Should I use a high mileage oil?
 

And which one?

We put way under 6000 miles a year on the Sable. So I have just been changing the oil once a year with whatever is on sale. While under 65k, it is a 2001. I know that the high mileage oil formulas tend to have higher measured viscosity than the regular oil counter part. With the low miles on this car, that likely won't have much benefit.

It has been mentioned in some threads that they may have seal conditioners. Which would seem to be a good idea to have considering the car's age.

A little background: the car had a transmission fluid leak from the pressure vent. The back of the engine is all gunked up, and still get a burnt oil smell at times. Need to clean it up in the spring, but there is a concern it might be the valve cover

If the high mileage oil has these conditioners, aren't they the same as in the stop leak additives? Just curious. The carrier oil is likely higher viscosity than the 5w20 recommended.

Should I stay with the cheap stuff(usually SuperTech), Motorcraft synblend, or a high mileage oil with seal conditions? With the low annual miles, a synthetic would be a waste of resources.

My understanding is that high mileage oils have mild seal conditioners and higher amounts of normal additives. I don't think the viscosity would be different from what is marked on the package, but there is a small amount of wiggle room within a viscosity rating and perhaps they run on the thicker side of that wiggle room.

I use SuperTech high mileage in all my vehicles.

My 2002 GMC with 212,000 miles does sound slightly better on it. I tried Valvoline MaxLife high mileage in it once and my cold start piston slap seemed to get louder. That's not conclusive evidence or even good evidence, just total subjective observation, but I switched back.

I was running regular SuperTech in my 1980 Buick (currently at 75,000 miles) but a used oil analysis with TBN indicated that it wasn't quite doing the job for my preferred 5,000 mile OCI. I also was hoping to reduce oil consumption. I switched to ST HM a couple oil changes ago but haven't sent a sample yet.

I've never run high milage in my cars my last Volvo had 300,000 and didn't leak or burn any oil. Just whatever was on sale name brand. Not even synthetic. It had 200k when I got it. Like you learned make sure the breather systems are not plugged extra pressure has to go somewhere and a seal is the easiest place to escape.

I say as long as you don't leak or burn oil, use regular oil. I use standard off the shelf 0W30 in my 98 GMC K1500 with about 183,000 miles on it. As long as it continues to not leak, and it runs well, I'll keep using it.

Thanks.

The vent issue was more that the required fluid level was high enough that fluid came out of it, collected on top , and then dripped onto the exhaust. The fix was a new vent and a piece of hose. An under carriage wash got rid of the burning for a bit, but it came back. More intermintent and fainter. Need to clean off the remaining tranny fluid.

Have noticed some seepage marks around the rear valve cover. So I'll give the high mileage oil a try if it is a minor issue. The car needs a PCV catch can. Oil was noticable in the manifold.

But winter finally arrived, so this all has to wait for spring.

Have you tired double checking the torque on the valve cover bolts?

That was a recommendation on a Taurus forum. Didn't have the proper torque wrench at the time, but I tried giving the bolts a quarter turn. It's how I found out about the oil in the manifold. Had to remove it to reach the valve cover. One of its self-contained bolts sheared off after it took a stately bow. Must of gotten over torqued at some point.

The seepage stains don't look fresh, and I got a couple cans of engine degreaser lying around. Cleaning the back of the engine of the transmission fluid is the first step.

I use Valvoline High mileage oil. Supposedly it has conditioners in it to minimize oil leaks around seals. Since I only change the oil once a year also I don't mind spending a few more dollars.