Oil Consumption with Different oils?

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My worn 1998 Honda 2.3 L would just drink Mobil 1 5W30. I have faulty valve guides where I always burn a bit on start up. With M1 it would shoot it out the tailpipe unburned when driving around town (perhaps it's the high flash point). This oil got black very quickly suggesting this thin oil was scavenging gunk built up from years past, probably from that time I inadvertently ran very low on oil, it had baked on some non synthetic that was hard to dislodge. I switched to 10W30 Castrol Syntec with a bit of Redline of the same grade, and oil consumption has dropped dramatically, I can't believe how clean the oil looks after 700 km as well. I also think I fixed a stuck ring with multiple Amsoil Powerfoam piston soaks. Both problems have been stubborn, and not things I had been able to address quickly with anything in a can.
 
Thought I'd try some Mobil 1 5w-30 Truck and SUV in my daughter's 1999 Volvo S70. Big mistake. Consumption went through the roof, something like a quart per 1K miles. Switched back to QS 5w-40 and consumption is back to normal at a quart per 4K miles.
 
Originally Posted By: rainman49
Thought I'd try some Mobil 1 5w-30 Truck and SUV in my daughter's 1999 Volvo S70. Big mistake. Consumption went through the roof, something like a quart per 1K miles. Switched back to QS 5w-40 and consumption is back to normal at a quart per 4K miles.


The super thick QS 5w-40 is starving the engine so it can't consume. And when its starved it wears, your tradeoff for not repairing it.
 
Originally Posted By: LeakySeals
Originally Posted By: rainman49
Thought I'd try some Mobil 1 5w-30 Truck and SUV in my daughter's 1999 Volvo S70. Big mistake. Consumption went through the roof, something like a quart per 1K miles. Switched back to QS 5w-40 and consumption is back to normal at a quart per 4K miles.


The super thick QS 5w-40 is starving the engine so it can't consume. And when its starved it wears, your tradeoff for not repairing it.

If a thicker oil accelerates consumption, then either the chemistry of that particular oil isn't suitable, or the oil is foaming up in the crankcase. It's true that thicker oil isn't optimal when it's not necessary, but I see no reason to presume that this oil is "starving" this engine.
 
Originally Posted By: d00df00d
Originally Posted By: LeakySeals
Originally Posted By: rainman49
Thought I'd try some Mobil 1 5w-30 Truck and SUV in my daughter's 1999 Volvo S70. Big mistake. Consumption went through the roof, something like a quart per 1K miles. Switched back to QS 5w-40 and consumption is back to normal at a quart per 4K miles.


The super thick QS 5w-40 is starving the engine so it can't consume. And when its starved it wears, your tradeoff for not repairing it.

If a thicker oil accelerates consumption, then either the chemistry of that particular oil isn't suitable, or the oil is foaming up in the crankcase. It's true that thicker oil isn't optimal when it's not necessary, but I see no reason to presume that this oil is "starving" this engine.

when thicker oil is necessary what is it doing? What does thicker oil do to stop/help/prevent consumption? Your ruling out "starving", but don't provide a replacement reason.
 
Wow. I just realized I completely misread rainman49's post. My apologies.

Here's a response that is hopefully more on-target.

Sometimes oil consumption is caused by fuel dilution or simply oil seeping past rings and valve seals. In those cases, a thicker oil might help reduce consumption by sealing the combustion chamber and resisting volatization better than a thinner oil.

That said, a sudden spike in oil consumption could be due to a number of factors, not all of them oil-related. Even if it is the oil, it could just be a result of the change in chemistry; in that case, simply running the same oil for a while will cause the consumption to settle down.

Either way, I still see no reason to think that the thicker oil is causing excess wear. It might not be optimal but I can't imagine it's particularly harmful.
 
This is like Coke vs Pepsi.

Its just down to composition, and some engines like one over another.
 
Since my truck started consuming oil, I've been experimenting with different brands. Started consuming Castrol GTX, approximately 1.5 quart in 3000 miles. Then PYB, similar consumption. Then VWB. It didn't use any valvoline. 6 quarts in, 6 quarts out. Now I have QSGB in there and it seems to have used maybe a small amount mid-way through the interval.

I find this odd especially considering that the add packs of VWB and GTX are so similar. Unless the more robust add pack from the pennzoil somehow conditioned the engine and prevented consumption during the valvoline interval (which I do not believe to be the case, seeing that it consumed the pennzoil itself), I suppose the next largest difference would be different base oils from valvoline and castrol, but I do not know much about these company's base oils or from where they come.

I have another change coming up in about a week, and I plan to use valvoline again to see how it affects consumption.
 
Originally Posted By: A1BadPizzaGuy

I find this odd especially considering that the add packs of VWB and GTX are so similar....I suppose the next largest difference would be different base oils from valvoline and castrol, but I do not know much about these company's base oils or from where they come.


Good points. My old Audi always consumed thinner oils, but had less problems with the thicker oils. Yet, it consumed primarily PAO GC, yet didn't with primarily PAO Delvac 1 ESP 5w-40 or RP 0w-40.

I guess sometimes engines just do whatever they want.
wink.gif
 
Originally Posted By: Garak

I guess sometimes engines just do whatever they want.
wink.gif



I think you may be onto something here haha. My understanding on using thicker oils to prevent consumption would generally see that a thicker grade would be used as opposed to simply a thicker oil in the same grade. Although, I see this as a continuum, so a small improvement may exist within the same grade.

Perhaps I should have mentioned before that I only use 5w30 in my truck. Maybe this will heighten the mystery!!
crazy2.gif
 
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Originally Posted By: A1BadPizzaGuy
Perhaps I should have mentioned before that I only use 5w30 in my truck. Maybe this will heighten the mystery!!


Well, the Audi burned the relatively heavy 30 grade GC, but not the 40 grades. In my Audi, the consumption definitely depended upon the thickness of the oil used. It was unkind to ordinary 5w-30 for sure!
 
I was using conventional motor oil in my 2003 Cavalier which does not leak any fluids and I always changed the motor oil every 3,000 miles on that car when I was using conventional motor oil. This car was always down about 1/2 a quart with 3,000 miles on the oil.

I bought a 1997 Honda Civic from the original owner in excellent condition two years ago. I switched this Honda and the Cavalier over to Pennzoil Ultra 5W-30 Full synthetic at the same time. Both of these cars do not leak/drip one drop of oil in the driveway at all. My experience has been the same on both cars with this oil. The oil level goes down more with the full synthetic than when using conventional motor oil. I would say I am adding almost 1/4 a quart of synthetic motor oil every 1,000 miles to keep both cars on the full oil mark on the dipstick. Synthetic motor oil lubricates your engine better and is slipperier than conventional, so it is blowing past the piston rings easier in both of my cars. It is getting burned up in the combustion chamber and going out the tail pipe.
 
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I just started a thread in the maintenance forum dealing with this topic. Zero consumption issues using M1 almost exclusively. Switched to PU one time because I got a good deal on it. Ran it for 12k. Lost about a quart in that time. Switched back to M1 and loosing 1/2 quart every 1k.
 
I had previously used 10w-30 in the Volvo, which has 170K miles, with a consumption rate of 1 quart per 4K miles. Bought the Mobil 1 5w30 Truck and SUV on closeout at Autozone and thought I would try it, thinking the T&SUV would be a stouter, possibly thicker oil. However, the oil disappeared at an alarming rate. I got about 30 quarts of the QS 5w-40 when Big Lots had it, so decided to try it to see if the consumption would subside or if another problem had developed. It went right back to the quart per 4K consumption as before. The Mobil 1 in the 5-cylinder engine obviously is a little thin for L.A.
 
In my RX300 using 5W-30:
Zero usage at 3K-4.5K mile OCI using VWB
1/2 quart per 500 miles using PP
1/2 quart per 1000 miles using M1-HM
1/2 quart per 1000 miles using GTX-HM

As you'd assume, I stick with the VWB...
 
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Originally Posted By: 2000RX300
In my RX300 using 5W-30:
Zero usage at 3K-4.5K mile OCI using VWB
1/2 quart per 500 miles using PP
1/2 quart per 1000 miles using M1-HM
1/2 quart per 1000 miles using GTX-HM

As you'd assume, I stick with the VWB...


My RX300 consumes no measurable oil in my 4k OCI's, sometimes 5k.

Also, what's VWB?
 
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Originally Posted By: hypervish
Originally Posted By: 2000RX300
In my RX300 using 5W-30:
Zero usage at 3K-4.5K mile OCI using VWB
1/2 quart per 500 miles using PP
1/2 quart per 1000 miles using M1-HM
1/2 quart per 1000 miles using GTX-HM

As you'd assume, I stick with the VWB...


My RX300 consumes no measurable oil in my 4k OCI's, sometimes 5k.

Also, what's VWB?


It sounds like your RX likes PP better than mine. I just hit the 150K mark on mine. Due to a new job farther from home, I was trying to stretch out the OCI's by trying something other than the VWB. (Valvoline White Bottle is VWB)
 
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