Hi guys,
Two weeks ago I've spent a Saturday to change the engine oil, differential and transmission fluid and the fuel filter (the tranny job included dropping the pan and changing the filter, cleaning, etc). Glad I did it since the differential "lifetime" oil was BLACK :yikes:, the tranny ATF a dark grey and the fuel filter was the original part.
Sadly the joy of running new stuff and the afterwards "smoothness" was shattered by a significant drop in my mpg. Before the change my average mpg city and highway driving combined was around 21.5. Today, 350 miles later it's only 18.6
I can definitely feel a slight "drag" when coasting compared to what it used to be before. Also before the change, when driving in straight line and no incline, giving gas only now and then was all that was needed to maintain a constant speed. But now ... I have to give it gas all the time :tsk: (which would explain the lousy mpg).
So here are my primary suspects:
1. Engine oil: have put in Mobil 1 0W-40. Although I used it with great results on my former 325 and it cleans the engine wonderfully, I think it's a little too thick for my car. I'll leave it in until I reach 3000 miles on it then I'll change it with German Castrol 0w-30.
2. Differential fluid: used RedLine 75W-90 Gear Oil and it was MUCH thicker than what it came out. I plan on changing it with Amsoil Extreme Gear 75w-90. According to published specs it is a little thinner at lower temperatures (I doubt the diff reaches 100 Celsius in normal driving).
3. Tranny ATF: that's a tough one to decide. Have put in Castrol Import Multi-Vehicle ATF. I will do a second drain and filter change in 700 miles and now I am wondering whether I should not go with Amsoil Import Multi-Vehicle or Valvoline Import ATF for second change since, if I remember the specs correctly, they both are just a tad thinner. But on the other hand I am reluctant to run a mixture 3 ATFs on my tranny (old, Castrol and Amsoil/Valvoline).
So any thumbs up/cons to my plan ? Have you had/seen this issue before ?
Thank you.
Two weeks ago I've spent a Saturday to change the engine oil, differential and transmission fluid and the fuel filter (the tranny job included dropping the pan and changing the filter, cleaning, etc). Glad I did it since the differential "lifetime" oil was BLACK :yikes:, the tranny ATF a dark grey and the fuel filter was the original part.
Sadly the joy of running new stuff and the afterwards "smoothness" was shattered by a significant drop in my mpg. Before the change my average mpg city and highway driving combined was around 21.5. Today, 350 miles later it's only 18.6
I can definitely feel a slight "drag" when coasting compared to what it used to be before. Also before the change, when driving in straight line and no incline, giving gas only now and then was all that was needed to maintain a constant speed. But now ... I have to give it gas all the time :tsk: (which would explain the lousy mpg).So here are my primary suspects:
1. Engine oil: have put in Mobil 1 0W-40. Although I used it with great results on my former 325 and it cleans the engine wonderfully, I think it's a little too thick for my car. I'll leave it in until I reach 3000 miles on it then I'll change it with German Castrol 0w-30.
2. Differential fluid: used RedLine 75W-90 Gear Oil and it was MUCH thicker than what it came out. I plan on changing it with Amsoil Extreme Gear 75w-90. According to published specs it is a little thinner at lower temperatures (I doubt the diff reaches 100 Celsius in normal driving).
3. Tranny ATF: that's a tough one to decide. Have put in Castrol Import Multi-Vehicle ATF. I will do a second drain and filter change in 700 miles and now I am wondering whether I should not go with Amsoil Import Multi-Vehicle or Valvoline Import ATF for second change since, if I remember the specs correctly, they both are just a tad thinner. But on the other hand I am reluctant to run a mixture 3 ATFs on my tranny (old, Castrol and Amsoil/Valvoline).
So any thumbs up/cons to my plan ? Have you had/seen this issue before ?
Thank you.
