SAE 5W30 or SAE 20W50 ??

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kiter18

kiter18

10 Year
Joined
Oct 6, 2012
Threads
13
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52
I must change the motor oil of my fj80 1992 3fe, I dont know what viscosity used the last owner. looking in the forum and FSM they recommend SAE 5W30, here in my country where temperature is between 45 F in winter 85 F in summer most common oil is 20W50. question for the experts: which one I must put inside motor?
 
Here we go!
5w40 she'll Rotella FTW
 
^^yep what he said. Most of us use some flavor or another of 40 weight oil. Be it 0-40, 10-40 or even 15-40
 
if the engineers that designed the motor recommend 5w30, why change?
 
In the US, it's less about "recommended by engineers", more about the mandate of politicians. The for everyone else but USA oil selection chart chart for the 1FZ.

AU viscosity chart
1FZFE motor
20w50 oil- -7C deg to 38C plus ; 19F to 100F plus
15w40 oil -10C deg to 38C plus; 14F to 100F plus
10w30 oil -18C to 38C deg; 0F to 100F
5w30 oil -30C to 8C deg; -22F to 46F
 
kiter18 said:
... here in my country where temperature is between 45 F in winter 85 F in summer most common oil is 20W50. question for the experts: which one I must put inside motor?
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I would run the 20W-50, two reasons: It's most common, will have zero problems pumping it at 45F cold starts. The newer oils have greatly reduced levels of ZDDP, a great additive for reducing wear in older design flat tappet motors (like the 3FE). The higher viscosity oils are formulated for older, classic motors, so most have higher levels of ZDDP. The F motors are known for being relatively hard on cam and lifters, so would take any advantage I can get on them.
 
I have tried tons of different oils including all flavors of Shell including 10W-30 synthetic blend, 5W40 synthetic, and 15W-40 dino but now am sold on 15W-40 Delo from Wal-Mart. It is by far the oil that burns the least in my truck.
 
X2. I use Rotella 15w40. Slows down the burn. Also reduces the smoke on startup due to the worn valve stem seals......Assuming worn valve stem seals.
kbahus said:
I have tried tons of different oils including all flavors of Shell including 10W-30 synthetic blend, 5W40 synthetic, and 15W-40 dino but now am sold on 15W-40 Delo from Wal-Mart. It is by far the oil that burns the least in my truck.
Click to expand...
 
kbahus said:
I have tried tons of different oils including all flavors of Shell including 10W-30 synthetic blend, 5W40 synthetic, and 15W-40 dino but now am sold on 15W-40 Delo from Wal-Mart. It is by far the oil that burns the least in my truck.
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If it works well for you, then use it. I had the opposite results. The Delo used 1 quart per 5000miles and the 15-50 Mobile 1 used 1 quart per 10,000 miles. Same driving conditions and filters for both oils. John
 
Part of oil burning is the kind of driving done at the time-high rpms/load/etc. Thinner oils used for better fuel mileage-pumps easier-less internal wasted power loss-oil pump, etc. I always figure when engine has 150-200k miles the bearing clearances/piston/cylinder wall clearances. etc/etc have opened up a lot-maybe almost doubled-that's where the oil lives so the recommended oil goes out the window-one of the reasons oil pressure starts to drop as it wears. Bumping up to thicker oil surely has to be beneficial
 
I'm going to say it again. You ALL need to go read this article on oil viscosity. I think 95% of people think they know what they're talking about when it comes to oil weight, but don't.

Here's a small quote to get you started. It is a long read - but since when was education a simple thing?


More confusion occurs because people think in terms of the oil thinning when it gets hot. They think this thinning with heat is the problem with motor oil. It would be more correct to think that oil thickens when it cools to room temperature and THIS is the problem. In fact this is the problem. It is said that 90 percent of engine wear occurs at startup. If we are interested in engine longevity then we should concentrate our attention at reducing engine wear at startup.
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http://www.bobistheoilguy.com/motor-oil-101/
 
CruiseOrlando said:
I'm going to say it again. You ALL need to go read this article on oil viscosity. I think 95% of people think they know what they're talking about when it comes to oil weight, but don't.

Here's a small quote to get you started. It is a long read - but since when was education a simple thing?




http://www.bobistheoilguy.com/motor-oil-101/
Click to expand...


Thanks! Good read
Im sticking with 5-30W
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Last edited:
Very good read so far. BUT all is assuming 10 grade is for all engines all the time. Maybe most newer engines with new clearances. And "said" that 90% of engine wear at startup. Is this still true for newer engines without carbs that wash down cylinders with liquid gas at full choke. Or if you don't immediately start and pull onto the highway at 3/4 throttle/load? The oil may bypass a lot when cold but not all. If it's run at idle/light load until warmed up it has to be much easier on all parts-that goes for all the expansion to different metals around gaskets/studs/bolts-pistons into bores/etc.
 
Oil

I have seen 0W20 to 20W50 in posts with no one saying "This oil blew up my motor". I think the key is to change it every so often as these motors seem to be about as picky about oil as they are about the octane of the fuel.
 
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