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.

 

[Midnight]

I dont like the idea of an engine flush. That stuff does a great job in cleaning the sludge and crap inside the motor, but that sludge gets up on the oil pickup screen and could cause the engine to starve from oil. A few quick oil changes may be all he needs to clean that engine up enough. Changing over to syn. should be safe.

 

[RHARVEY]

Yes I did change at 145,000 and I did not do the engine flush. I use the Amsoil Series 3000 and have had great results...



Rick

 

[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 to 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

 

[Dieselnerd]

I recently changed to Amsoil 15-40 Heavy Duty Diesel Oil and I did do the engine flush. My truck is at 65K so it's not really high mileage. I used 2 cans of the flush with a new Fleetguard Microglass filter and then threw away the filter and installed another new one after the flush. I think it took out a lot of stuff because the oil came out very black, much darker than I've seen before.