Truck Oil Question

[mtreno]

ok i have a 2000 Ford f-250 with the 6.8 liter motor. somewhere around 70k miles the

Jiffy Lube boy talked me into using a synthetic motor oil. around 100k i noticed that the

oil level was always low when i checked so i started adding about 1 qt every third tank.

when back at Jiffy Lube a ask the new boy what the deal was and he went on to explain to

me that you cannot move to a synthetic after so many miles and who told me to do that in

the first place...... After we chatted about that for awhile we went on to explain that my

seals have gone bad due to the oil and the engine is burning it. he also said that i cannot

move back to normal oil because it will cause more issues. the dealer quote for a seal job

was off the charts because they have to remove the motor from the truck to get the job

done. anyway so now it seems to be burning more and more oil. we are up to one qt

every tank. i would really like to go back to normal oil and start burning like Napa oil

at$1 then this synthetic at $5 a qt.

any thoughts on why i could not just make the change back?

what would you do if your truck was going thru this much oil?

[Whoaru99]

It's entirely possible that none of what's happening is related to the synthetic oil.

If you have a bad seal, going back to conventional oil will not fix the seal, but it will ease the burden on your pocketbook.

If it were me, I'd just go back to conventional oil if that's what you want to do.

Mostly the recommendation to not start using synthetic on high mileage engines (and I'm not sure that 70k counts as high mileage these days) is because synthetics tend to have higher detergency than non-synthetic oils. Thus, a possibility to loosen up crud that already exists in the engine.

As far as the ruining the seals, I doubt it. Seals on vehicles that new should have good compatibility with synthetics. The '58 Packard (or whatever), maybe not....

[caseymcq]

Bad valve seals would lead to burning more engine oil. I wouldn't think a dealer would have to pull the entire motor from the truck, probably just the valve covers.

If a main seal was bad you would notice engine oil on the bell housing of your transmittion. A bad main seal wouldn't lead to the motor burning more oil. To replace a bad main seal the motor would however have to be pulled.

There are some engine oil treatment products that may be a temporary/quick fix. Justice Brothers (a.k.a. JB) has a product called Engine Stop Leak. It is supposed to do just what the name suggests. You may want to give that a try before you dump a ton of money into repairs. Justice Brothers has a HSOforum that you can get product information off of.

[Whoaru99]

Those oil stop leak products actually do work in many cases.

Just be aware that their typical method of stopping/slowing the leak is by using chemicals that cause the seals to swell up.

Probably will buy you more time, but how much more is another question difficult to answer.

[bucketmouth64]

You could try going onto ford truck world HSOforum that is similar to this forum and pose the same question. Some responders are ford mechanics.

[Jeremy airjer W]

Those quick lube employee. I have seen numerous siezed engines from lack of lubrication, plenty of engines that they didn't drain and filled up with four additional quarts of oil (coincidently if this happens on a older toyota they blow an extreme amout of smoke out the tailpipe, its amazing what happens with 8 quarts of oil in your crankcase!), lots of incorect filters that blew off the cars, and many, many, striped drain plugs and/or oil pans.

After seeing what they charge to do all this damage I wonder how they stay in business.

Most of these places employ young adults that don't know anything about correct vehicle maintenance and are only as smart as the B.S. they have been fed by there managers and training seminars. The majority of these people are not automotive professionals and do not care about your service needs but rather how many "additional" services they can nail you for. PCV valves making a rattling noise, must be broke. You vehicle needs "higher mileage oil" for an additional $$$$.

Yeah they can change your oil, check the air in your tires, top of or exchange your fluids but when was the last time you saw one of these "quick lubes" put a car on the hoist and check the front end? How about peaking through the wheels (if possible) to get an idea of the condition of your brakes? How about checking the condition of your tires? how about shocks and struts? exhaust? fluid leaks? belts? hoses? These people see a drop of anything on the underside of your car and they won't touch it.

Back to the question. They don't recommend switching back and forth. for example one oil change regular, the next sythetic, the next regular, the next synthetic and so on. Switching back to regular and staying with it will not be a problem. In fact it may fix your problem. Here is the theory. Synthetic motor oil has a more consitent uniform sized "lubricating molecule". That is they are all very close to the same size. Regular motor oil is has a variety of sizes that are close enough, some big, some right on, some small. Because synthetic is so uniform it can leak more through the some size hole, where as regular motor oil only has maybe of third of its molecules that can fit through the same hole.

If this is true than switching back may improve your sitution. I would try this before trying a stop leak product.