oil recommendation

[mebanditws6]

I'm wanting to switch from Penzoil HM 10w40 to M1 but am not sure if the 0w40 or 15w50 would be better for my application. I have a 94 Grand Cherokee with 131k and it has the 318 motor. I know the HM stuff is on the high end of the viscosity range, but am not sure if the 15w50, though probably thinner than most 50's is too much even for my motor. I am not interested in any of the Delvacs or fleet motors as I have the notorious bad intake plenum gasket leak and I use at least 1.5 qts every 3k miles. I also want to keep this OTC for convenice as I'll be out of town for 10 weeks and M1 seems to be about the best in that regard. thanks for the help

Jason

 

[sprintman]

A tip for what it's worth. Do an Auto-Rx clean before changeover and get the full value of the syn. It's worth the effort IMO.

 

[TR3-2001SE]

I'd use the 15w-50 in the summer and the 0-40 in the winter.

 

[mebanditws6]

I've done 1 auto-rx treatment thus far, and intended to do a second as it's been about 2k miles since I drained the oil with the rx in it. However, I'm leaving for Florida in a week which is about a 700 mile trip for me, and when I get down there I won't be able to change or get the oil changed for at least a week, probably 2. Going 200 miles over a treatment doesn't bother me, but the fact that I may not be able to change oil until the rx is at least 1000 miles old doesn't sound like a good idea to me as the filter will be in bypass mode for a long time. Also, I don't have a credit card yet (i'm 20 yrs old), and one of my friends who ordered the 1st bottle won't be able to order it until late this week, so I may not even be able to take the bottle down with me to put in later.

How much thicker is M1 15w50 than Penzoil HM 10w40 and how much thinner is the 0w40 than the HM stuff? I just don't want to put something too thin in my high mileage motor, but don't want something too thick as it's in pretty good shape.

Jason