Hi-mileage change to synthetic ?

[Josparkz]

A fellow I am working with recently bought a used 95 or 96 one ton. He has about 130 K on it. He was wanting to change to a synthetic motor oil. He has recently become concerned that the engine flushing proceedure and switch to the synthetic may cause problems such as leakage, or internal encrustations of the engine to become dislodged and and get into stuff.

The manufacturer's tech line has only been able to tell him, "it should be alright".

I have heard of engines where crud is built up on valve stems or rings where using an engine flush treatment has caused problems.

Has anyone changed there Cummins to synthetic at over 100K miles? If so, did you use the engine cleaner/flush beforehand?

Where there any adverse effects?

Thank you.

 

[HC]

I have only an opinion, based on some limited personal experience: I would change to synthetic, but, because I don't know enough about it the engine flush scares me. I've changed about 3 high-mileage vehicles including at least one diesel, with no problems.

My recommendation: Skip the flush, but, after changing to synthetic, change out the new synthetic and filter once or twice at shorter intervals, like maybe 3 to 5k, before considering going to longer drain intervals.

 

[paccool]

I agree with HC. I switched mine over at around 120K. Didn't do a flush. Everything seems to be doing well, at 168K, doesn't use any oil to speak of(maybe a quart in 5000 miles or so but thats when I chang the filters anyway) Used to change filters at 2500 but now have a bypass so will extend that a little. Trucks smokes a little but it ain't oil smoke!

 

[Extreme1]

I changed without a flush at 148,000 miles and added a bypass filter. I have't changed the oil or the bypass filter yet. I change the full flow about every oil analysis (18,000 miles).



I wouldn't do a flush, what are yo trying to do? Get all the other oil out? Let it drain overnight. If you use a flush (most are a diluted kerosene), then you will have a small amount of that left in it. I'd rather have a small (insignificant) amount of old oil than flush.

 

[Roger rodbolt]

Josparkz,

If the engine has been well maintained a direct change to synthetic should be fine. Since your friend just purchased the truck I'd recommend a valve adjustment to see how clean the upper engine is. Cold thermostats and extended oil changes change can cause sludge/varnish build up. I blame a change semi-synthetic oil in a 6 cylinder aircooled aircraft engine for loss of oil pressure resulting in a successful dead stick landing (old Beech Bonanza). This is permanently burned into my long term memory

 

[ctdodgeram]

Dumb question, what is a bypass filter? What does it gain you?

 

[Mactruck]

do a search...

A bypass filter supposedly eliminates the need to change your oil. It is made by AMSOIL & uses two filters to keep the oil clean. However the oils should be checked for contamination every ( help me out here guys ) 5 - 10 K miles .

I'm looking at getting one for my truck with the CPFF adaptor and braided hose. Considering your location ( CPFF lives in Lebenon CT) you might want to touch base with him if you are interested.



Heres a link Amsoil dual bypass info