i've seen cars and trucks with over 600,000km running on convectional oil with no engine replacement, mostly on toyota and hondas as well on a 2.9L ford ranger i had. i still trust the cheap castrol and quaker state oil just for that reason, its the oil change millage that is very important!!!

and to people who are putting in synthetic oil because you dont need to change it as much and think you can drive further millage on it because it comes dark less as fast... if you change the oil and the next day a big piece of metal shaving would get caught in the oil, you will run that motor twice as long before changing the oil beacause you got synthetic so i am sure of more potential damage right?


that is the main reason i still use the convection oil from castrol or quaker state and change my oil and filter every 5000km (most dealer says 6000km) and the oil price is half the price of the synthetic, so put half of the money you spend on syntetic oil in a jar (15-20$ an oil change) and if you drive alot like me you will get enough money for a replacement engine over a year time!! and for every year you dont replacement that engine thats a bunch of cash in the bank for sumthing else.

synthetic sure got their advantage,dont get me wrong but at the price it sells for its not worth putting it in my car/truck

if id use it it would be on a lawnmower,tractor,snowblower,atv... sumthing that runs and work hard

Personally, I'm mostly interested in the improved protection at start up.  That's part of the longevity issues with our engines oil pressures and the timing chains.  I change my oils regularly anyway.  Think I'll go with the synthetic blend as a compromise.  I have used and like Castrol products for over a decade and I don't see that changing.  I just wanted to post Bob's explanation of the oils, the differences between standard and synthetic and how they react in differing temperatures.  I thought it was interesting.

I'm not going to tell you not to use Castrol (although I no longer do), I'm just going to suggest that you watch closely as you pour it into your engine - especially as you get to the bottom of the bottle, what you're looking for is to see if the oil coming out stays the same golden brown, clear liquid all the way through.

My experience is that you'll often see a darker streak as the bottle empties - ask yourself this question - what is that dark stuff at the bottom of my new, sealed, bottle of Castrol and why is it there?

And I have no intention of answering that question - I'm going to let you figure it out for yourself - but after more than a decade of using Castrol products exclusively, I've switched.

I sorta second the guy who says mineral oil can work just fine.  I live in SoCal now, so cold winter starts aren't an issue (I would, and did, use Mobil 1 when living in the frozen tundra areas, to notable benefit).  Here in SoCal, we have a gasser and had a diesel with ~280kmi on them using only mineral oil.  The gasser is a minivan, and friends are surprised to find the engine's original (although they don't ask about the tranny - that's been rebuilt, a LOT!!).  Not so surprised on the diesel, but that's an '84 so it doesn't have all the niceties of today's piezoelectric multi-squirt injection & controls.  But I use synthetic exclusively on my small four-cyl turbo (VAG 1.8T), along with some other additional additives for gelling (AutoRX).  What I've started to do is sample my oil; I've found 3kmi is short; some cars can go only 5kmi, some almost 10kmi before a change is recommended.  It's another $25 or so per change, but still small when compared to the cost of an engine or car.  And it helps me manage the waste production yet still get longevity from the vehicles with some science behind the decision making.  We only have one change on our recently acquired pair of 2004 GV's, so if/when I find anything of note with their testing, I'll let you know.  And I'm using mineral oil on the changes...  Again, if I were living in cold winter areas, I'd probably use synthetic at least in the winter, and maybe get a block heater, too!

It's interesting thsat a lot of new cars sold in Europe now specify synthetic, and 15,000 miles between changes.  The warranty is sometimes 5 years, so they must be confident.

Yeah, you'd like to think that with all the gelling issues of late '80's & '90's they've learned their lesson.  Not so w/VAG 1.8T/2.0T, it took them 6-8 years on the market (& a lawsuit...) to figure it out.  So I'm happier sampling the oil to get confirmation that longer changes are appropriate.  Auto RX is one of two or three additives I'd use after some extensive talking w/tribologists (lube engineers).  Their web site looks tacky, but the stuff works reasonably! 

Having a oil sample sent in for eval(I use Blackstone) can be a great way to catch wear on bearings, cam caps etc as each presents as a different particle in the oil as well as combustion blowby. I will send one after the second oil change of a newly acquired used vehicle. and then every 40K miles or so.

Yep, it seems oil sampling would be the final word on the condition of the engine and the lube.  I agree IanL, I sometimes I can't help but  wonder if the differences in what is recommended (on different continents) has more to do with turf wars concerning governments and capitalism than it does with actual necessity.

I'm not going to tell you not to use Castrol (although I no longer do), I'm just going to suggest that you watch closely as you pour it into your engine - especially as you get to the bottom of the bottle, what you're looking for is to see if the oil coming out stays the same golden brown, clear liquid all the way through.

My experience is that you'll often see a darker streak as the bottle empties - ask yourself this question - what is that dark stuff at the bottom of my new, sealed, bottle of Castrol and why is it there?

And I have no intention of answering that question - I'm going to let you figure it out for yourself - but after more than a decade of using Castrol products exclusively, I've switched.

i dont know  were you found those quarts but i did 2 oil change since you mention it and never seen a diferent color as i poured in the engine, i even cut open the quart to look in the bottom and its the same color, then we took a old windsheild washer clear jug (4L) and got it all cleaned and pour in the castrol gtx oil into and notice nothing wrong with it. maybe 15-20 years ago it was like that, i dont know, but for the past 7-8 year i've never had issues

The debris in the castrol oil is probably nothing but additives falling out of suspension. I have seen it often enough after the oil has seen a freeze or two over the winter sitting in the garage and not just Castrol. If there is any visible "change" towards the end of a bottle of oil, I drain the oil completely from the engine again and get new oil.

Just so you guys understand - it doesn't get below mid 70's here - and I'm talking about oil that's been purchased no more than a week before use, both of which rule out oil that's seen any freezing.

The only oil I've ever had sitting around the garage has been full synthetic MobilOne 75w90, and that was because I knew the ExxonMobil importer had stopped importing it and I bought the last of his stock.

I have to say that sounds "just not right" (yeah, no kidding).  No oil sold today should have anything settle out of it.  If it does, I'd recommend just draining the sump and refilling it with a "new" oil.  Sounds like something went really bad with that batch, not normal at all.  BUT, having some time in the chemical processing industry, "stuff happens", and to all processes.  You were observant enough to catch what should be a very unusual event.