i know this is a hashed over question, but i have to ask it again, i have been using wolfs head 5 or 10 w30 as i find the old girl seems to love it. she runs quiet and seems to idle smoother imo. i will put a oem filter on as well when i remember.

 

 

Rotella T6 5W-40 ...

 

Been using Valvoline MaxLife in my cars.

 

I bought my Maxima in 2006. It had 100k on it.

I found a couple of receipts in it for Mobile One
Synthetic.

​​​​​​I have continued use of synthetic oil. Either. Mobil One or O Reilys. Usually 5-30, sometimes 10-30. My car is generally used on the highway.
My oil change interval is around 6000-8000 miles.

My car has about 215k on it now.
My engine still has good compression.

I removed the lower oil pan when I replaced my water pump at about 200k. I saw no sludge or deposits at all. Just a very clean engine.

​​​​​

 

Castrol Edge 0w30

 

Being that 30 weight oil is specified, is there any negative issues with using 40 weight, other than perhaps slightly less fuel economy?

 

It's my opinion, which is based on reading I've done over the decades, that if a 40 weight is used in applications where a 30 weight is specified, synthetics are a better choice based on their flow characteristics.

Typically, a synthetic will flow similar to a conventional of the lower specification ... meaning, when hot a 40 weight synthetic will flow similar to a 30 weight conventional.

If you choose your [x]W-40 wisely, there should be no down-side.

I have found that my mileage using a 10W-30 (synthetic or conventional) as opposed to the 5W-40 (synthetic) doesn't change in the least.

 

Amsoil FTW.

 

I used to use 5w-30 Mobil One full synthetic. I put 7,000 a year at most so only 2 oil changes a year. I removed the valve covers for a 00VI swap and did not like what I saw at 136k. It was very dirty inside compared to the much higher milage donor DEK. It got me thinking.

I switched to Pennzoil conventional, either regular or high milage, for all my vehicles. I can't say if it made a difference on the inside. At least I save a few dollars. With what little miles I put on my vehicles I should just change it every 3 months.