hey guy's I have 125K on my truck, I bought it with 115Kbut I found I can get synthetic motor oil cheaper than regular oil so my question is do I have too many miles to start using synthetics? also what gear oil do you recommend for differential?<br><br>Thanks!<br> DRecu!

Synthetic oil cheaper than regular dinosaur juice :o What brand?

drecu, I wouldn't be afraid to on the Cummins engine. The only concern that I might have is the seals starting to seep, but as new as the truck is that probably won't be a problem. Of course, just changing brands of oil (oil additive packages)can do the same thing. The best thing to do before putting the synthetic in is to flush the engine to give the synthetic a clean place to start.<br><br>

I saw the oil @ Napa for $.88 per Qt. <br><br>How would I flush the engine Billy?<br><br>Thanks<br> DRecu!

Since we're on the topic, I just started to run Mobile 1 in mine the last oil change, roughly 10,000 miles. Now I've located the Valvoline preimum blue thats been recomended here before, however I can't find any info on the product, not even at the Valvoline site [eyecrazy]. Can anyone tell me which is better and why??????

I hope when you said &quot;Mobil 1&quot;, you really meant to say &quot;Delvac 1&quot;. Mobil 1 is formulated for gas engines and some diesels, but the label can be misleading because it just says &quot;diesels&quot;. Mobil also makes Delvac 1, which is the version that is formulated for and meets all requirements for heavy duty diesels like our Cummins.
If you use Mobil 1 in the Cummins, it won't do immediate damage, but the wear rates will be higher than with a good dino oil, so you wouldn't get the benefits you're paying for - in fact, just the opposite, you'd be wearing out faster.
To answer your original question, the Valvoline Premium Blue would be much better than Mobil 1 because VPB carries the proper ratings for our engine. IMHO, Delvac 1 would be a hair better than the VPB. Personally, I'm happy with the Amsoil 15W-40 I'm using now, but I think Delvac 1 and A15W-40 are both excellent choices and I really don't know which is &quot;better&quot; - I've seen too many opinions both ways on that and no studies that truly prove it beyond all doubt one way or the other.
P.S. - I wouldn't trust any synthetic I could buy for under $0.90 / quart in my $6000 engine. There's got to be a reason it's that cheap, and the cost of good Dino oils like Delo is just too good to take chances. I like synthetics, but I would choose Delo, then Rotella, long before risking my engine on a synthetic that was priced unbelievably low.

Thanks for the info, and I did mean Mobil 1, so I guess I'll be changing it this week. Where do I look for oils rated for our motors? I'm in philadelphia, pa and all the stores I've been to (Pep boys rs straus and the likes) have oil for the gasers only?

You can find the oils at good prices at your neighborhood wallyworld, Sams warehouses and even Kmart.

I buy my Delo 400 at Walmart. ;D It's 6.17 a gallon! ;D<br><br>Tony

<br>I buy my Delo 400 at Walmart. ;D It's 6.17 a gallon! ;D<br><br>Tony<br> <br><br><br><br> If you have a Sams Club close by its $33. for 6 gals.<br> Or $16 for 12 qts.

Switched to Amsoil 15w40 HD Synthetic at 275,000 miles. No Leaks yet and Im at 281,000+ miles. <br><br>DRecu - send me your address and I will gladly send you a bottle of Amsoil Engine flush. Free ofcourse.<br>(Of course unless you live in Indonesia or somewhere like that ;D)<br><br>

I have heard good things about amsoil? Where can I find this brand of oil and flush? I just bought my truck and am looking to start a normal service schedule and am just trying to descide what to run in her. Thanks<br><br>Mike

I beleive you can go to www.amsoil.com and find a dealer near you or go order on line. Its not the cheapest stuff in the world - but most good things are not cheap.

<br><br>I buy my Delo 400 at Walmart. ;D It's 6.17 a gallon! ;D<br><br>Tony<br> <br><br><br><br> If you have a Sams Club close by its $33. for 6 gals.<br> Or $16 for 12 qts.<br><br><br>I do have a Sams club real close, unfortunately, they only sell Rotella. They do have that in a 55gal drum though! [laugh]

Who is selling the new Valvoline Extreme synthetic?

Did anyone even answer his other question about diff fluid? Anyhow, I use Royal Purple 85W-140 in both mine... ;D<br><br>Tony