Not sure if previous owner used synthetic oil or regular

[CARGUY40]

I bought a 1994 infiniti j30 with 106k miles and have no idea if the previous owner used synthetic or regular oil so i was thinking to use a high mileage synthetic blend? what do you guys think?

Also can high mileage oils cause leaks from swelling the seals up if your car is not leaking?

 

[ctechbob]

Use what meets the specs for your car and that you are happy with. It doesn't matter what was used before.

 

[Escape08]

1994? Most likely dyno. There's nothing wrong with dynos. There are million plus mile vehicles that ran with dynos alone

 

[CharBaby]

All oils meant for your vehicle/engine can be mixed. Don't worry about the notion of, you can't use Dino oil after using Synthetic or visa-versa.

 

[PF52]

And besides all that, have you shopped for regular dino oil lately? There's aren't a lot of choices any more.

I use regular oil in two of my cars and I had to order from Amazon to get the brand I want.

 

[Pablo]

Use a good oil of your choice in the correct grade and specification

Joined 2011?

Dyno?

Wah? Blowback thread?!?!?

 

[kschachn]

Use a good oil of your choice in the correct grade and specification

Joined 2011?

Dyno?

Wah? Blowback thread?!?!?

The whole thing is a bit over the top.

 

[Hohn]

I bought a 1994 infiniti j30 with 106k miles and have no idea if the previous owner used synthetic or regular oil so i was thinking to use a high mileage synthetic blend? what do you guys think?

Also can high mileage oils cause leaks from swelling the seals up if your car is not leaking?

HM oils have "seal conditioners" not necessarily "seal swellers."

I've always believed that an engine that not leaking doesn't need HM oil.

Any blend or full syn oil you can get today is light years ahead of whatever juice was used in 1994.

Use any full syn you prefer. If you want to baby your way into it, start with some red jug MaxLife, it's my standard "cheap oil" because it's affordable and good.

 

[Auto tech]

I would use a full synthetic oil. To me the price difference between a full synthetic and a blend makes full synthetic oil a no brainer.

 

[Drifter]

High mileage oils scare me. STP at Autozone is what I use for older vehicles. Works great and doesn't leak as much as Synthetic if you have a leak or the potential for a leak

 

[Auto tech]

High mileage oils scare me. STP at Autozone is what I use for older vehicles. Works great and doesn't leak as much as Synthetic if you have a leak or the potential for a leak

What scares you about high mileage oils? Basically they have more seal conditioners, sometimes they are a little bit thicker, they are completely safe for brand new engines or older engines.

 

[Speedy3861]

If it was ever serviced at an Infinity dealer, perhaps a VIN search by a dealer might reveal some service history.

 

[Drifter]

What scares you about high mileage oils? Basically they have more seal conditioners, sometimes they are a little bit thicker, they are completely safe for brand new engines or older engines.

The seal conditioner. No real world or scientific reason. Just my two cents. Why would a new engine need seal conditioner ? Also if a used high
mileage engine is not leaking why take the chance ? Front and rear main seals are a lot of labor hours to replace. Once again I am no expert. Cheers

 

[JohnnyG]

We just had a thread about the nonsense that was being said about synthetic oils being incomapitble with "dino" oil in the early days.
Some things just refuse to go away.

 

[4wheeldog]

If you are certain it is reasonably clean use whatever appeals to you. If there is a possibility that it is sludged up, why not try Valvoline R&P?

 

[NormanBuntz]

I know from personal experience that as late as 2010 some Infiniti dealers were still using Mobil conventional in those V-6 motors. Going by that, a solid synthetic blend today should be plenty good enough for a 1994 J30.

 

[Auto tech]

The seal conditioner. No real world or scientific reason. Just my two cents. Why would a new engine need seal conditioner ? Also if a used high
mileage engine is not leaking why take the chance ? Front and rear main seals are a lot of labor hours to replace. Once again I am no expert. Cheers

All oils contain seal conditioners

 

[D1dad]

What scares you about high mileage oils? Basically they have more seal conditioners, sometimes they are a little bit thicker, they are completely safe for brand new engines or older engines.

Yep. I’ve got a 2018 in my driveway that saw nothing but maxlife synthetic from its 1st oil change till 85k and is spotless, doesn’t leak or use a drop. I’ve since used Schaeffers and HPl with the same results.