Boy, is there a bunch of bad information coming out in this thread.

1. Running 10w30 over 85,000? Not necessary. 5w20 is good for the life of the engine provided it's been properly maintained. You don't have to stick to Motorcraft oil and filters.

2. Synthetic causing oil leaks and lack of lubrication? Bunk. If an engine develops a leak after switching to synthetic then it was going to leak anyway, regardless of what oil is in it. Sludge only develops when the oil isn't changed at the proper mileage intervals. Whatever sludge is in there isn't likely to move, unless a heavy duty cleaner is run through that's designed to break it down and move it. Switching to synthetic isn't going to do that.

3. This one's my personal favorite: extended change intervals with synthetic. Synthetic oil needs to be changed at the same mileage as conventional oil because it picks up the same amount of dirt over that 3-5000 miles. Oil filters are only designed to work for about 5000 miles, after that they clog up and the oil starts going through the bypass valve and back into the engine unfiltered. You can run a synthetic for 10,000 miles but the filter stopped working 5000 miles back. Yes, you could just change the filter and keep running the oil but why? Just so you can feel like your getting your money's worth? If you've already pulled the filter it's only a couple more steps to drain the oil. Oil is cheap when you compare it to the cost of a new engine.

I've already said this but it's worth repeating. People think too much about oil. Use any brand you prefer, use a good filter and change it at the proper intervals and that engine will go 200,000+.

 

So you're saying a synthetic with added detergent can't possibly expose a weakness in a bad gasket that was otherwise clogged with build-up by eating away at the build-up thus causing gasket bleeding?

Or that oil passages and oil screens can't get blocked? I just want to make sure I understand what you're trying to say.

 

What I'm saying is syn oil isn't going to move that sludge around to clog things in the first place. If an engine has that much buildup inside then it's already been neglected and the syn isn't going to do any more damage then has already been done. If a gasket has a leak blocked by buildup then it's only a matter of time before it develops more leaks, regardless of what oil is used.

 

So you refute the action of detergent additives that almost all synthetic manufactures use in their oils?

Actually, we don't know how much build-up this guys rig has in it. He wanted to know about potential concerns for switching to a synthetic oil in a car with high milage and everyone responded with known valid advice. I'm sorry you think it's "bunk". However, the concern is valid and a potential complication of switching over a vehicle at high mileage.

 

I've been using Pennzoil Platinum full synthetic and a Motorcraft filter since the first change (first change I did I didn't get a Motorcraft filter, though). I change the oil every 3k and it seems to be doing it's job so I'll be sticking with it.

 

Yup changing any oil at 3-4K intervals will give the most mileage from any mill!....It's simple ,cheap, & worth it!

 

I have not changed the oil yet. But I do as you said(stay with 5w 20). My truck is a v6, 4.2; cant recall if its DOHC or single.

Besides taking it off, how can it be determined if there is "clog in the oil filter or oil pickup screen"?

Also in warmer or colder tempertures doesnt the weight of the oil need to be adjusted?

 

The 4.2 is not a DOHC, if your pickup screen clogs you will lose oil pressure and seize your engine. You can change weights depending on how hot or cold it is, but if you stick with the manufactured recommendation you won't have any issues.

 

On my '99 the truck exhibited the dreaded 'metal shavings between head & block' oil leak symptom after I switched from dino to synthetic. My father-in-law was the original owner and the engine had never been worked on/out of the truck before he sold the truck to me.

The truck MAY have had a VERY slight leak there before the switch, but after the switch every time I parked the truck I could smell burned oil and I had to put carpet under my spot in the garage the drip spots got so bad. My spot at the firehouse looks pretty bad too...


ETA: father-in-law was/is a dedicated 3500 - 5000 mile oil changer. If the Owner's Guide said a service was due at xxxxxx miles he did it.

 

The oil light gauge is not low nor is it at the engine. I just thought that the oil should be changed every 3k miles. How can I tell if my "pickup screen is clogged"?

 

I would stay away from Mobil 1, I used it in my 2006 mustang GT and soon after I had a loud knock, sounded like it was from the cam phasers. Changed oil and it went away.

 

http://www.aircooled.net/gnrlsite/re...s/synthoil.htm

 

Anybody running Castrol Edge synthetic?

 

I think its a crock to blame oil for such problems, if the engine has build up to begin with to "stop leaks", then the engine is not well maintained to begin with, which is why things like leaks start in the first place.

I changed oil at a shop full time during my college days and never had synthetic cause problems, ever. I switched more vehicles from conventional to synthetic then I can count and never heard of engines magically leaking or clogging the oil pickup. Its perfectly safe to switch back and forth with any oil/weights. As long as you change the oil on a regular basis, you should get long engine life. But the newer engines are a little "tighter" so they do recomend a lighter oil, like 5w20. I wouldnt run anything too thick in it even at 100k. Thats just me. Maybe 5w30.

The only thing that Royal Purple recomended was to wait something like 12k miles before making the switch. I think it was basically an average year before using their full synthetic in a brand new engine.

 

This is what I've been saying but there are alot of "experts" here that swear it's not the case.