I have a 1994 Ford Thunderbird with the 4.6 liter V8. The owner's manual only recommends 5w30, but now that I have over 100,000 miles, I have been considering other weights. All right, I'll be honest. I've been reading so much here on BITOG, I'm starting to get the "itch" to try something different! I've used only 5w30 throughout the car's life, and have switched between dino, synthetic blends, and most recently, high mileage oils and even full synthetic. I'm currently running an Auto-RX treatment with plain old Castrol GTX. Once I'm done with the cleaning and rinsing phases, I've been thinking of something more robust like Shell Rotella T 5W-40 synthetic. Would this be too thick? Could it harm the engine? I live in Illinois where it is very hot and humid in the summer, but very cold in the winter.
40 weights in Ford 4.6
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No reason to sway from the MFG's specs no matter what the 'experts' on BITOG say.
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That is probably sound advice, buy my questions still stand...is 5W-40 too thick for this engine and could it harm it?
5W-40 won't harm your engine at all. The manufacturers usually specify a 5W-20 or 5w30 to meet CAFE fuel mileage requirements, but sometimes at the expense of upper engine noise. The only thing you may notice with the Rotella is a slightly quieter running engine.
First, no, it most probably won't harm it, but, it isn't somehow "BETTER", either. However, IF your oilways are not as pristine as new, and a slightly thicker oil is pushed by a slightly tired pump, there might be a slightly decreased flow rate at the end of the oilway. That's not what I'd want. If 5-30 is recommended, and been performing well...continue to use it. Experiment instead with trying to find Pennzoil Platinum at 1.99 a quart, or some of the other great deals on 5-30. Just a suggestion....!
Okay if you're worried about flow, I've watched Valvoline Synpower 5W-40 go down a funnel and let me tell you - it flows!
my vic and other fords require 5w30 i been using a high 10w30 mix for years redline 10w30/motul 10w40
If it is not burning oil or running bad, why change?
Weren't the specs for the 4.6L changed to allow the use of 5W-20 in addition to 5w30? If so, why change to a 5-40?
He wants to try something more robust. For some strange reason, I always equate the more popular porn stars with that word.
40 weight oils are all wrong for the Modular Motors. In fact I tried Syntec 0W-30 (a very thick 30 weight) in my '96 4.6L and had to drain it out on the same day. The power loss to the oil system was stunning, and the top end made noise.
Try one of the thicker 5W-20 synthetics or blends like the Syntec Blend. You will like it.
Try one of the thicker 5W-20 synthetics or blends like the Syntec Blend. You will like it.
At my shop we put 15w40 delvac in everything. Its a local gov shop so we service everything from buses to police cars.
All get 15w40 even the 4.6 crown vics. Delvac is in my F250 7.3, Ford explorer 4.0 and my escort 2.0. Next change I'm going to try the new rotella CJ rated oil. My explorer is quieter and still gets the same highway milage as with 5w30.
All get 15w40 even the 4.6 crown vics. Delvac is in my F250 7.3, Ford explorer 4.0 and my escort 2.0. Next change I'm going to try the new rotella CJ rated oil. My explorer is quieter and still gets the same highway milage as with 5w30.
What brand oil did you use mostly in your engine? How much oil does it use between changes? Iam just curious. I would suggest a 10w30 its a lttle thicker and would give you good results. Iam Mr. Pro thick oil and will argue all day about 5w20, but I think the 4.6 is one engine that does like a thinner oil. I dont think the 4.6 would benefit from a 40 wt like the 5.4 would.
Now we're talking! This is the kind of conversations I was hoping to get from my original question. First off, my car does not use much oil to speak of. I haven't had to add oil during most 3-6 month OCIs. I've never used anything but 5w30, but I do have some GC 0W-30 on hand I was planning to use before the 40 bug hit me. I certainly don't want to bog my engine down. The add packs I've heard are in Rotella have me wishing they would work in my car, that's all.
By the way Merkava, your "robust" comment had me rolling!
By the way Merkava, your "robust" comment had me rolling!
Why not then just install your GC 0w30 erogers? It is a thick 30 weight, so your "robust" is there, and is highly praised for it's composition, protection, and lasting power. Or did you have another vehicle in mind for it?
Well, I've got an '89 Jaguar XJ6 I've been working on, and I was planning on using the GC for that, but that project is coming along very slowly, so I was thinking of trying in in the T-Bird for one OCI, to see how it works. That sounds like a plan, Dad2leia. If my 4.6 likes the GC, that may indicate a move to 5W-40 would work also. Good idea.
Oh, for the Jag...
The Ford will be OK with it too.
Let us know how that engine likes it.
The Ford will be OK with it too.
Let us know how that engine likes it.
Do any of the 4.6L's still blow the filter case into the weeds on cold start like they used to? You should put 5W-20 into a couple of the patrol cars, and ask the officers what they think after driving them. I find that even straight 5w30 gives a noticeable power loss in my Mustang engine over 5W-20 or a 5W-20 blended with a thicker oil. A 15w40 is unthinkable.
5W-40 would be fine. But I see no reason to use it in fall or winter...
They do if dummy police mechanics use SAE 50!
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