1. What is it?
Timing belt is simply a rubber made belt similar as those driving belt.
It is called timing belt because it connects Crankshaft with Camshaft
and make them turn at the same time. Moreover, the phase of both shafts
are really important because Camshaft rotation control Valve opening and
closing and Crankshaft connects to piston. They must be synchronized and
precisely set. That is why timing belt replacement is not easy. It must
make sure that the relation is not changed when replacing the belt.

2. What if timing belt is broken?
Valve open and close is not properly synchronized with piston movement.
Moving piston might hit open valve and thus damage both of them.
Whether this damage occur depends on the engine design. If there is
enough space between valve open position and piston's highest position,
this damage won't occur. Otherwise, definitely engine must be rebuild,
which will cost around $1500 to $2000.

The first design is called Non-Interference design. Howover, since it
needs more space, the compression is not high. Most moderm high power
engine don't use it. Almost 85% is Interference.

3. How much does it cost?
Belt itself is simple and only cost $40 for most models. But the labor
is high. Normally, it takes $250 - $300 to replace it for all.

4. Can it be done by myself?
Yes. But first make sure you understand its mechanism. Then bought a
repair manual for your own car and follow the instruction. Use right
tools for the right job and be careful about the timing relation of
Crankshaft and Camshaft.

Here is a link about general replacement timing belt.
NOTE: there are 3 pages. This is the first one. Follow the link
in the page and be sure to read all of them. READ THEM CAREFULLY.
INCORRECT TIMING BELT REPLACEMENT WILL DAMAGE ENGINE AS THE SAME
AS BROKEN TIMING BELT.

http://autorepair.about.com/library/weekly/aa051102a.htm

5. Belt or Chain?
Some model use steelless chain instead of rubber belt to do the same
thing. It lasts much longer than timing belt. But it costs more and
makes larger noise. It also need replacement after long use. But I
heard someone said it will give larger noise before it dead out. So
it is much better than belt, which could dead any time you won't expect.

6. California myth?
For some car, a same model has different timing belt replacement interval in
California than in other states. For example, one model says replace
timing belt every 60k in all other states, but 90k in California. That is
all because of a trash law in California. It requires the manufacturer not
to let owner to repair their own in that earlier mileage. It said user
should be able to use their car for 90k before they can do any major
maintenance. Thus manufacturer just simply change the number in the manual
and use the same timing belt. It is really silly to introduce that law
because timing belt broken has nothing to do with people's restriction.

7. Change Water pump at the same time?
Most people recommend this because it will only cost $50 more for the
parts. The labor is already included in the timing belt replacement.
However, I read some article, which said water pump will most probably
last much longer than the life of the car. So it is not required to change
it at 60k or so. But if it went wrong, you have to pay the same amount
of labor as timing belt to replace it. So both ways make sense. It is really
up to you to make a choice.

8. How can I know when to replace and what design is my engine.

Acura Engine Interference Replace
1.6 Yes N/A
1.7 Yes 90,000
1.8 Yes 90,000
2.2 & 2.3 Yes 90,000
2.5 (5 cyl.) Yes 90,000
2.5 (V-6) Yes 90,000
2.7 Yes 90,000
3.0 Yes 90,000
3.2 Yes 90,000
3.2 (SLX) No 90,000
3.5 Yes 90,000
3.5 (SLX) No 90,000


Audi Engine Interference Replace
1.6 No 60,000
1.7 No 60,000
1.8 (SOHC) No 60,000
1.8 (DOHC) Yes 60,000
2.0 (Gas) No 60,000
2.0 (Diesel) Yes 60,000
2.2 & 2.3 No 60,000
2.7 Yes 60,000
2.8 Yes 60,000
3.7 Yes 60,000
4.2 Yes 60,000


BMW Engine Interference Replace
2.5 Yes 60,000
2.7 Yes 60,000


Daewoo Engine Interference Replace
1.5 No 60,000
1.6 No 60,000
2.0 Yes 72,000
2.0 (Calif.) Yes 102,000
2.2 Yes 72,000
2.2 (Calif.) Yes 102,000


Daihatsu Engine Interference Replace
1.0 Yes 60,000
1.3 Yes 60,000
1.6 Yes 60,000

Diamler-Chrysler Engine Interference Replace
1.4 Yes 60,000
1.6 (SOHC) Yes 60,000
1.6 (DOHC) Yes 60,000
1.7 No N/A
1.8 Yes 60,000
2.0 (SOHC) No 60,000
2.0 (DOHC) Yes 60,000
2.2 (SOHC) No 90,000
2.3 (Diesel) Yes 50,000
2.4 (SOHC) Yes N/A
2.4 (DOHC) Yes 60,000
2.5 (4 Cyl.) No 90,000
2.5 (V-6) Yes 90,000
3.0 (SOHC) No N/A
3.0 (DOHC) Yes 90,000
3.2 (DOHC) Yes 90,000
3.5 No N/A


Ford Engine Interference Replace
1.3 No 60,000
1.6 (SOHC) Yes 60,000
1.6 (DOHC) No 60,000
1.8 No 60,000
1.9 No N/A
2.0 (SOHC Gas) No 100,000
2.0 (DOHC Gas) Yes 60,000
2.0 (Diesel) Yes N/A
2.2 Yes 50,000
2.3 (SOHC Gas) No N/A
2.3 (Diesel) Yes N/A
2.5 (4 Cyl.) No N/A
2.5 (6 Cyl.) No 30,000
3.0 (SOHC) Yes 60,000
3.0 (SHO) No 60,000
3.2 (SHO) No 00,000
3.3 Yes 60,000


General Motors Engine Interference Replace
1.0 Yes 60,000
1.3 (SOHC) Yes 60,000
1.4 (DOHC) Yes N/A
1.5 Yes 60,000
1.6 No N/A
1.6 (Tracker) Yes N/A
1.8 (Gas) No N/A
1.8 (Diesel) Yes N/A
2.0 No N/A
2.2 (Diesel) Yes 60,000
2.3 No N/A
3.0 Yes 60,000
3.4 No 60,000

Geo Engine Interference Replace
1.0 Yes 60,000
1.3 Yes 100,000
1.5 Yes 60,000
1.6 (SOHC Prizm) No 60,000
1.6 (Storm) No N/A
1.6 (SOHC 8 Valve) No 60,000
1.6 (SOHC 16 Valve) Yes N/A
1.6 (DOHC Prizm) Yes 60,000
1.6 (DOHC Storm) Yes N/A
1.8 (DOHC Prizm) Yes 60,000
1.8 (DOHC Storm) Yes 60,000


Honda Engine Interference Replace
1.2 Yes N/A
1.3 Yes 60,000
1.5 Yes 60,000
1.6 Yes 90,000
1.8 Yes 60,000
2.0 (SOHC) Yes 90,000
2.0 (DOHC) Yes 90,000
2.1 Yes 90,000
2.2 (SOHC) Yes 90,000
2.2 (DOHC) Yes 90,000
2.2 (DOHC Passport) Yes 75,000
2.3 Yes 90,000
2.6 Yes 75,000
2.7 Yes 90,000
3.0 Yes 105,000
3.2 Yes 75,000
3.5 Yes 90,000


Hyundai Engine Interference Replace
All Yes 60,000


Infiniti Engine Interference Replace
3.0 Yes 60,000
3.3 Yes 105,000


Isuzu Engine Interference Replace
1.5 Yes 60,000
1.6 (SOHC) Yes 60,000
1.6 (DOHC) Yes 60,000
1.8 (DOHC Gas) Yes 60,000
1.8 (DOHC Diesel) Yes 60,000
2.2 (DOHC Gas) Yes 90,000
2.3 Yes 60,000
2.6 Yes 60,000
3.2 Yes 60,000
3.5 Yes 60,000


Jeep Engine Interference Replace
2.0 No N/A


Kia Engine Interference Replace
1.6 (SOHC) No 60,000
1.6 (DOHC) Yes 60,000
1.8 (DOHC) Yes 60,000
2.0 (DOHC) No 60,000
2.0 (DOHC) Yes 60,000


Lexus Engine Interference Replace
2.5 No 60,000
3.0 (Inline 6, 92-97) No 60,000
3.0 (Inline 6, 98-00) No 60,000
3.0 (V-6) No 60,000
4.0 (DOHC) Yes 60,000
4.7 (DOHC) Yes 90,000


Mazda Engine Interference Replace
1.5 No 60,000
1.6 No 60,000
1.8 (4 Cyl.) No 60,000
1.8 (V-6) No 60,000
2.0 (SOHC) No 60,000
2.0 (DOHC) Yes 60,000
2.0 (Diesel) Yes 60,000
2.2 Yes 60,000
2.3 (4 Cyl.) No N/A
2.3 V-6) No 60,000
2.5 No N/A
3.0 Yes N/A
3.0 (MPV) Yes 60,000


Mitsubishi Engine Interference Replace
All Yes 60,000
3.0 (SOHC 12 Valve) No 60,000

Nissan Engine Interference Replace
1.5 Yes N/A
1.6 (SOHC Up To 1985) Yes N/A
1.6 (SOHC 1986-1993) Yes 60,000
1.6 (SOHC 1997-2002) Yes 105,000
1.6 (DOHC) Yes 60,000
1.7 (Diesel up to 1985) Yes N/A
1.7 (Diesel 1986-1993) Yes 60,000
1.7 (Diesel 1997-2002) Yes 105,000
1.8 (DOHC) Yes 60,000
2.0 (up to 1985) Yes N/A
2.0 (1986-1993) Yes 60,000
2.0 (1997-2002) Yes 105,000
3.0 (SOHC up to 1985) Yes N/A
3.0 (SOHC 1986-1993) Yes 60,000
3.0 (SOHC 1997-2002) Yes 105,000
3.0 (DOHC) Yes 60,000
3.3 Yes 105,000


Subaru Engine Interference Replace
1.2 (SOHC) No 60,000
1.2 (DOHC) Yes 60,000
1.8 No 52,000
1.8 (Impreza) No 60,000
2.2 (SOHC) No 60,000
2.2 (DOHC) Yes 60,000
2.5 (SOHC) No 60,000
2.5 (DOHC) Yes 60,000
2.7) No 60,000
3.3 Yes 60,000

Toyota Engine Interference Replace
1.5 (1A-C, 3A-C) Yes 60,000
1.5 (5E-FE) No 60,000
1.6 (SOHC) No 60,000
1.6 (DOHC) Yes 60,000
1.8 (Gas) No 60,000
1.8 (Diesel) Yes 60,000
2.0 No 60,000
2.2 (Gas) No 60,000
2.2 (Diesel) Yes 60,000
2.4 (Diesel) Yes 60,000
2.5 No 60,000
2.8 No 60,000
3.0 (Inline 6) No 60,000
3.0 (2JZ-GE) Yes 60,000
3.0 V-6) No 60,000
3.4 No 60,000
4.7 Yes 90,000


Volkswagon Engine Interference Replace
1.5 (Gas) No 60,000
1.5 (Diesel) Yes 30,000
1.6 (Gas) No 60,000
1.6 (Diesel) Yes 30,000
1.7 No 60,000
1.8 (Turbo) Yes 60,000
1.9 (Diesel) Yes 30,000
2.0 Yes 60,000
2.1 No 60,000
2.2) No 60,000
2.5 Yes 60,000
2.8 No 60,000


Volvo Engine Interference Replace
2.1 (Up to 1985) Yes 40,000
2.1 (1986-1994) Yes 50,000
2.1 (1994-2002) Yes 70,000
2.3 (B23 Up to 1985) Yes 40,000
2.3 (B23 1986-1994) Yes 50,000
2.3 (B23 1994-2002) Yes 70,000
2.3 (B230, B230F, B230FT) Yes 50,000
2.3 (5 Cyl.) Yes 70,000
2.5 (5 Cyl. Gas) Yes 50,000
2.5 (5 Cyl. Diesel) Yes 75,000
2.9 (Up to 1992) Yes 20,000
2.9 (1993) Yes 60,000
2.9 (1994) Yes 50,000
2.9 Yes 70,000