deandec
El Dorado Hills, CA
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Joined: 09/26/2001
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I have a 8 yr 50,000 mile average fuel mileage of 7.2 mpg.
That includes about 500hrs generator use while driving 60mph on the West Coast with a 4500# toad and a 31,000# chassis.
The engine is the 300HP C8.3L mechanical Cummins.
I agree the engine is durable and reliable.
I understood the purpose of the newer electronic controls was to improve fuel mileage and provide pollution controls.
Dean
95 CC Magna, Jeep GC
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deandec
El Dorado Hills, CA
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Joined: 09/26/2001
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Quote:it warms up the oil pressure drops down to the 8 to 10 range....this sounds TOO low to me, is this something I should be concerned about or is this normal for the C8.3 mechanical engine?
I do not know if you should be concerned, but our 15 yr old rig does not drop below the 35 -75 lb range specified in the Country Coach owners manual. I do not have the Cummins manual at hand.
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jtfcons
Washington State (The dry side)
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Joined: 06/02/2004
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deandec wrote:Quote:it warms up the oil pressure drops down to the 8 to 10 range....this sounds TOO low to me, is this something I should be concerned about or is this normal for the C8.3 mechanical engine?
I do not know if you should be concerned, but our 15 yr old rig does not drop below the 35 -75 lb range specified in the Country Coach owners manual. I do not have the Cummins manual at hand.
The 35-75 psi range mentioned is the same with me. Never see below 35 even at idle when fully warmed up. There is a oil pressure regulator within the oil cooler housing that may need attention (replacement). If the 8-10 is correct psi reading, I would have it checked out.
My 325 hp produces 915 ft-lb torque @ 1300 rpm. As said above, the engine/transmission is a good combo. Have had very good service since owning the vehicle about 5 years, and putting about 35000 miles on.
John & Sharon, 2 Daughters, 2 Sons-in-law, 5 GK
Scottish Terriers (Bonnie & Chloe)
1997 HR Imp., 38CDS, 1 Slide
325 Cummins C8.3Mech., MD3060, EBw/Cst.Sw.,
Toad-98Tracker 4X4 or 03GMC Envoy 4X4, Excallibar TB, Pressure Pro TPMS, Henderson Mot. Ctrl. Units
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tommy wilson
southern ca, usa
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Joined: 10/18/2001
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my 1996 cummins 8.3 has oil pressure of 80 psi cold and when hot the oil only drops to 10 psi when at idle. 80000 miles.
get final charge for coolant so you dont need chemicals added to the radiator.
tommy wilson
1996 kountrystar dp
spartan mountainmaster chassis
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dieseldave56
central oregon
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Joined: 08/25/2007
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Actually the Cummins service manual spells out that 10 psi at IDLE with engine at operating temperature is the MINIMUM . But there are several areas that can cause this misread oil psi(1) as mentioned the oil pressure regulator valve ( oil cooler). (2) the wrong oil filter. (3) oil pressure sender weak. Have the oil pressure tested at the engine (attach a gauge in place of the oil sender). I added all Cyberdyne digital gauges to the dash as they are easier and more accurate to read than the OEM gauges
The worst thing for a genset is not to be exercised. The Kubota engine is the least problemactic but the coils windings in the generator will corroide . The Onan 7.5-8.0KW costs $8,000 last time I looked. Always exercise the genset every few months for an hour or two under a load ( air conditioning, microwave ( with big bowl of water, ect). Obviuosly the Onan will have to be serviced with filters and fluids and the hoses, belt replaced ( also for convenience ,the water pump as they can be a problem).
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wny_pat
Western NYS
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Joined: 08/11/2007
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Any Cummins mechanic can work on that engine, without a computer!!! Less to go wrong!!! I would in a heartbeat just because it is mechanical.
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FormerBoater
South Florida
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Our 98 American Eagle has the 325 HP version of the mechanical Cummins C Engine.
57,000 miles now....48,000 when purchased.
I use Optilube Summer Blend (live in Florida) as a hedge against lift pump issues due to ULSD. Don't know if it helps but it is an inexpensive hedge that seems to be working so far.
No issues at all since we bought the coach in January. Mileage has been as low as 8 mpg and as high as 10. Difference seems to be headwind vs. tailwind.
Oil pressure at start-up is 60 lbs.+, stays at 40 lbs running down the road at 65 mph. Drops to 10 Lbs at idle when fully warmed up.
Also married to the the Allison 3060 six speed which seems to be a perfect match. Plenty of get up and go and climbs hills easily.
The one question about the C engine that I have is the oil drain intervals. Manual calls for every 6K miles, but this was before the days of ULSD and engine oils that meet today's specifications. Engine oil seems extraordinarily clean for a diesel using the current Rotella T Triple Protection dino (not synthethic) oil.
As the new ISC engines call for a drain interval of 15,000 miles (ULSD+oils produced to meet more rigorous standards?)...are we stuck with the 6,000 mile drain intervals now that we are burning ULSD and using the higher performance motor oil?
Thanks in advance for any input on the drain intervals!
Dave Stansel
1998 American Eagle 40EVS
Cummins C 8.3 Liter 325 HP
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FormerBoater
South Florida
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Just to bump this up in case someone has some information on oil change/drain interals on these older engines using the new fuel and lubricants.
Dave
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deandec
El Dorado Hills, CA
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Joined: 09/26/2001
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Dave, post new topic for your oil change interval question. I asked the question several years ago and got reasonable answers as to the required intervals, but not the answer I wanted.
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dieseldave56
central oregon
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Lube oil/ filter change recommended once a year ( pre winter storage) to prevent damges by corrosion and wear from moisture and acids caused by combustion.
With modern oil blends and upgraded filters ( OEM Fleetguard LF3000 to LF9009 lube filter)extended mileage should be a problem at all. I send periodically oil samples to Blackstone Labs in Indiana. But even when full timing I didn't rack up 15,000 in a season.
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