Oil Change

[DBADA004]

Hi, I want to make an oil change for my Ford Explorer 1999 5.0L Limited Edition, but last time my mechanic put a 15w40 synthetic oil. He said it was because it was an old car.
My truck has 150K miles.

 

[Pete Deering]

Hi, I want to make an oil change for my Ford Explorer 1999 5.0L Limited Edition, but last time my mechanic put a 15w40 synthetic oil. He said it was because it was an old car.
My truck has 150K miles.

That nonsense. He uses that oil weight because that what Had.
I Notice years ago they used heavy weight oil in the south, because of the heat. 5w30 is harder to get in your area. But I move over too synthetic high mileage oil. You should use, what the owners manual states. Now when the temperature are colder in the winter time, it will be harder to start.

 

[410Fortune]

You are in Miami I would just run 10-30
Or 10-40

15-40 will also work

Oil Viscosity is chosen based on your
Climate for these pushrod engines. Full synthetic is a good idea.
I run valvoline or
Mobil full synthetic 10-30
With a motorcraft filter

Your
Mechanic choice will also work nothing wrong with 15-40 in Florida

 

[J_C]

^ I second that. If I were changing the oil twice a year, then I'd be fine with 15W40 in summer and run 10W30 in winter.

 

[sehaare]

For some other makes, the low oil pressure switch setpoint is so high that on high mileage engines, the increased clearance between parts, due to engine wear, results in lowering the oil pressure enough to get a warning at idle. This might be were the mechanic is getting his recommendation for a heavier weight oil.

My other addition is old water-cooled VWs and at a some point the owners all have to change to 20W-50 (which didn't exist when the cars were built) to clear the warning . In my case I use it in the summer for my 1981 and 1992.

 

[C420sailor]

Air cooled engines are a whole other beast. My airplane is air cooled and when it lived in Florida, it used SAE50 in the summer. That oil was literally thicker than molasses in the winter. Wild.

 

[Fix4Dirt]

The Herbie gets 15-40 or 15-50 in summer.

That said the Explorer everything gets 5-30 in witner 10-30 in summer.

The 4.3 gets 15-50 since it sees high rpm use.

I see nothinng wrong with 15-40 in the other sunshine state.

 

[V8]

I'd be careful, 15W40 is primarily spec'd for the heavy diesel truck market. Some people use it in older engines because truck oil contains more zinc for the bearings. The current truck oil spec is CK4, which is a low zinc synthetic but there are plenty of oils out there that still contain zinc for older engines as mentioned above. However, zinc and catalytic converters are pretty much incompatible. The oil weight itself isn't a problem, especially in the tropics, but the additive packages always need to be known. I use 10W30 high-mileage in my '01 5.0 at 240,000 miles. Along with a Motorcraft filter of course. Motorcraft filters are so inexpensive that it doesn't make sense to me to use anything else. Besides, my '95 Bronco uses the exact same filter, so I buy 'em by the case.