Probably been posted 100 times at least.

[Rkb53]

Hello there everyone.
My first post as a new member so please bear with me. I just bought a 2008 V8 limited with only 63 yes that's right 63,000 miles in beautiful shape. My first question of the day is, what oil to use. The book, and oil cap both say to use ONLY 5w-20 which I am sure the perfect oil for this engine. However, I want to use something a little heaver. The oil I prefer to use weight wise is 10w-30. Is there any reason I can't use this? OK fuel mileage may suffer a tiny bit but other than that ,is it going to cause any problems down the road? I don't want to end up with stuck rings or anything like that, I just like that 10w-30 oil is thicker and in Connecticut plus the little towing I do 10w- 30 has always worked best for me. I'm sorry this is such a long post for a question that has been asked a 1,000 times I'm sure but thank you for reading it. RKB

 

[Ed Fenwick]

Welcome Rkb, I am sure that there are many guys that know more than I and soon they will chime in. 5wt when you start up especially in the winter will flow faster than 10Wt. I live in Hawai'i and I crank my engine until the oil pressure is up before it fires.
That said, if you give it a warm up before driving off, I don't think that 10Wt is much thicker.
I just spent over $4k on my engine so I am overly careful. When I was in the car business, my boss said that oil is cheep insurance.

 

[Richard McAlister]

RKB, welcome.
I have a '10 ST 4.6L with 55k on the clock. I had it professionally supercharged (Roush) a couple of years ago and was concerned about the extra heat that would be inherent with the supercharger. The installer recommended that I keep 5W-20 in it because of the clearances of the engine, but if concerned, to go with a good full synthetic oil. I have followed that recommendation.

 

[Rkb53]

Thank you Richard. I plan on using a synthetic oil, but I was hoping to hear from more people about using the heaver weight oil. I agree with your installer that if the factory recommends a certain product, they have done more testing than I will ever do. Is it all about that extra mpg or is it that the engine needs it because of X reason? That is what I'm trying to find out.

 

[Ed Fenwick]

Rkb, I am sure that the engineers were more concerned about the clearances than mpg.

 

[Todd Z]

The motor clearances are not designed for the thicker oil especially on cold weather start up...…. Im well over 100K and most people with the 5w20 are staying with that... I also only use Amsoil or Valvoline synthetic.

 

[Rkb53]

Is there REALLY that much difference between 5 weight and 10 weight oil? That is what I really want to know. Does anyone out there have a write up report on the different rates of oil flow at a certain temp.? I have the same question for 20 verses 30 weight oil. We talk about tight clearances in an engine which is true. H however when you start a cold engine, the clearances are bigger and as the oil comes up to temp.and the engine too, the clearances get tighter not looser. I worked in the power equipment industry for 100 years and in snow blowers you always use 5 20 W oil. The W was for winter . Yes the clearances are not as tight as a modern engine but still they are not very different. Another thing, one year Ford says to use 10 30 oil. The next year it says to use 5 20. Nothing changed in engine design or clearances so why change oil? That is why I believe it is all for fuel economy and nothing else. How many people out there agree with what I just said? Do all of you only use 5 20 and no one uses anything else? I find that hard to believe.........

The motor clearances are not designed for the thicker oil especially on cold weather start up...…. Im well over 100K and most people with the 5w20 are staying with that... I also only use Amsoil or Valvoline synthetic.

 

[Todd Z]

https://www.undergraceovercoffee.com/oil-weight-vs-temperature-chart/

Google others....

Have fun reading and enjoy..... you asked and then argue the answers people gave you..... Do the research and use any weight you want to... Its your truck... Have at it !!!

 

[Rkb53]

Welcome Rkb, I am sure that there are many guys that know more than I and soon they will chime in. 5wt when you start up especially in the winter will flow faster than 10Wt. I live in Hawai'i and I crank my engine until the oil pressure is up before it fires.
That said, if you give it a warm up before driving off, I don't think that 10Wt is much thicker.
I just spent over $4k on my engine so I am overly careful. When I was in the car business, my boss said that oil is cheep insurance.

https://www.undergraceovercoffee.com/oil-weight-vs-temperature-chart/

Google others....

Have fun reading and enjoy..... you asked and then argue the answers people gave you..... Do the research and use any weight you want to... Its your truck... Have at it !!!

I guess Im just stubborn. After 65 years of using one oil, I just want to stick to what Im use to. Also my last Ford was a 69 Boss 429 which I wish I still had, but time moves on. So this 4.6 is very different from what I'm use to. Thanks for the article. Some interesting reading ahead.

 

[JC2008SportTrac]

RKB, welcome.
I have a '10 ST 4.6L with 55k on the clock. I had it professionally supercharged (Roush) a couple of years ago and was concerned about the extra heat that would be inherent with the supercharger. The installer recommended that I keep 5W-20 in it because of the clearances of the engine, but if concerned, to go with a good full synthetic oil. I have followed that recommendation.

Going with full-synthetic is a big NO DUH! I'd say, go with the recommended specs for the motor if 'stock' (whatever Ford suggests for that non-positive-displaced motor will be good. However, if you supercharge or turbo, go with only what that manufacturer suggests.

 

[JC2008SportTrac]

I've had this 3-valve V-8 in my 2005 Mustang GT that I put a Kenne Belle SC on, and it woke it up from 300 to 450-ish HP. I notice that the ST is stock 298, while the stock '05 3-valve Mustang is rated at 300 HP (I think they're both rated at 320 torque). Anyone know why the Mustang, with that I assume is the same motor, is show as 300HP, while the ST, with the same motor, is shown to be 292 (or 298)?

 

[JC2008SportTrac]

I've had this 3-valve V-8 in my 2005 Mustang GT that I put a Kenne Belle SC on, and it woke it up from 300 to 450-ish HP. I notice that the ST is stock 298, while the stock '05 3-valve Mustang is rated at 300 HP (I think they're both rated at 320 torque). Anyone know why the Mustang, with that I assume is the same motor, is show as 300HP, while the ST, with the same motor, is shown to be 292 (or 298)?

Did they have different heads in some way? In the past, truck heads were designed to have more torque. But it seems to me they have the same motors. Was it that, perhaps, Ford just listed the same motor differently between Sport-Trac and Mustang GT V-8?

 

[JC2008SportTrac]

Did they have different heads in some way? In the past, truck heads were designed to have more torque. But it seems to me they have the same motors. Was it that, perhaps, Ford just listed the same motor differently between Sport-Trac and Mustang GT V-8?

I'm having to take my truck into the shop for a P0300 (or something similar) code read-out. It's the generic "something's not 100% right" code, and could be anything of 90+ different things. Coil packs, spark plugs, etc. I'm having a tune-up done, meaning changing these bad-bad-bad spark-plugs. My shop will change out these piss-poor 2-piece plugs, and if one breaks off, they give me the first break-off for free. But if they have to fish out a spark plug of the old design, that will cost me $200 per spark plug!!!

 

[JC2008SportTrac]

I'm having to take my truck into the shop for a P0300 (or something similar) code read-out. It's the generic "something's not 100% right" code, and could be anything of 90+ different things. Coil packs, spark plugs, etc. I'm having a tune-up done, meaning changing these bad-bad-bad spark-plugs. My shop will change out these piss-poor 2-piece plugs, and if one breaks off, they give me the first break-off for free. But if they have to fish out a spark plug of the old design, that will cost me $200 per spark plug!!!

Anyone that's had one of these 3-valve motors for any length of time knows what I'm talking about; the spark plugs are like 2-foot long, and are prone to breaking off in the head of whatever vehicle you're working on...

 

[JC2008SportTrac]

Anyone that's had one of these 3-valve motors for any length of time knows what I'm talking about; the spark plugs are like 2-foot long, and are prone to breaking off in the head of whatever vehicle you're working on...

Anyway, I have a good mechanic, and he went 23 visits of 3-valve motors without breaking off a plug. I'd change the packs and plugs mysel, but F the idea of breaking off a plug.

 

[PRA4SNW]

Did they have different heads in some way? In the past, truck heads were designed to have more torque. But it seems to me they have the same motors. Was it that, perhaps, Ford just listed the same motor differently between Sport-Trac and Mustang GT V-8?

With that small amount of increase in HP, my guess is one or several of the following:
- Free-er flowing exhaust
- Free-er flowing air intake
- Slight difference in tuning
- Ford wanted to make sure that the Mustang sounded more powerful than an 'ol pickemup.

My '13 Charger V6 with sport package had the same exact rating: 300HP over the stock V6's 292HP. It has a straighter exhaust path and bigger air intake from the factory. Everything else is the same.

 

[Len Jorgenson]

Since the warranty ended on my 2009 Adrenalin 4.6L 3V engine, I’ve used Mobil 1 synthetic 0W-20. 330,000 km on the truck now and no issues. My industrial lubricant advisor made this recommendation.