What oil should I use?

[harbiison]

it’s coming time for me to do an oil change and i’ve been using 5w-30 for the winters so now it’s summer should i switch to the 10w-30? also i’ve been using the Napa gold should i switch to something else? reading the factory service manual I read i needed 6 qts but just wanted to confirm.

 

[DWR]

Just grab whatever cheap conventional 5w-30 or 10w-30 is on sale and roll with it. 5w-30 may be marginally better in the winter, but either way these engines are more like tractor engines… they just need SOMETHING to lube them.

 

[bromel]

Use whatever 10w-30 is on sale. Personally I use Valvoline synthetic blend, and 5w-30 in the winter.

 

[Jerry Bransford]

I'm a big fan of a conventional 10W-30 engine oil in the 4.0 engine, it's less likely to encourage rear main seal leaks like some synthetics do. Valvoline, Castrol, NAPA, Mobil, Shell, Wallmart, Pennzoil etc. brands are all fine.

If you see a High Mileage version of any of those I'd go for that. It will help keep your seals, especially your rear main seal, in good condition and leak-free.

 

[PCO6]

I run Castrol GTX High Mileage 10W30 with a NAPA Gold (Wix) filter year round in my Jeeps. I haven't blown anything up ... yet. The oil goes on sale at my supplier every 4 or 5 weeks so I stock up.

 

[Fishtaco]

I'm a big fan of a conventional 10W-30 engine oil in the 4.0 engine, it's less likely to encourage rear main seal leaks like some synthetics do. Valvoline, Castrol, NAPA, Mobil, Shell, Wallmart, Pennzoil etc. brands are all fine.

If you see a High Mileage version of any of those I'd go for that. It will help keep your seals, especially your rear main seal, in good condition and leak-free.

So what is it exactly that makes an oil high mileage over conventional.
cheers

 

[Fishtaco]

it’s coming time for me to do an oil change and i’ve been using 5w-30 for the winters so now it’s summer should i switch to the 10w-30? also i’ve been using the Napa gold should i switch to something else? reading the factory service manual I read i needed 6 qts but just wanted to confirm.

Yes 6 quarts but I find that 6 puts me just above full mark on dipstick (flat level ground)

 

[Jerry Bransford]

So what is it exactly that makes an oil high mileage over conventional.
cheers

Exactly? No clue. Basically just additives/seal restoratives to keep the seals in good condition.

 

[Fishtaco]

Exactly? No clue. Basically just additives/seal restoratives to keep the seals in good condition.

Sorry the "exactly" was just an inquisitive figure of speech

 

[PCO6]

So what is it exactly that makes an oil high mileage over conventional.
cheers

I'm sure there's a bit of hype in this but here's what Castrol has to say about its high mileage oil.

https://www.castrol.com/en_ca/canad...strol-gtx-brand/castrol-gtx-high-mileage.html
I like to stick to one brand. I have used Castrol (right or wrong) since about the mid '70s when I owned and started restoring British cars. There was a LONG oil brand thread on the XJ forum a few years ago. It was all over the place but contained a lot of good info. Shell Rotella seemed to be the top choice for many. They also like Mishimoto rads though.

 

[Fishtaco]

I'm sure there's a bit of hype in this but here's what Castrol has to say about its high mileage oil.

https://www.castrol.com/en_ca/canad...strol-gtx-brand/castrol-gtx-high-mileage.html
I like to stick to one brand. I have used Castrol (right or wrong) since about the mid '70s when I owned and started restoring British cars. There was a LONG oil brand thread on the XJ forum a few years ago. It was all over the place but contained a lot of good info. Shell Rotella seemed to be the top choice for many. They also like Mishimoto rads though.

Thanks, pity it doesn't come in a 10w 40, I still have 6 litres left of my Magnatec (bought it on half price sale) but I will give it a try on change after next.

 

[Pressurized]

I run Castrol GTX High Mileage 10W30 with a NAPA Gold (Wix) filter year round in my Jeeps. I haven't blown anything up ... yet. The oil goes on sale at my supplier every 4 or 5 weeks so I stock up.

This right here... Castrol GTX High Mileage 10W30. WINNER!

 

[Jerry Bransford]

This right here... Castrol GTX High Mileage 10W30. WINNER!

That's a good choice, every bit as good/no worse/no better than Valvoline, NAPA, Mobil, Pennzoil, Havoline, etc.

 

[Pressurized]

That's a good choice, every bit as good/no worse/no better than Valvoline, NAPA, Mobil, Pennzoil, Havoline, etc.

I agree... We grew up racing small block dodges and my grandfather swore by Castrol GTX and we never lost a motor. It has stuck with me since about 1970.

 

[Jerry Bransford]

I agree... We grew up racing small block dodges and my grandfather swore by Castrol GTX and we never lost a motor. It has stuck with me since about 1970.

In 60+ years of running Shell, Valvoline, NAPA, Castrol, Pennzoil, etc. brands of conventional oils I've never lost an engine either. Volvo and Mercedes had ads in the 70's showcasing their customer's cars with >1,000,000 miles on them. Those were the days of nothing but conventional engine oils.

It's not the brand or type of appropriate engine oils that protect our engines, it's nothing more than regular oil and filter changes at appropriate intervals.