OCI for Ford 3.8 Mustang convertable

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Apr 19, 2004
New York
My brother is driving his 03' Mustang 3.8 conv. from NYC to Florida where he will leave it to use for his visits there. He is retired and plans to spend about half his time in NY and half in Fla. The car calls for 5w20. Is this motor like the Ford modular V8 which seems to like the thinner oil or would he be better off with Mobil 1 5 or 10w30 year round in Florida. Also would 1 year /7500 mile OCI be okay with M1. Thanks
I had an 88 3.8L, basically the same motor. It liked thin oil. I ran 5w30 in it all year round with no problems. The rest of the car fell apart before the engine. The 3.8 is a good motor, just have to watch the head gaskets. I replaced mine at 95,000.
Is this the same 3.8 that they used in the Taurus. I had heard that that motor should be avoided and that the Vulcan 3.0 was a better motor. Any thougths on this?
They finally fixed the headgasket problem in 02 on the mustangs. It took em over 10 years to figure it out. My headgasket on my 1993 cougar(3.8) costs me 900 bucks, but I had the heads shaved and aligned before the new gaskets were put on. Its good that your bro has the 03, cause it won't have those probs anymore since they put on better headgaskets.
So do you guys think Mobil 1 5w30 at 7500 mi OCI (which might be close to a year of use) would be OK?
pbm, Unless the engine has some kind of problem or is exposed to some really hostile driving conditions--like lots of idling or short trips in cool weather without longer drives to get the condensation out of the oil--the 7500 OCI should be fine.
Originally posted by pbm: So do you guys think Mobil 1 5w30 at 7500 mi OCI (which might be close to a year of use) would be OK?
I think that would be fine. [Big Grin] But, check the owner's manual for what Ford requires for Warranty. They used to require 5K changes, but I don't know now. If warranty has stricter requirements, follow it and Motorcraft would be good enough.
I have 4.2L V6 in my F150. Its a stroked 3.8 basically. Speed parts, heads and such from a 3.8 will bolt right up to a 4.2L My oil choice has always been a Xw-30, it seems to be the sweet spot even though 5w-20 is recommended. Thicker (xw-40 and GC) makes it vibrate a little until fully warmed up and thinner (Xw-20) makes it loud and irrating. I've got Amsoil 10w-30 in it now, and its just a tad thick, but it seems to like it.
have the 4.6L mustang gt (2003), and i have red line 5w-30 in there now. 5,000 mile OCI. you will be fine with either a 5w-30 or 10w-30 weight synthetic, but if you are only going to change it once or twice per year, i wouldn't put anything other than red line in the motor.
The 3.8L has had the headgasket problem fixed. They "fixed" it in 96 but when the put them in the Windstar, the problems came back. We had (key word... had), a 2000 Windstar. They fixed the headgasket for good on 2001 models so I'm sure this Mustang has no problems. Strong engine! We had 5w30 in ours, before the 5w20 spec came out. My father had the oil changed at the dealer so I assume they used 5w20. We liked the van, just hated the other problems that came along with it. Use a good 5w20 or 5w30, either will be good. Oh.... the 3.8L is a 5.0L V8 minus 2 cylinders. Yes, the 4.2L a bored out version but its setup for torque, not HP, hence why they have under 180hp. The newer 4.2Ls make 201hp?
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