I have a 1995 f150 with a 5.0.

I used to run castrol gtx part synthetic 10w-30 and had no problems ever. I recently installed a mech. Oil pressure gauge and was wondering one day (when it was cold outside) how quicker is a full synthetic to reach the full PSI pressure that my truck gets to. I do not know what is acceptable but it seemed like the oil was taking a little while to build to 50psi.

So I went to a castol edge full synthetic and it made a huge difference in the time it takes for the oil to become pressurized to 50psi. It probably decreased by 70%

 

Faster couldn't hurt but I always used Motorcraft oil and filter in my '87 U150 302 and got 295K miles on the engine before it spun a bearing. My Taurus has 335K on the original engine and is spotless inside- no sludge buildup at all. They extra cost of full synthetic isn't worth it for me.

 

Do you have to add a quart between oil changes ?

 

I do on the car. Oil pan leaks a bit.

 

I use the cheapest oil, Motorcraft filters and try not to drive too aggressively until it's warmed up.


As long as you have oil in it and change it on time it shouldn't really matter. Going synthetic or not isn't going to undo the last 20yr of wear and tear.

Mechanical gauges will always lag behind the engine because they're at the end of a long skinny tube that's almost certainly got a fitting that restricts it where it plugs into the block. Thinner oil = less lag.

 

I try to stick with an oil that has a higher ZDDP level (Valvoline vr1 or lately I've been using Quaker State defy high mileage.)

Amsoil Z-rod is supposed to be good as well but I have never seen it for sale.

 

Why do you want zinc in your oil so much? Do you have a flat tappet cam

 

10w30 Royal Purple here with a mobil 1 filter.

1996 f150 with a 5.0 2wd 196xxx miles just for compare