Synthetic Oil-- why can't you switch back/worth it?

[viper69]

My 1995 Volvo 850 GLT has always had regular oil, changed every 3,000 miles. I don't have any known issues w/my car needing more oil between changes, perhaps because I don't put too many miles on it lately.

My questions

1. Should I switch to synthetic? It doesn't save me any money, the cost of an oil change every 3k is the same as every 5-6k miles where I live, so that's not a reason to change.

2. Why can't one switch back to normal oil after one uses synthetic?

3. What synthetic oils do people recommend? For normal oil I have used Castrol GTX with few exceptions.

Thanks in advance.

[JeffHicks]

First and foremost, if you get 10 replies you're going to get 10 differing opinions. So take it all for what it's worth.

In my years of driving and wrenching, I'd have to say that the single most important part of oil is to keep it changed regularly, and always change your filter.

Synthetic oil is better in some ways - one of the biggest of which is ease of starting in extreme cold. But it's also more expensive, so the longer intervals between changes means you don't save anything.

Also, I've never bought the "you canNOT switch back to dino after synthetic!!!" hype. I've switched back and forth in many vehicles over the years, and have never had any problems.

The one thing you will notice, if you go with synthetic, is that any small oil leaks you might have will be a little worse.

[polskamafia mjl]

You can switch back and forth as much as you like.

The advantage of synthetic is not that you can go 5k miles but rather that you can do 10 to 15K miles. That depends on the health of the engine of course. Even if you were changing once every 6K miles it should still be saving you money...

Besides that, fuel economy and wear protection are improved with a synthetic.

Mobil 1, Castrol Edge, and Rotella T6 are commonly recommended oils.

[erikv11]

If you hardly drive the car, then frequent changes with dino oil is pretty reasonable way to go.

I use full synthetic Rotella 5w-40 in all of the Volvos in my signature.

[tryingbe]

I use AMSOil.

Here's my oil report after 5,700 miles on my engine. The only way to really tell if the oil is for you is to do a oil analysis.

[JeffHicks]

I use AMSOil.

Here's my oil report after 5,700 miles on my engine. The only way to really tell if the oil is for you is to do a oil analysis.

I like this.

The one thing I will say about guys like you (NERDS!!!! ) is that a guy who is fastidious enough to use Amsoil is probably extraordinarily careful about everything else with his car. In other words, while Amsoil is part of your success, it's only a part.


By the way, did I read that correctly? Over 345,000 miles? Love it!

[abscate]

Yeah - oil analysis is the only real data. I get flak from the BMW forum because I change mine every 12-15k - folks there love to say 3k synthetic oil changes are the only way to make your engine last...whatever.

[oragex]

the cost of an oil change every 3k is the same as every 5-6k miles where I live, so that's not a reason to change.

This is a possible advantage of synthetic oil vs mineral (normal) oil: you will buy twice the amount of mineral vs synthetic because "supposedly" the synthetic can be used longer than the mineral.

Since your vehicle is not a turbo, synthetic will have little impact on the engine, except for the PCV system.

I also have used synthetic on my non turbo for a few reasons: PCV sytem (I do short trips and imagine a synthetic oil will cause less deposits), I also use a high quality synthetic - not just any bottle that reads synthetic - and change the oil once a year or less than 6000 miles. Still costs me 50% more than mineral. Finally, I just feel a little better about feeding it with a quality product, but I'm fully aware that this is 99% psychological because the non turbo engines go forever even with mineral oil.

I switched to synthetic from mineral on two cars. On both situations, after the first synthetic oil change, the filter got clogged very fast, perhaps in less than 1000 miles.

[zhenya]

Even if synthetic offered no other advantages, the fact that it can go a year between changes is enough reason alone. I don't mind changing oil, but with 4 cars once a year for each is more than enough.

I've also had excellent luck with high mileage synthetic oils greatly reducing oil consumption I believe through their seal conditioners. My 855 burned more than 1qt every 1000 miles when I bought it with 120k on it. With 205k on it now it has never burned more than 1qt every 3000 miles since making the switch.

[abscate]

Ive now converted 5 high mileage cars to synthetic and found no change in leakage and reduced usage internally, so I don't buy that everything on the internet is accurate.