I am here to confirm that thinner/ synthetic oil reduces piston slap noise dramatically. I switched from Castrol 10w-30 to Q Horsepower 5w-30, and the noise went from "a rod coming through the block" to "exhaust leak" levels.

 

 

 

 

 

 

actually I just wanted to use the banana

I am here to confirm that thinner/ synthetic oil reduces piston slap noise dramatically. I switched from Castrol 10w-30 to Q Horsepower 5w-30, and the noise went from "a rod coming through the block" to "exhaust leak" levels.

 

 

 

 

 

 

actually I just wanted to use the banana

I went to a thinner oil then what you described above and experienced a reduction in noise..I have also tried the thicker syn. oils.. ( I believe it is not just my imagination speaking here)

Sometimes thicker oil is not the answer because it doesn't get into the very small oil paths in todays engines. Thicker oil can cause no oil delivery where it's needed.

I was just told by a subaru master tech to use 10w-40 instead of 5w-30 to reduce piston slap and it did. The car in question was a 98 Impreza 2.2 It also could have been that the previous owner had crappy oil in it and just putting fresh oil of any weight in would have made it quieter.

I use at least 10-30 or 10-40 in higher mileage subies. 5-30 is too thin once they have some miles on them IMO.

Probably an unwelcome non-Subaru specific comment to this thread, but my 2 cents: If they call for 5w30, and you live where it gets really cold, thicker grades are NOT the answer. I live in upstate NY, in the Adirondacks, and it can get well below zero here in the winter (thats my definition of real cold, for reference) Ten years ago or so, we had a real bad cold snap and it was in the negative digits several mornings in a row. During that cold spell, we had 3 Nissans with the KA series engine that SNAPPED camshafts right in half at one of the cam bearings. All 3 were running 10w30 or 10w40. Ive never seen it again, before or since. But my conclusion is that it takes a thin oil at cold temps to move through so tight tolerances. I cant imagine Subaru oil passages being any more forgiving. Damn the piston slap, give them some lubrication!

I am a firm believer in using what the manufacturer recommends. They engineered the car to use certain lubes so that the car will live a long happy life. They are not trying to get people to use a cartain weight so that the car breaks early and often, that would cause people to run like he:: from that brand and never go back. My 98 calls for 5w-30, so that is what I will use. Engineers are not stupid people, they recommend things for a reason.

I am a firm believer in using what the manufacturer recommends. They engineered the car to use certain lubes so that the car will live a long happy life. They are not trying to get people to use a cartain weight so that the car breaks early and often, that would cause people to run like he:: from that brand and never go back. My 98 calls for 5w-30, so that is what I will use. Engineers are not stupid people, they recommend things for a reason.

 

Except the engineers aren't making the call on the specs. The big wigs are.

 

The trend to recommending thinner oil is mostly because of EPA milage ratings and CAFE standards.

 

If a manufacturer can make each of it's products even 1 MPG more efficient, it helps them meet CAFE regulations without as much REAL engineering.

 

The thinner oil does help the gas milage, but in the end it's not as good for the engines. *newer Variable Valve timing engines excluded. they need thin oil pumped at high pressure.*

 

Obviuosly in VERY cold places in winter, thinner oil is nessecary. But only in winter and I'd say only 5-30. 5-20 or 0-20 are way to thin.

 

I'll stick to 10-40 for summer and these mild Oregon winters. I'll run 5-30 when I travel to Wisconsin in February.

Except the engineers aren't making the call on the specs. The big wigs are.

 

The trend to recommending thinner oil is mostly because of EPA milage ratings and CAFE standards.

 

If a manufacturer can make each of it's products even 1 MPG more efficient, it helps them meet CAFE regulations without as much REAL engineering.

 

The thinner oil does help the gas milage, but in the end it's not as good for the engines. *newer Variable Valve timing engines excluded. they need thin oil pumped at high pressure.*

 

Obviuosly in VERY cold places in winter, thinner oil is nessecary. But only in winter and I'd say only 5-30. 5-20 or 0-20 are way to thin.

 

I'll stick to 10-40 for summer and these mild Oregon winters. I'll run 5-30 when I travel to Wisconsin in February.

 

actually sometimes we do get to make the calls

 

Subaru hasnt really been in that "we need to get bigger, faster every year" race. But the piston slap came about because of EPA polution standards. Longer piston skirts are more mass to heat up. Mor emass alos means slower throttle response etc. There is always a bit of a learning curve with these things as sometimes the mandates come out before the sollutions can be fully tested. It still takes time to pile the miles on cars even as test mules. This is why i am against CA instantly requireing tougher standards as no one will be able to meet them.

 

Oil also changes as time goes on. What was available the day the car was made may be much better today then yesterday. So as long as your out of warrenty go with what works.

 

 

nipper

Except the engineers aren't making the call on the specs. The big wigs are.

 

The trend to recommending thinner oil is mostly because of EPA milage ratings and CAFE standards.

 

If a manufacturer can make each of it's products even 1 MPG more efficient, it helps them meet CAFE regulations without as much REAL engineering.

 

The thinner oil does help the gas milage, but in the end it's not as good for the engines. *newer Variable Valve timing engines excluded. they need thin oil pumped at high pressure.*

 

Obviuosly in VERY cold places in winter, thinner oil is nessecary. But only in winter and I'd say only 5-30. 5-20 or 0-20 are way to thin.

 

I'll stick to 10-40 for summer and these mild Oregon winters. I'll run 5-30 when I travel to Wisconsin in February.

 

Even if the "big wigs" wanted a thinner oil for EPA ratings, Engineers can engineer the car to those thinner oil specs. That is why they call them engineers. Take the Ford Escape with the V-6. That vehicle requires 5w-20 motor oil because of the tolerances. People who think that is too thin were putting 5w or 10w-30 in thinking that it would be "better". What started happening is that those engines started siezing up due to oil starvation. Ford investigated why that was happening and found the oil viscousity was to thick. So because you think that it is ok to put thicker oil in than required because you think the "bigwig" is putting the screws to you, then you should not be surprised if one day you buy a newer vehicle and do not get the long life that it was designed to get by using the thinner oil.:-\

Even if the "big wigs" wanted a thinner oil for EPA ratings, Engineers can engineer the car to those thinner oil specs. That is why they call them engineers. Take the Ford Escape with the V-6. That vehicle requires 5w-20 motor oil because of the tolerances. People who think that is too thin were putting 5w or 10w-30 in thinking that it would be "better". What started happening is that those engines started siezing up due to oil starvation. Ford investigated why that was happening and found the oil viscousity was to thick. So because you think that it is ok to put thicker oil in than required because you think the "bigwig" is putting the screws to you, then you should not be surprised if one day you buy a newer vehicle and do not get the long life that it was designed to get by using the thinner oil.:-\

 

I agree that in most situations it's best to stick to the MFR's suggested oil, but that sounds like some seriously bad engineering on the Ford Escape to require such precise tolerances on the viscosity of the oil- let's face it, at most normal temperatures, the viscosity of 5w-20 versus 5w30 isn't all that different. It's not a 2:1 ratio or anything. I'm sure that there are tolerances between different brands of oil labeled "5w20" and even some batch-to-batch variations.

I can see engineering an "exotic" vehicle to be unforgiving about type of oil or viscosity, but a FORD? People who buy Fords are used to throwing in whatever kind of oil is on sale at Wal-mart!

 

Nathan

I agree that in most situations it's best to stick to the MFR's suggested oil, but that sounds like some seriously bad engineering on the Ford Escape to require such precise tolerances on the viscosity of the oil- let's face it, at most normal temperatures, the viscosity of 5w-20 versus 5w30 isn't all that different. It's not a 2:1 ratio or anything. I'm sure that there are tolerances between different brands of oil labeled "5w20" and even some batch-to-batch variations.

I can see engineering an "exotic" vehicle to be unforgiving about type of oil or viscosity, but a FORD? People who buy Fords are used to throwing in whatever kind of oil is on sale at Wal-mart!

 

Nathan

 

 

And thats why they were siezing engines. The 2nd costliest and 1st most complicated thing people buy are thier cars. They need to remember that, cars are actually exotic things in todays modern world. All cars have to meet the same emissions, have the same common denominators.

 

People need to get re-educated.

 

nipper

Nipper,

 

I hear what you're saying... most current car designs are less tolerant of incorrect servicing than in the past. Having said that, there are plenty of other engine designs which meet current emissions requirements and won't seize if you use marginally thicker oil than is called for. Surely a design engineer has got to consider the possibility that an "Iffy lube" tech will occasionally use whatever's handy, and unless it's GEAR LUBE or something completely insane, the engine shouldn't grenade.

I

I can see engineering an "exotic" vehicle to be unforgiving about type of oil or viscosity, but a FORD? People who buy Fords are used to throwing in whatever kind of oil is on sale at Wal-mart!

 

Nathan

 

People who buy Fords probably buy their car at Walmart!