Normal Engine Readings

tllapointe · 08-31-2009, 06:13 AM

Never had a diesel and buying one with a 400 hp Cummins ILS.

What should I expect when test driving for oil pressure, oil temp, air pressure, water temp, etc.?

Our Time · 08-31-2009, 07:48 AM

I can only give you estimates from a 2008 ULSD engine. It should be about the same for most ISL engines. (400 HP)
Oil Pressure at least 50 PSI at operating temp
Temperature in the 185 to 192 range.
Transmission temp in the 175 to 185 range.
Normal idle speed 700 RPM.
Alternator/battery volatge 13.8
Can't answer obout oil temp. No way to measure with my instrumentation.
Air pressure should be about 110 PSI after the compressor kicks out and the compressor will engage again at about 80 PSI. It should not fall below 75 PSI unless you are on the brakes often or on a rough road and the air bags are really getting a workout.
Hope this helps.

Elkhartjim · 08-31-2009, 08:43 AM

Thank you Chuck. You unknowingly answered my question. We recently were on a long trip and the low air pressure warning buzzer came on. I stopped checked everything I could think of, started up and it never came on again. Hwy 287 in OK is rough as a wash board...airbags were taking a beating. Thanks, thanks, thanks.

Our Time · 08-31-2009, 03:11 PM

Your welcome! I have been on that miserable excuse of a road in my pickup and can see why your air bags were in overtime!

jimandsue60 · 08-31-2009, 06:21 PM

Engine temps will vary with engine installation on different coaches. Rear radiators may be significantly different then side radiators.

I have never been able to find what cummins calls normal operating temps for my ISL installed in my 2007 side radiator Vectra. The 2008 rear radiators in the Vectras seem to run at the temps Our Time quoted. My engine and transmission seem to run @ 10 to 15 degrees higher than Our Time quoted.

Some coaches have larger radiators then what Winnebago spec out for the Vectra line.

I wish someone could point me towards Cummins operating parameters for their engines.

I have been told that the temperature alarm will come on at 220 degrees??

Jim

GaryKD · 08-31-2009, 07:38 PM

Hi Jim,
You are correct about the alarm coming on at 220 degrees. I've been there a couple of times. Mine comes on a little over 220 degrees. The engine will derate itself. After just a couple of minutes at 2200 RPMs, in first gear and 20 MPH, the temp drops to a safe level and we are once again on our way. Both situations were on very long and steep climbs, in the desert Southwest, in the summer (>110 F) and hauling a total weight of a little more than 37K lbs.

jimandsue60 · 09-01-2009, 11:41 AM

Gary, I think the trick is to get the rpms higher before the temp starts climbing. I think I might consider unhooking the toad and atv (we drag about 8000 pounds) before I started a prolonged steep hill climb at 110 degrees.

Jim

GaryKD · 09-01-2009, 01:57 PM

Hi Jim,
I do get the RPMs up and manually down shift to keep it at about 2K RPM. This happens rarely. The bottom line is I have not acquired the skill to determine the gear I should be in and how slow I need to go to stay under 220 degrees. I was in 2nd gear and around 2K RPMs and the temp still went up. I hope I don't get too much practice at this particular skill. We had the Gkids and the only time I can get them for any extended period of time is the summer. So there I am, in the desert, in the summer.

Unhooking the toad is a good idea. It is about 5700 lbs. Sometimes the obvious is overlooked by those in the middle of the battle. thanks

chicken legs · 09-01-2009, 05:00 PM

I have the ISL 400 on the Freghtliner chasis and can add that at 205 dgf the side fan kicks in and drops the eng temp back to the 180's rather quickly. I can actually hear the fan start as it is on the driver side. I operate at very much the same temps as stated but have never had an over temp issue . I've really been very pleased with this set up and have climbed the rockies with a 5k toad and no issues.

**Gary RVRoamer** · 09-01-2009, 06:41 PM

My 2003 ISL (in an 04 side rad chassis) generally runs in the range that Our Time quoted. My tranny runs up to around 200 in the mountains and I see engine temps to 197 at times.

My oil pressure is always 55 - the value comes from the ECM and it always sets the gauge at 55 if the pressure sensor reports 'OK' oil pressure. I assume to goes to zero if the sensor says 'Not ok', but fortunately have never experienced that. This phony 55 lb oil pressure is on late model Freightliners with the ISL - other chassis builders probably do it differently.

nutensteve · 09-05-2009, 12:25 PM

My 06 ISL runs the same readings as Chuck reported. I run a little higher oil pressure usually around 55-58 at 60 mph. I always take the readings from the Alladin system as the dash gauges are not anywhere close to being accurate. I travel mostly in California and includes plenty of mountain passes. I have to climb a 10 mile grade to get to my house and I keep the RPM's around 2000 and the temp has never gone above 198.

Steve