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Discussion Starter · #1 ·
Under what circumstances would it be acceptable to run 20W-50 oil in a 4.7L?

Reason: I just bought 24 qts of Lucas Synthetic 20W-50 for $1/qt. It was on a clearance "sidewalk sale" table at Pep Boys (along with a bunch of other odds and ends.)

I drive in hot climates. Engine has 250k miles on it.

If I can't use it for the Tundra, I have other uses for it.
 

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I know this isn't the same engine, but I ran GTX 20W-50 for years in both my '90 & '91 2.4L Toyota trucks. Never had an issue except a little noisier during the winter months.

If used just during the summer months I'd think the only harm would be decreased mpg and higher oil pressure. So, if your truck already has weak oil seals @ 250K, the higher oil pressure could just do them in and cause a leak. JMHO:tu:
 

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Folks, there's a reason why the manufacturer calls for a specific viscosity rating on their engines. Just because the OP purchased 24 bottles of oil at a great price, doesn't mean it makes long-term financial sense to use it in an engine just because he has it handy.

I think using a 20W cold/startup viscosity rating in the 4.7L is asking for trouble, even in a "hot" climate.

Your call. Just do us all a favor, if you take any of the previous posters' suggestions and use the oil, please report back on the outcome of your little experiment.
 

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man you sure got a deal on that. try to sell it on ebay or something. 24 dollars for 6 gallons of oil isnt bad
 

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Discussion Starter · #7 ·
Thanks. My daughter's Hyundai can use 20W-50, so I can always use it during the summer.

I think I will not use it in the 4.7L because it is so far out of spec. Maybe I will use it for some engine flushing since there is evidence of sludge in it.

Or I might add a quart or two of it for future oil changes and use 5W-30 for the 4-5 remaining quarts. I wouldn't think that would be a risky combination.

Or maybe I'll just use it as chain lube for my chainsaw. :happy:
 

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I think that is the best thing i heard yet. Use it in chainsaw for bar oil. I would not use that thick of oil in the truck. The only pros I see is you getting the oil cheap but then again what use is it. Sell it to someone that has a beater that burns oil and has to add oil to every 100 miles. The clearances that are set up in the motor are not made to carry that thick of oil through it not to mention trying to get it to bearings on cold start up. It is your truck though. A motor, you may not get that good of a deal on!
 

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Folks, there's a reason why the manufacturer calls for a specific viscosity rating on their engines. Just because the OP purchased 24 bottles of oil at a great price, doesn't mean it makes long-term financial sense to use it in an engine just because he has it handy.
Long term financial sense???... Where not talking about a cream puff here... The OP's truck already has 250K on the clock, he's already reached his long term financial paybacks on this truck by keeping it and driving it this long. At this mileage it should be a bigger concern that the increased oil pressure might cause an oil seal to start leaking (if he doesn't have leaks already), than if he's going to reduce the engines life span by "X" miles.

If it was anyone else on this board with a new engine at the begaining of it's lifetime... then yes... Use what is spec'ed as it's a no brainer.;)
 

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...Maybe I will use it for some engine flushing since there is evidence of sludge in it.
That's a great use for it on your next oil change. Drain out old oil, add this bargain oil in and some SeaFoam, then take a short drive to the store, then drain and refill with bargain oil again, drive a day or so, then drain and fill with regular 5W-30 oil. :tu:
 

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That's a great use for it on your next oil change. Drain out old oil, add this bargain oil in and some SeaFoam, then take a short drive to the store, then drain and refill with bargain oil again, drive a day or so, then drain and fill with regular 5W-30 oil. :tu:
That's the most idiotic and dangerous advice I've ever heard on this forum regarding oil.

A previous poster laid out the main point: the simple fact is this viscosity oil is NOT made for the channels designed into the 4.7L. Sure, he has 250,000 miles on it, but are you saying he doesn't really care whether he gets 50,000 miles more? 100,000 miles more? a few 100,000 miles more? And you want him to dump in that thick oil AND ask it to suspend the sludge that will assumedly get dissolved by the SeaFoam?

Long-term financial sense is the difference between dumping the wrong oil in because it's cheap and the cost of a new engine when the seals, pump, bearings, etc etc go because you wanted to experiment.

OTOT, Your chainsaw will love it.
 

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Discussion Starter · #12 ·
That's a great use for it on your next oil change. Drain out old oil, add this bargain oil in and some SeaFoam, then take a short drive to the store, then drain and refill with bargain oil again, drive a day or so, then drain and fill with regular 5W-30 oil. :tu:
That's exactly what I was thinking. I have a couple bottles of SeaFoam laying around, but this time I was thinking about mixing kerosene and oil (exact ratio TBD.) But that issue might best be dealt with in a separate thread.
 

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I'll echo what others have said here. I would not recommend using 50wt oil in our trucks. You would be fine using most 40wt, but with 20W50 your going to have horrible cold start protection plus way to thick of an oil up top that will destroy your mileage and power and could possibly prevent adequate lubrication due to flow and cause engine damage.
 

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That's exactly what I was thinking. I have a couple bottles of SeaFoam laying around, but this time I was thinking about mixing kerosene and oil (exact ratio TBD.) But that issue might best be dealt with in a separate thread.
Obviously, the OP is willing to dump just about anything in his engine, so...

GO FOR IT WILLEM!!!

Just do us a favor. Post up:

1. pics of your engine with the valve covers off after a couple thousand miles on the 20W-50, and
2. a copy of the repair bill!

I'm done with this thread...
 

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Discussion Starter · #15 ·
Obviously, the OP is willing to dump just about anything in his engine, so...

GO FOR IT WILLEM!!!
Yes, I am getting a little O.C.D. today. I'm vacationing at the beach and it is raining, windy and -- horror of all horrors -- the cable TV ain't working.

So I'm spending the day "researching" stuff I can do to mess with the truck. Maybe I should just wash and vacuum it.

:ts: THANKS FOR THE REALITY CHECK :ts:
 
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