The manual for my 2003 VW Passat says I need to use high octane gas, which I have for 6 years. BUt I wonder if this is really necessary. Could I save money by usinf regular?
Yes, this is necessary. That’s why the manuals tells you it’s required.
No, you won’t save money by using regular. Your efficiency will likely suffer and you may even cause engine damage.
Why is it that so many people don’t believe their owners’ manuals? Why do they look for a complete stranger over the internet to contradict the true experts, the guys that wrote the owners’ manual from the engineers’ design package, all to save a few bucks?
You won’t save any money using regular. You’ll probably spend more money because the gas mileage will be reduced. That’s not to mention possible long-term internal damage, which can be VERY expensive. The engine in your car needs premium. Feed it premium only.
I will give the OP credit for actually reading his Owner’s Manual, since so few people seem to do that. However, if you don’t intend to follow the advice contained in the manual, then it really doesn’t even make sense to read the book. That Owner’s Manual is the authoritative source for a wealth of information on your car, so I would suggest that you take its advisories seriously.
To continue on a point made by mountainbike, I want to ask:
If an anonymous stranger advises you via the internet to go against the advice of the people who designed and built your car, to whom will you complain when that advice inevitably results in lower gas mileage, less power for acceleration, and possible engine damage?
You don’t need to, but you will likely use more fuel, have less power and may damage the engine. You might have no problems, but if it were mine, I would do as it says.
Do you have the turbo 4? I would definitely keep using premium for that engine.
I actually asked this question of a BMW dealer mechanic. He stated that yes the VW engine, especially the turbo is a high perfomance engine which requires a higher octane. However, he did say you could go with midgrade - he also warned absolutely do NOT to use the low grade octane fuel. He said with midgrade you will be sacrificing some performance - like that little extra pick up and go when you step on the gas, and you will suffer a tiny bit in fuel efficiency. If you have a costco nearby you can go to their fueling station, the high octane fuel at costco is usually about the same price as regular gas at other gas stations.
my dealer asked me when i went in to have my check engine light turned off if i used 93 octane. i told him yes and he said that was why the cel came on. he gave me some reason i don’t remember but i figured he was full of it.