So im sure this has been talked about for a long time now but im going to bring it up again.
So I was in the local service shop for a new pinion seal. while there I also had them change my oil for me I was at 2800 miles so what the heck I thought go ahead and change it they used 5w-30 instead of the 5w-20 my question is will this hurt the engine or would this grade oil do better in my truck it seems to run smoother and not as noisy any and all help or tips will be use full
p.s. I also go told that since they made a mistake that my next oil change will be free and they said it wont hurt the engine at all

 

IMHO, on a short term duration, not a biggie. Although the engine itself does seem to like the heavier weight oil better, the supporting assemblies (including hydraulically actuated timing chain tensioners) do not like the heavier weight oil....as they tend to function slower because of the increased viscosity which on a longer term can promote issues. If it was summertime (as I see you live in Tx), I don't think I would give a second thought about running it for 6 months but with winter, personally, I think I would give my appreciation for the dealers considerations, free oil change, etc but drain it and put in the 5-20.

 

Not good for your phasers! Use 5W-20!

 

Im in Montana and its regularly down in the -40 range where I live not including wind chill. but I will go and have them change it out again and make it right that extra weight will be kinda thick in thos temps im guessing thanks for the reply man

 

These engines are pretty picky about the oil, 5-20 is the way to go. Much better than tearing into the engine due to improper oil.

 

Lots of Paranoia. The 5w30 will not hurt the engine at all. I run 5w30 or 5w20 whichever I can catch on clearance. My truck still runs just fine. The 5.4 3 valve in the Australian Falcon specs 5w30 of course that is a warmer climate. Would I run 15w40? No, but 5w30 no problem.

 

Kinda curious what they charge for pinion seal replacement? Mine is leaking also.

 

rear pinion seal cost me like 135.98 here in Montana its artic temps here. so instead of me doing it on the ground with no garage I did it at the dealer I bought the truck from. I have extended warranty coverage and it cost me 200.00 for any drivetrain repair and the seal repair cost only 135.00 so I just paid the 135 to fix it
pinion seals are cheap 20 bucks tops and gear oil ant to bad in price either
plus labor and they changed rear gear oil to

so I did some reading and if the oil is suppose to be 5w-20 that means at temp the oil acts like a 20w and cold like a 5w if im right could be wrong
then the 5w-30 would be better in the summer and the 5w-20 would be best in the cold or do I have this all back a**wards

 

No , the correct answer is , never use anything but 5/20 with a motorcraft filter.

 

I run Motorcraft Synthetic Blend 5W-20 in mine and a Motorcraft FL-820S filter. I've used Mobil 1 full synthetic 5W-20 in the past, but my valve-train is louder with it, I've noticed.. I don't have that problem with Motorcraft, though.

 

thanks for all the help with the comments guys 5w-20 is in it again and I have to admit the 5w-30 oil did quiet down the valves more then the 5w-20 ever did.
once again thanks im sure I will have more questions for this forum as the seasons get warmer and im rolling around under the truck with a beer and doing routine maintanace

 

How many miles on the 2008? 5W30 could be indicated if the engine is well-used with a little more clearance than new.

 

this 08 has 34680 I do believe as of this morning give or take a few all and all its in really nice shape I just notice that with the 5w30 I had less valve noise then with the 5w-20 that I had the dealer switch out after they made a mistake