1) Find out the year, make and model of your car. The VIN number is a good place to start for this. It's usually on the dash, visible through the windshield.
2) Find out if the motor is one of the stock options, or something swapped in. To do this, you will have to become familiar with the basic configurations offered for that chassis. Not too hard- most chassis only had a couple possible stock motors, and more than likely your motor is one of them.
3) If it's not stock, try to find some identifying badges, or otherwise ID the thing. If it's really exotic, take pictures and seek help on forums.
4) If it's a stock motor, you should be able to find out where to look for its serial numbers, which will tell you exactly what it is, so that you can look it up in an appropriate manual and find the displacement, among other things.
5) If you get stuck, try to find an online forum for your car. Search Google for it. Like, if you have a 1979 AMC Gremlin, just type "1979 AMC Gremlin forum" into Google and see what leads you get.*
Good luck!
*10 points to everybody who said "Wait a minute! In 1979 the Gremlin became the Spirit!"
You can find out what causes oil to get into your water in most engine service manuals. You can find the service manuals at most local libraries.
You can find a wiring diagram for your 1.2 liter engine in most service manuals. The service manuals can be found at most local libraries.
haynes manuals
Amazon.com sell diesel engine manuals online. You should also look at half.com for these manual as well.
You can find a vacuum diagram for your 1987 2.4 liter nonturbo engine in most service manuals. The service manuals can be found at your local library.
any of the DIY auto repair manuals will usually show an exploded view of the engine.
There are 1000cc's in a liter so a 125 would be .125 liters or 1/8 th of a liter.
Get the complete Manuals I bought them 3 in e-bay for about $35.00
You can find a 2000 Pontiac Bonneville engine diagram at your local General Motors dealerships. Pontiac service manuals will also have the engine diagram and can be found at most local libraries.
You can find some of the manuals on docin.com
If you go to AutoZone .com and check with there repair manuals on-line you can find the engine codes for your tracker
You can find an exploded view of the 1996 Mazda Millenia 2.5 liter engine at most Mazda dealerships. You can also find the exploded view in most Mazda service manuals.