Using Premium Gas in my Beetle?!


Hey guys,

here is goes, this morning I took my 2005 Beetle in to have the oil changed and tires rotated. My car has 42,000 miles on it and has already had lots of problems: replaced water pump, broken windshield washer fluid reservoir, the windows dont go and up down properly…

Most recently the car has been having problems starting, it takes about two or three tries to get it going in the morning. And, a few times this week, in the middle of driving (40-60mph) my RPM drop down below 1 and the gas pedal wont give it anymore power.

Well, I told the dealer this and asked if they could look at my transmission, and they said no, that all I need to do is use premium gas and get the 40,000 mile service.

Is it my transmission, my engine, something else, or do I just need to use better gas?



If you have the 2.0L then you should be using regular, if you have the 1.8L Turbo you should be use 91 octane. Engines that use forced induction almost always require premium fuel (some newer Saabs and GM’s turbo’d Ecotec engine with direct injection can run on regular). On turbo’d cars especially the knock sensor cannot totally compensate for using low octane fuel, as you can’t electronically disconnect the turbocharger. Try a tank of 91 octane and see if things improve. If they don’t you’ll only be out about $4.


Sounds like it might be a fuel problem to me, like a dirty fuel filter or dying fuel pump.


This is not a transmission problem but we cannot say what is actually wrong. Maybe you just need routine maintenance, or maybe some additional simple repair. Accept FoDaddy’s advice about matching your fuel grade to the engine.

BTW, there is no need to go to a VW dealership for maintenance or routine service. Any independent garage can do the same thing, often for much le$$. Ask around for a competent mechanic.


Thanks guys. Its actually a 2.0L so I have been using regular gas. I’ll ask them to check the fuel filter and pump though.

And I go to the dealer because in Delaware, where I live, there is only one other place that will work on it, and they are very comparable in price. Also, I have had my oil changed many other places and they always forget to put the cap on or dont tighten it enough or they cant rotate the tires because they dont have the right tool! So, alas, I go to the dealer.

Thanks for the info!


Read the owners’ manual and follow its instructions about fuel grade. If it says that regular (87 octane) is OK, you don’t need to buy premium and your car’s problems are caused by something else. On the other hand, if the manual specifies premium (91 octane) only, that’s what you should have been using all along.


If the owner’s manual says use premium use it don’t argue. If it says you should use premium, use it anyway. What little you will save on the price of the gas you will loose more due to the small reduction in mileage you will get when the engine retards the spark to keep the engine from being damaged by the lower octane.
NOTE: For anyone who drives a car that does not call for premium don’t use it. It is not a better fuel, it is just more expensive and is needed for some cars, it will not help a car that does not need it in any way. The “Premium” name only refers to the price and the oil companies use it to get people to buy something perceived as better. It does not have more power or better additives.


Premium fuel has less BTU’s than regular, and hence less potential power. However they do have a somewhat better additive package, not as much as they would have you believe, but still a superior package than the regular grade fuel gets.


Wrong on both counts. Premium fuel burns more slowly but has the same BTU content. And gas companies use the same additive packages (except for the octane boosters) for all their grades, unless they say otherwise (and believe me, they WILL say so if that’s the case).


Two statements typically uttered by dealership service writers:

“They all do that.” (In response to virtually any complaint.)

“Even though the manual specifies regular gas, use premium gas, and it will run better.”

If you hear either of these hog-wash statements, it is best to disbelieve everything else uttered by these people, and to patronize a different service facility.

However, sometimes you can use their own idiotic words against them, and to your own advantage. Years ago, when I complained to a Chevy service manager that the door lock button on my passenger door constantly rattled despite several visits for repair, he told me, “It’s supposed to be like that”. My response was, “Gee–the one on the driver’s door doesn’t rattle. Make sure that you adjust the one on the driver’s door so that it rattles like it’s supposed to. I want everything to work as it’s supposed to.”

Yup, you guessed it. They finally fixed the rattling lock button on the passenger door since it was easier to fix that than to try to make the one on the driver’s door rattle. I took advantage of this guy’s stupidity on a couple of other occasions also. Sort of like shooting fish in a barrel!


Upon further review, the BTU’s are about the same (about 111,500 BTU’s per gallon). However I do maintain the the additive package will vary amoung the grades in much the same way motor oils have different additve packages for the same weight (regular Vs. high mileage).


I have a better one. My sliding moon roof wasn’t closing completely, allowing a wind leak. The service writer told me they all leak. The service manager told me it was because I was using it too much.

I went to another dealer. They not only fixed the wind leak, they showed me how to reset the roof. Turns out the whole thing can be reset by “reinitializing” the program. Takes two seconds. Guess who gets my business next time?


Nope. It was once true that premium had a better additive package in order to entice drivers whose cars didn’t require premium, but the FTC made them stop this practice years ago. Now the only difference is the octane.


Don’t agree. The New Beetle 05 2.0 engine is 10:1 compression ratio. The PCM will map advance to utilize higher octane fuel. Premium isn’t cost effective. My rule of thumb is to use Mid grade if within 5 percent of Regular. Better performance and better MPG. In the noise if not breakeven or better. We have an 05 Sable with the Duratec 30 rated at 10.5:1. Ford says regular. Indeed, the PCM will adjust advance to regular but will also efficiently use higher octane rated gasoline. My personal ride is an Accord EXL V6 10:1. An ICE Swiss watch. VW crapped after the Bug. If the Japanese have unrestricted EU access, they will kill them.


The service writer told me they all leak.

Yea, and then you ask him to put that in writing on company letterhead. :slight_smile: