I recently changed my oil Royal Purple (which I've used before) but used 10/30 instead of 5/30, I alse used a K&N oil filter (never used before). After I added the recommended 5.5 qts I started the engine and checked the level, the dipstick was fine but my oil gauge was reading high, at idle it sit's at over 40! Any ideas why it's reading so high. The K&N oil filter has an anti drain back plug which stops the oil from draining into the filter when the engine is shut off, maybe this is why the pressure is reading high!

 

The antidrainback valve in an oil filter should have no effect whatsoever on the oil pressure reading higher. Your cold oil pressure will be higher with 10w30 than 5w30, simply because 10w30 is thicker than 5w30 when cold.

How is your hot oil pressure, is it still high once the oil is warmed up?

 

After the car warms up my needle drops to a little under the 40 mark, which I guess seems to be in the norm for this car. Thanks for the feed back