15W-40 too thick???

GIXER1307 · December 10, 2004

i HAVE A 01 SIERRA 5.3 AND I LIVE IN SOUTH LOUISIANA AND I RUN SHELL ROTALLA T 15W-40 IN MY TRUCK. I WOULD LIKE TO GET OTHERS OPINION ON RUNNING A THICKER OIL THAT A 10-40 OR 10-30.

kirkRHughes · December 10, 2004

I don't know if I'd go that thick, sounds like it would be bad for start-up.

Speaking of beating a dead horse, my Pinto needs a push.

JayMan · December 10, 2004

In summer I ran Mobil 1 15W-50, which helped get rid of that "CSK." In winter I ran Mobil 1 0W-30, which made the motor tap and tick like crazy when hot.

It's a judgement call, isn't it?

I suppose you want to use the HDEO due to the better additive package? Most HDEO are now offered in 10W-30 as some new HD diesel motors specify this weight, at least for some temps.

MMM · December 11, 2004

I live in south Louisiana as well. I use Mobil 1 Synthetic 5w-30 in a 5.3 engine. According to the manuel, it says to use 5w-30 or 10w-30. I do a lot of towing, and I have 75,000 miles on my truck. If I had a diesel engine, I would without a doubt use Shell Rotella. I think it is a great oil, and I use it in my tractors. I would just worry a little about getting the proper lubrication with the thicker oil. However, this is just my opinion, and you do whatever you are comfortable with your truck. A lot of people would not be comfortable with going 8,000 miles between oil changes as I do, but I use synthetic oil, and this is what I am comfortable with. MMM.