Anyone see a problem with going to a full synthetic after 100k miles on a motor? I have been told this is just broke in so thought it may be a good time to switch to maybe Mobil1 or something. I asked a mechanic and he stated that it should have been done around 20K and now that the miles are up there I should just stick with the conventional. All I want is this baby to stick around for the long haul. I have not done any mods to the truck yet but have purchased the KWIK filter and have yet to install it. What are some of you high milers running?

 

Me I think leave it alone,stick with what got you there.
Synthetic's tend to be thinner and tend to vaporize and usage goes up due to pcv(gas engine) sucking it in to the intake slightly more than conventional oil.
Just my past expeirence.
Rich

On edit I didn't see where you said it was a diesel. The kwik filter should have tipped me off
I mean we have gas engines going that long also!
Sorry for confusion

 

I'd be interested as well. I've read the 5w40 Rotella syn. is great for the engine. I'm using Rotella dino now.
But, I've also heard that switching to syn. with high mileage on the engine can cause oil leaks. I'd like to switch, but not if it going to cause leaks.

 

Thanks for the info. Maybe the ole "If it ain't broke don't fix it " comes into play here. I guess if I stay religious on the oil changes and keep the fuel cleen it will be a good test on longevity.

 

the syn will only improve your cold starts if its not cold than i would not worry. A PAO oil like mobil won't add a single mile more to that engine than the cheapest diesel spec'd oil with at least a CH rating CI-4+ is the newest and best.

 

Looks like I'll have to study up on my oils then. I just bought this truck and have never owned a diesel before with the exception of my Ford 3930 4wd tractor and I believe it would go 100K without any oil in her at all. I love that thing and now it has a friend. Do you have a personal favorite brand that is easy to purchase?

 

I have used syn since 1980 and it is my religion. But I probably would not put syn in an old engine mostly because by 100K miles, you already have the wear and deposits that syn is supposed to prevent.

Syn has a much lower problem with vaporization. That is one of the "earmarks" of syn that it does not vaporize which causes sludging. What the other fellow may actually be seeing is that syn can leak faster in loose engines. the new dinos are approaching syn in characteristics, but vaporization was not an issue with syn.

I would only put syn in at these miles for religious reasons and only in an engine that does not have any significant leaks. Syn does not cause leaks but because it is thin it may leak faster in old tired engines. I am also guessing engine with loose rings or bad valve guides may suck up syn faster.

It comes down to a personal preference. Syn will not hurt an engine but it is overkill on an old engine. If your engine is in great shape and you plan to run it another 100K miles, then syn might make sense.

Also make sure the syn is diesel rated. If your diesel is one of the newer Powerstrokes it uses oil to activate the injectors under high pressure. Standard automite oils do not have the anit foam ingredients to handle the diesel.

If it was me, I would use a good diesel rated dino oil and change regularly. If the engine was new, I might use a diesel rated syn.

Just my opinion,

Jim Henderson

 

Thanks to all for your input. I will probably stick with a good dino oil and let the dice roll. I believe that with proper maint she should keep rolling for a long time to come. Maybe if I ever can afford a new one I'll give the synth a try and see if it goes farther.

Leon

 

I would go with synthetic, but at 100,000 I would stick with a 15/40 - better heat protection, start up protection, better for a hot turbo -