Question for u guys running fully synthetic ?

[55gasser]

I have been running Mobil 1 fully synthetic 5w40 turbo diesel oil (takes place of 15w40) in my truck since day 1 & love it.

runs better, quieter & smoother & better mpg`s.

Here is my question, whats the most milage i can get away with before changing my oil,

i have been doing it about every 4500 mi but its just so expensive, i think thats why i have never had injector probs before.

whats your opinion ? thanks for the help.

05, 6.0, F-350 4 door long bed, 4x4

[nylyon]

I am running Rotella T6 and change every 5000 miles. I do not do oil analysis so I don't risk it. I am thinking of switching to T5 which everyone seems to like as well.

[bfrank81]

Run it for 4,000 and send a sample to Blackstone Laboratories that is the safest way. If you don't want to buy a pump just grab a sample at your next 4500 mile change and ask them if you can go another 1k next time. Then do the same thing at the next change.

[ebusa]

Originally Posted by 55gasser

I have been running Mobil 1 fully synthetic 5w40 turbo diesel oil (takes place of 15w40) in my truck since day 1 & love it.

runs better, quieter & smoother & better mpg`s.

Here is my question, whats the most milage i can get away with before changing my oil,

i have been doing it about every 4500 mi but its just so expensive, i think thats why i have never had injector probs before.

whats your opinion ? thanks for the help.

05, 6.0, F-350 4 door long bed, 4x4

I'm running the same oil as you, and go 5000 between changes. IMO stick with that interval. Diesels are expensive...

[55gasser]

thanks for the help

[work&play]

I run the Valvoline blue extreme and change it every 5000.

[HeavyAssault]

I run Mobil 1 with an OilGuard by-pass kit. I go to 7500 miles then I change the oil and filter.

[55gasser]

thanks, i know the book says 5000mi with hard use & 7500 normal use, reason i asked is because your supposed to get more out of synthetics, i didnt know if diesel was diff ?

[smokersteve]

I had it at 6k before it was changed. Even though I did not test the oil, the oil looked much cleaner than previous changes of 5k. This was my first time using mobil 1. The previous oil was amsoil.

The best way to tell is to go 7k and test it, then test others. 5k or 6k will not show the differences in each oil as much as 7k will, with out a bypass.

[Baddestt]

Try Shell Rotella T5 10w30 from walmart...it's 16/gallon. You may never go back to anything else