I have a 98 Dodge Ram 1500 with the 5.9. The truck has 160000 miles. Right after I bought the truck I had to have a new oil pan put on it. I am assuming the mechanic used regular oil. The po said he used full synthetic with every oil change (don't normally trust and of the po hence the post). I am due for an oil change and would really like to use a full synthetic oil but I've heard about switching vehicles with higher mileage to full synthetic can result into oil leaks. Any suggestions? Any recommendations on oil? I normally use Valvoline or Castrol. Maybe a high mileage full synthetic?

 

Use whatever you prefer. The leaking problem on higher mileage engines is mainly due to the synthetic oil doing its job, and cleaning things up. The high mileage engines tend to have a bit of crap drifting about, and it accumulates in the cracks, which would normally be leaks. Synthetic cleans that out.... so, you get a leak.

 

Makes sense. So I guess if the po had used full synthetic I should not have the leaking issue. Do you suggest a High Mileage oil?

 

NO do not use high milage oil, I did not like it one bit nor did the motor. Just pick a top of the line syn oil, like Redline, Liqui Moly. I am also not a liker of M1 oils I found they start to break down after time.

I use Liqui Moly Synthoil Premium 5W-40 and very much like it. But my understanding is that Canada gets a diff version of this oil compared to the US.

This is just my op and you will get lots of ops on this.

 

I switched to full synth at ~140K... no issues.

 

Some folks also experience lifter tick with synthetic oil in high mileage motors......

 

Idk if I would call my motor high mileage but it did suffer from lifter tick on occasion, this was one reason I went to syn over dino oil. But I have also seen just what you have described.

 

+1 on this. I had awful experience with high milage oil. But then I'm still using 0w30 Dino oil, so...

 

Full synthetic it is.

 

Are you guys referring to the oil that is intended for high mileage motors, or the oil that is meant to be used for higher mileage intervals?