30 replies to this topic

[xtc]

I have a 98 S70 with 145 000km or 90 000 miles on it. So far I have used natural motor oil but I am thinking of changing to synthetic. Is there any reason I shouldn't? I have heard that switching once the car has a few clicks can be a bad idea because the seals can leak. Is there any truth to this or this an old wives tail?

[prasamin]

you already have 90k miles on the car, with regular oil...as long as you're changing it regularly, I say it's best to stay with regular oil....it is possible to get leaky seals by switching to synth, but it also may not happen...I was deciding the same thing a while back, but I'm on top of my changes, so using synth or regular would have no change in performance, so I just stuck with reg.

[DEWFPO]

On the flip side, I changed our 95 960 over to synthetic oil at 120,000 miles and had no problems.

DEWFPO

[merlin390]

try it. if it leaks just put the regular stuff in it the next oil change

[VolvoT5]

I have a 98 S70 with 145 000km or 90 000 miles on it. So far I have used natural motor oil but I am thinking of changing to synthetic. Is there any reason I shouldn't? I have heard that switching once the car has a few clicks can be a bad idea because the seals can leak. Is there any truth to this or this an old wives tail?

Yes it can and does happen, but not every time. It's a risk you take if you want to run your car on a better oil.

I ran my old engine on semi-synth (or blend) as I didn't want to cause leakage as the car had done 120,000 miles. However, after that engine blew and I got a new engine, I'm using fully synth as this engine only has 60,000 on the clock.

With 90,000 miles I'd say go for synth oil, and if you get leaks then get them sorted - they will happen sooner or later anyway, the syth oil will only accelerate them at worst.

[FINN]

Changed to synthetic at around 86k miles. Been running it since and i have about 115k on the clock. No problems.

[Hilton]

I switched to synthetic at 151K. No leaks.

[Che'_Moderator]

I would switch. Most of the old tales of leaking afterwards were due to seals swelling on the old formulas. Modern oil does not have those issues.

[pete0r]

but really, what's the real difference?

my car's always been on dino, and i just bought it and today changed the oil. i considered syn but i don't want to get leaky seals or anything like that. i don't see why it's worth me spending way more money on syn oil, if i'm going to continue to do a regular oil change every 3k miles. i have time to do it, so i don't see what the big deal is if the only reason is to change it at 3k with dino or 5k or whatever with syn

[Che'_Moderator]

but really, what's the real difference?

my car's always been on dino, and i just bought it and today changed the oil. i considered syn but i don't want to get leaky seals or anything like that. i don't see why it's worth me spending way more money on syn oil, if i'm going to continue to do a regular oil change every 3k miles. i have time to do it, so i don't see what the big deal is if the only reason is to change it at 3k with dino or 5k or whatever with syn

Your car is turbo and you upped the boost. I have sent Mobile 1 tri-syn out with 3k and it came back with very high oxidation. And thats a semi-syn Dino oil can break down in hours depending on what your doing to it.

[T5BRICK]

synthetic can withstand heat better than dino.

i switched at 93k miles, and i still have a tiny leak. it may just be my oil return line gaskets and seals, which i am replacing during my next oil change.

[T5BRICK]

i thought the reason synthetic leaked where regular non-syn did not is because synthetic is "thinner" and more likely to find tiny holes to escape through.

[pete0r]

i mean if i swtich to syn, what am i looking at? i've got 130k, i'm just scared to death my rear main seals are going to start leaking eariler then they otherwise would or something. i've already spent too much on this, i don't want to have to put down 400 bucks before i have to

[xtc]

If I change to Synth do I have to flush my engine first?

[Bay13]

No flush required to change the brand or type of oil you are using.

And CostCo has some of the best prices on Mobil 1, it's under $25 for a six pack.

[KLS]

Synthetic lubricates much better when very cold (Toronto winters), much better when very hot (turbocharger bearings), has greater resistance to oxidation for longer oil life and less sludge/carbon buildup, and, if PAO based like Mobil 1, Castrol (German) 0W-30, or Amsoil, has higher film strength.

At 90,000 miles, I'd do an Auto-Rx cleaning with conventional oil, then use either conventional or synthetic as you choose.


Ken

[FINN]

And now mobil-1 synthetic is warranteed for 15k miles or one year, whichever comes first.

[T5BRICK]

And now mobil-1 synthetic is warranteed for 15k miles or one year, whichever comes first.

i've wondered how the warranty works on something like that.

[Plan_B]

And now mobil-1 synthetic is warranteed for 15k miles or one year, whichever comes first.

So how often do you change synth. oil?

[FINN]

Not sure. Im just happy that theyre so confident in their product.

I just changed my oil at 8k.

Edited by FINN, 30 April 2005 - 06:45 PM.