5w20 or 10w30
10-02-2010, 05:56 PM
#1
4th Gear Member
Thread Starter
Join Date: May 2006
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5w20 or 10w30
I know this has been beat to de3ath, but I still want a specific opinion for my car.
I know that the owners manual says 5w30 or 10w30 or something for a 99GT, but in the newer years it says 5w20. I have always run mobil 1 synthetic 10w30 and have never had a problem. So I am kind of thinking I should just stick with it. I have 245,000 kms on the engine right now and even when I drive it hard, it doesn't give me any issues.
Should I stick with my good ol faithful 10w30? Or should I switch to 5w20? And upsides or downsides?
I know that the owners manual says 5w30 or 10w30 or something for a 99GT, but in the newer years it says 5w20. I have always run mobil 1 synthetic 10w30 and have never had a problem. So I am kind of thinking I should just stick with it. I have 245,000 kms on the engine right now and even when I drive it hard, it doesn't give me any issues.
Should I stick with my good ol faithful 10w30? Or should I switch to 5w20? And upsides or downsides?
10-02-2010, 06:16 PM
#2
3rd Gear Member
Join Date: Jan 2009
Location: Florida
Posts: 570
Lighter is better when you measure power at the flywheel, heavier is better when you suck the oil pan dry as the cam bores and bearings will last longer. Ford specs 50W for the modular in the Shelby, I have run as light as 0W10 and as heavy as 5W50 in these motors. You can run whatever you desire in all reality.
10-02-2010, 07:12 PM
#3
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Join Date: Jul 2008
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Lighter is better when you measure power at the flywheel, heavier is better when you suck the oil pan dry as the cam bores and bearings will last longer. Ford specs 50W for the modular in the Shelby, I have run as light as 0W10 and as heavy as 5W50 in these motors. You can run whatever you desire in all reality.
10-02-2010, 10:46 PM
#5
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Join Date: Feb 2008
Location: Pensacola, Florida
Posts: 1,465
Also, for the 4.6L modular a robust 5W-30 is all that is required. Anything more is too heavy for an OEM internal build. 5W-20 is only because Ford is trying to lessen their pay outs to the US government due to CAFE laws. Just stick with a top grade 5W-30 and never think twice about it.
Last edited by Unleashedbeast; 10-02-2010 at 11:08 PM.
10-03-2010, 11:55 AM
#6
TECH SAVANT
Join Date: Dec 2006
Location: Saint Augustine, FL
Posts: 10,938
You did that exactly backwards. You always run the heavier weight in the summer, not the winter.
Also, for the 4.6L modular a robust 5W-30 is all that is required. Anything more is too heavy for an OEM internal build. 5W-20 is only because Ford is trying to lessen their pay outs to the US government due to CAFE laws. Just stick with a top grade 5W-30 and never think twice about it.
Also, for the 4.6L modular a robust 5W-30 is all that is required. Anything more is too heavy for an OEM internal build. 5W-20 is only because Ford is trying to lessen their pay outs to the US government due to CAFE laws. Just stick with a top grade 5W-30 and never think twice about it.
As to the SAE grade it all depends on where you live, or more accurately what the low and high ambient temperatures are in that locale.
Here in Florida I run 10W-30 synthetic in the Mustang year-round, have been for 75k miles now--on my wife's '03 Highlander (185k miles) I run 20W-50 Valvoline MaxLife dino juice--been doing that since 125k miles or so.
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"getafewlives", where do you live?
10-03-2010, 01:47 PM
#7
Underboss
Join Date: Jan 2006
Location: Helaware
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10-03-2010, 01:58 PM
#8
5th Gear Member
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Location: austin,TX
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10-03-2010, 04:35 PM
#10
