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Royal Purple Oil Analysis Results

alvocado

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alvocado Enthusiast

alvocado

Posted
Posted

Since the topics of oil change interval and oil choice are common sources of debate, I decided to send my recent used oil out for an official laboratory analysis. Hopefully the results will be helpful to those of you debating how frequently you should change your oil and which brand oil to use. For background, I'm the original owner of my 2002 Yukon Denali and have always performed my own oil changes. I've used a combination of conventional and synthetic oils over the 6 years but have mostly used Mobil 1 synthetic, always following the oil life monitor which trips around 3500 miles. Because I own a BMW with a factory recommended 15k mile oil change interval, I became intrigued with how one manufactuer can recommend such long change intervals while domestic companies continue to promote the 3000 mile interval. Since Royal Purple claims 12000 mile or 12 month change intervals (with proper filter,) I decided to give it a try and test the oil.

 

Interval details:

Royal Purple 5w-30

Mileage at install: 95993

Mileage at change: 105421

Total mileage in service: 9428

Oil Filter: Carquest 85522, Premium filter supplied by Wixx, rated for extended drain

Time in service: 6 mos.

Oil added during interval: 1/2 quart

 

Test Results:

I sent a 2 oz sample to Blackstone Laboraties (http://www.blackstone-labs.com/) and paid for the basic analysis plus the additive analysis. The full report is attached for download so you can read the details. Overall, the oil was 100% in spec and still had sufficient additive remaining to properly lubricate. The only noteable item pertains to the amount of lead in the sample which can be due to bearing wear. However, I feel this is a result of my sampling technique. I drew the sample after letting about 8 oz of oil drain from the pain. The instructions (which I read after taking the sample) recommend taking the sample at the halfway drain point to ensure that any settled items don't sway the results and give a false high reading. I also let the car sit for an hour after driving which may have allowed some settling in the oil pan. I will test again after the next drain and compare lead readings. Otherwise, the oil was perfectly fine with no signs of engine wear. I will let the current oil run for the full 12k miles before testing again.

 

My Summary:

I know many of you swear by frequent oil changes but my test makes me perfectly comfortable running Royal Purple synthetic for the full 12k mile interval with no risk of adversely affecting my engine. Keep in mind that it's important to use an oil filter rated for extended drain intervals (which the AC Delco filters are NOT) or change the filter more frequently. Wixx are rated for this and others may be as well. I did not research beyond confirming Wixx. This means two less times per year that I have to crawl under the truck.

 

I hope this helps.

D51692_1_a.pdf

D51692_1_a.pdf

D51692_1_a.pdf

D51692_1_a.pdf

alvocado Enthusiast

alvocado

Posted
  • Author
Posted
Thank for sharing your analysis. Great to have data backing a claim!

 

Happy to help. It was a well spent $32 to put some science behind a topic that stirs a lot of speculation and personal opinion.

alaska511 Senior Enthusiast

alaska511

Posted
Posted

I posted one on the break in oil change, and as you did I will post my RP change as well. Coming up on 6K, I have done a lot of towing so I think that is going to be my limit on this one.

svensk Senior Enthusiast

svensk

Posted
Posted

Good to know. I run Amsoil 5w30 at 7500 mile change intervals and I feel at ease knowing it's probably fine. Like you say I just make sure it has a clean filter every 3,000.

callyer Enthusiast

callyer

Posted
Posted

I always hear talk of changing the filter without changing the oil, how does this work? and also, if you are gonna get under there and get dirty, and have oil all over the place, really, it maybe takes an additional 5 min to drain and fill the oil (usually the filter change is the most painful part of the change) why wouldn't you just change the oil? is it just to save a few bucks? and also, I really wouldn't mind just changing the filter, but I always thought the oil would drain out when you remove it, is this not true?

 

Hi my name is Craig, and I am a oil change-aholic! I would like to be "on the wagon" so to speak!

callyer Enthusiast

callyer

Posted
Posted

by the way.. that is the best part of the lift on my truck.. is just being able to go under it without jacking it up, or putting it on ramps!! that ALONE is worth the cost of the lift!

2000DV4.8 Senior Enthusiast

2000DV4.8

Posted
Posted
I always hear talk of changing the filter without changing the oil, how does this work? and also, if you are gonna get under there and get dirty, and have oil all over the place, really, it maybe takes an additional 5 min to drain and fill the oil (usually the filter change is the most painful part of the change) why wouldn't you just change the oil? is it just to save a few bucks? and also, I really wouldn't mind just changing the filter, but I always thought the oil would drain out when you remove it, is this not true?

 

Hi my name is Craig, and I am a oil change-aholic! I would like to be "on the wagon" so to speak!

 

 

That's always been my thinking... :) 5 minutes usually turns into 3 hours though, I'll pull the drain plug, then go watch a baseball or football game... :D

callyer Enthusiast

callyer

Posted
Posted

yup.. it's kinda like sayin' you don't have to put the toothpaste on your toothbrush everytime you brush your teeth!! that's not exactly the difficult part! I am liking the idea of an extended life filter though.. but even that worries me, what if you get a bad filter, you wouldn't even know it until it's too late!!! Do the extended life filters come with a motor guarantee? would they stand behind it?

svensk Senior Enthusiast

svensk

Posted
Posted

Because Amsoil is 80 bucks a case. I'm not going to change it after only 3,000 miles.

I'm testing a long life filter right now I drive 74 miles a day so I'm looking to push it as far has it will go.

callyer Enthusiast

callyer

Posted
Posted
Because Amsoil is 80 bucks a case. I'm not going to change it after only 3,000 miles.

I'm testing a long life filter right now I drive 74 miles a day so I'm looking to push it as far has it will go.

 

 

Good point.... that's pretty freakin' pricey!! I just grew up listening to my grandpa BIOTCH and complain (about everyting actually) about that $%@$%@ quaker state, and what they did to trash his engine, and they didn't back it up b/c he changed his own oil!!! Damn Parifin!!! Will they really fix, or replace your motor for a 15- 20 dollar filter? I really would like to know.. or do the lawyers F it all up.. as always!?

minibike132 Senior Enthusiast

minibike132

Posted
Posted

This in no way means don't change your oil but I just remembered this and thought it was funny. Back when I first started I worked in a tiny two bay independant shop. The manager had a friend who had a Cadillac with a 4.3 I think. I don't remember how many miles she had on this thing but she never, I mean not once changed her oil. One day the engine locked up and put a long block in it. We had this sign that said "Penzoil because it's cheaper to change your oil than change your engine". The manager decided to do the math and it was actually $60 cheaper to change her engine than change her oil every 3000 miles. I think she could have got 3 engines for cheaper than oil changes if she was using $80 a case oil.

svensk Senior Enthusiast

svensk

Posted
Posted
This in no way means don't change your oil but I just remembered this and thought it was funny. Back when I first started I worked in a tiny two bay independant shop. The manager had a friend who had a Cadillac with a 4.3 I think. I don't remember how many miles she had on this thing but she never, I mean not once changed her oil. One day the engine locked up and put a long block in it. We had this sign that said "Penzoil because it's cheaper to change your oil than change your engine". The manager decided to do the math and it was actually $60 cheaper to change her engine than change her oil every 3000 miles. I think she could have got 3 engines for cheaper than oil changes if she was using $80 a case oil.

Remember though you get 2 oil changes out of an $80 case on a 5.3L engine. Then with the full synthetics your stretching the interval to over 7500 miles. Not to mention my engine now at 150,000 miles is as clean as it was at 50K.

callyer Enthusiast

callyer

Posted
Posted
This in no way means don't change your oil but I just remembered this and thought it was funny. Back when I first started I worked in a tiny two bay independant shop. The manager had a friend who had a Cadillac with a 4.3 I think. I don't remember how many miles she had on this thing but she never, I mean not once changed her oil. One day the engine locked up and put a long block in it. We had this sign that said "Penzoil because it's cheaper to change your oil than change your engine". The manager decided to do the math and it was actually $60 cheaper to change her engine than change her oil every 3000 miles. I think she could have got 3 engines for cheaper than oil changes if she was using $80 a case oil.

 

 

HA... nice!!!

DamageInc Enthusiast

DamageInc

Posted
Posted

Back when I was a Chevy tech, I had an S10 come in with a seized engine. It had about 20,000 miles on the original oil and filter, which had never been changed. I pulled the oil pan and flipped it upside down, and the oil didn't even move. It had solidified into tar. I suppose that as the oil broke down enough that it couldn't lube properly, the engine started running hot, and cooked off the lighter hydrocarbons. Obviously a synthetic would have lasted longer, but I guess 20k is the limit for dino oil. :)

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