Introduction

The Sienna was first introduced in 1998 replacing the discontinued Previa. The Previa was excellent, long lasting minivan. The only one problem - it was designed for Japanese market with only four-cylinder engine available. Since the engine in Previa was placed underneath the car, there was no way to install V6 in it. As a solution for North American market, Toyota came up with the Sienna, which is basically extremely popular Camry with a minivan's body.
The Sienna is front-wheel drive and features Camry's 3.0 liter V-6 engine and four-speed automatic transmission.
Handling is good and the ride is very smooth, it actually even feels like Camry, just slightly heavier.
The engine is very smooth and quiet and in the same time is fairly powerful.
Inside, the Sienna feels roomy and comfortable. User-friendly controls are conveniently placed, the instrument panel is very simple and easy to read. Lots of convenience stuff - handles, cup holders, storages, etc.
Second-row bench seats or captain's chairs can be folded and a third-row seat (although it's pretty heavy) can be removed for extra cargo space.
Anti-lock Brakes (ABS) are standard, Traction Control available on later models. IIHS Best Pick for Offset Frontal Crash, Five stars for both driver and passenger in NHTSA frontal crash test.

The engine

The Sienna has the 3.0-liter 24-valve DOHC V6 enigne (model 1MZ-FE). Models from 1998 to 2000 have 194 hp and starting from 2001 the engine power has been increased to 210 hp by using VVT-i (Variable Valve Timing) technology. The engine provides very smooth power at all rpm ranges, and in the same time it's fairly quiet. The Sienna engine has a timing belt that must be replaced regularly.

Strengths

- Good crash test rating
- Good sedan-like handling
- Fairly reliable
- High resale value
- Interior quality and comfort
- Standard ABS

Weaknesses

- Front cup holders placed almost at the floor - a little inconvenience.
- The engine is very sensitive to the oil quality or oil change interval.
- Since it's basically the Camry with minivan's body, some components (transmission, front end, etc.) may not be so good at standing heavy load.
- Not as roomy as some of the competitors (Dodge Caravan, Honda Odyssey).
- Third row seat is heavy to remove.

Overall

If you like the Camry, you will probably like the Sienna too. It's comfortable and drives good. Toyota parts are usually not so expensive and any garage can handle the repair.
From competitors I'd highlight Honda Odyssey, which has more room, more powerful engine and folding flat third row seat.

Few simple tips on engine maintenance

Few tips how to keep your engine in a good shape:
- To keep your engine in a good shape change the engine oil regularly; I'd suggest do this job at your local Toyota dealer, it will cost just a few dollars more, but you will have a peace of mind.
- Synthetic oil will be perfect if you want extra protection for your engine.
- Always check your parking space for leaks, and if you find one, get it fixed as soon as you can.
- Try to avoid overheating the engine, it may cause serious damage to the engine.
- Don't use front end covers - some of them make more restriction to the air flow causing the engine to run with higher temperature.
- Change the automatic transmission fluid regularly using the right fluid type (I'd recommend to buy it directly from Toyota)
- It make sense to replace the water pump when you change the timing belt.
- whenever your engine is serviced, ask to check and if necessary to clean PCV valve (PCV - Positive Crankcase Ventilation) which is the important part of engine ventilation system. Clogged PCV causes increase in amount of carbon deposits (sludge) inside the engine.
- Try to stick with original Toyota parts, they are reasonable priced.

Toyota Sienna short specifications (2003 LE US model)

Dimensions

Length: 194.2 (4933 mm)
Width: 73.4 (1864 mm)
Height: 67.3 (1709 mm)
Curb Weight: 3,932 lbs (1784 kg)

Engine

3.0-liter 24-valve DOHC V6 with VVT-i
210 hp @ 5,800 rpm 220 lb.-ft. @ 4,400 rpm

Transmission
4-speed electronically controlled automatic transmission
with intelligence (ECT-i)
Brakes
Power-assisted ventilated front disc,
rear drum with Anti-lock Brake System (ABS)