Which oil is better?

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May 9, 2003
Fayetteville, NC
If my main concern is keeping oil consumption to a minimum on my Ford 4.6L v8 modular engine with 85,000 miles, which of the following is better? -Castrol syntec 10w-40, or -Mobil 1 0w-40 -Pennzoil High Mileage 10w-30 and 40 -Which one is the thickest and thinnest oil? -Which one is safest for old seals? I'd appreciate it greatly for opinions asap. Have to change oil in 24 hrs.... Thank you all so much!!!
Originally posted by 97tbird: If my main concern is keeping oil consumption to a minimum on my Ford 4.6L v8 modular engine with 85,000 miles, which of the following is better? -Castrol syntec 10w-40, or -Mobil 1 0w-40 -Pennzoil High Mileage 10w-30 and 40 -Which one is the thickest and thinnest oil? -Which one is safest for old seals?
Based on what you said is your "main concern," I'd go with the PZ High Mileage 10W40...it is thicker than M1 0W40; I think it would be better for your seals; it's much cheaper;left Castrol out of the equation because I could not find any info on it.
Going from memory, I recall that Pennzoil high mileage 10w40 is a very thick 40wt, while M1 0w40 is middle of the road (14.4 cst) and Castrol 10w40 is a low 40wt (13.5) 10w30 Pennzoil high mileage is a very thick 30wt of around 12cst.
Patman, You are right...PZ 10W30 is 12cSt and 10W40 is 15.5cSt...but he said he wanted to prevent consumption...that ought to do it. [Smile] [ August 08, 2003, 08:02 PM: Message edited by: pscholte ]
97, I know previously you said that you used 1/2 quart per 2,600 miles. Which in reality is darn good and really barely qualifies as "using" oil. And the previous owner used Penzoil 10W-40. But I still think that with 4.6L with the small oil usage you have you might be better off with the Penzoil 10W-30 high mileage oil. In fact the 40 weight oil could be causing extra wear and also more oil comsumption due to the larger spread in viscosities and more VI improvers needed. The 10W-30 Penzoil high mileage oil has the extra additives and will cause less strain than the 10W-40 on the motor while still giving you full protection. Just a thought. Whimsey
Then any brand of CI-4/SL 15W40 would be a better choice again if VI improvers are suddenly a problem and a 15.5 cSt @100C is the objective to minimize oil consumption.
Userfriendly, 15W-40 is just way too thick for that 4.6L SOHC engine! That's a quick way to kill it and really increase your oil consumption. Thicker is not always better for an engine, especially if it's not really using much oil to begin with. You might do more harm than good by going really thick. If you have an older and loose push rod engine then maybe you can get by with such an oil. Whimsey
user, These SOHC engines need to get oil to the top end faster than the old design pushrod motors to avoid wear on the cams. Hence 15W is definitely out. Also the 4.6L Ford engines are built with tighter specs to allow them to get a LEV certification, newer ones anyway. Less oil usuage and blowby = cleaner engines. With the tighter specs the use of 40 weight oil can starve your bearings and other wear items for oil, thus increasing wear. I think Bob has done tests that have shown thicker oil doesn't always protect better. Especially if an engine was designed for enegry savings and emissions. If you're not burning any real measureable amount of oil, as 97tbird, then the use of a thick oil is of no real benefit and could be detrimental. In all likelihood with a good synthetic 0/5W-30 oil he might even reduce his oil consumption after a change or two to allow the new oil to clean out the debris left by the 10W-40 dino. Or better yet go the autorx cleaning route. Lastly, I do have to put some credence in what the Ford engineers say, since they built the engine. Whimsey PS: Patman, no disparagement was meant to you GM pushrod guys! [Big Grin]
user, I should have added that I can't speak for European OHC engines since they seem to be all over the place as far as the oil viscosity recommendations go. At least with the slightly older engines. But remember, just because it's "good" for a European engine doesn't mean it's good for an American OHC engine. They most likely are built differently for different markets. Whimsey
Ford recommends synthetic for 4.6L engines with oil consumption problems. Sorry, I don't have the citation handy, but I was just researching this last week for my bro. It's Out There somewhere. [Smile] Cheers, 3MP
If it matters I have two 4.6l Mod cars; A 95 T-bird and a 95 Cougar. The bird I've had since 97, purchased with 40K miles on it ford brand dino since day1. I put Mobil 1 from purchase to 100K miles typically using .5 quart oil/3000 mi. I then switched to Motrlube 10-40 and my consumption is down to 0 at a 10k change . The Cougar I purchased last October with 87K miles. Previous owner used dino, what ever was avail, I guess. Engine used 1 quart/ 3000 miles. Switched to Motrlube 10-40. 97k on the odo, consumption down to less than .25 quart for 9k miles. My cousin(who works at ford in VA) said that 4.6 mods from 91-94 had an oil pump design that could have difficulty with thicker oils, (especially dinos and especially if you're down .5 quart or more) at startup. This was changed to a better design in 94-95, so this should not be an issue for a 95 and up properly maintained engine(but you still wouldn't use higher than 10-40). Unfortunately, on the cougar I think the previous owner was less than timely on changing the oil so there is a bit more usage. Hope this helps. Cheers, Dennis
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