Motorcraft 5-20

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Any thoughts of mixing Motorcraft 5-20 with Motorcraft 10-30 (50/50). I got a 98 Ford Taurus and it calls for 5-30. Would that combo work since the 5-20 seems to be the norm for the newer Fords. Any comments would be appreciated.
 
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If the motor in this car is on Ford's list of motors that can switched to 5w-20 then use it with confidence. Otherwise just use 5w-30. I don't believe in mixing different weight oils. I just don't believe you know what you will end up with.
 

Al

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Not gonna hurt-imho. I am running 2 quarts Reline 5W-20 and 2 quarts 10W-30. I personally have no problem with mixing. I think there are certain benefits. Take for instance mixing Mobil 10W-30 with 15W-50. It gets you a more shear stable oil than the 0W-40. A number of folks have done this. Can't fault anyone who doesn't like the idea though. [Smile]
 
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several 4.6L Mustangs (GTs) have blown engines on the 5W-20 weight viscocity. My pal was rhomping on the gas when all of a sudden, bang bang bang bang...rod knock, and now he's buying a forged engine. I'd stick with a Xw-30 weight in the newer Ford modulars.
 

Bill Morris

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Seems like the 5-30 is doing alright, I just realise what I've learn on this forum that the 10-30 is more shear stable...Think I'll go with the 10-30 during the summer and 5-30 during the winter. Engines is doing real fine with the 5-30..Thanks for post...
 
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Bill- If you get a shear stable 5W-30, like Red Line, you will have no problem. That's what's in my 03 GT Stang, and I've run it a few times at the track.
 

pmt

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quote:
Originally posted by mf150: several 4.6L Mustangs (GTs) have blown engines on the 5W-20 weight viscocity. My pal was rhomping on the gas when all of a sudden, bang bang bang bang...rod knock, and now he's buying a forged engine.
I'm curious - what is a "forged engine"? Thanks.
 
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forged engine means a shortblock is built up using stronger parts that are made through a forging process, and not a cast process. Technically the 4.6 has forged rods from the factory, they are toothpicks though, the manley forged rods are much thicker.
 
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quote:
Originally posted by mf150: several 4.6L Mustangs (GTs) have blown engines on the 5W-20 weight viscocity. My pal was rhomping on the gas when all of a sudden, bang bang bang bang...rod knock, and now he's buying a forged engine.
[Roll Eyes]
 

pmt

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quote:
Originally posted by mf150: several 4.6L Mustangs (GTs) have blown engines on the 5W-20 weight viscocity. My pal was rhomping on the gas when all of a sudden, bang bang bang bang...rod knock, and now he's buying a forged engine.
To mf150: Any idea what brand(s) 5W-20 was used in these engines that are are failing? One would think that Motorcraft 5W-20, which is partially synthetic and not that much thinner @ 100 C than M1 5W-30, would be able to handle pretty heavy loads. Thanks.
 
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quote:
Originally posted by mf150: several 4.6L Mustangs (GTs) have blown engines on the 5W-20 weight viscocity. My pal was rhomping on the gas when all of a sudden, bang bang bang bang...rod knock, and now he's buying a forged engine. I'd stick with a Xw-30 weight in the newer Ford modulars.
My guess is it isn't the oil that's causing these engines to blow. 5W-20's are dam good oil.
 

pmt

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Many years ago I did not trust multi weight oils and so would use SAE 10 in the winter, SAE 20 in spring and fall, and SAE 30 in the summer. I remember in particular one time in April that I got caught with SAE 20 in my small block 350 c.i. 1970 Chev Impala on a 400 mi trip coming back home with ambients over 90 F. It worried me some, but must not have done much damage since the engine was still going strong at 263,000 mi when I had to junk the car due to a rusted out frame. The oil I used back in those days was Conoco, same company that make Motorcraft 5W-20 I guess. I know that a few hours on the freeway with a SAE 20 oil at high temperatures doesn't prove a lot, but that wasn't the only time it happened to me and all my vehicles back then always went many miles with no major engine work ever required. Once in awhile I still had SAE 10 in during some pretty warm weather. And I would think today's 20 weight oils are much better than back in the 70's and 80's. I guess I tend to believe the old saying that more engines are worn out with too heavy oil than too thin. Anyone agree or disagree? [Smile]
 
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With M1 5W-30 so close to a 20 weight. I find it hard to believe the 5W-20 "blew" an engine.The engine had to have other issues. Ford would not spec an oil that would come back and bite them in the butt!!
 
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Pmt - I guess I tend to believe the old saying that more engines are worn out with too heavy oil than too thin. Anyone agree or disagree? My Grandfather had a 1940 Chevrolet and used 10W DX Brand motor oil the year around in Indiana. He ran it for 75,000 miles with no major engine work required. Grandma finally crashed it into a pole to end it's life.
 
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quote:
Originally posted by JustinH: forged engine means a shortblock is built up using stronger parts that are made through a forging process, and not a cast process. Technically the 4.6 has forged rods from the factory, they are toothpicks though, the manley forged rods are much thicker.
The rods from the factory are not forged. they are melted and pressed powder, so, too are the pistons. These factory internals are good to the 400 HP mark.
 
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quote:
Originally posted by pmt:
quote:
Originally posted by mf150: several 4.6L Mustangs (GTs) have blown engines on the 5W-20 weight viscocity. My pal was rhomping on the gas when all of a sudden, bang bang bang bang...rod knock, and now he's buying a forged engine.
To mf150: Any idea what brand(s) 5W-20 was used in these engines that are are failing? One would think that Motorcraft 5W-20, which is partially synthetic and not that much thinner @ 100 C than M1 5W-30, would be able to handle pretty heavy loads. Thanks.

Motorcraft 5W-20 was in my pals engine that blew a rod. His 2002 Gt was serviced at the local Ford dealer. The other couple engines were also run on 5W-20 viscocity...not sure what brand. Before the switch to Motorcraft 5W-20 viscocity, I have never heard of a 4.6L blowing rods. The facts are the facts, and Mobil 1 5W-30 is a 30 weight.
 
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quote:
Originally posted by Fred Bear: With M1 5W-30 so close to a 20 weight. I find it hard to believe the 5W-20 "blew" an engine.The engine had to have other issues. Ford would not spec an oil that would come back and bite them in the butt!!
No-one is saying that 5W-20 blew the engine, but it is coincidental that 5W20 has been in a few engines (Ford 4.6L SOHC)when the con. rods. failed. The 4.6L triton/SN-95 GT engines are known to be bulletproof performers. These are the first 1999+ 4.6Ls that I have heard any problems about. A 4.6L Mustang engine can run safely up to 400HP, after which point you would need to upgrade to forged internals. If the GTs, naturally asperated, aren't hitting the 400HP mark, then why are the rods failing and the engines blowing? could it have to do with lubrication??? What do these engines have in common? 5W-20 anyone? Especially since I haven't heard of many engines before the switch to 5W-20 blowing.
 
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quote:
Originally posted by bottgers:
quote:
Originally posted by mf150: several 4.6L Mustangs (GTs) have blown engines on the 5W-20 weight viscocity. My pal was rhomping on the gas when all of a sudden, bang bang bang bang...rod knock, and now he's buying a forged engine. I'd stick with a Xw-30 weight in the newer Ford modulars.
My guess is it isn't the oil that's causing these engines to blow. 5W-20's are dam good oil.

10W-30 is a **** good oil, so is 5W-30, so is 10W-40, so is 15W-50, so is 20W-50, so is 15W-40, so is... catch my drift?
 
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Your conclusion that these engines gave it up while using 5W-20 and then blaming the 5W-20 is flawed. (Therefore, it is) like saying, “2 different people were driving to work today and the moon was full. They were killed, so the full moon caused them to be killed.” 5W-20 has been proved. Safe in engines designed for it. This includes the motors that Ford “retro-speced” for the 5W-20. 400hp or not. And we know M1 5W-30 is a 30 weight. But it is on the thin side of the spec.
 
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