German Castrol 0w-30?

[SComp23]

I have heard nothing but good things about this oil, it is used in my girlfriends BMW and it runs very nice. Would it hurt my Blazer to run 0w-30? I use Mobil 1 now but it makes my rear main leak. I know everyone will tell me it isn't the oil, but I had the seal replaced professionally and it still leaks, but only with the Mobil1. Maybe I need an oil that will swell my seals up a bit better. Suggestions guys?

[BlazerBoyLT98]

What viscosity of mobil1 are you using?

[SComp23]

I am using 5w-30 right now.

[BlazerBoyLT98]

I would only use 0W-30 of any oil ifit was the dead of winter and the temps were constantly well below freezing for our trucks that are supposed to have 5W-30 in them. I can tell you that after a few oil changes with Mobil1 after using crap Dino my oil leak got worse for an oil change or two and then completely dissapeared. I am a firm believer in using Mobil1 and will not switch. If you still feel compelled to use Castrol make sure you use the bottles that say made in Germany on the back, if you don't, I believe the ones that say made in America are not true synthetics. Now don't qoute me as I might be wrong here but I do believe Mobil1 is the best. Plus you can buy it in the 5 quart jug for under $20 at Walmart. You can't beat that!!!! And as always make sure to use nothing but an Ac Delco, Wix or Napa, oil filters, stay away from Fram. Good luck and let us know what happens.

[SComp23]

Does GC come in 5 or 10w-30? I am just sick of this stupid seal dripping. I also heard that since Mobil1 isn't derived from ester it doesn't swell the seals as well as it should because it doesn't have the best additive package. Any thoughts on this?

[BlazerLT]

Originally Posted by BlazerBoyLT98

I would only use 0W-30 of any oil ifit was the dead of winter and the temps were constantly well below freezing for our trucks that are supposed to have 5W-30 in them. I can tell you that after a few oil changes with Mobil1 after using crap Dino my oil leak got worse for an oil change or two and then completely dissapeared. I am a firm believer in using Mobil1 and will not switch. If you still feel compelled to use Castrol make sure you use the bottles that say made in Germany on the back, if you don't, I believe the ones that say made in America are not true synthetics. Now don't qoute me as I might be wrong here but I do believe Mobil1 is the best. Plus you can buy it in the 5 quart jug for under $20 at Walmart. You can't beat that!!!! And as always make sure to use nothing but an Ac Delco, Wix or Napa, oil filters, stay away from Fram. Good luck and let us know what happens.

The 0w30 can be used all year around.

The German Castrol 0w30 technically is thicker than the Mobil1 5w30 which is why you can only compare 5w30 to 0w30 within the same brand and type.



Here you can see the difference in viscosity between the two and many others.

They are both 30 weights at operating temperature which is the crucial point. I use 0w30 all year around and you won't find a better all temperature oil.

[SComp23]

Thanks LT. Also, I notice you are quite active on the oil drop forums, what is your take on Mobil1 seal conditioning properties. This is the only oil that leaks out of my truck, mostly the rear main which is brand new. Should I give the GC a try?

[BlazerLT]

Originally Posted by SComp23

Thanks LT. Also, I notice you are quite active on the oil drop forums, what is your take on Mobil1 seal conditioning properties. This is the only oil that leaks out of my truck, mostly the rear main which is brand new. Should I give the GC a try?

Scomp23, if the rear seal is leaking after it was replaced, you should take it back to them and have them fix it. You don't pay good money to have an improper job done.

Also, replace your PCV valve and clean both the fresh air and PCV lines out. This will rule out elevated crankcase pressures causing the leak and pushing the oil out the seals.

Mobil1's PAO based Group 5 baseoil should not cause leaks. In some or most cases, when it causes a leak, it will stop it within 10,000miles seeing after it cleans the crud that was causing a false seal, the additives will quickly plump the seal back up.

I think this is a bad seal that was installed if it didn't stop it.

[SComp23]

Thanks a lot LT, I have only driven for 3k miles or so with the Mobil 1. The GC won't hurt my truck will it? 0w-30 is perfectly fine? I think it is the 30 that I should be concerned with right, as that is the thickness at operation. Will the 0w give me enough protection at startup?

[BlazerLT]

Originally Posted by SComp23

Thanks a lot LT, I have only driven for 3k miles or so with the Mobil 1. The GC won't hurt my truck will it? 0w-30 is perfectly fine? I think it is the 30 that I should be concerned with right, as that is the thickness at operation. Will the 0w give me enough protection at startup?

As you can see above, the 0w30 Castrol is actually a bit thicker at any given temperature than the Mobil1 5w30.

You will have the EXACT same protection on startup or even better. You see, the X in XwYY is not a weight at all, it is a cold flow number and everyone knows that there is not a zero weight oil which means the oil would not be there.

0w30, 5w30, 10w30 in THE SAME BRAND AND TYPE of oil are all 30 weights at operating temperature which is 100c or 212f. The only difference is that the lower the number at the front, the lower the temperature the oil can take before it gels and hits its' pour point.

Now you have to consider that you are NOT comparing apples to apples here. You are comparing two different manufacturers oils at two different grades and they are not directly comparable.

Here let me show you numbers extracted from the chart above:

GC 0w30

-20c: 2609cst
100c: 12.0 cst

M1 5w30

-20c: 2225.1 cst
100c: 10.0cst

So there you can see why you cannot directly compare two different manufacturers oils and different grades. The GC 0w30 is actually thicker than the M1 5w30 at -20c.

[DINO55]

Where can you Buy German Castrol 0w-30 Oil at? How expensive is it?

[SComp23]

Autozone here in the states, its the same price as American Castrol Syntec

[BlazerLT]

Originally Posted by DINO55

Where can you Buy German Castrol 0w-30 Oil at? How expensive is it?

Should be around the same price as all the other synthetics.

You have to turn the bottle over and look at the back and see if it says "Made in Germany"

There is a 0w30 USA version but it isn't as sought after or as good.

It is the ONLY syntec that is actually synthetic, all the rest are hydrocracked conventional oils and are not a true synthetic.

[BlazerBoyLT98]

Thanks for the info LT

[SComp23]

Well I am going to make the switch tomorrow from M1 to GC, I will let everyone know how it goes.