high oil pressure Cat C-9

[Gary and Judy Doran]

 2006 Beaver Monterey 44,000 miles Cat C-9.
 At start up the oil pressure gage buries the needle on high side. Aladdin reads 121 PSI.  In a minute or two the oil pressure drops to the 80's. If I switch on high idle it goes back well over 100 psi.
The oil pressure does not drop lower then 80 sitting at idle for several minutes.
 When I start off slowly the oil pressure goes well over 100 up to 120.
 When the coolant registers 150 degrees the oil pressure will drop to the low 80's.  After the coolant reads 175+ the oil pressure  will drop to the 60's high 50's,  at operating temp 194+ the oil pressure is within the normal operating range.
  I am then good for the day even after shutting down for a half hour stop.
  I tried the engine preheat and it did not make a difference on the oil pressure at start up.
  I goggled "Cat C-9 high oil pressure" and found the same problem described but did not see any suggestions or recommendations.
  I am a long way from home in Newfoundland Canada.  Should I be concerned about damaging the engine or having a break down?
    Gary  

[Mark Bryant]

Gary

What is outside air temp? This doesn't sound to out of line of what I have experienced in cooler weather.
I don't have preheat from aqua-hot, only electric, so I let the engine idle a little bit longer before starting out. The cooler the outside air the longer it takes to warm up. I can tell when the thermostat opens the oil pressure comes down to normal faster.

Hope you are having a great trip! We leave Sunday for the northwest!

Mark & Joyce

[Bob Adams]

Gary

I have an '05' with the same engine and similar mileage. I experience similar readings and it's never caused a problem for me after 4 years with this coach. I decided it was just the nature of the beast.

Happy trails,
Bob

[Gary and Judy Doran]

 Thank you for your replies  I will relax.  Just never noticed it that high previously but I really only would look to see that I had pressure and did not pay attention to what the oil pressure was until I was running down the road.
 This morning when starting it was 110 and decreased in a shorter time period.  The temperature was probably in the low 60's last night the previous nights had been in the mid 50's.
    Gary

[Roger Bowton]

What weight oil are you using? A lot of people think that they should use Rottella or some other multi viscosity oil when in fact the engine is designed for 30 .  

 That might make a difference at start up. Just an old Caterpillar Engine Division employee's thoughts.  If you look in your manuals you probably have a manual for the engine with a number in it to contact Cat's tech support center for verification

[Gary and Judy Doran]

This is a follow up to the question of high oil pressure and the oil viscosity for a C9 engine. As Roger suggested I checked the Operation and Maintenance Manual and then called the Caterpillar RV engine support to verify if the info is still current.  The manual clearly stated that the preferred viscosity for a C9 engine is 10W- 30 (if the ambient temperature is between is above -18 F and below 104 F.) The Caterpillar tech verified that 10W-30 is the preferred viscosity, in that temperature range.  
 The Monterey owners manual stated that the engine was shipped from the factory with 15W-40 oil. The Caterpillar rep said that all engines are shipped from the factory with out oil.   I had assumed that shipped from the factory was from Caterpillar when it was referring to being shipped from the assembly factory.  
  I changed the oil to 10W-30  at the end of September.  Since then the Aladdin system reads in the low to mid 80's at start up and then quickly drops to the normal range.
   Gary