At 124,000 miles can I switch from dino 5-30 to full syn without any problems?

 

not recomended

 

I did it on my 98 at about that same mileage and didn't have any problems *shrug*

 

it shouldnt do any harm, just make sure to do an oil change, and not just start adding in the synthetic...

 

you may find out that it burns oil and leaks past gaskets easily.

 

it shouldnt do any harm as long as you do what hondaracer said and change the oil all at once. my old civ was on dino oil till i got her and i switched to mobil 1 full synthetic when i got it. no problems. of course it was only at 75k at the time but still the same concept applies. yours and mine are/were about in the same age as far as honda engines come.

 

You absolutely can. run an engine flush for thirty minutes, drain it out and pour in the synthetic. I've been to seminars on that subject and as long as it isn't burning oil,leaking or has sludge build up, it's good . I put it in mine right after I bought it with 125000 miles on it. The only problem is if the previous owner let it build up sludge. Synthetic oil will loosen up sludge and particles of it can damage the engine by blocking oil ports. Make sure there is no sludge.