I have over 400,000 miles on my 2000 Silverado 4.8 engine and in the last three years my oil pressure has gone down to about 20psi at hot idle now with a little more cold start noise . I Have been using mobil 1 10w30 extended performance and was wondering if I could blend in some of their new 5w40 blend with it to help bring back some pressure and prolong the life a little. Im not sure which of the mobil 1 blends are compatible or incompatible, I was told that some blends would cause separation
Mobil 1 blending recommendations
- Thread starter BobSmith
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They are all compatible. Blend away or simply switch to 5W40.
OVERKILL
$100 Site Donor 2021
Bringing the pressure back up a bit isn't going to prolong the life, 20psi is more than good for hot at idle for an engine with that kind of mileage, I'd continue to use what you've been using. Your oil pump may be getting tired at this point, which, if the bottom end is still in good shape, may be where your pressure has gone. No oil is going to fix or help that.
Mixing (you aren't blending, blending is done in a controlled environment with a knowledge of all variables involved and testing of the product) oils isn't going to cause any problems but it's not going to improve things either; you don't end up with a better product.
Mobil also makes a high mileage 10w-30 that is heavier (12cSt @ 100C vs 10.2cSt for the EP 10w-30) which is probably an all-around better choice.
The 5w40 is designed for European engines , not sure why but would using all 6 quarts of it be safe ?
Would that be better than the extended performance (20,000 mile oil) 5w30 ?
OVERKILL
$100 Site Donor 2021
Depends on how cold it gets where you are. The Winter rating (10w-xx vs 5w-xx) really dictates which is the most suitable. The 10w-30 should tend to be more shear stable, all else equal.
Unless you are taking advantage of the extended drain intervals, I'd assume the 10w-30 high mileage oil is your best bet.
NC weather isn’t bad really, extended drain intervals are nice, but not absolutely necessary. The 5w40 sounds good, and Im guessing there is plenty of wear on all moving parts inside of my engine in addition to the aging oil pump .
They are all excellent oils. If you don't need 0w or 5w for cold starts, then the M1 HM 10w-30 is an excellent choice. It is just a hair thinner than the M1 FS 0w-40 at temp.
I don't know if I would run extended OCI on a motor with that many miles.
Thanks
Safe for what? Getting 400,000 miles out of the vehicle , we should be asking you what to do.
20 PSI at hot idle is good. Could it be better? Sure, but it's plenty for idle RPMs.
As for the cold start noises... if they are not severe and they go away quickly, I would just keep doing what you have been doing. 10w30 is a good choice. Also Mobil makes a 10w40 syn blend called "Super" , I might check that out if I were you... definitely don't need to run full syn in your engine. But again it's not necessary, the 10w30 is working good for you.
And 400k is quite an achievement on an old V8, congrats on that.
As for the cold start noises... if they are not severe and they go away quickly, I would just keep doing what you have been doing. 10w30 is a good choice. Also Mobil makes a 10w40 syn blend called "Super" , I might check that out if I were you... definitely don't need to run full syn in your engine. But again it's not necessary, the 10w30 is working good for you.
And 400k is quite an achievement on an old V8, congrats on that.
How would a 40-grade oil be unsafe?
Not sure if that particular grade is of the same chemical formula/ingredients. Maybe newer bearings or European parts require different materials in the oil . Maybe they are all the same, I am not sure
That’s why approvals and licenses are important. It’s unnecessary to guess and be unsure.
But having said that no ACEA or API oil will be unsafe due to chemical composition. Imagine the lawsuits if that was ever true.
wemay
Site Donor 2023
Reading the back of the bottle will tell you if the oil is compatible with your vehicle. Since API SP is backwards compatible to at least SJ (2000 or 2001), you should have no worries using those or anything in-between (SL, SM, SN, SN+).
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20 psi at a hot idle sounds good for most engines. If is was to change up oil, I would consider a 10w40 oil. You don't say where you're located so we don't know where you are located. I'm not a fan of blending oils. Ed
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Are you saying a tired oil pump (aka one with more internal clearance from wear) Is not going to be better protected by a higher HTHS oil? I was under the impression that higher HTHS correlated to the oil being able to maintain a physically thicker oil film. I'll admit that I've never done any science on the loads on oil pump gears, but it would seem to me that larger clearances would benefit from heavier oil (which you also suggest).
