1993 Mercury Cougar 3.8L. Not backspec'd to 5w20.

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217
Location
NY
This is my current ride and it's time for an oil change. I noticed that Ford has not backspec'd this engine to 5w20...is there a reason for this? Does this engine like the thicker oil? I've been using 5w20 year 'round forever in everything, but I don't want to risk harming anything.
 
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9,427
Location
Pensacola & Vero Beach FL
Alas, I'm sure that Ford will not explain the basis for their decision. I'm sure that there is some characteristic of this engine that causes them concern enough not to back-spec this particular engine. Might be clearances, might be consumption, might be several other things. But we don't know. I'd just not worry about it and use what the manual suggests.
 
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34,999
Location
NY
 Originally Posted By: JonnyHotcakes
This is my current ride and it's time for an oil change. I noticed that Ford has not backspec'd this engine to 5w20...is there a reason for this? Does this engine like the thicker oil? I've been using 5w20 year 'round forever in everything, but I don't want to risk harming anything.
I think it has something to do with the oil pump your engine uses. That was the reason some of the older 4.0L engines were not back spec'd.
 
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15,056
Location
Canada
Blend your 5W-20 with a thicker oil - 5W-40 or 10W-40, to make it the visc. you need. No point in wasting good oil.....
 
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1,027
Location
Wisconsin
To find out if the manufacturer has changed the specification(s) for oil, or other fluids.....you will need to get a list of Technical Service Bulletins (TSB's) for your vehicle. You can do this online....through Alldatadiy, or at your dealership. This is NOT to be confused with a RECALL...where the customer is sent a letter. A TSB is NOT sent out to the customer.....but is sent to the dealerships.....and can be gotten through various sources...however you have to check into it on your own.
 
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11,284
Location
Spring HIll
AEHaas runs 20 grade oils in his Ferrari which is spec'd for 60 grade! I run 20 grade in my little Saturn even though it's never been spec'd for 20 grade, ever. Good Pennzoil 7300mile UOA to prove in the UOA section. If it were me, I'd try my favorite 5w-20 dino for 3K, then do a UOA to verify.
 
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3,756
Location
CA
 Originally Posted By: ToyotaNSaturn
AEHaas runs 20 grade oils in his Ferrari which is spec'd for 60 grade! I run 20 grade in my little Saturn even though it's never been spec'd for 20 grade, ever. Good Pennzoil 7300mile UOA to prove in the UOA section. If it were me, I'd try my favorite 5w-20 dino for 3K, then do a UOA to verify.
AE Hass also states that he runs his Ferrari very easy with the thin oil.
 
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39,806
Location
Pottstown, PA
I'm sure that many 3.8's ..along with SBC's, 5.0's ..and millions of other engines..ran millions of miles on shear prone 5w-30 ..dumped into them (imagine "glug-glug" sound) by the gallon ..and all lived happy lives .. ..until the head gaskets blew ..or the LIM gaskets went south ..or ...etc..etc..
 
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5,945
Location
Texas Hill Country
Yeah that 93 3.8L motor is known for blown headgaskets. The 3.8 likes a little thicker motor oil. I would run 10w30 dino in it.. Keep the coolant clean, and hope the gaskets don't blow.
 

JonnyHotcakes

Thread starter
Messages
217
Location
NY
 Originally Posted By: JustinH
The 3.8 likes a little thicker motor oil.
Does this mean I might be better off with a thick 5w30 or a 5w40?
 
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