Too many miles to switch to synthetic oil?

[Scollins]

So I've been thinking of switching to synthetic oil, but I wonder if I have to many miles on the Cummins. I currently have just over 102,000 miles. I currently use Delo 400 15w40 and Fleetguard filters. I've only owned the truck for a few months, but I do know that the previous owner changed the oil between 3000 and 5000 miles intervals.

Do I have too many miles to switch to synthetic? I've heard of other high mileage engines (all gassers though) developing oil leaks by switching to synthetics. Apparently, synthetics can slip past old gaskets whereas dino juice just seals it up (sludge buildup. )

What do you all think?

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Scott Collins
'98 Ram 2500 4x4 12 Valve Cummins. Slightly BOMBed! #ad

Renton, WA

[This message has been edited by Scollins (edited 01-14-2001). ]

 

[Turbo Thom]

Scollins:
I switched to Amsoil at 145,000. It seemed to take a little for the engine to settle into a pattern, but now at 185,000 every seem to be just fine. I have the duel-bypass system on mine so I don't change oil other than what it takes with the filters. Between filter changes I use about a quart. All analysis have been OK.
Hope this helps you a little.
Preston #ad


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96 3500, Black SLT, 5 speed, turbo diesel, , with US Gear overdrive, Rhino liner, Reese 15,000 lb. fifth wheel hitch, US Gear de-celarator exhaust brake, muffler elimination kit, Amsoil lub. , Mag-hytec rear cover, dual-remote by-pass filters, and Roadmaster Active system

 

[rhoads]

You DON"t want to switch to straight syntheic's
But most like can get away with going to a semi-syn oil.
The first on the market was-- HINT look under your hood !!
Why did they jump into the oil market? Only to protect there name plate (Eng). After the first oil embargo and in the big rig market Detroit D iesel's silver 92 eng sank to a supplier market share of about 3% and Cummins was #1 some owners and fleets were using oil based on the $ sign and saw bearing failure's and who was getting the rap? Cummins. That s when they intro'ed Blue then deloveped cummins semi syn .
End of triva for the day.

 

[Steve]

scollins
I switched a 318 gasser over at 110. 000 miles ,It was useing a little and leaking some from the valve covers. After the switch it would an extra 300 miles before adding oil. I would not use the motor flush some recomend thats when you get oil coming past the seals. If I get a dirty motor I keep changing oil until it cleans up.

 

[SMorneau]

I switched to Amsoil at 100K. That was about 76k ago. Oil consumption never changed and my oil analysis looks good even after 30k. I attibute this to the oil and an bypass filter.

Like you, I had concerns. More recently I changed a V6 Toyota with 170k on it and have had no problems. According to my sources, a lot depends on how bad your previous oil and maintenance habits were. If the oil was "let go" to long the seals may swell and get stiff. The change to synthetic will then make them return to the original shape and they might leak. I am told that about 50% of the time the seals will leak and then limber up enought to re-seal.

You can alway change back... if you have problems.