Is there any problems doing this after 100000 miles?

 

As long as it was previously maintained with a quality detergent oil, I see no reason that switching to synthetic will be a problem. I am running mobil one on mine after 100K with no issues and I don't know the maintenance history of the engine before I bought it at ~95K miles.

The only time I think you will see a problem switching oils is if the engine has seen years of non-detergent type oil in it. Then if it is switched to a detergent oil that cleans all the deposits out it will start leaking.

 

I've run pennzoil 10w30 from 62000[when I bought it]to 105000 now.With my new Procharger set-up running 12psi of boost at 5900 rpms I thought I should switch.I don't know if pennzoil is a detergent oil.If there could be a problem I'll just leave it alone.

 

Most all multi-weight oils today are detergent oils. That being said pennzoil is widely discussed as being a nasty sludge leaving oil that clogs and destroys engines. I'm sure the formula has changed from the old days and that may all just be a rumor to begin with. Either way I don't here near as many bad things about other oils so I won't touch the yellow bottle. Castol and Valvoline are generally percieved as better choices for conventional oil. IMHO.

As far as conventional vs. synthetic oil goes it really doesn't much matter as long as your change intervals are reasonable. That seems to be the main benefit of syns is the extended change interval.

 

i dont think there will be any problem switching to synhetic. i did the same thing starting at 80K, now i use the royal purple, the one for boost and ntrous apps., and i like it alot. its really just peace of mind for me.

 

Check this stuff out first ----> Auto-Rx

It's made for prepping a high mileage motor for a swap to synthetic. I've heard that if you just make the change on a high mileage vehicle that often oil leaks will appear soon after.

 

Looks like hocus-pocus to me. I wouldn't waste my money on it.
Just get some seafoam if you want to clean out the engine.

 

I've got a '98 Blazer with 203,000 miles on it. I switched to Mobil 1 about 20,000 miles ago and I haven't seen any leaks or any problems.

 

I agree...snake oil.

 

Go with Royal Purple its worth it i saw a difference on mine.