Author Topic: C7 Oil Pressure Reading Issue  (Read 291 times)

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Offline BobRV21

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C7 Oil Pressure Reading Issue
« on: September 29, 2020, 11:20:35 AM »
I have owned a 2007 Winnebago Journey 36G with a CATC7-350 for the last 2 years, bought it with 68,000 miles and now has approx. 74,000 miles on odometer.  Had it checked out before I bought it and it has been serviced regularly in all respects.
About 300 miles into a recent 1600 mile trip last week I noticed that the standard freightliner/winnebago oil pressure gauge dropped to lower pressure at 70mph on the interstate, then when I pulled onto an exit it dropped to nearly zero pressure on the gauge.  I left the engine running since it sounded normal and then went back to inspect....it also looked fine at the rear of the coach and underneath...but it still read zero pressure on the gauge.  I then got back inside and shut down the engine and restarted it 10 seconds later, and this gauge reading issue never happened again for the remaining 1300 miles of my trip and hasn't happened since (or a least I didn't notice that it happened).  In other words, the engine performed and sounded fine the entire time.  I changed the oil myself about 1,000 miles before this happened, Rotella T5 synthetic blend 10W-30 and CAT Oil filter.  Obviously I'm hoping/thinking that this is a sporadic bad oil pressure sensor.  HOWEVER....Any thoughts or suggestions are appreciated!!

Offline RIch

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Re: C7 Oil Pressure Reading Issue
« Reply #1 on: September 29, 2020, 12:56:28 PM »
This sounds like an electrical issue to me. Probably a slightly corroded connection on the oil pressure sender. Also take a look at the ground connections in this circuit.

Offline trekker01

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Re: C7 Oil Pressure Reading Issue
« Reply #2 on: September 29, 2020, 03:23:07 PM »
Bob,
T5, 10W30 is not the correct oil for you engine.  It is intended for gasoline engines.  Is that a typo and you really used 15W40?

Gary
1998 Safari Sahara 3126B Cat 300HP
CAT #7AS01206, Allison #6510139688
FMCA, Escapee, Good Sams
Central Florida

Offline BobRV21

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Re: C7 Oil Pressure Reading Issue
« Reply #3 on: October 01, 2020, 05:32:07 PM »
Actually the CAT recommendation footnoted in the viscosity chart is ... QUOTE...."SAE 10W-30 IS THE PREFERRED VISCOSITY GRADE FOR C7 ENGINE ........WHEN THE AMBIENT TEMPERATURE IS BETWEEN 0degrees F and 104 degrees.  AND Separately 15-40 is called for between 15 degrees and 122 degrees. So....15-40 is "required" above 104 degrees....And thus 104 is the tipping point to go with 15W-40. Some would err to 15-40 if above 15 degrees ambient always....but that isn't what CAT is recommending in the chart footnote.

Offline BobRV21

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Re: C7 Oil Pressure Reading Issue
« Reply #4 on: October 01, 2020, 05:37:15 PM »
Also, the Rotella T5 10-30 Oil I'm using clearly is labeled for Heavy Duty Diesel use.