I use the German made Castrol 0w-30, I only have 4 qts left and I am going for an oil change today. All 3 local Autozones are OUT of the European Formula. WTF do I do? Do I use the 4 qts and have them mix another synthetic with it? Save the 4 until I get more Castrol for later? Recommendations?

 

MIxing wont hurt, i'd just settle for mobil 1.

 

If it's important enough to make a few quick phone calls, call the stores and see if they're getting any in. Maybe they have some coming on a truck later this week. If not, it won't hurt to mix it with something else.

 

Problem is I am right on 4000 miles where I change at, and I am going for tuning/spark plug& wires/dyno this Monday. So i wanted to put fresh oil in now, good idea right?

 

I would just put a quart of M1 in it. When i changed my oil a few weeks ago I called all over Indianapolis and no one had it/didn't know what it was.

 

Ah dude, if you're changing your GC at 4k you are missing out on a lot of the life you get out of it. Most of the UOA's on Bobistheoilguy forums show that even at 7k there is very little wear on the oil and that pushing it to even 9 or 10k is "safe". I usually run mine until 7kish and this time I'm going to around 9k. I'm almost at 9 now, and the oil is still relatively clean looking. Granted, I have to top it off once or twice a month, but still, that's damn good for any oil.

 

I was just figuring for the dyno and tuning it would be best to have fresh stuff in there, actually went out and looked and I am at 5000 miles, should I leave it be?

 

I'd leave it, but it's your car and if you're more comfortable with brand new oil in there while getting it tuned and dynoed then go for it. If you're spending the money on a tune and dyno runs, then a little more on some fresh oil isn't too much of an extra expense.

 

Just checked the oil and it is a tad dark. I DD the car 250 miles a week, half in heavy stop and go traffic. I am at 5233 since the last change in January

 

I DD my car as well. I can't think of any DD that would be as much fun and still get the same kind of mileage.

Another thing if you're getting a tune and doing some dyno pulls is check your spark plugs. They'll make a much bigger difference than your oil. If they've never been changed you may want to throw some properly gapped tr55's in there before you go.

 

They are installing new MSD wires and NGK plugs before tuning and dyno. That's all covered. Oil is the only thing left to cover. Is it a bad idea to put brand new oil in and have them tune it right after with no break in?

 

There's no break in with oil. Only have to worry about that with a new motor, or internal components like a cam etc.

 

You have several choices.

Keep the oil you have for another couple thousand miles. GC is good for it. Don't stress your oil change even at 5k miles for GC.

If you are going to change oil now the closest Castrol product in viscosity higher is 5w- or 10w-40 Syntec, or lower would be GTX High Milage 5w-30. Castrol Syntec 5w-30 is the lowest viscosity 30w, if that concerns you.

If you're going to get on the dyno shortly it wouldn't be a bad oil to use, then change if you have a problem with running it longer. I'm using as my next fill this afternoon. But it really doesn't matter if you have new oil or old. GC will be fine at it's current mileage...New will be good...Lighter oil will give you a hp or two, maybe... It's all good.

If you feel that viscosity is important, rather than the oil chemistry, you can gheck out this thread at BOBISTHEOILGUY. Look for the chart listing viscosities, it's post #892314.

Good luck on the dyno checkup.

 

i wouldn't ever mix oil. i'd drive it around for 1,000 more miles. i usually change my oil at the 4,800 mile mark.

if you still can't find any GC 0W-30 within the next 1,000 miles, i'd put some mobil 1 5W-40 in there. the oil is "okay". it's much better than any of the 30 weights they make.

if you're concerned about dyno numbers, you could put some syntec 5W-30 in there because a thinner oil will show better numbers, then just change it out when GC 0W-30 becomes available again.

 

You're a strong proponent of GC and you change it at 4800?? Why?!

 

leaving it be, no change Ill post dyno and tuning numbers

 

Mixing oils should be done within the family if you have to do it. Castrol w/Castrol. Mobil w/Mobil. Valvoline w/Valvoline. You run the risk of incompatible additives when you go out of the family. Conflicting additives could leave with with much less, rather than much more, protection.

 

so you guys run this GC for that many miles? I finally found some last week 200 miles away when i was on vacation. scored 12 quarts at like $4.6X each

 

Good stuff, ran Mobil 1 and the ticking was horrible. GC quieted it down enough to notice for me.

 

Question: I'm thinking about trying GC 0W-30 in my car, does anyone know how it performs in LT1s? Also, my engine burns about a quart every 1,300 miles, which I believe is due to bad valve seals, and has some seepage from the front and rear crank seals. Should I try this oil, or could it aggravate any of the existing problems? I'm using convential 5W-30 now.