine-destroying belt failures are really the fault of the balance shaft belt, rather than the main timing belt.

Most people find it convenient to change all the belts at once. There are five belts on 1G DSMs (and probably on 2Gs, as well) as well as tensioners and pulleys. For a complete list, see I need to replace my timing belt. What other parts should I replace? Also, read Why is it so important to change the timing belt on a [DSM]?

Brief answer: most belt failures on DSM engines result in major internal engine damage, and very high repair bills.

With the exception of the 1.8L NT engine, DSM engines are of the 'interference' style. This means that the pistons and valves occupy the same space, but not at the same time. This type of engine design might seem stupid, but is done for many reasons. (1.8L owners please note that you are not necessarily immune to these problems - keep reading.)

Of course, the engine needs some mechanism for ensuring the pistons and valves don't try to occupy the same space at the same time. The component that does this job is (you guessed it) the timing belt. It's main function is to keep the position of the camshafts (which run the valves) and the crankshaft (which runs the pistons) constant. So long as this is true, it is not possible for the pistons to hit the valves.

There are several reasons why the timing belt mechanism might fail. Obviously, if the timing belt itself breaks because of stress, age or contamination, the valves and pistons will get out of sync. Less obvious is the possibility for damage by the often-unnoticed balance shaft belt.

The balance shaft belt (known as timing belt B in dealership circles) has a much less important job than the main timing belt. It's function is to operate one of the balance shafts in the engine, a component that does nothing but smooth out the engine vibration. Balance shafts are not essential in an engine, and many engines don't have any at all. If the balance shaft belt should break, the worst symptom the driver should notice is an increased 'buzziness' to the engine.

Unfortunately, it's usually not that simple. This little balance shaft belt runs immediately alongside the main timing belt. If it breaks, it almost invariably strikes the timing belt with great force. This results in one of two things: either the main timing belt breaks as a result of the impact, or it 'skips' - that is, jumps teeth on the gears - and the timing between the crankshaft and camshafts becomes radically incorrect. Either way, the end result is usually the same.

Should the timing belt break, the camshafts will be held in a static position while the crankshaft is still turning. In other words, the pistons will be moving, while the valves will be staying still. If the valves are stuck in a position where they are 'in the way', the pistons will strike them during their normal travel.

A similar problem exists if the timing belt has skipped out of position. Although it is still driving the camshafts, it is causing the valves to open at the wrong time. Often, it is the same time during which the pistons are trying to use the same space inside the cylinder, and the pistons will still hit the valves.

During these encounters, the valves almost invariably lose, and get bent out of shape. They are then unable to do the job of sealing the cylinder intake or exhaust ports, and the engine cannot run. This is a virtual certainty on the 2.0L turbo and non-turbo engines, but even 1.8L owners have been known to have similar problems.

Since many of the DSM engines have 4 valves per cylinder, there is a high probability that at least one valve per cylinder will be bent, no matter what position the camshafts are in. Most owners find they lose at least half the valves (all the intake or all the exhaust valves), and many find all sixteen valves are damaged. A compression test usually tells the sad tale: zero pressure in the cylinder because a valve is stuck open.

Unfortunately, the only way to repair these valves is to remove the head from the engine. The 'head' is essentially the top half of the engine, which holds virtually everything in an engine aside from the cylinders, pistons and crankshaft. To get it off, about half of the engine components must be removed and/or disconnected. While it is off, the head must also be reconditioned and inspected for damage. All of this translates into major labor and high repair bills.

Sometimes the pistons are dented or gouged as well, requiring them to be replaced. This usually involves the 'block', or bottom half, of the engine to be removed from the car, which requires even more labor as well as the cost of new pistons.

The moral of this story is: always change your belts, on schedule, with the best replacement parts you can afford. This is truly a situation where an ounce of prevention is worth a pound of cure, as engine repairs cost three to six times as much as timing belt changes.

Those who dislike the idea of keeping the balance shaft belt in the engine may wish to consider removing the shafts - Has anybody ever removed the balance shafts in a [DSM]? .

There are a lot of threads on mods and upgrades, but it is very important to make sure that all the maintenance is done on your car. Check your repair manual for the complete list, here is the minimum list that I recommend:

Every week or every 250 miles or when you get gas/fuel:
1) Check engine oil level
2) Check brake fuild level
3) Check tires and tire pressures

Every 3000 miles or 3 months
1) Change engine oil and oil filter
- The most commonly used oil is synthetic 10W30, 10W40 and 15W50.

Every 6000 miles or 6 months
1) Rotate tires

Every 15000 miles or 12 months
1) Change PCV valve. (When you buy it, blow on one end and then blow on another, you should only be able to blow one side. If you can blow on both sides, it is bad, get another one)
2) Change spark plugs
- If you have no or mild mods get - NGK BPR6ES or Autolite 63 Copper
- If you have moderate mods get - NGK BPR7ES or Autolite 62 Copper 
- If you have a LOT of mods get - NGK BPR8ES
Gap plugs to 0.028 to 0.031". Use no other plugs. No platinum or dual electrode stuff. 
If you are experiencing stuttering from high boost, try to gap plugs in the range of 0.020" to 0.024"

Every 30000 miles or 24 months
1) Replace air filter
2) Spark plug wires - (I use NGK premium wires: part# ME77, stock# 8100)
3) Coolant flush - 50/50 (with one or 2 bottles of water wetter if you want to use it)
4) Change the tranny fluid - most commonly used on manual transmissions is Pennzoil Synchromesh, which is a cheaper alternative to BG Synchroshift. After having issues with Synchomesh for a while (it is too thin), I switched to a combo of Redline heavy and light. 
5) Change the transfer case and rear diff fluid (if you have AWD) - most commonly used gear oil is Redline Heavy Shockproof gear oil.

Every 60000 or 48 months
1) Replace fuel filter
2) Timing belt change: A complete list of 60k timing belt service would include all these:
- Timing belt
- Balance shaft belt
- Timing Tensioner
- Water pump
- Timing belt tensioner pulley
- Balance shaft tensioner pulley
- Idler pulley
- Crank seal
- Oil pump seal
- Balance shaft seal
- 2 Cam seals
- Harmonic balancer
- All other belts
Get only MITSUBISHI parts for the list above. OEM part does not always mean that the part is made by MITSUBISHI. If you don't know where to but parts from, this is a good start - Where Can I Buy OEM Parts Besides Junkyards and Ebay? - DSM Forums.

If your car is old, go ahead and replace all the vacuum hoses. RRE makes a good kit here - RRE's Larson Silicone Hose Kit

There are many things in and around the timing belts that should be checked when doing a timing belt job, especially if replacements are done infrequently. (Owners who perform timing belt changes on a more frequent basis (perhaps as part of engine rebuilds or other work associated with motorsports) need not necessarily check everything each time, and will of necessity have the experience to judge what to replace and what not to.)

The following is a list of parts that should be checked, repaired and/or replaced during a timing belt replacement. The list is based off of experience with 1G cars. 2G owners can still use this as a guide, but 2Gs may have certain other specific problems not mentioned here.

For more information on why belts are so important on DSMs, read the section Why is it so important to change the timing belt on a [DSM]?  in this FAQ.

Note that after a timing belt job has been performed by an outside source, it is important to check and/or adjust the base engine timing. Not an alignment issue, this involves taking a timing light and double-checking that the base timing has not gotten screwed up.

This is not as straightforward as it may seem, since the ECU generally controls the timing and can 'fool' the mechanic into believing the base timing is ok. It is necessary to ground the timing adjustment connector in the engine bay to disable the ECU control and allow the engine to run at its true base timing. Otherwise, the ECU will do it's best to dynamically adjust the timing to the 'correct' value, even though the base timing is messed up.

Failure to do this check may result in the ECU lacking sufficient range to advance the timing as far as it should go, leading to a loss of power. Some Digesters have (belatedly) checked their base timing only to find that their timing was set all the way back, presumeably when a timing belt recall was done on their car. Once they reset the timing to the correct value, the car 'wakes up' and runs stronger than ever.

Read this post by GAS_MAN on DSMTuners first.
http://www.dsmtuners.com/threads/boost-leak-test-how-to-with-boostpro-net-tester.169435/

If you want to build your own boost leak tester that won't scare the crap out of you if it blows apart,
check out this video Ultimate Boost Leak Tester

Then follow Oldman on DSMTuners list.

1. Disable your mbc.

2. Turn your motor to 30* ATDC to avoid valve overlap. (you will lose pressure if any valves are open)

3. Start your test at the TB elbow and focus on area behind the TB first.

4. Spray soapy water at TB gasket, BISS, TB shaft on both sides, IM gasket, injector insulators, brake booster, afpr and all vacuum lines/connections.

5. Open your oil cap and listen for leaks. (PCV, valve seals/guide, rings)

5. Listen to your tailpipe for leaks. (EGR, valve overlap, jumped timing, bent/unseated valves)

6. Once all leaks are fixed, move the tester back to the turbo inlet.

7. Spray down the compressor cover (known leak), BOV return/flange (DO NOT TAP YOUR BOV LINE FOR YOUR MBC!!!), IC end tank/fins and all connections. Re- test.

8. Note that you will leak air into the crankcase through the turbo seal but do not panic, this is normal during a static pressure test as long as there are no shaft play.

The desired test result from the begining of the LICP (bypassing turbo) is around 20psi (on boost gauge) with the compressor set at 30psi, while taking no less than 30 seconds to bleed down to 0.

As a reference, my last test on my 500 mile new engine, I was able to pressurize the system to 25psi, bled down to about 16psi (my 1G bov) in about 30seconds, then took about 3 mins to 6psi and just kinda lingered there for a while. It's not easy to do but the point is it's possible. My next goal is 30psi After motor break in and Dodge modding my BOV. A boost leak test is one of most pita but important regular maintenace task, the key is patience and endurance