Jumping on the thin-oil bandwagon

[Klutch9]

...Despite the fact the my engine has 174,000 miles on it. Last year, i began experimenting with different oils. Last winter, i did a fill a GC 0w-30. It did okay, although i noticed what seemed to be increased consumption. Then, my next fill was Pennzoil Platinum 5w-20 (which is a thin 5w-20 at that), and my engine ran quieter and smoother than it ever had since i owned the vehicle since 133,000 thousand miles, and it didn't burn much oil either. Right now, i'm just using the factory recommended 5w30, in the Quaker State Ultimate Durability flavor. But i just picked up a 5 qt jug of Motorcraft 5w-20 blend, SN spec'd. If i still like how the thin oil acts this time around, i'll be hooked for good.

 

[beast3300]

Make/model/engine?

 

[Klutch9]

Originally Posted By: beast3300
Make/model/engine?


pontiac grand am, 1997, 2.4l twin-cam "LD9".

 

[sangyup81]

you're going lower than factory? i'll have to use 0w10 to match you then!

 

[electrolover]

i bet i would run quiet and not burn any oil if you ran 20/50.
better let it warm up tho lol

 

[Oldwolf]

I have the same engine in my Cavalier. I have just switched from Mobil 1 10w30 to Mobil 1 0w40. I went the other direction than you. Almost 195k miles on my engine.

 

[Zaedock]

Originally Posted By: electrolover
i bet i would run quiet and not burn any oil if you ran 20/50.
better let it warm up tho lol


X2 LOL


Running 20 wts in vehicles "spec'd" for 30 wt is nothing new. People have been doing it for decades. IMO, you're actually going too thin, because you have increased consumption with no perceivable benefit.

 

[Fallguy]

I understand the thin desire for start up reasons (count me in for 0w-30) but what is the desire for a thinner top number grade at operational levels than recommended.

What is to be gained besides a bit of mpg and flow?

Better heat dissipation or what?

Regards

 

[Samilcar]

Fallguy, I'm running a thinner oil (5W-20) than recommended (5w30) because of how I use my vehicle. Because I have a short commute, my oil temps hardly ever get up to normal temperature (100°C). Because of this, I want my oil viscosity to be as low as possible between 20°C and 60°C, yet still be just thick enough to protect when the oil does get up to normal temperature (long vacation trips, etc). used oil analysis so far show that this lower viscosity use is doing OK in my application (no excessive wear caused by inadequate viscosity at full temp).

The widman calculator graph shows the low temp viscosity difference between 0W-20 and 0w30 oils. Notice that the 5W-20 oil (thrown in for comparison) is slightly lower in viscosity at the temps I'm most interested in than is the 0w30 oil.

 

[addyguy]

A GM 2.4 twin-cam engine is NOT the engine I would be doing this in, especially one with high mileage.

Those engines tend to get 'loose' and rattly as they get older, and often start burning oil - they don't age particularly well.

A thinner oil is just going to magnify these problems.

 

[shpankey]

This is the quad four engine right? I so love those. I had one in a 99 Beretta GT and also in a 96 Z24, both ran great. I ran the Z24 till 180k miles on cheap bulk dino done at the cheapest places available, usually walmart. I rarely if ever checked the oil and when I did it was usually below the fill line and I'd eventually take it in for a change. I always went at least 6k miles. I once ran it so low it wasn't even showing on the stick and drove it 20 miles to get to my brothers house to borrow some money for a quart.

All this I assume led to some sludge because when I finally became a bitog member and learned what to do, I switched to a good cleaning synthetic oil ((Pennzoil Platinum 5w30)) and also put a quart of MMO. This apparently shocked the system too fast and clogged the oil pump screen. I noticed a ticking. I loaned the car out to my niece who didn't have a car, who drove it really hard. Then loaned it to a friend who was in between cars. He was enthralled with how quick the car was and admitted to me racing it everywhere he went, never even letting the car warm up. He then raced my car one day and when he pulled up behind me the tick turned into a horrendous knock.

So I sold it to another niece who needed a car bad whose boyfriend was a mechanic at a rebuild shop who rebuilt it. He said the oil pump screen was completely clogged so oil wasn't getting through the pickup to the top of the engine.

If I knew then what I have learned here since, when I went to the synthetic and MMO, I would have pulled the pan and cleaned it all up and cleaned the oil pump screen.

I have to say though, we beat on this car its whole life without issue until then. That car was quick and fun to drive. I wish I had known that when I went to do a cleaning phase I should have pulled the pan and cleaned the screen after driving it awhile. But great engine though, only my ignorance led to its problem. After the guy did a minor rebuild and replaced the oil pump, it ran great again for awhile... but then the transmission (4 speed auto) went out in it. It never had the transmission fluid changed or filter changed... though I had 24 quarts of AMSOIL ATF that I bought for it and a filter change kit. I didn't give them the amsoil but did give them the filter kit and told them they should change it as it had some minor symptoms (delay going into gear and minor slipping when cold). I think had I done that change I might of saved it.

 

[Klutch9]

i've actually heard a number of instances where people switch to a thinner oil and oil burnoff actually decreases. why, i dont know.

 

[CATERHAM]

Yes it's pretty much a no brainer to run a 2.6cP HTHS 20 wt in the winter in your GM engine.
The summer is a different story where more thought as to the application is required.

 

[Klutch9]

Originally Posted By: CATERHAM
Yes it's pretty much a no brainer to run a 2.6cP HTHS 20 wt in the winter in your GM engine.
The summer is a different story where more thought as to the application is required.


i do 5,000 OCI's, with about a quart of top-up in that amount of miles. since i'm adding a little top-up oil to freshen the sump and since my trips aren't usually of the stop and go variety, i think a good 20wt in the summer would be okay too. and i live in Michigan, so our summers dont get too crazy hot. maybe a few 100 degree F days per year, if that.

 

[CATERHAM]

Yes you appear to be on top of things so I'm sure you'll be fine in the summer as well.
Your climate is the same as mine. Dropping one grade below spec'is rarely enough to run into a situation where the oil is too light.
On those occasional 100 degree days when you think the oil is as hot as it will ever get, simply avoiding WOT markedly lowers the viscosity demands of the engine.

Also be aware of the HTHS vis rating of the 20wt oil you choose.
You can choose a somewhat heavier 20wt like Pennzoil Ultra 5W-20 with it's HTHS vis of 2.7cP or Mobil 1 5W-20 at 2.77cP. With these oils there's likely very little viscosity difference at the end of a 5,000 mile OCI and a 5w30 conventional.