INSANELY good gas mileage - should I worry?

[TheClunker]

Probably a dumb question: I'm getting INSANELY good gas mileage in my 2000 New Beetle GLS with a 2.0 AEG engine, five speed manual. It has always gotten great mileage since I bought it (I bought it used in 2009). Other than using a little oil, about one quart between 5,000 mile oil changes, she's a great car (and using some oil between changes is kind of par for the course with a Volkswagen).

I think the last time I filled up I did the math and I was getting just a hair over 31mpg combined city / highway, mostly highway. One time when I did the math I think I actually got 36mpg out of a tank, during the winter (no A/C, driving with the windows rolled up which reduces drag, etc.). I'll admit that I generally cruise right at the speed limit and don't use the A/C, so I'm sure that's helping, but I just read that I'm supposed to get 24mpg combined:

Fuel Economy of the 2000 Volkswagen New Beetle

Should this worry me? The only reason I ask is because I also own a 1971 classic Beetle, and I know that insanely good gas mileage in those can mean problems with your valves. I'm not experiencing any problems, car is very peppy, lots of torque, doesn't seem to run hot or anything that would indicate a lean fuel mixture (like going through catalytic converters).

Edit: Oh, and if it matters, I use 5W30 oil when I top off the NB between oil changes; at oil change time, the dealership puts in whatever they put in.

[MyOtherRidesAVette]

The Dealer is probably using 5w40 Castrol Full Syn, and what you should be adding between changes. If not, they should be, especially as the engine ages, full syn and 5w40 or 0w40 as recommended by VW. I'm using a quart between 10k oil changes.

Congrats on your gas mileage, no doubt a combination of a well cared for engine, not using your a/c, your driving habits, and I'm betting the gas your using is not E10.

M.

[antonym]

Yes you should worry .. as a matter of fact you should just go ahead and give you car to me . Pm me for my address

[lil.smartie]

I get that kind of mileage too from my 1.8t

Nice isn't it!!??

Kate

[akasha1963]

I have gotten that kind of mileage out of my '01 2.0. Sounds like she is purring like a kitten.

[SMG]

Pull a spark plug out. If it's white you should look for vacuum leaks, test the MAF and primary O2 for proper operation. If they're coffee brown you're fine. If they're black or oil covered you have problems, but you wouldn't be getting 36MPG on an engine running that poorly.

It's kind of funny, after working mostly on my TDI the last few months spark plugs seem strange to me now. There was a Jetta at a local shop one day getting work done. The symptom was insanely good fuel mileage and the culprit was a sensor. I can't remember which one though this was like 8 years ago now.

[redgtijohn]

I get 33 mpg with 234k on the speedo 2000 nb

[kcfoxie]

I never got better than 30 out of my 2.0's. I think it's funny a bad sensor can take the car from 26 to 30mpg.

[TheClunker]

Thanks for the replies. I think I'm just a little freakin' paranoid ... when I bought Valerie-Sunflower in 2009, she had SO MANY PROBLEMS (drank about 3 quarts of oil between changes, ate through two catalytic converters in about 18 months, was sluggish, hard to start in the winter, didn't accelerate worth crud).

Once all that stuff got sorted out (oil usage was a head cover gasket and PCV valve, catalytic converters were probably also the PCV valve, and the sluggish drive was some vacuum hose drama) I realized I was getting HUGE mileage. Surely, something had to be wrong Before I had my two bugs (one for daily driving & one for play) I had two pickup trucks (again, one for daily & one for play). Sometimes I forget I'm not driving them anymore and am shocked when my trip counter reads nearly 400 miles since my last fill-up.

Plus, like I said - if her sister, Karen-Starshine (my 1971 aircooled Beetle) ever got gas mileage like that, I would FOR SURE think valve problem ... I forget if it's valves to tight or valves too loose on the old aircooled engines leading to great milage, but either way it leads to screwed up valves and possibly a blown piston / cylinder head if you don't fix it. I just thought I'd see if there was anything to worry about.

Just washed her for the first time in a few weeks today ... except for the few scratches & dings and missing VW emblems on two of my rims, she still looks showroom new from a distance of a few feet

[Smileybug]

I got over 30 only on the highway, and that was not all the time. I got 36 once, but it was usually 30-32 at best on pure highway trips. I usually got around 26 mixed, 23 in town. Pretty consistent through my ownership of my 2.0. Not a hypermiler, but not an aggressive driver either.

[Borninabeetle]

I've got a '98 NB with nearly 275,000 kms on it. Normaly I get between 550 and 600kms per tank. Once, about 2 years ago, I got just over 780 km out of one tank. The car had been running a little rough so I decided to change the plugs. One of the plugs had the ground wire completly broken off - it hadn't burned away, it had broken.

I changed the plugs and it ran much smoother but, I haven't gotten mileage like that since!

[MyOtherRidesAVette]

Perhaps we all have a cylinder we don't need? (lol)

[simonsi]

Originally Posted by Borninabeetle

I've got a '98 NB with nearly 275,000 kms on it. Normaly I get between 550 and 600kms per tank. Once, about 2 years ago, I got just over 780 km out of one tank. The car had been running a little rough so I decided to change the plugs. One of the plugs had the ground wire completly broken off - it hadn't burned away, it had broken.

I changed the plugs and it ran much smoother but, I haven't gotten mileage like that since!

Ground wire??? Plugs only have a high voltage wire to the coil - certainly NOT ground (that comes to the plug through the engine block itself - so don't treat it as such or you can damage the ignition components.

[IndyTom]

Congrats on the great mileage! Now you did say you are getting milles per gallon not Kilometers per gallon, right.

Maybe you have that new and advanced feature that shuts of 2 of the cylinders during cruising speeds like the Chrysler Hemi's have. Seriouly though, you should check your spark plugs for white residue. It's possible you are running a tad lean which could result in better than normal mileage for a little while until other problems surface.
Or it could just be a freak and get great mileage. I wouldn't worry too much about it. Other people here on line are saying they are only getting 11mpg and their car purrs like a kitten. Hmm, perhaps you can give some of your mileage to her and split the difference
Another thing you can get is a great little device call the SCANGAUGE II. It will give you all sorts of information like Intake temp, coolant temp, average mpgs etc, etc. invaluable gauge and it is very accurate. I don't leave home without it. ScanGauge - Trip Computer + Digitial Gauges + ScanTools
I think Autozone sells it for about $159 bucks.

My 2000 1.8 Beetle has 160+k miles on it and it gets about 24.2 mpg average. Never taken it on a major highway trip but I bet it could get about 28-29 Highway but I don't think much more. However, I must have a freak too because it doesn't use any oil at all between changes. Of course I do change my oil between 4000-5000 miles.

Good Luck and enjoy your gas mileage.