My 98 F-150 has alittle over 117k miles on it now and for the last couple yrs it's not been getting much use at all other than on weekends. I've always R&R'ed the oil & filter every 5k miles since new and the oil of choice was always Valvoline 10w30 dino. At the 115k service I got lazy and took it to one of those Quick Lube places and went with their house brand Castrol 10w30. Man was that a mistake. First change I noticed in my otherwise quiet running 4.6 Romeo was either the valves rattleing or piston slap when cold. Once it warmed up the rattleing would go away but I started to get concerned about this new occurance that just so happened to co-incide w/the oil change. The rattleing coupled with long none-use times got me concerned that the thin oil film that was supposed to be in the bearings and on the cylinder walls wasn't where it should be with this Castrol.
So this past weekend I decided to finally change over to a true synthetic in hopes that it's thin film would either stay longer or flow better when cold.
And much to my pleasent surprise, it seems to do just that!
I went with Mobile 1 10w30 and the difference was immediate and very obvious. The engine started much easier and there was NO rattleing, none, nata, zilch
It was back to running as smooth as a sewing machine.

I had originally thought about using 5w30 or even 5w20 but figured the 10w30 would be better for the mileage I had.
The jury is still out on whether I spring some new leaks or it starts burning the synthetic oil as it will take awhile to build up some miles on it but the improvement in cold starting and the lack of a loud internal noise whilst it warms up is worth the change away from Castrol dino to Mobile 1 syn.
I could have went back to Valvoline dino but since it's sitting all week now I wanted the reputed benefit of synthetics superior long lasting lubrication properties.

Thought I'd share this positive experience.

Volfandt

 

try motorcraft 5w30 next time.

 

5W30 will flow better when its cold outside and will have the same thickness when hot as 10W30. I would recommend 5W30 like the manual does. You will gett better mileage with the thinner oil, (less work for the pump to push it around).

Heres one for everybody, How long to you all go between engine oil changes? I run Quaker State Q advanced synthetic in my 4.6 and change oil and filter every 10,000 miles. What do you guys do?

 

I agree with mrsteveo on using 5w30. I have a 97 F150 4.6 with 194000 miles and just switched to MC 5w30. I have always run what is says to use in the manual and have had no problems with my truck. I bought it at 170000 and have used 5w30 the whole time.

 

I used Chevron 10W30 for a good 2-3 years then switched to the MC 5w20 for about a year when it was the big fad. After deciding I didn't like its water like properties (too thin for my taste) I went with MC 5W30. None of the oils helped with piston slap but I am at about 210K and use the same qt. between changes that I did at 60K and the egine still runs great.

Almost forgot I change every 3-4K and use MC filter as well.

 

I noticed a change when I changed to synthetic. I wont use anything but synthetic in my vehicles from now on.

 

Is MC 5w20, 5w30 a synthetic?

I could be wrong but it seems I remember reading somewhere that MC brand oil is rebadged Valvoline, anyone else seen this?

I've always used MC air, fuel & oil filters and have had great service from them.

I may try 5w30 on the next change but at this point I'm very happy with the performance of Mobile 1 10w30.

Volfandt

 

Quote:

Originally Posted by Volfandt

At the 115k service I got lazy and took it to one of those Quick Lube places and went with their house brand Castrol 10w30. Man was that a mistake. First change I noticed in my otherwise quiet running 4.6 Romeo was either the valves rattleing or piston slap when cold.

I would venture to say that the problem was not in the Castrol 10w30 that the Quick Lube place put in but more likely in the cheap oil filter that they installed. Some oil filters do not employ a check valve that prevents oil drain back like MC filters do. Motorcraft filters are the best to use.

MC 5w30 is a dino/syn blended oil. I don't know for sure, but I don't believe that MC oil has anything to do with Valvoline. Like preppy said.

 

Not trying to hijack the thread but,

I just changed from Pennzoil 5w30 to High Mileage Pennzoil 10w30. It had a couple of minor taps while cold, but switching to 10w30 lets the engine run smoother, it seems to have better get up and go (not a whole lot, but it's noticable). Heck, it even fires up quicker, it doesn't seem like I'm cranking forever like I was with 5w30. *shrugs* Opinions?

 

Excellent thread on such a basic vital engine maintenance subject so I will ask a question if I may. I have a 2000 with 75K miles, 5.4L and have had the dealer change the oil every 3K miles since new. Just started changing it myself last month and found Auto Zone carries the same Motorcraft 5W30 synthetic blend the dealer uses so I stuck with that. Sure makes it easier when you can buy the same oil at the corner auto parts store! The only difference is I put in a Fram filter and not the stock Mortorcraft. Is Fram OK as far as filters go and just wondering if the oil should be upped to 10W30 with the high mileage.

 

I agree with King Ranch, it was probably the cheap filter, instead of the Castrol......

 

Well, it was a Motorcraft filter and it even had the date scribbled on it when it was installed. Same part number and it was identical to the new MC filter I installed.
Looks like it's still pointing to the house brand Castrol

btw, I went out and started the F150 tonight just as soon as I got home and it started right up and didn't make any rattleing/piston slap. Man I likes i when it purrrrssss

re. Fram filters, I remember reading on a site somewhere a comparison of oil filters and the Fram oil filter was one of the lowest rated filters to use. It's filtering medium was more porous which allowed smaller debris to pass. I hate to post this without a link but it may be still out there via a search.
That said, if one is changeing oil & filter at 3k, the Fram is probably all right but the MC would be better

 

I vote wrong oil. When I was in school I worked at an auto service shop. One of the jobs I had once a year was to clean out the oil containers. It always surprised me the junk in the bottom of major brand oils. Ever since then I change my oil and only buy oil by the quart.

 

I have heard and seen about using synthetic once you go synthetic there is no going back, due too high risk of spinning bearings. I had some friends blow the motor soon after using synthetic, sticking with manufactures is best and I believe most owners manuals say not to use synthetic as well in transmissions

 

I was told by a Mobil rep that Motorcraft oil is made by Citgo. I don't know how true that statement is.

I don't recommend 10W anything in a modular motor. With all of the cams and wear items at the top of the engine, you need the 5W to get the oil up there as quick as possible. Most engine wear occurs on start up.