what oil weight to use.

[SlowMach]

I've been running 5w50 Mobil 1 Gold synthetic ever since I bought my car , and ever since my issues started I was recommended to try running 5w50 Oil ..
Any input on that ?
It's so expensive

[DSG2003Mach1]

did you typo what youve been using? what issue are you having

[4a7191a]

Rotella t6

Use it in the lightning, f250 and evo as well.

[Mach828]

The castrol syntec is reasonably priced if you want 5w50. I have ran it before.

I usually run the 5w40 shell in the winter and 15w40 chevron/exon in the summer.

[DSG2003Mach1]

based on some other reading I run 5w30

[not a gt]

I still run 5W20 since she was born

[Big Ron]

^^^^^ I'm with Larry. 78K miles.





Big Ron

[DSG2003Mach1]

I ran 5w20 in my stock motor for around 80k and everything under the valve covers looked great (I did not pull the cams or anything)

[tmhutch]

Click Link: Oil Viscosity for DOHC Ford

[4a7191a]

Dang that post was forever ago.
Used to use 5w30 before I learned and after owning a built turbo car I truely know

[VA-Mach1]

5W30 unless this thread shows me some sort info to change my mind....

[4a7191a]

Shelby's have the same tolerances that we do and they recommend 5w50. That's should say something right there alone.
To me 5w30 is fine, I used to run it. My car was alot more stock than it is now as well.
I run 5w40 because the t6 is proven to have a zinc, phosphorus, and calcium level better than that of mobil1 , its not healthy for cat converters so they say, but none of my cars have those anyways.
Top dog oil I'd say would be amsoils new 5w50 but with oil changes on 4 vehicles..... That's kinda pricey.

[DSG2003Mach1]

I wonder if the Shelby oil weight has anything to do with the piston lining process in those motors (the 5.8 anyway)

[Nekasrof]

If I was still using the Mach as a DD, I'd be using the Mobil 1 5-20 that was in the motor for 105k+. It went in with about 100 miles on the clock.

Currently, with racing, I'm using the Ford 5-50.

[DSG2003Mach1]

interesting to see a few 5-50 recommendations, seems before everyone was worried about the cams/heads going beyond the 5-30

[4a7191a]

Ford isn't worried about the Shelby's breaking their cafe cap they as a company are supposed to hit. Few of them are made as compared to run of the mill cars they put out.

[tmhutch]

The thicker the weight of the oil, the better the protection, period. The trade off is horsepower (and mileage as if we care). 5W-20 isnt appropriate under any circumstances and does a poor job of protecting the engine. Will your engine blow up from running it, yes, it could if you run it hard. They usually end up spinning a rod journal, I've seen too many to count. Can a 5W-20 car last 100k miles without blowing up? Sure, happens all the time. But the minimum weight is 5W-30, it loses very little power (1-2hp) over the 5W-20 and represents a large jump in cam journal etc. protection. Theres no reason to run 5W-20.

Diesel spec is used because of the increased zinc and phosphorus which provides better protection for friction areas like the metal on metal cam journals. But beware, diesel oil manufacturers are slowly phasing out ZDDP without notification. Last I checked, Rotella was OK, but Chevron Delo (previously one of the best) is not. Best bet is to run a good quality 100% synthetic.

Ford specifies 5W-50 in the Shelby because the increased loading of a boosted, high HP engine requires the additional film strength to insure protection. Same goes with high RPM engines. To compensate for the heavier oil they opened up the oil galleries in the cam followers (lifters). Some people have contended that the heavier weight in engines with followers spec'd for 5W-30 would have a pump up problem at high RPM. I havent seen it.

Again, the heavier the oil the better the protection. Synthetic oils have put the days of bearing clearance concerns and cold weather start issues behind us. Run whatever you want, except 5W-20.

[Mach828]

Didn't know that they were phasing out zddp. How can you tell? We have ran chevron in our semis forever may need to switch to shell.

[tmhutch]

Oil manufacturers are very tight lipped about their formulas but some inside scoop can be gleaned from themotoroilevaluator.com and bobistheoilguy.com.

[VA-Mach1]

All I know is that after changing to 5W-30 my motor made less noise, and I like it better that way. Nice and simple

[Andrew03Mach]

I have been running Mobil 1 full synthetic 5w-20

[liv2roc]

mine has 103000 miles and been running motor-craft synthetic blend 5w-20 but I bought Valvoline full synthetic 10w-30 I'm changing to Saturday

[Khyren]

I'm switching from Castrol edge 5w-20 likely to something thicker Saturday morning. No ifs ands or buts.

[j rick kirby]

All the evidence points to the fact that the 20 is too thin and is suggested because of CAFE standards.

[not a gt]

Yea I think I may switch as well, have maybe 30 miles on latest change, filter will stay.