330 excal low oil presure at idle when hot

[Graeme V]

Hi all.
I have a 2003 196 with the 330 Excalibur motor. On start up in the morning the oil pressure at idle is 40 psi. When it is hot it drops right down to below 10. At any rpm above 1000 it goes right back up to over 30 then any rpm above that it is at 40. Why would it be goo when t is cold? I have now changed the oil to an SAE 40 from a 15w40 and there is no recognisable change. Should I go 20w60? y ideas??
Cheers
G

[Graeme V]

Sorry - 'why would it be GOOD' - NOT goo!

[Nautiquehunter]

Start by testing it with a known good oil gauge if you don't have one any mechanic should have one. You may just have a bad oil sender or gauge.

[Graeme V]

Start by testing it with a known good oil gauge if you don't have one any mechanic should have one. You may just have a bad oil sender or gauge.

Thanks - I do have one & am going to check it this Sunday. Do I check at the switch by the distributor?

[core-rider]

Mine does the same. You will notice this with all engines if you put a good gauge on them. Once the oil gets warm its thinner and moves better/easier. The pressure drops as a result. As long as the pressure is coming up off idle like you are seeing then you will be fine. Only time I would worry is if the pressure dosen't change when the RPMs go up. I wouldn't recommend oil viscocity without at least talking to PCM first and getting their recommendations. They might even be able to tell you expected pressure for given oil types, RPMs, and hot/cold start conditions.

[jbach]

i wouldn't worry about it if it's climbing with rpm's. general rule has always been 10lbs/1000rpm. but testing with a mechanical guage on the block is free for peace of mind.

[Graeme V]

Thanks for the input. I am going to check with a mechanical gauge and will post the results.
G