I always get pitched the “high mileage” oil at the oil change place. What is the difference between that and regular oil? What are the advantages of synthetic?
We’ve probably been over these oil change topics before, but this “high mileage oil” is a new one to me.
I’m driving a car that runs well, but has 150k miles on it. What should I be using? Yes, I’m buying a new car soon, but in the meantime…
And this should probably be in IMHO… sorry, mods please move.
Until one of our mechanical types checks in, my take is that, in the absence of your car showing obvious signs of engine wear (such as blowing smoke), the 150k miles is as nothing between friends, and just use regular oil.
My '91 Camry has 225k kilometres on it, but it doesn’t miss a beat, and I use regular oil. No problems so far. I once had an old Ford with 300+k on iy, and that was the only one of my many cars (old and new) where a mechanic has advised special oil (and the engine died within weeks - not the oil’s fault, but the engine was extremely old, so I think that says something).
Normal oil for you, IMHO.
I’m with TLD on this one. High mileages aren’t the bad thing that many people think. It is how the high mileage was achieved that makes the difference. As most of the wear is on start up from cold and in the time it takes to get the motor to it’s optimum operating temperature, cruising around all day in a car is not going to do it much harm, as long as service intervals are maintained.
I have a C5 (don’t all laugh at once) with 160,000 miles on it and it runs like new. It is fully synthetic oil prescribed for it but it barely uses any and the service interval is 12,500 miles.
The high mileage oil is I believe of a higher viscosity and probably more additives to compensate for the wear in the bearings.
I’d put more faith in frequent oil changes and the addition of a dollop of STP or Wynne’s Friction Proofing - chicken soup for internal combustion engines.
Edit - silly typo’s-twice!
high mileage oils are not of a higher viscosity than regular oils. The difference is in the additive package. The oil maker has tailored the additive package for an engine with higher mileage (probably adjusted the amount of detergent, for example) We have a couple of real oil experts on the board, so I will shut up till somebody that really knows what’s what shows up to discuss the actual differences.
As far as synthetic goes, yes it is different. Yes it is better for many (If not most) applications. Synthetic use a base stock that is not derived from dinosaurs. This synthetic stock has a much higher burn point. If you have an engine that runs at high internal temps, the oil is much less likely to burn from the heat inside the engine.
I have an old pickup (77 GMC) with a 454 cubic inch engine. This engine runs extremely warm. Over 220F at the thermostat. I buy Castrol Syntech oil for it. Full synthetic at the correct weight for my car. When I buy a six pack of the stuff, it costs me a $1.00 more per quart. Cheap insurance if you ask me.
That’s probably the real answer to the OP. Maybe. Any time oil change places offer me synthetic, it’s completely obvious that they’re placing a significant premium on the synthetic, often to the tune of an additional $25. zuma, does it just so happen that the oil for cars with higher mileage that they offered you comes at such a premium?
The point Rick made about temperatures is well worth noting. My quad bike, after a service (very 1000km!) with normal oil (motorbike rated), would have a silky smooth gear change (engine and transmission shared the oil). However, the first time I got the bike really hot the gear change would become stiff and stay that way until the next service. When I switched to synthetic, the gear change stayed smooth until near the next service. I started using this as an indicator as to when the next oil change was due.
HTF does anyone manage to do 160K miles in a Sinclair C5? 
Kids
Not a Sinclair, a Citroen C5
How is that pronounced? Sit-Ro-En?
Yep. though some say Sit-Ro-Eng
The e has a sideways thingy over it -> ë which I suppose stresses that letter.
Others (more commonly) say Citron, like the lemon that many perceive them to be.
From Wikipedia
They were very individual and quirky in the past but since Peugeot took charge they are more mainstream. They don’t market them in the US anymore due to not being able to comply with a regulation on bumper height due to the hydropneumatic suspension, although Burt Reynolds famously trashed one in “Mean Machine”
Terry Dyson is the best oil analyst who offers his services to consumers, and he argues that HM oils are more or less a marketing scam intended to segment the motor oil consumer marketplace and extract slightly more money with appreciable benefit.
The formulations are slightly different, with different additive levels and viscosity within grade, but standard non-synthetic oils are just fine for your older engine.
You asked about synthetic, which is really its own thread.
I’ll pull up some links to past threads on that topic.
Briefly, synthetic is good for a couple of things:
Oh, as an incidental note, some HM oils a few years ago had the distinction of being semi-synthetic blends while the non-HM oil in the same line was wholly conventional. That was a worthwhile upgrade [it wasn’t a pure rip-off], but the truth is that there were no good arguments for semi-syn at the time.
Thanks to newer OEM and API specs [especially API SM], 95% of motor oils marketed to drivers of passenger cars with gasoline engines are semi-synthetic or better, at least per the definition of semi-synthetic that was in play 5 years ago in the USA[1].
Many diesel oils, especially the 15W40 blends, may properly be considered conventional.
[1] European criteria for a synthetic label are much tighter. A US blender can refine the crap out of crude oil and call it synthetic. EU regulators will haul you off in chains if you try that over there.