1990 4Runner V6 w/ 205,000 miles. Should I switch to synthetic oil?

[haikuman]

I have owned (3)... 4Runners the best vehicle ever me thinks Toyota makes great vehicles.
when we take care of them they last a very longtime. The older the vehicle the thicker the oil needs to be me thinks.... 10-50 vs 10-30.

[mikebw]

I have read that switching to synthetic on an older engine may lead to leaks that were not apparent before. The synthetic oil may find it's way through some worn seals and gaskets that the dino oil may not have. Of course I don't know that to be true, first hand.

[DharmaDog]

mikebw wrote:
I have read that switching to synthetic on an older engine may lead to leaks that were not apparent before. The synthetic oil may find it's way through some worn seals and gaskets that the dino oil may not have. Of course I don't know that to be true, first hand.

Seconded. Dino oil tends to gunk up the seals more, possibly hiding potential leaks. Synthetic oil usually have more detergents in it that will ungunk your engine to some extent and may reveal leaks that were plugged by gunk. It's not a certainty that this will happen, just a possibility.

I'm all for using synthetic initially in an engine, and it you do so, there is no reason to not keep using it. But I am wary of switching to it in a much older and well used engine.

Why mess with it if it's running well?

[DRR]

"Dino oil." LOL. Never heard that.

[Racer X]

DRR wrote:
"Dino oil." LOL. Never heard that.

i use that phrase all the time, or dino juice.

[Lew Zealand]

Late to the party here, but thanks for the info. I have a lower mileage old car ('83, 140K) and was considering going to synthetic but I guess I'll stay with what's been working.

[Dennis S]

I'll ask my oil change guy what he thinks of the 10/50. That sounds like a good idea. Thanks for the help.

[Racer X]

i've never seen 10w50. i have seen 15w50 synthetic and dino oil, and 5w50 synthetic.

[Grateful11]

I've got a '91 Ford Explorer 2WD with 234K on it with no major repairs,
it's always had Havoline 10W30 since the first oil change. It does leak
about 3/4 of a quart between 5K mile oil changes, it's never smoked
except a tad when started which a lot of the time that's only about every
2 months now, it's semi-retired.

[davester]

oops, double post