Synthetic Oil?

[shaolin]

Was sitting around thinking about my car, and I remember when I had my oil changed I asked my serviced advisor what he thinks about synthetic oil (I have 10 free oil changes at my dealer). He told me that he doesn't think it's necessary, and actually would prefer me not to use it. Said something about the "flashpoint being higher" and that it would be harder on the engine. He said after 75K miles to use it.

He also said that RX-8 motors would be destroyed if synthetic was used. He told me that they would last about 1000 miles if you used synthetic...

I dunno if there's truth to any of it, but thoughts or comments?

 

[spicyzoomzoom]

if you put syn in after 70,000miles you will BLOW YOUR s*** UP

syn oil-thinner. 70,000-small oil leaks.
thinner oil+small leaks = big leaks.

never go to syn that late in engine life (unless you rebuild)
use syn. we all do.
(come on man, do it. do it... peer pressure)
my friends my tech at the mazda dealer. he put syn in, cause he knows i want the best for my car.

but do it ater 7,000 miles seems to be the general concensus
like when he did mine.

(i am not saying that if you run syn you have to go to regular at 70K, just dont go to syn that late in life)

 

[shaolin]

Yeah that makes more sense...I'm at about 3500 miles right now...so I have a while before 7K.

 

[VegasMSP]

Gawd the people at Courtesy are idiots! Shaolin I switched to synthetic oil after 6k. I'm using Mobil 1 5w-30. I asked the mechanic at Courtesy in Henderson. He's been working on Mazda's for over 20 yrs. I asked him is it ok to switch to synthetic he said sure it wouldn't hurt anything. On another note my friend has a RX-8 and runs synthetic fine. So I wouldn't always listen to those retards at courtesy. I've been running synthetic for over 2k and my car is fine.

 

[mazdaspeedpower]

he probably doesn't want to pay for sythentic for you, since you have 10 free oil changes. Maybe he meant 7500miles???And i really doubt it will damaga an rx-8 motor.

EDIT* my courtesy guy is pretty smart about cars. He knew My car could handle synthetic after breaking it in very well, waiting three -four oil changes, so it'll pick up any debris in the engine from break in, and being new and all. Car goes synthetic in two weeks.

 

[DZnutz]

oh geez... everyone is gonna have their opinion on this and so far both these opinions seem ludicrous

mineral oil provides less friction protection than synthetic oil. this is why you want to use mineral oil while breaking an engine inn... it allows the rings and cylinder walls to wear and conform to each other quickly thus making a tight seal in the end

you can switch to synthetic oil at about 5K once the engine is throughly broken inn to at that point reduce the friction. higher mileage motors BENEFIT from synthetics because of this reduction in wear... truth is if you have oil leaks in your motor it wont make a difference whether you have syn or not, itll leak either way, the syn will simply greatly reduce further wear

my opinion is to use mineral oil for your first oil change and then switch to syn

now in terms of the rx8 i can definately give you my opinion since i own an rx7 and have run synthetic in it for the last 4 years. the reason why people argue that running syn in a rotary motor is bad is because a rotary engine consumes oil during combustion. the oil is injected directly into the combustion chambers in order to lubricate the housings and rotors... this unfortunately causes the oil to burn as well. now the reason for the no no is because synthetic oil leaves a residue once its burnt while mineral oil does not to the same extent... this gradual residue buildup can eventually cause the rotary to seize up. but like ive said ive used it for 4 years and have never had a single prob so its all up to you.

my recommendation is that syn is far better than mineral... after breakin that is. good luck

 

[shaolin]

Hmmm thanks for the help guys...by the way VegasMSP, did you happen to go to that big drive this morning. Had I not been all beat up, I would have gone...

Sorry for the threadjack of my own thread

I am going to go synthetic now though...

 

[03MSPRO]

I've always use Mobil1 10w-30 syn. oil in all my cars.

 

[Glowmunkey]

you can switch to synthetic oil at about 5K once the engine is throughly broken inn to at that point reduce the friction. higher mileage motors BENEFIT from synthetics because of this reduction in wear... truth is if you have oil leaks in your motor it wont make a difference whether you have syn or not, itll leak either way, the syn will simply greatly reduce further wear

my opinion is to use mineral oil for your first oil change and then switch to syn

There is also plenty of evidence suggesting that modern cars don't need the same amount of time for break-in... many claim that the rings and cylinder bores (of most cars) are properly worn in after less than 1000 miles.

As for synthetics, plenty of people have switched high mileage cars to synthetic oil... if everything's tight, it won't leak. You have to take it on a case by case basis, nothing is set in stone.

All I'm saying here is, these are ongoing debates. The best you can hope for is to do a lot of research, talk to those wiser than you, and make your own decision. Nobody knows EVERYTHING, so everyone's opinions should be suspect.

 

[VegasMSP]

Nah I didn't make the Vegas drive this morning Shaolin. I got in late last night, Syntrix asked me last night. I told him maybe. Plus I want to be done with my car before I go out and hang out with the big boys.

 

[MrDiggler]

FWIW, I've been told not to switch to synthetic on a higher mileage (75k +) engine unless you are very sure that the engine is free of sludge and deposits from years of conventional oil use. Supposedly the sludge deposits can be quickly loosened up with a switch to a full synthetic and some of these deposits are large and/or thick enough to plug up an oil galley or passage. Can't remember where I read this, but the recommendation was to run a blend for a couple of oil changes and hope the filter catches the loosened gunk. I never switched to synthetic on my '91 Escort GT (Mazda 1.8 motor) because of this. When I replaced my valve cover gasket at about 80k I did see a fair amount of this sludge hanging around in cracks and crevices. At least the dinosaur oil seems to work pretty well because I now have 160k on the motor and the compression at 125k was 175-181 psi on all four at that time.
My MSP now has just over 8k on it and will be receiving full synthetic at the next oil change. If nothing else it should be better at protecting the turbo bearings.

 

[DZnutz]

then you were clearly lied to

the only way an engine will develop deposits of sludge is if it was severely neglected, like unfortunately some people do, and dont change the oil for 15K+... if that

an engine which has atleast had the oil changed every 5K will not have any noticeable deposits even with 150-200K

 

[MrDiggler]

Pretty bold statement there nutz. It must be a well-accepted lie. You got my curiousity piqued and I did a little googling to see what I could turn up. Looks like Amsoil distributors and others recommend using an engine flush to remove built up sludge and deposits before switching to a true synthetic oil. According to them the synthetic oil will do that on its own, but they recommend the flush because the solvents in the flush will thin the deposits and reduce the chance for them to plug something up on their way to the filter.
I'm not about to digress into a big argument on the subject, I have bigger fish to fry with my MSP right now, but you're welcome to search using the same parameters (switching synthetic oil loosen deposits high mileage) and take a look at what I read on the subject.

 

[JFW]

As far as waiting to put synthetic oil in until after the break-in period is over, C-5 Vettes come from Bowling Green with Mobile 1 already in the sump.

 

[70]

And Porsche's come form the facroy with Mobil One in them as well.

But, Mobil One is not a full synthetic...It is still partly dyno based.

 

[LinuxRacr]

This is like the millionth thread on this topic. Please do a search, and all truth will be revealed. Closing.