View Full Version : How bad did I screw up?

04-29-2008, 08:53 PM
Just over 100 miles ago, I changed my oil. Of course this was before I got the Bentley manual. I put in 10w30. Should I go out and grab a new filter and throw in some 20w50?

04-29-2008, 09:53 PM
Either that, or move to the North or South pole.

04-29-2008, 10:00 PM
As long as you still had oil pressure, which I am positive you did, you are fine. Change it to the thicker grade and don't sweat it.

Don Elliott
04-29-2008, 10:06 PM
I ran the engine I had just re-built last spring for more than 3000 miles last summer using Castrol 10W30. It ran fine. I changed the oil last fall, before I put it away for the winter and it is ready for another summer of hot driving - again with Castrol 10W30.

If your oil pressure is more than 20 or 30 psi at idle when the engine is hot, that's fine. If your oil pressure when driving at 50 or 60 MPH is 45 to 70 psi, that's fine as well. If your pressures are lower than the values above, then switch to 20W50.

04-30-2008, 01:51 AM

First of all, you certainly haven't done any damage.

As for lighter weight oils there are pluses and minuses. First of all on shorter trips you get good lubricant flow MUCH quicker. Since these cast iron blocks take a while to heat up this is a very good thing. Of course once they reach full temp they are a bit thinner. If you engine is in good shape, you should still have plenty of pressure and all is well. There is the minimal additional benefit of slightly reduced wear on the cam drive/chain.
However if your engine is a bit on the loose side, then you could well get to the point where there is insufficient pressure. That is not good.

Personally I have 10w-40 in my engine and it gets rather hot here. At HOT idle (after a long drive with the temp gauge climbing) I have ~15psi, and when I rev it it jumps up right up to ~50 +psi with the gauge vibrating like crazy, which I believe is the relief valve dropping pressure back down.

04-30-2008, 04:33 PM
It's to hot in Atlanta for 10W-30, maybe not in Canada. Why don't you just read the owners manual? Oh, I forget, they didn't know what they were doing.

04-30-2008, 04:51 PM
to quote the lad:

<div class="ubbcode-block"><div class="ubbcode-header">Quote:] Of course this was before I got the Bentley manual. [/QUOTE]

And rarely have I seen a "manual" accompany a 28 year old LBC.

He's HERE now, so we'll keep things straight. :thumbsup:

I would say drain and refill with 20/50 Castrol or whatever the choice (NOT Quaker State, tho... a personal pet peeve) for the sake of old engine tolerances.

04-30-2008, 06:03 PM
Whassa matter DK Doc?

Don't like varnish formation????:&gt;

04-30-2008, 10:14 PM
As in "wax"!?!