I currently own a 1994 Ranger with a 4.0 v-6 with 197000 miles.(bought new) It has been maintained with Mobil 1 since new with the exception of 1 foolish oil change with Castrol
5w30 conventional. Since that change I have developed a, what seems to be a lower end knock till the engine warms up. After about 100 miles I dumped the oil and used Penzoil Plat. 5w30, the noise seems to last about 5 minutes then goes away... Any ideas ? Nothing has been done to the motor since new, I think this shows what a quality oil Mobil 1 is...
Any ideas or sugestions will be greatly appreciated.

 

[sm=welcomesign.gif][hr]I would go back to Mobil one and mabey the start up knock will go away completly.

 

very odd , Ive ran Castrol in all my Fords over the years , as well as all 3 of my Sons truck's use it an never had a problem with it.

I had a 1984 F250 , with 387000 miles on it, never had any major engine repair work done ,, body was looking a tad rough, till oldest Son flipped it doing about 80 MPH, finally landed on its pass. side an slid down the right away for a lil over 90 feet, an stopped with a telephone pole next to the cab that you could just put your hand between it an the roof of the truck,,,,,,, blew the right rear tire off the bead, we flipped it back over on all 4 tires with another p/u ,, swapped out the tire an He drove it home !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!