moving from synth to semi synth
Discussion
Fully synth seems a bit of an overkill for my 2.5 NA 944 but the last owner has been using 10/40 Quantum Synta each oil change. The car has done about 88k miles and I've done about 1000 in the last 3 weeks and have noticed it does use a little bit of oil although the porsche workshop manuals suggests 1.5l in 1000Km is acceptable and it certainly doesn't use that much.
Would the car be better suited to a 15/40 semi synth and would this reduce the oil consumption or is this just the way these cars are?
Also, if I was to move from synth to semi-synth on the basis of cost (assuming the semi is up to the job) what's the routine to do this? Can I just drain the synth and refill with semi or do I need to use flushing oil? Is there any danger of creating oil leaks when moving from synth to semi?
Thanks for any advice offered.
Regards,
Mark
Would the car be better suited to a 15/40 semi synth and would this reduce the oil consumption or is this just the way these cars are?
Also, if I was to move from synth to semi-synth on the basis of cost (assuming the semi is up to the job) what's the routine to do this? Can I just drain the synth and refill with semi or do I need to use flushing oil? Is there any danger of creating oil leaks when moving from synth to semi?
Thanks for any advice offered.
Regards,
Mark
No probs with oil leaks, its mineral to synthetic that can cause that.
In ya fancy s very decent semi synth my choice would be to shove in Castrol Magnatec 10w/40 or the 15w version.
Costco (one of thiose big outlet centre type places) are doing amasing deals on various car oils at the mo- 4.5l of 10/40 magnatec at £12!! (thats less than many garages pay!!)compared to the £25 or so most motor factors charge.
In ya fancy s very decent semi synth my choice would be to shove in Castrol Magnatec 10w/40 or the 15w version.
Costco (one of thiose big outlet centre type places) are doing amasing deals on various car oils at the mo- 4.5l of 10/40 magnatec at £12!! (thats less than many garages pay!!)compared to the £25 or so most motor factors charge.
Since many of the members of this forum are in UK, I've posted a UK based club for the basis of this article, although it's posted all over the world in other forums. www.ac427.com/html/cobra_32.shtml
It is a great article and will help the buyer become much more informed about the oil they are using, way beyond what is available on the can or from the various marketing efforts.
Here are a few tips from my synthetic oil experience, the particulars regarding your car and your experience may vary.
Virtually everything I've read about premium synthetics such as Mobil-1, Amsoil, Red Line, etc., say it's the next best thing to a "no wear" situation you can find. Amsoil appears to be near the top. I used some and it worked great, but I'm now sticking with Mobil-1 for motor oil. Less friction and therefore less internal heat, better lubricity, less ash when burned, less change to VI, you name it. The link has it all and I didn't write it.
For high milage cars that are consuming oil, perhaps synthetic is not the best choice. I guess it depends on how the stuff works in your particular car. I have a great little 944 with 165,000 miles on it now and I'm using Mobil-1 15W50 with very good results. I like the fact that it flows down to -55 degrees F, and still performs like a 50-weight when it's hot (in other words, a 50-weight will act somewhat like a cold 30 when hot), but the synthetic flows so much better. My oil pressure looks like a new car, however this car has been maintained like an aircraft and has had huge amounts of oil though it over the years, on a very good PM routine.
It will puff some smoke when allowed to sit up for a week or more, and I suspect the superior flowing synthetic is seeping into the valve guides or somewhere, because after a startup it will not smoke at all, nor will it smoke on subsequent daily startups.
Synthetic will not "cause" a leak, but if you have one with natural oil (or some mechanical problem such as a loose oil pan), the synthetic will leak out faster. This has been the cause of lots of discussions over the years.
I've heard of semi-synthetic being used with good results. Oil control might be one of these. You won't get better wear resistance or protection with a semi synthetic though, as everything I've seen suggests full synthetic is superior in every way (and more expensive). With aircraft engines that use lead, the full synthetic is not a solvent for the additives, and semi synthetic such as AeroShell are used because the natural oil will dissolve the "gum" that will otherwise form on the pistons.
For the best protection, the synthetic is best. For an engine that is using oil, perhaps the natural product is best, especially one with added esters intended to swell up the seals. I do point out that the Mobil-1 burns with "no ash". I'm using the Mobil in two other Porsches and a pair of big 35-year old Ford marine engines, and this oil has performed very well under all conditions I've exposed it to. This is my opinion, I'm sure there are others.
Good luck with your car. Enjoy the article, it's loaded with good info.
Dogsharks
It is a great article and will help the buyer become much more informed about the oil they are using, way beyond what is available on the can or from the various marketing efforts.
Here are a few tips from my synthetic oil experience, the particulars regarding your car and your experience may vary.
Virtually everything I've read about premium synthetics such as Mobil-1, Amsoil, Red Line, etc., say it's the next best thing to a "no wear" situation you can find. Amsoil appears to be near the top. I used some and it worked great, but I'm now sticking with Mobil-1 for motor oil. Less friction and therefore less internal heat, better lubricity, less ash when burned, less change to VI, you name it. The link has it all and I didn't write it.
For high milage cars that are consuming oil, perhaps synthetic is not the best choice. I guess it depends on how the stuff works in your particular car. I have a great little 944 with 165,000 miles on it now and I'm using Mobil-1 15W50 with very good results. I like the fact that it flows down to -55 degrees F, and still performs like a 50-weight when it's hot (in other words, a 50-weight will act somewhat like a cold 30 when hot), but the synthetic flows so much better. My oil pressure looks like a new car, however this car has been maintained like an aircraft and has had huge amounts of oil though it over the years, on a very good PM routine.
It will puff some smoke when allowed to sit up for a week or more, and I suspect the superior flowing synthetic is seeping into the valve guides or somewhere, because after a startup it will not smoke at all, nor will it smoke on subsequent daily startups.
Synthetic will not "cause" a leak, but if you have one with natural oil (or some mechanical problem such as a loose oil pan), the synthetic will leak out faster. This has been the cause of lots of discussions over the years.
I've heard of semi-synthetic being used with good results. Oil control might be one of these. You won't get better wear resistance or protection with a semi synthetic though, as everything I've seen suggests full synthetic is superior in every way (and more expensive). With aircraft engines that use lead, the full synthetic is not a solvent for the additives, and semi synthetic such as AeroShell are used because the natural oil will dissolve the "gum" that will otherwise form on the pistons.
For the best protection, the synthetic is best. For an engine that is using oil, perhaps the natural product is best, especially one with added esters intended to swell up the seals. I do point out that the Mobil-1 burns with "no ash". I'm using the Mobil in two other Porsches and a pair of big 35-year old Ford marine engines, and this oil has performed very well under all conditions I've exposed it to. This is my opinion, I'm sure there are others.
Good luck with your car. Enjoy the article, it's loaded with good info.
Dogsharks
Guys,
Might I point out that as far as I am aware, no semi synth sold in this country has any British Standard associated with it.
This means that manufacturers can make any claim they like about a semi synth and it doesn't fall under the beady eyes of the BSI.
Magnetised oil? My arse. Give me a decent synthetic oil every time.
Might I point out that as far as I am aware, no semi synth sold in this country has any British Standard associated with it.
This means that manufacturers can make any claim they like about a semi synth and it doesn't fall under the beady eyes of the BSI.
Magnetised oil? My arse. Give me a decent synthetic oil every time.
GregE240, I'm with you. I would generally say "lose the semi-synthetic" because it's just a way to claim there is "some degree" of "synthetic" product in the can. I would say you could not go wrong using products from Mobil, Amsoil, or Red Line, and I'm sure there are many others on the east side of the pond (too).
The Aeroshell product has a specific use, but I don't really see any advantages to using it in a car that runs on unleaded fuel, as no solvent action is needed from the natural oil to dissolve the additives, as needed in high octane lead avgas.
Dogsharks
The Aeroshell product has a specific use, but I don't really see any advantages to using it in a car that runs on unleaded fuel, as no solvent action is needed from the natural oil to dissolve the additives, as needed in high octane lead avgas.
Dogsharks
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