Shop put in "wrong" oil- to change or not?

[Brofessor]

Recently I had my car at a shop for a 120k service which required changing the oil. Two days later, looking at the receipt more closely, I see that they have put in Pennzoil 5w30. At $7.05 a quart, I assume it is some kind of synthetic if not PP.

The car is a 1990 Nissan 300zx non-turbo with 108k that has ran either Castrol GTX, Havoline, or Chevron 10w30 for the past 3-4 years. This same shop said that the rear crank seal "seaps" very slowly.

The manual calls for 10w30 in the local temperature range, and only for 5w30 in colder climates than here year round. Why would a shop do this?

I'm tempted to dump the $30 of oil that's in there and put in some non synthetic 10w30 tomorrow. It seems like a waste but I'm just not comfortable with that grade of synthetic in there with possible leaks, it's not the brand. Oil has been in there for 50 miles +/-.


Should I change it ASAP? What about the filter?

Thanks!

 

[Mr Nice]

NO !!!!

Keep that 5w30 oil for another 5K miles.

 

[ZZman]

It will be fine.

 

[4x4taco]

yeah dude, if it doesn't burn it or have knock when it starts keep it. If the engine is strong and in good shape, I'd stick with a 5-30.

 

[ThirdeYe]

Beautiful car. Don't worry, it will be fine. The 5w30 grade is not necessarily thinner than a 10w30, unless it's at extremely cold temperatures. In some cases, it's thicker. The VG30DETT engine is excellent

 

[c3po]

You will be fine, no need too change the oil, just check your oil level from time to time.

 

[Warstud]

Originally Posted By: 4x4taco
yeah dude, if it doesn't burn it or have knock when it starts keep it. If the engine is strong and in good shape, I'd stick with a 5-30.

 

[RacerE7773]

Originally Posted By: ThirdeYe
Beautiful car. Don't worry, it will be fine. The 5w30 grade is not necessarily thinner than a 10w30, unless it's at extremely cold temperatures. In some cases, it's thicker. The VG30DETT engine is excellent

I agree. The only way I could ever have afforded one is a Matchbox size.

 

[KLowD9x]

I don't understand this "anything less than 10w30 is too thin!!" logic.

Why is it too thin? It's still a 30 when at operating temperature.

 

[SLCraig]

Originally Posted By: ThirdeYe
Beautiful car. Don't worry, it will be fine. The 5w30 grade is not necessarily thinner than a 10w30, unless it's at extremely cold temperatures. In some cases, it's thicker. The VG30DETT engine is excellent

The VG30DETT is excellent, I agree! His is N/A though, so even less to worry about in the oil used. VG30DE

 

[blackdiamond]

I wouldn't even think that you got synthetic oil at $7 a quart. Dealerships aren't called stealerships for nothing.

 

[KLowD9x]

Originally Posted By: blackdiamond
I wouldn't even think that you got synthetic oil at $7 a quart. Dealerships aren't called stealerships for nothing.


Easy.

We get M1 at my dealer for a killer price and we give the customer a break on it at about 7.50 a quart. You can't do much better than that at an auto parts store.

 

[StevieC]

Keep it and run it for at least 5K miles

 

[aquariuscsm]

Originally Posted By: Brofessor
Recently I had my car at a shop for a 120k service which required changing the oil. Two days later, looking at the receipt more closely, I see that they have put in Pennzoil 5w30. At $7.05 a quart, I assume it is some kind of synthetic if not PP.

The car is a 1990 Nissan 300zx non-turbo with 108k that has ran either Castrol GTX, Havoline, or Chevron 10w30 for the past 3-4 years. This same shop said that the rear crank seal "seaps" very slowly.

The manual calls for 10w30 in the local temperature range, and only for 5w30 in colder climates than here year round. Why would a shop do this?

I'm tempted to dump the $30 of oil that's in there and put in some non synthetic 10w30 tomorrow. It seems like a waste but I'm just not comfortable with that grade of synthetic in there with possible leaks, it's not the brand. Oil has been in there for 50 miles +/-.


Should I change it ASAP? What about the filter?

Thanks!


^^Hey there fellow Z32 owner!

 

[mechtech2]

Just to get things straight, the first number in a multigrade oil is it's characteristics at 0 deg F, and the second number is for about 200.
I would always choose an oil with a lower first number, as it is already 20 times as thick when real cold as when real hot.
So the 5-30 is an upgrade, and possible thicker even at operating temps.

 

[crinkles]

Originally Posted By: mechtech2
Just to get things straight, the first number in a multigrade oil is it's characteristics at 0 deg


you fo real?

isn't the first number at 40 deg C, about 105 F?

 

[demarpaint]

The shop put in 5W30 in a car calling for 10W30, no problem. Now if they put in 5W20, or 20W50, I'd make them change it out. In fact if they put anything but a 30 wt oil in there, they'd be changing it out on their dime!

IMO if they put in a synthetic 5W30 vs a 10W30, they did you a favor, sepecially if you run it into the winter months.

 

[Familyguy]

Not to worry at all. Why did they do it? Probably because they have 55gal drums (or a big tank of) bulk oil in 5w30. I'd be pretty surprised if they sprang for synthetic without you specifically asking for it.

My next door neighbor has 230k miles or so on his similar vintage non-turbo Z. He got there with 4000-5000 mile changes on whatever 5w30 rotgut bulk oil and brand-X filter that was being sold by his local gas station. I always rib him about not using quality synthetic oil and he just doesn't care. Runs like a top.

 

[AlanRebod]

I think it used to be the case that 10w30 was preferred over 5w30 because the amount of VII required with the quality/process of the oils of the day really made the oil prone to shear/thin out of grade more quickly than the 5w30's of today (and 10w30's of the time).


The 5W-xx rating does not refer to how thin the oil is; it refers to the oil's ability to flow at lower temperatures. 5W flows better than 10W but as I explained above, it is a compromise because the blenders have to add more VII additives (viscosity index improvers) to the oil which can make the oil shear more quickly than a 10W-xx oil.

You did say your car was a 1990, so just keep in mind that the recommendation was made based on the oil technology of that time. The 5W-x oils of today are much more robust and will be fine.

 

[aquariuscsm]

The most popular oil of choice on Twinturbo.com and 300zxclub.com for our cars is Mobil 1 15W50.