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Question on oil and water temps

June 12, 2014, 09:45:43 pm

I just received a phone call from a friend, not on this forum (doesn't do internet), questioning what the correct oil pressure and water temp should be running, going down the highway. He has a 98 U320, M11 with 450 Hp. He said if he is reading the gauges correctly, the water temp is right at 200, and the oil pressure is 30# and drops to around 15 at idle.

He recently bought the coach at FOT, they told him the readings were good, but he has concerns. I turn to the experts. What should they be?

Thanks in advance,
Larry

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Re: Question on oil and water temps

Reply #1 – June 12, 2014, 09:52:44 pm

I have an ISM 450. My coolant runs 175-180 most of the time.  About the same for the transmission. Oil pressure is about right and typically will drop some at a stop light.

Roger

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Re: Question on oil and water temps

Reply #2 – June 12, 2014, 10:07:01 pm

 I have the 350 and my water is 180, pressure is 50 cold, 40 hot and does not drop below 20 at hot idle. I would be worried with 15 and would consider replacing pump ( but I may be way out of line in my thinking this was not good) Maybe Brett can weigh in on this one.
JohnH

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Re: Question on oil and water temps

Reply #3 – June 12, 2014, 10:31:00 pm

The M11 and ISM engines do not carry as much oil pressure as the ISL and 8.3

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Re: Question on oil and water temps

Reply #4 – June 12, 2014, 10:48:29 pm

 You are one of the experts Ron on these things. I learn something all the time.
JohnH

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Re: Question on oil and water temps

Reply #5 – June 13, 2014, 12:54:16 am

It looks like just under 200 on the gauge but Silverleaf says 180-190. Oil pressure is about 35 and drops to 20 or so under idle.  This was the same on both my 320s.

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Re: Question on oil and water temps

Reply #6 – June 13, 2014, 08:40:24 am

My '99 320 runs at about 180+ and oil pressure about 38 lbs while driving. I have noticed that if head lights are on or running Dash air, it pulls the volts on the chassis batteries down(over time),at least on the gauge, to closer to 12.7-13 volts, and then the oil pressure shows lower and temp shows higher. I understand they are all using same wires and thus loses some.
If I turn off the lights and dash air or others, the shown volts go back up and oil pressure goes back up and Temp comes down. I have checked with Silverleaf and it is a gauge reading issue, not a real issue. Silverleaf actually shows slightly lower Temps and lower oil pressure (about 35 lbs)

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Re: Question on oil and water temps

Reply #7 – June 13, 2014, 01:27:58 pm

Dash volt meter gauge does not reflect voltage at battery. Additional volt meters directly connected to battery will do a better job.

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Re: Question on oil and water temps

Reply #8 – June 13, 2014, 02:00:59 pm

Larry,

Both oil and temp readings are good.  Believe it or not 10 psi at idle is acceptable and 30 psi at rated revs is also OK.

Keith

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Re: Question on oil and water temps

Reply #9 – June 13, 2014, 08:47:41 pm

Thanks everyone for the responses. I knew that the answer was a mere click away. I'm trying to convince my friend he can get the same results if he were to join this great group of wisdom. I appreciate all that you all do for my help.

Larry

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