friendly_jacek

The idea does sound rediculous and the 20-30% improvement in MPG must be bogus. However, I spend a few hours reading about it and it sounds like some (not all, but majority) who tried it experienced 4-10% MPG improvement, easier starts in cold and smoother idling and reving. It may be just cleaning action though. As for safety, we are talking about 0.25-0.3% acetone in gas. Did you now that diabetic people or people on Atkins diet have some acetone in blood (it is type of keton bodies)? The fuel lines are already solvent resistant, gasoline is potent solvent itself. Finely, some gas additives contain acetone already (chemtool B12, I was told). Nothing to loose. I will try it in next tank.

can't help but noticed that he got positive feedback!

I could be wrong but i thought some MYs (mid 90's) required 89 gas.

My car is 2000 legacy, but alternator is very hot. 220 F by IR thermometer. Still works fine.

Agreed, I havn't tried this one. Changing subject, it may be just me but I never saw any diffrence in MPG from going from recommended tire pressure to maximum pressure, in any car I tried. There is usually an improvement in handling with a potentially worse traction in adverse weather. But again, I did not see MPG improvement with the FWD fuse thing, so it could be just me.

The new API SM certification requires for 5W30 oils to use higher quality base oils (at the expense of additive pack). Many companies started adding group 3 semisynthetic oil to the cheap group 1 dino. This type of oil is usually marketed as standard dino oil (MobilExon for example) but some companies you mentioned above chose to market them as "blend". It is a marketing gimmic. Other companies use group 2 or group 2+ oils (chevron or so). Pick and choose.

Thanks Lawsonmh15, I will try these things, nothing to loose. I have a new set of NGK double platinums on hand, just waiting for the 60000 mark. I have heard good things aboud ground mods. Will do for it for fun.

All the above advices re: improving MPG are well meant but not very usefull. It is a fact of life that some cars have better MPG, some worse. Also. driving technique can contribute to a large variation. I tried tons of things to improve MPG im my subaru to no avail. I would say your MPG is avarage given the circumstances. Good luck.

Unless you have a hi performance turbo motor, start car in arctic temps, or have an engine with high oil temp (corvette or similar), good dino oil (like ACEA A3 certified) is more than fine.

Replaced all brake pads at 46000 miles, no unusual wear. The engine temp as checked via OBD2 is correct. I covered all the basis and still clueless about it. BTW, wheels are perfectly aligned (took several tries though). I suspect that the -10% long term fuel trim has the answer. I measured fuel pressure and it appeared 10PSI too high, but didn't change when I replaced fuel regulator.

Most "diesel oils" in US are actually universal fleet oils with double diesel/gas (CH-4/SL) rating. If your car can take 15W40 API SL, then you can use diesel/gas CH-4/SL universal oils (delval, rotella, delo, etc.). I personally tried rotella synth 5W40 with good results in summer.

Thanks for the comprehensive listing. 1. I have MAP sensor and not MAF (MY 2000+). 2. Spark plugs, all filters, all fluids replaced at 30000, will replace again at 60000 soon. 3. Spark wires OEM but resistance checked and OK. 4. Tires inflated to 40-44 PSI (depending on load). 5. PCV checked and works OK. 5. Injector cleaners run a couple of times (redline and techron). 6. No OBD2 codes, but approx -10% long term fuel trim. 7. O2 sensors confirmed to work OK (replaced at 20000 due to a recall anyway). 8. Did I mention that all fluids are synthetics? 9. It does smell rich on cold starts, I thought fuel pressure regulator was defective, replaced, no change. 10. ECU resetted a few times. 11. BTW, it is NA 2.5L, phase 2 (SOHC). I had the car since new, and the poor MPG was from day 1, dealer could newer find a problem, except for defective TPS, that did not affect the MPG after all, despite my initial impression otherwise. I run a couple of used oil analysis, one result showed fuel in oil (4%), but that was after idling. Wear metals (especially Chromium) were high normal, otherwise nothing obvious.

Thanks for pointing out the common knowledge fact. Ethanol has roughly half of the energy per volume unit compared to gasoline. So, with 10% ethanol fuel , you can expect 5% loss of MPG, and power, maybe little bit more due to the need to dowshifting. The change you observed was more of underfiling with subsequent overfilling or perhaps cheating at the pump. I use 87 gasoline with 0% alcohol and still experience 16-20 MPG city and 22-24 MPG hwy. Any suggestions for me?

I agree with the poster above that hybrid technology is good and will be improved soon. Personally, I am impressed by the plug-in hybrid concept. The solution of electric engines driving rear wheels for “hybrid AWD” is also neat. The issue that bothers me a lot is the fact that Subaru made a decision to go after high end, premium car market and abandoned its roots: affordable, reliable, environmentally sound car. Subaru is entering the large SUV craze in the wrong time, and lack of hybrid to improve the image does’t help either.

Second that. The usual scenario with AT failing after flush is that neglected tranny starts to malfunction and owner suddenly remembers that tranny never had ATF change. The flush in these circumstance will vigourously remove dirt from clutches and seals and suddenly clutches slip and seals leak affectively trashing the tranny. Doing a tranny flush in a well maintained tranny is not a very bad thing and any shop can probably do it just fine, but dropping the pan, like cookie said, will give an oportunity to clean magnets and such.

To add to the confusion, this is quoted from http://www.stealth316.com/2-breakin.htm "Using synthetic-oil in engine break-ins By Road & Track, Technical Correspondence Column, July 2000 issue Many readers have questioned us on engine break-in procedures when using synthetic oil. Conventional wisdom has it that a new or freshly rebuilt engine should be broken in using mineral oil, then, once enough mileage has accumulated to ensure rings and cylinder walls have lapped themselves into harmony, synthetic oil can be used. Readers have correctly pointed out that several major brands come from the factory with synthetic oil, among these being Corvette, Mercedes-Benz and Viper. How can these engines break-in if run on synthetic oil from day one, they ask? To find out, we spoke with Mobil and Redline Oil companies for their take on the synthetic break-in question. Mobil's response was that engines break-in just fine on synthetics, and that any wear point in the engine significant enough to be an interference, and thus susceptible to rapid wear, would be a wear point no matter what lubricant is used. Redline, on the other hand, has found it best to recommend a mineral oil break-in. Occasionally an engine will glaze its cylinder walls when initially run on Redline, they say, so by using a mineral oil for 2000 miles, verifying there is no oil consumption and then switching to the synthetic, glazing is eliminated. Cylinder-wall glazing is not a deposit left on the cylinder wall, but rather a displacement of cylinder-wall metal. This happens when the high spots of the cylinder wall crosshatch are not cut or worn off by the piston rings, but rather rolled over into the valleys or grooves of the crosshatch. This leaves a surface that oil adheres to poorly, against which the rings cannot seal well. Compression is lost and oil consumed, and the only cure is to tear down the engine to physically restore the cylinder-wall finish by honing. Why is glazing not a problem for the major manufacturer? Because they have complete, accurate control over their cylinder-wall finish and ring type. Redline deals with a huge variety of engines and manufacturers, both OEM and from the aftermarket. Cylinder-wall finish and ring type thus vary greatly, and glazing can therefore occur, albeit rarely. While we were at it, we queried about synthetic oil-change intervals. Mobil says to use the maximum change interval specified by the engine manufacturer, regardless of oil type. Redline said that once past an OEM warranty, anywhere from 10,000 to 18,000 miles, or one year, whichever comes first, is appropriate depending on conditions (dust, short trips). They also recommend changing just the oil filter at 6000 to 7000 miles as a precaution against overloading the filter. Redline further noted a caution when using synthetics with leaded fuels, as synthetics do not hold lead in suspension as well as mineral oil. Aviation is one area where leaded fuel is still widespread, and avgas is often used by off-road and racing enthusiasts, so a relatively short oil change interval may thus be indicated."

Please correct me if I am wrong but IIRC both fans should work when: 1. The temp of coolant is too high 2. AC is on and compressor is running So, if only one fan runs then you need to fix the other one.

Did you check if the cooling fans ARE actually working while the engine is overheating?

Lets see: you drained 4L and filled 10L, then you proceded to drive without checking the ATF level. Now complaining of the fluid spilling over. Aren't you wasting everybody's time on this forum?

This discussion confirms my suspicion that there are mainly 2 types of 2.5L subarus: 1. city 18-22, hwy 22-24 MPG 2. city 24-26, hwy 26-30 MPG Mine belongs to group 1, except for occasional dips to 16 MPH with shorter trips :-(

That is a lot of consumption in a new engine! If I remember correctly, there was a similar thread couple of months ago. The ring seating thing is an old story and controversial. But there could be some truth in it though, especially since the boxer desigh is old. I would try a different oil for a time beeing, probably something in the range of heavy 30 (german syntec 0W30) or light 40 (rotella synthetic 5W40). If yours is naturaly aspirated, there is nothing wrong with quality dino oil, though.

Good luck! I keep the tire pressure at 40-44 psi, no MPG difference that I can tell.

I have a 2000 legacy and not forester but will chime in anyway (same engine). My wife is getting only 16 MPG in city driving (hot climate but short trips) and 24 MPG is the absolute record (hwy, long trips) for the car. The engine seems to run rich (unburn gas smell on starts). No codes and O2 sensors are fine. At one point, I thought I diagnosed the problem: excessive fuel pressure according to my pressure gauge, got a new fuel pressure regulator ($70) from a dealership, but not change in pressure or MPG. To me, it sounds like some pressure regulators are defective from the factory, but this is just a theory, anybody cares to elaborate?

I am surprised no one mentioned noise. I personally can't stand the noise of idling diesels. I drove my share of small diesels in Europe and just couldn't get used to. Even the advanced VW's TDI is unpleasant to my ears.

I tried in 2.5 H4 and didn't seem to damage the engine. The rinse oil was kind of dark after 1000 miles but hard to say how much it cleaned the engine. Engine still noisy like hell and drinks gasoline like crazy (55000 miles).