What weight oil???
Thread Starter
Pro
Joined: Jul 2007
Posts: 670
Likes: 0
From: Culver City California
What weight oil???
I would like to know what weight oil everyone is running in their L98s. especially the higher mileage examples. my 1989 L98 has 113,000 miles on the clock and runs great but I want to keep it that way! what does everyone think about me running 10w-40 with a K&N filter? or because I have increased bearing clearences should I go with a 20w-50? I will of course be using a full synthetic so thats not even a question
thanks
thanks
Team Owner
Joined: Dec 1999
Posts: 34,873
Likes: 487
From: Lacey WA RVN 68-69
NCM Sinkhole Donor
10W-30 will be fine for the climate in the LA area. 5W-30 would also be fine. I seem to recall that at one point, GM specifically did not recommend the use of a 10W-40 oil in small block Chevy motors and they even stated that use of that specific weight oil would void factory warranties. I think this was in the 70's and maybe into the 80's.
Melting Slicks
Joined: Mar 1999
Posts: 2,830
Likes: 20
From: Las Vegas Nevada
10W-30 will be fine for the climate in the LA area. 5W-30 would also be fine. I seem to recall that at one point, GM specifically did not recommend the use of a 10W-40 oil in small block Chevy motors and they even stated that use of that specific weight oil would void factory warranties. I think this was in the 70's and maybe into the 80's.
Pro
Joined: May 2006
Posts: 583
Likes: 0
From: Pittsburgh PA
I thought the 10-40 was cool until I read some of the posts here. They made sense to me. Currently I am running 5-30 Royale Purple. Also I have been known to use Amsoil and Moble One.
Thread Starter
Pro
Joined: Jul 2007
Posts: 670
Likes: 0
From: Culver City California
so what is the problem with the 10-40 I can see no problems with using a 10-40 in an engine with 113,000 miles but if anyone has an actual argument against it that would be great. also what is the oil capacity of a bone stock 1989 L98, 5 or 5.5 quarts??????
Melting Slicks
Joined: Mar 1999
Posts: 2,830
Likes: 20
From: Las Vegas Nevada
I don't think it's going to cause any problems for you. I just picked up 10W40 today for my 'vette. Don't know why I grabbed 40 instead of 30 but that's what I did. I'm not too concerned.
10W-30, 10W-40 I don't think it matters all that much as long as you keep it changed regularly. That's the key.
10W-30, 10W-40 I don't think it matters all that much as long as you keep it changed regularly. That's the key.
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Team Owner
Joined: Dec 1999
Posts: 34,873
Likes: 487
From: Lacey WA RVN 68-69
NCM Sinkhole Donor
There is probably no big deal in running 10W-40 in a motor with 113K on it, but it's not a weight that listed in the owner's manual. 5W-30 (shown as the preferred weight in my owner's manual) or 10W-30 are the two recommended weights and either can be used. You can even use a straight 30W oil if the usual ambient air temps are always above freezing. Unless you have already bought some 10W-40, the 10W-30 will work fine.
As far as capacity, the L98 uses 5 quarts with a filter change. You can use a slightly larger filter like the AC Delco PF1218 that was used on 350 cid V8's in light duty pickups and large cars. This filter won't stick out below the oil pan. It holds a full quart and the filter material is larger than the stock PF25.
Melting Slicks
Joined: Mar 1999
Posts: 2,830
Likes: 20
From: Las Vegas Nevada
There is probably no big deal in running 10W-40 in a motor with 113K on it, but it's not a weight that listed in the owner's manual. 5W-30 (shown as the preferred weight in my owner's manual) or 10W-30 are the two recommended weights and either can be used. You can even use a straight 30W oil if the usual ambient air temps are always above freezing. Unless you have already bought some 10W-40, the 10W-30 will work fine.
As far as capacity, the L98 uses 5 quarts with a filter change. You can use a slightly larger filter like the AC Delco PF1218 that was used on 350 cid V8's in light duty pickups and large cars. This filter won't stick out below the oil pan. It holds a full quart and the filter material is larger than the stock PF25.
As far as capacity, the L98 uses 5 quarts with a filter change. You can use a slightly larger filter like the AC Delco PF1218 that was used on 350 cid V8's in light duty pickups and large cars. This filter won't stick out below the oil pan. It holds a full quart and the filter material is larger than the stock PF25.
Good info there. I have no idea what posessed me to buy the 10W-40 but I don't think it's worth the hassle to return it I'm just going to put it in. The oil cap on my '93 Chevy pickup recommends 5W-30 as well. Seems chevy recommends this weight for their TBI/TPI 305s and 350s.
Burning Brakes
Joined: Jul 2007
Posts: 751
Likes: 0
From: Eau Claire Wisconsin
As long as your oil pressure is good stick with 5w-30 or even 10w-30. The molicules of 10w-40 have to stretch to far inorder to achieve there specific weight. 10w-40 is not as durable of an oil as the others and will be worn out sooner. I don't think you can even get a synthetic it 10w-40, can you?
Racer
Joined: Feb 2006
Posts: 269
Likes: 0
From: Vancouver B.C.
New 383 Stroker Using 5W30(Mobile 1) I was concerned. Hot idle [200 degrees] showed only 7 -10 psi. (Off idle rpm showed maybe 25 +/-)
So I switched to 10W40. Now hot idle is 20 psi & off idle is 50 +[200].
I'm concerned now. With the 10W40 cold idle is 30+ psi. Cold off idle 60+ (Way too 'thick' I'm thinkin')
Will be changing to 10W30 this week to try to stabilize pressures.
Any thoughts?
So I switched to 10W40. Now hot idle is 20 psi & off idle is 50 +[200].
I'm concerned now. With the 10W40 cold idle is 30+ psi. Cold off idle 60+ (Way too 'thick' I'm thinkin')
Will be changing to 10W30 this week to try to stabilize pressures.
Any thoughts?
Slingshot
Joined: Dec 2001
Posts: 3,817
Likes: 24
From: Charlotte NC
New 383 Stroker Using 5W30(Mobile 1) I was concerned. Hot idle [200 degrees] showed only 7 -10 psi. (Off idle rpm showed maybe 25 +/-)
So I switched to 10W40. Now hot idle is 20 psi & off idle is 50 +[200].
I'm concerned now. With the 10W40 cold idle is 30+ psi. Cold off idle 60+ (Way too 'thick' I'm thinkin')
Will be changing to 10W30 this week to try to stabilize pressures.
Any thoughts?
So I switched to 10W40. Now hot idle is 20 psi & off idle is 50 +[200].
I'm concerned now. With the 10W40 cold idle is 30+ psi. Cold off idle 60+ (Way too 'thick' I'm thinkin')
Will be changing to 10W30 this week to try to stabilize pressures.
Any thoughts?
You better check your oil pump ASAP !!
Instructor
Joined: Aug 2007
Posts: 141
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From: Western Suffolk, Long Island NY
