What's the current thinking on which grade of oil to use in a 5cyl 20V?
12-14-2003, 03:22 PM
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What's the current thinking on which grade of oil to use in a 5cyl 20V?
Hi Everyone,
I know that this topic has been done to death and everyone seems to have a different theory but I just thought I ask what the general consensus is on what grade of oil (not which brand) to use in a 90q20V motor.
The owners manual makes all sorts of recommendations based on climate, but I'm sure that oil formulations have been through multiple generation changes since the car originally came out which is why I thought I'd ask the forum what the latest thinking is.
For what it's worth I live in Melbourne, Australia. It's currently summer and the temperature ranges from 15C to 42C. In winter around 5C to 20C is about right, although -10C is not unheard of up in the mountains.
My car's done 140,000km and doesn't use much oil (around half a litre per 5000km), but the lifters do rattle a bit. Up until recently I've been using a non-synth 15w-50 but just for laughs on the last change I've given a 20w-60 a try (again non-synth). When using the 20w-60 the lifters are noisier initially (for say 5mins) but are much quieter there after when compared to the 15w-50.
So:
Is 20w-60 silly, even for a Melbourne summer?
Should I flip back to a 15w-50 and live with the lifter noise?
etc. etc.
Any and all comments are most welcome.......
I know that this topic has been done to death and everyone seems to have a different theory but I just thought I ask what the general consensus is on what grade of oil (not which brand) to use in a 90q20V motor.
The owners manual makes all sorts of recommendations based on climate, but I'm sure that oil formulations have been through multiple generation changes since the car originally came out which is why I thought I'd ask the forum what the latest thinking is.
For what it's worth I live in Melbourne, Australia. It's currently summer and the temperature ranges from 15C to 42C. In winter around 5C to 20C is about right, although -10C is not unheard of up in the mountains.
My car's done 140,000km and doesn't use much oil (around half a litre per 5000km), but the lifters do rattle a bit. Up until recently I've been using a non-synth 15w-50 but just for laughs on the last change I've given a 20w-60 a try (again non-synth). When using the 20w-60 the lifters are noisier initially (for say 5mins) but are much quieter there after when compared to the 15w-50.
So:
Is 20w-60 silly, even for a Melbourne summer?
Should I flip back to a 15w-50 and live with the lifter noise?
etc. etc.
Any and all comments are most welcome.......
12-14-2003, 03:48 PM
#3
Re: What's the current thinking on which grade of oil to use in a 5cyl 20V?
20w60 is "silly"...20w50 is less so, and is what I use in the summer in the CQ (part synthetic, breaks down less). Temps up to high 90's-low 100's (so mid/upper 30C range). Never had any hint of overheating, even when autocrossing.
I use 10w30 in the winter, where it can get quite cold, below 0F/-18C pretty easily during the day. Its been 20-25F here the past couple days, but is going back into the 30's and 40's this next week (0-6C or so?). I'd use 10w30 up to temps in the 75-80F range, then think about using a 20w50. But only if your oil appears to be breaking down faster, or getting <u>really</u> thin.
I use 10w30 in the winter, where it can get quite cold, below 0F/-18C pretty easily during the day. Its been 20-25F here the past couple days, but is going back into the 30's and 40's this next week (0-6C or so?). I'd use 10w30 up to temps in the 75-80F range, then think about using a 20w50. But only if your oil appears to be breaking down faster, or getting <u>really</u> thin.
12-14-2003, 03:50 PM
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Yes, that would be an ideal solution, the trouble is....
Out here in Australia, the lifters cost AUS$33 each! So, 20x$33 before I even crack open the cam cover is a little pricey for me at the moment....
Still, it may work out cheaper in the long run if I end up wearing out the cyliner bores and the valve stems because of using too high a viscosity oil......
Perhaps a 15w60 would be a nice compromise in the short term?
Still, it may work out cheaper in the long run if I end up wearing out the cyliner bores and the valve stems because of using too high a viscosity oil......
Perhaps a 15w60 would be a nice compromise in the short term?
12-14-2003, 04:03 PM
#5
20w50 is better....has to do with the spread between the XX and YY of the XXwYY...
Don't ask me to explain it, as I am not a lubrication/oil guy. What I have been told is that a 20pt difference is fine, 30 and up is not so good, but 20w50 is fine to use due to some properties it has.
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12-14-2003, 05:17 PM
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Thanks guys, some good info there....
Hi guys,
My very limited understanding of viscosity indexing is that for an oil marked XwY, it means that "X" is the rating at 0C and "Y" is the rating at 100C when compared to a single grade SAE oil. To make a 20w50 they start with an SAE 20 base oil and then add some long chain polymers that thicken it up in the higher temperature ranges so that it acts like a 50 SAE oil at 100C.
So it makes sense that if the difference is big between X and Y it could get a little unpredictable as the long chain polymers get chopped up and generally decay. I would guess that the oil would start to move back to its original base grade, in the case of 20W50, a 20 SAE weight oil.
Now from what I can tell Synth oil is totally different in that it's designed from the word go for a specific range of viscosity's. It's not "improved" with additives to make it thicker and so the large difference between "X" and "Y" is not an issue.
Anyway, thanks for your thoughts. I'll change over to something a little more sensible next weekend.....
My very limited understanding of viscosity indexing is that for an oil marked XwY, it means that "X" is the rating at 0C and "Y" is the rating at 100C when compared to a single grade SAE oil. To make a 20w50 they start with an SAE 20 base oil and then add some long chain polymers that thicken it up in the higher temperature ranges so that it acts like a 50 SAE oil at 100C.
So it makes sense that if the difference is big between X and Y it could get a little unpredictable as the long chain polymers get chopped up and generally decay. I would guess that the oil would start to move back to its original base grade, in the case of 20W50, a 20 SAE weight oil.
Now from what I can tell Synth oil is totally different in that it's designed from the word go for a specific range of viscosity's. It's not "improved" with additives to make it thicker and so the large difference between "X" and "Y" is not an issue.
Anyway, thanks for your thoughts. I'll change over to something a little more sensible next weekend.....
