Oil Change
Thread Starter
Tech Contributor
Joined: Dec 2003
Posts: 19,384
Likes: 87
From: Horncastle Lincolnshire, England
2023 C5 of the Year Finalist - Unmodified
Oil Change
I changed the oil today. My 02 has had changes every year since new or when the DIC showed 10%. I've always used Mobil 1 until now.
I went with Amsoil for the first time. Changed it at 45% on the DIC but left it for 18 months since the last change. Put in 6.5 quarts which put me up to full on the dipstick. I've always needed closer to 7 qts before so I hope I got all the old oil out. I noticed just before the change that I was starting to hear the tappets (lifters) a lot more on start. Oil pressure at cold down to 40 psi.
After the change, as quiet as ever and back to 45 psi cold.
I plan to send the old Mobil 1 to an analyst to see how it fared after the extended period in service. Could be interesting but I'm sure it'll still show that Mobil 1 copes well.
I went with Amsoil for the first time. Changed it at 45% on the DIC but left it for 18 months since the last change. Put in 6.5 quarts which put me up to full on the dipstick. I've always needed closer to 7 qts before so I hope I got all the old oil out. I noticed just before the change that I was starting to hear the tappets (lifters) a lot more on start. Oil pressure at cold down to 40 psi.
After the change, as quiet as ever and back to 45 psi cold.
I plan to send the old Mobil 1 to an analyst to see how it fared after the extended period in service. Could be interesting but I'm sure it'll still show that Mobil 1 copes well.
Le Mans Master
Joined: May 2008
Posts: 5,892
Likes: 47
From: Helotes TEXAS
I used to use Amsoil. And would still use it today except for the fact that's its more expensive to buy, even as a "dealer". The cost of shipping and the "recycle" fee that is charged negates any and all savings.
I can get Mobil one and a filter cheaper locally and the local auto parts store take my recycle oil for FREE !
I can get Mobil one and a filter cheaper locally and the local auto parts store take my recycle oil for FREE !
Race Director
Joined: Aug 1999
Posts: 11,119
Likes: 672
From: SE Pennsylvania
St. Jude Donor '03 thru '26
Oldtimer
Motor oils ?
I used to use Amsoil. And would still use it today except for the fact that's its more expensive to buy, even as a "dealer". The cost of shipping and the "recycle" fee that is charged negates any and all savings.
I can get Mobil one and a filter cheaper locally and the local auto parts store take my recycle oil for FREE !
I can get Mobil one and a filter cheaper locally and the local auto parts store take my recycle oil for FREE !
I guess I'm lucky, my 2003 LS1 was always quiet once it gets to 175 degrees, and at 200 it's fine. I know that all LSX engines are a little noisy when first started and are cold. I too would like to use Amsoil if it showed promise, but with the MLM scheme under which it's sold, it cost close to 1/3 more to do so. Just not worth the trouble. If i found Royal Purple to be better then I would use it as I can buy it locally. But I only drive about 2-3000 miles a year. I just want to change the oil & filter once a year and I feel that GM said when I bought the car to use a good synthetic motor oil that exceed GM4718M specs. That's all I want to know about motor oil ! So long as I can trust Mobil-1 5W/30 then that's what I'll use, it hasn't let me down in the last 9 years.
Pro
Joined: Nov 2005
Posts: 626
Likes: 0
From: Fresno CA
"After the change, as quiet as ever and back to 45 psi cold."
I notice that my low speed oil pressure rises after the car warms a bit from being completely cold. Maybe 35ish cold to 40+ warm. At full temp at a hot idle is pressure is lower around 30.
I notice that my low speed oil pressure rises after the car warms a bit from being completely cold. Maybe 35ish cold to 40+ warm. At full temp at a hot idle is pressure is lower around 30.
Race Director
Joined: Mar 2001
Posts: 11,405
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From: Whippany NJ
CI 6-7-8-9 Veteran
St. Jude Donor '08-'09
NCM Sinkhole Donor
I used to use Amsoil. And would still use it today except for the fact that's its more expensive to buy, even as a "dealer". The cost of shipping and the "recycle" fee that is charged negates any and all savings.
I can get Mobil one and a filter cheaper locally and the local auto parts store take my recycle oil for FREE !
I can get Mobil one and a filter cheaper locally and the local auto parts store take my recycle oil for FREE !
Im a former Amsoil user. Its no doubt a top quality oil especially for the track but its expensive. I think their pricing model is geared for die hard road racers who buy in quantity.I also tested their oil at Blackstone Labs. The 5000 mile oil sample showed minimal viscosity break-down and I was advised I could have used the oil for another 2k miles.
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I've always used Mobil 1 in my C5s and so far have been pleased. But sounds like the Amsoil is a very good product too.
Thread Starter
Tech Contributor
Joined: Dec 2003
Posts: 19,384
Likes: 87
From: Horncastle Lincolnshire, England
2023 C5 of the Year Finalist - Unmodified
Prices here in UK are crazy so the high cost of oil would make your eyes water
Amsoil cost me $145 for 7 qts whereas Mobil 1 of the correct spec was $180. Add the price of the oil filter - another £18 and an oil change is not a cheap activity here.
Luckily recycling is free.
Amsoil cost me $145 for 7 qts whereas Mobil 1 of the correct spec was $180. Add the price of the oil filter - another £18 and an oil change is not a cheap activity here.
Luckily recycling is free.
Thread Starter
Tech Contributor
Joined: Dec 2003
Posts: 19,384
Likes: 87
From: Horncastle Lincolnshire, England
2023 C5 of the Year Finalist - Unmodified
Without a doubt, the engine is quieter on start up with the new oil. It's been the same now after the last 3 changes. I'm always conscious of noises on start up. Mine's an 02 and I've never suffered from excess oil use. I rarely have to top up between oil changes nowadays.
Team Owner
Joined: Mar 2004
Posts: 30,055
Likes: 351
From: Big Red Ne
I used to use Amsoil. And would still use it today except for the fact that's its more expensive to buy, even as a "dealer". The cost of shipping and the "recycle" fee that is charged negates any and all savings.
I can get Mobil one and a filter cheaper locally and the local auto parts store take my recycle oil for FREE !
I can get Mobil one and a filter cheaper locally and the local auto parts store take my recycle oil for FREE !
Racer
Joined: Sep 2011
Posts: 462
Likes: 56
I know this is a touchy subject but Mobil 1 is not the same high quality oil it used to be, back when our c5s were made. Back then it was a true synthetic, a group IV base stock. Now its just a more refined group III which is not synthetic, but passes the synthetic tests. Lots of oil companies do this now.
Anyway our cars dont really need the best oil around, they are well made machines and can live on just about any decent oil. With that said Mobil 1 shows fairly poor results on analysis when compared to other major brand synthetics like amsoil, castrol, etc. For the money i run castrol as in side by side tests it kills mobil 1 and costs about the same.
My 2 cents, after years of following this topic combined with my own experimenting.
Anyway our cars dont really need the best oil around, they are well made machines and can live on just about any decent oil. With that said Mobil 1 shows fairly poor results on analysis when compared to other major brand synthetics like amsoil, castrol, etc. For the money i run castrol as in side by side tests it kills mobil 1 and costs about the same.
My 2 cents, after years of following this topic combined with my own experimenting.
Premium Supporting Vendor
Joined: Aug 2001
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From: King George VA
For those that would like to try AMSOIL but feel it may be too expensive, more than happy to get AMSOIL products for forum members at dealer wholesale pricing, about 25% below retail, via the AMSOIL Preferred Customer Program. Drop me a PM if interested. 
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AMSOIL Preferred Customer Program (Members buy at Wholesale - a savings of about 25%)
C66 Racing #66 NASA ST2, SCCA T2
AMSOIL Dealer (Forum Vendor)
AMSOIL Preferred Customer Program (Members buy at Wholesale - a savings of about 25%)
Burning Brakes
Joined: Aug 2011
Posts: 1,071
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From: Odessa TX
Prices here in UK are crazy so the high cost of oil would make your eyes water
Amsoil cost me $145 for 7 qts whereas Mobil 1 of the correct spec was $180. Add the price of the oil filter - another £18 and an oil change is not a cheap activity here.
Luckily recycling is free.
Amsoil cost me $145 for 7 qts whereas Mobil 1 of the correct spec was $180. Add the price of the oil filter - another £18 and an oil change is not a cheap activity here.
Luckily recycling is free.
Tech Contributor
Joined: Aug 1999
Posts: 16,376
Likes: 404
From: Should this thoughtful, valuable contribution meet with no acknowledgement or 'thanks' this post----
Prices here in UK are crazy so the high cost of oil would make your eyes water
Amsoil cost me $145 for 7 qts whereas Mobil 1 of the correct spec was $180. Add the price of the oil filter - another £18 and an oil change is not a cheap activity here.
Luckily recycling is free.
Amsoil cost me $145 for 7 qts whereas Mobil 1 of the correct spec was $180. Add the price of the oil filter - another £18 and an oil change is not a cheap activity here.
Luckily recycling is free.
... Anyway, wouldn't it be way cheaper for you to order oil from the States, and have it shipped over?
We pay generally around $30 for a 4 to 6 quarts depending on the source and if a sale is going on....
