can synthetic oil be detrimental?

[MrAl]

Hello there,

I have a feeling the best answer is related to the time factor in owning the car.

I have read that using synthetic helps lubricate the engine better, but that it can damage gaskets. I used half and half in my old Hyundai, and the reason the car failed was because of the front and rear seals that started to leak badly. It would cost too much to fix so i dumped it to a mechanic who had all the tools to do the job for almost nothing.

This leads me to believe if you own the car for a long time then it may be long enough to hurt the gaskets or seals, but it must take a lot of time for this to happen. I used half and half though not full synthetic.

I use non synthetic in my Volvo though mostly because i am afraid t use synthetic again. Since i put low mileage on this car anyway it should not matter. I think i put 700 miles a year IF that on it.

[bmdubya1198]

Well, if changing to synthetic blows out seals, they were going to fail soon anyway. That's how I look at it at least. It's rarely total fault of the oil.

[the padre]

Eric the Car guy has an interesting post on this. Essentially, he says that synthetic oil can find leaks due to the fact that it flows better than conventional. To answer your question, no, it won't harm your engine, but it might find leaks that conventional will not. If conventional is working for you, then stick with it.

https://www.ericthecarguy.com/faq/findi ... -oil-leaks

[wizechatmgr]

Synthetic doesn't cause the seal to go, it is just better at seeping through a bad seal and thus leaking more under the same conditions. It may be more likely to leak in time due to the lack of build-up behind the seals - this isn't really a problem of the oil as much as an unintended consequence of a lack of contamination and breakdown.

If you're a compulsive 3,000 mile oil changer -- synthetic oil may not be for you if money is a concern. Overall both dino and synthetics can do the job - synthetics just perform better in extreme conditions.

[erikv11]

... I think i put 700 miles a year IF that on it.

Holy cow! That's low. be sure to check the PCV for blockage every few years (even though that is only 2k miles!).

[ZionXIX]

I switched to full synthetic 2 years ago and recently to LiquiMoly 5w40. I'm about to hit 200k with no engine problems.

[scot850]

I run synthetic in all but our newest car as the idiots at Kia insist we use dino oil and some additive. We get free oil changes for 5 years and typically we only need to do one a year as my wife does about 6,000km/year as she does not use it for work, but uses transit.

I use synthetic on our 06 XC70 (well the dealer does) again my son uses this car and typically change the oil once a year due to low mileage. It runs 5W30 syntheic oil from Volvo (whoever they use). Car being a turbo also means I prefer synthetic.

On my 2000 R I use synthetic 5W40, usually Castrol Edge or whatever they call it these days. I do the changes myself now on it. Car did have all the mail cam and crank seals replaced shortly after buying due to leaks. Decided it makes sense again with the cars low annual mileage (about 2,000km/year) and our extreme weather (can be as high as 35C to -45C) it makes the car easier to start in the winter if no plug-in is available for the block heater. Again turbo motor with about 165,000 miles on it.

Project V70 NA/base, also with about 165,000 miles on it. When I did the prep for use, I knew the PO clearly did not take car of it, so changed the filter and used dino oil (Castrol GTX 5W30), mainly as it was not going to be used otherwise as I bought a case in error, and also I'm using it as a flushing oil and plan to change it and the filter again after about 1000km, along with all the other oils. I may or may not use the rest of the dino oil and if I run short will top up with synthetic. Have thought to change to 5W40 as per the V70R as is means less oil cans needed, but I may not have both long enough to worry about that being an issue.

I have heard all the horror stories of changing to synthetic, but I think the issues is not so much the oil but it has better cleaning properties and cleans a lot of the old crap out and tired seals then fail. In older Volvos the PCV lack of system maintenance is often means the seals are lose to failing and then idiots like me buy the cars, fix them and then give them fresh clean oil and bingo, they start to leak!

Also here the one about more oil being burnt in synthetic oil, but again probably due to worn engine and cleaner flowing oil leaking past worn valve stems/turbo seals/piston rings until they carbon up enough to stop leaking through.

Bottom line is I prefer synthetic, and due to our low mileage, I change more frequently due to time (usually once a year) rather than due to the oil needing to be changed as it is done.

Strangely, the XC70 is the only car we have that uses oil so far between services.

Neil.