Hey guys, I know switching the oil ain't a big deal but I figured I see what ya'll think before I convert to synthetic 5W-40. Well it all started when I realized I hadn't changed my oil in 6,500K miles. Then I thought about converting to synthetic and after some reading, I see some turbo diesel motors run 5W 40?? Is 5-40 better for my engine with the turbo or does it really not matter?? From what I understand, I thought that 5-40 was too thin for these motors?? Thoughts?

I am switching to synthetic regardless of it being 15-40 or 5 40.

 

I just switched mine to mobil one 5w40 when i bought my truck, and it has seemed to run good. The oil pressure is normal, but i'm not too sure on it. If it wasn't -10 degrees every night i would switch it but the price was cheap at the time. In my last truck i had 15w40 amsoil and it started up in the coldest of mornings, or at least it cranked over fast as hell. The motor was almost trashed, but it didn't seem to mind cranking over that oil at -20 tho.

 

thats what im running too.5/40 mobil synthetic with the large extended service filter M1-601.
instant 50 psi cold start oil pressure @ -10 without block heater use.

 

Just looked at the price...ouch! $59 a gallon!

Edit: $59 for a pack of two gallons, my bad

 

but oil change intervals of 10-15k actually make it cheaper.
at 5k miles i did have to have a quart thus far.being a diesel,this is to be expected.
im going to send a sample at 10k and see how it looks and go from there.if all ok,i'll go to 15k and test again.

 

I guess so, did you notice any difference in the engine behavior after going synthetic?

 

the only thing i noticed was easier cold starts and a quieter engine.didn't see anything for fuel economy or power that i could notice anyway.

 

any special way you changed your oil to synthetic? flush of any type or just change it like normal?

 

with such a low mile engine,i didn't bother doing anything at all.just changed it like normal.
some have claimed that the synthetic is so much cleaner oil,that will loosen up loads and loads of sludge built up from dino oil and suggest changing the filter after 1k miles.i think it was oero that ran into that situation or knew someone who did.
with a block off plate over my stock fuel pump hole,the fuel bypasses my crankcase,so there's never a risk of fuel contaminating my oil,which could be costly in this case.though not overly common,we do read about those lift pumps leaking fuel into the oil from time to time.
edit;
and a new example of just this appears to have just come in;
https://www.ford-trucks.com/forums/1...-on-7-3-a.html

 

yeah thats what i planned on doing bout every 1-2k until the next oil change. thanks bud!

 

just put in rotella t6 synthetic 5w-40 50 miles ago, not really big deal didnt notice anything different

 

Just changed to Rotella T5 synthetic blend 0W-40. I do notice a huge difference but being -40C recently the 15-40 wouldn't even crank without charging the batteries fresh + battery warmers... I'd imagine that doesn't apply to everyone, but hey its a lot nicer on my starter.

I do get pressure sooner now though, and my sender is right on top of the turbo so by the time it gets there I figure its been well circulated.

 

Yeah, I'm also getting a few cheap filters to switch out early on. Is it true that once you go to synthetic, the engine can't go back to non-synthetic? Thats what some guy told me at the auto store.

 

i run synthetic 15w40. and ya, about 1-2000 miles you r gonna wanna change the oil. filters are cheap enough, change the filter at 1000 and the oil and filter at 2000. you can run a cheap synthetic for the first run just to get it swapped over. it will bring out some super nasty sludge like you wouldnt believe. and if you have a leak, fix it now cause it will get worse when the synthetic cleans out the junk.

 

I have a leak where the oil pressure sensor used to be, not bad, I plan to fix in the summer. Whats a cheap brand synthetic? Rotella?