Best off the shelf nonsyn high mileage oil

[mustang john]

Hey guys I have an 03 GX470 that has... 363k miles on it. Yes its not a typo lol! I bought the car from a customer at my dealership where I work at 290K miles and it has run great for me for 5 years. I am the second owner and also the tech that has done 80% of the services on this car since it was brand new. It has never seen a drop of synthetic oil just the standard 5W30 that the dealership sells and has always had 5k mile oil changes.

The motor has started having a slight knock which is understandable at this mileage but it goes away after a minute or two once the motor has some heat in it. It has also started smoking some on cold starts due to oil leaking by the valve stem seals, again once warmed up no smoking what so ever.


I would like to start using a high mileage oil (better late than never lol) and want to use the best non synthetic off the shelf oil that will help control the oil leaking past the valve stem seals.

Suggestion?

 

[SID297]

I have no real reco here, but you may want to consider stepping up to a 10w40.

 

[mustang john]

I have no real reco here, but you may want to consider stepping up to a 10w40.

I was planning on stepping up to 10w40 for sure but was mainly wondering which high mileage oil out there was the best. I have tried subbing in a quart of lucas oil stabilizer in the last few oil changes and that has helped with both the cold knock and smoking but I know the valve stem seals could really use some kind of seal conditioner found in the high mileage type oils.

I have done enough valve stem seal jobs on older high mileage cars and know the rubber in those seals can get rock hard with age.

Just trying to get myself to the 400k mark before I have to do any major work! lol

 

[5.0Flareside]

I've always seen good luck with Valvoline Maxlife. It's a syn blend.

But to be honest if it's knocking now ya might as well work on it. You'll be wasting money on additives (ya shouldn't have to use ever) and also on trying to prolong its life.

 

[mustang john]

Its not knocking that bad, about two minutes in the morning and its completely quiet the rest of the day. A used engine is $2k and a rebuild would be just as much but more time consuming and i cant have it down that long its a daily driver. It will go 400k+ the way it sits im just wanting to try to cut down on the smoking and i think a good high mileage oil in a thicker weight is the way to go just wasnt sure which brand to pick up.

 

[UnleashedBeast]

Valvoline Maxlife is my choice as well, in a 40 weight.

 

[mustang john]

Valvoline Maxlife is my choice as well, in a 40 weight.

Thanks! I will report back how well it works on this tired old dog. lol