Originally Posted By: walk23
@ 70 MPH, 2900 RPM vs 2800 RPM
NO WAY IS THIS HAPPENING!!!!!
@ 70 MPH, 2900 RPM vs 2800 RPM
NO WAY IS THIS HAPPENING!!!!!
5W-20 vs. 5W-30
- Thread starter walk23
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Originally Posted By: tig1
RPMs are controlled by the computer and the gearing you have, not oil. If anything thinner oil will slightly reduce oil temps, but will do nothing for water temp. Also I started using Mobil 1 5w20 in 1978 in engines spec'd for 30 & 40wt oils. No problems.
tig1 my friend, your a braver man than I am.
RPMs are controlled by the computer and the gearing you have, not oil. If anything thinner oil will slightly reduce oil temps, but will do nothing for water temp. Also I started using Mobil 1 5w20 in 1978 in engines spec'd for 30 & 40wt oils. No problems.
tig1 my friend, your a braver man than I am.
Originally Posted By: MuzzleFlash40
Ive own'd a few of the big body fords from the 90's models all the way to the 2006 I have now. I've always wondered if it would be better to run the 5-30 oil in the new engines, even though they call for 5-20.
I'd run the GF5 MC-SS over the green bottle - it is initially a more viscous 20. Tried a super 5w30 in my not yet broken in Ranger and it balked.
Ive own'd a few of the big body fords from the 90's models all the way to the 2006 I have now. I've always wondered if it would be better to run the 5-30 oil in the new engines, even though they call for 5-20.
I'd run the GF5 MC-SS over the green bottle - it is initially a more viscous 20. Tried a super 5w30 in my not yet broken in Ranger and it balked.
I also wonder about what higher RPM. mean.
Originally Posted By: lexus114
Originally Posted By: tig1
RPMs are controlled by the computer and the gearing you have, not oil. If anything thinner oil will slightly reduce oil temps, but will do nothing for water temp. Also I started using Mobil 1 5w20 in 1978 in engines spec'd for 30 & 40wt oils. No problems.
tig1 my friend, your a braver man than I am.
At the time I was living in Maine and cold starts on my 77 Chev V8 was painful to hear with 30-40Wt dino. I knew some guys using Amsoil and I even tried it for a short time until it became hard to find. The local Mobil station owner told me about this new oil called Mobil 1 so I tried it even though it was 5-20. He assured me several of his customers were having good cold start success so I tried it. The only negitive I noticed was a little more oil consumption which I put up with compared to the great cold starts with the Chev. Also used it in a new 77 Dodge pick up Slant 6. Also more consumption but very good cold starts.
Originally Posted By: tig1
RPMs are controlled by the computer and the gearing you have, not oil. If anything thinner oil will slightly reduce oil temps, but will do nothing for water temp. Also I started using Mobil 1 5w20 in 1978 in engines spec'd for 30 & 40wt oils. No problems.
tig1 my friend, your a braver man than I am.
At the time I was living in Maine and cold starts on my 77 Chev V8 was painful to hear with 30-40Wt dino. I knew some guys using Amsoil and I even tried it for a short time until it became hard to find. The local Mobil station owner told me about this new oil called Mobil 1 so I tried it even though it was 5-20. He assured me several of his customers were having good cold start success so I tried it. The only negitive I noticed was a little more oil consumption which I put up with compared to the great cold starts with the Chev. Also used it in a new 77 Dodge pick up Slant 6. Also more consumption but very good cold starts.
Originally Posted By: A_Harman
That does not make sense.
Same highway speed, different engine rpm.
Perhaps you're torque converter clutch is not locking up.
Changing oil viscosity will not have anything to do with engine speed on the highway.
Agreed, there would have to be some slippage... Normally in modern O/D transmissions the torque converter is no longer in play and the transmission is coupled directly to the engine output, RPM can't increase for a given speed no matter what is used for oil in the engine...
That does not make sense.
Same highway speed, different engine rpm.
Perhaps you're torque converter clutch is not locking up.
Changing oil viscosity will not have anything to do with engine speed on the highway.
Agreed, there would have to be some slippage... Normally in modern O/D transmissions the torque converter is no longer in play and the transmission is coupled directly to the engine output, RPM can't increase for a given speed no matter what is used for oil in the engine...
Wouldnt the A/C being on affect the RPM? I'm wondering if that could be the difference the OP is seeing and not related to viscosity.
Originally Posted By: hominid7
Wouldnt the A/C being on affect the RPM? I'm wondering if that could be the difference the OP is seeing and not related to viscosity.
No, unless the car slowed down. RPM is the same at any given speed regardless of whether the A/C is operating or not.
Wouldnt the A/C being on affect the RPM? I'm wondering if that could be the difference the OP is seeing and not related to viscosity.
No, unless the car slowed down. RPM is the same at any given speed regardless of whether the A/C is operating or not.
Originally Posted By: walk23
Switched from 5w30 to 5W-20 PP hoping to improve millage in my 2006 Toyota Matrix XR. Noticed that the RPM's were a tad higher and the temperature gauge ran too a tad higher With the lighter oil I would have thought there would be a MPG gain but it looks like the engine is working harder.
Searching for comments before I switch back to 5w30. The car has 150K on it and has used Synthetics 95% of the time.
Thanks
You would only see fuel-economy benefits from switching to a lower viscosity if you drove gently. It's normal not to see any benefit in fuel economy if you drive hard. But you would definitely see a fraction of MPG (perhaps 0.5 MPG or so) improvement if you drove gently.
Regarding RPM, once your transmission goes into lock-up (after 45 MPH or so), the only thing that determines the RPM is the vehicle speed and tires. If you pumped more air into your tires or if it's hotter outside, your tire pressure would increase and the tire diameter would increase and you would see a slight decrease in engine RPM.
So, the slight increase you're seeing in the engine temperature is due to hot weather -- while there is a thermostat, it's only a negative-feedback-control system, meaning there is always a small (or sometimes large) effect of the outside temperature and engine load on the coolant temperature. Oil has little to do with and certainly not when you use a thinner viscosity.
The slight decrease you're seeing in the RPM is due to your tires getting slightly bigger (more air pressure) because of hot weather.
By the way, if you see tailpipe smoke after acceleration from a stop or increased oil consumption, you should switch back to 5w30. That would indicate that you're burning too much oil after your switch to a lighter viscosity, and it could lead to increased deposits and O_2-sensor and catalyst problems. Sometimes, switching to low viscosity could cause a significant increase in oil consumption; so, be careful.
Switched from 5w30 to 5W-20 PP hoping to improve millage in my 2006 Toyota Matrix XR. Noticed that the RPM's were a tad higher and the temperature gauge ran too a tad higher With the lighter oil I would have thought there would be a MPG gain but it looks like the engine is working harder.
Searching for comments before I switch back to 5w30. The car has 150K on it and has used Synthetics 95% of the time.
Thanks
You would only see fuel-economy benefits from switching to a lower viscosity if you drove gently. It's normal not to see any benefit in fuel economy if you drive hard. But you would definitely see a fraction of MPG (perhaps 0.5 MPG or so) improvement if you drove gently.
Regarding RPM, once your transmission goes into lock-up (after 45 MPH or so), the only thing that determines the RPM is the vehicle speed and tires. If you pumped more air into your tires or if it's hotter outside, your tire pressure would increase and the tire diameter would increase and you would see a slight decrease in engine RPM.
So, the slight increase you're seeing in the engine temperature is due to hot weather -- while there is a thermostat, it's only a negative-feedback-control system, meaning there is always a small (or sometimes large) effect of the outside temperature and engine load on the coolant temperature. Oil has little to do with and certainly not when you use a thinner viscosity.
The slight decrease you're seeing in the RPM is due to your tires getting slightly bigger (more air pressure) because of hot weather.
By the way, if you see tailpipe smoke after acceleration from a stop or increased oil consumption, you should switch back to 5w30. That would indicate that you're burning too much oil after your switch to a lighter viscosity, and it could lead to increased deposits and O_2-sensor and catalyst problems. Sometimes, switching to low viscosity could cause a significant increase in oil consumption; so, be careful.
No, unless the car slowed down. RPM is the same at any given speed regardless of whether the A/C is operating or not. [/quote]
I agree. The engine may require more fuel to get to the specified rpm with the additional drag from the AC but the rpm vs speed is determined by the gear ratio.
I agree. The engine may require more fuel to get to the specified rpm with the additional drag from the AC but the rpm vs speed is determined by the gear ratio.
My daughters mazda3 is the only vehicle in our family that requires 5W20. The OM states nothing about other oils. I have used 5W30 often and we see no noticable differences in engine performance, MPG compared to the 5W20. ATMOF, the engine is a bit quieter on the 30 and often better MPG by the smallest margin even in the colder temps. I have a bunch of OCI's of 5W20 just for her car.
Originally Posted By: lexus114
And most 5W30`s shear down to a 5W20 anyway. Maybe the Texas Heat is a little too much?
I read this statement in a lot of forums.. If 5w30 shears to a 5 w 20, what happens to a 5 w 20?
And most 5W30`s shear down to a 5W20 anyway. Maybe the Texas Heat is a little too much?
I read this statement in a lot of forums.. If 5w30 shears to a 5 w 20, what happens to a 5 w 20?
Originally Posted By: johnachak
Originally Posted By: lexus114
And most 5W30`s shear down to a 5W20 anyway. Maybe the Texas Heat is a little too much?
I read this statement in a lot of forums...If 5W30 shears to a 5W20, what happens to a 5W20?
I have read that the 5W20 is more shear stable. Mainly because most 5W20's start near the top of a "20" range and the 5W30's start lower in their range.
Even if a 5W20 experiences some fuel dilution, it should still maintain it's "20" weight. I could be wrong though!
Originally Posted By: lexus114
And most 5W30`s shear down to a 5W20 anyway. Maybe the Texas Heat is a little too much?
I read this statement in a lot of forums...If 5W30 shears to a 5W20, what happens to a 5W20?
I have read that the 5W20 is more shear stable. Mainly because most 5W20's start near the top of a "20" range and the 5W30's start lower in their range.
Even if a 5W20 experiences some fuel dilution, it should still maintain it's "20" weight. I could be wrong though!
Last edited:
Originally Posted By: TomYoung
Originally Posted By: walk23
@ 70 MPH, 2900 RPM vs 2800 RPM
NO WAY IS THIS HAPPENING!!!!!
Two things come to mind, one is a bit of a stretch. The tires were grossly under inflated and the OP added air to them. The other is the transmission is going out to lunch.
Curb idle might increase but the computer would sense that and adjust it down. JMO
Originally Posted By: walk23
@ 70 MPH, 2900 RPM vs 2800 RPM
NO WAY IS THIS HAPPENING!!!!!
Two things come to mind, one is a bit of a stretch. The tires were grossly under inflated and the OP added air to them. The other is the transmission is going out to lunch.
Curb idle might increase but the computer would sense that and adjust it down. JMO
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