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Topic: ‘96 U295 Engine Temps (Read 1864 times) previous topic - next topic

‘96 U295 Engine Temps

We are just south of Raton. We are towing Jeep Liberty.

I'm seeing temps over about 208-210 on analog factory dash temp gauge. I'm running about 63 mph, in Econ mode.

Should I have any serious concern other than continuing to monitor?

Re: ‘96 U295 Engine Temps

Reply #1 –
Assuming you have the 8.3 Cummins it's a higher then normal temp.Would check fans for turning, radiator for dirty fins, oil and coolant level and if you have one use a infared temp gauge to engine temp.PS,no clue where Raton is.

Re: ‘96 U295 Engine Temps

Reply #2 –
Couple of things:

Mode will make no difference at 63 MPH unless steep grades, you will be in 6th gear either way.

While the gauge may not be dead accurate, the fact that it is reading higher than normal means you are OUT OF COOLING CAPACITY.

Possible causes:

Thermostat not completely opening-- they ARE a wearing component.

Coolant level low-- when cold check at the pressure cap and verify that level in the overflow reservoir changes with coolant temperature-- level rises when coolant hot and lowers when it is cold.

Hydraulic fan issue.  Start by checking fluid level in reservoir.

Dirt or debris in cooling package.  Look in from the side of the coach and make sure that you didn't suck a plastic bag, etc.

Keep us posted on what you find.

Re: ‘96 U295 Engine Temps

Reply #3 –
Your coach still has a 5.13:1 axle ratio, which is a VERY good thing.  We also towed a Jeep Liberty with our 1995 U295.  In my opinion - despite the performance axle ratio - you're asking a bit much of your 300 hp C8.3 engine (in the Raton area).  Have you checked engine temps when throttled back to 53 mph in 5th gear?

Larry

Re: ‘96 U295 Engine Temps

Reply #4 –
The 5:13's I thought could cause trans rear carrier issues?  Replaced with 4:68's?

I agree with Brett as you seem to have run into some limit in the system.

The temp itself should not hurt anything as far as I know

Re: ‘96 U295 Engine Temps

Reply #5 –
I'd have the 5.13s installed on our new-to-us 2002 U320 if we could afford the swap.  Our 1995 - with 5.13s, was a joy to drive (especially congested interstate on-ramps).  The ISM equipped U320, with 3.91 gears, however is a chore to drive on those same on-ramps.

Re: ‘96 U295 Engine Temps

Reply #6 –
The temps look OK to me, if younare going over Raton Pass you should be in a lower gear, probably 4th watch coolant and transmission temps. Same gear going down with a notch of retarder.

Re: ‘96 U295 Engine Temps

Reply #7 –
Raton in July! I think your fine. The little engine that can!!! I try to keep the rpm's at peak torque value when pulling uphill

Re: ‘96 U295 Engine Temps

Reply #8 –
We run all over the west Montana, Idaho, Wyoming, never get over 205 MAX towing a 4 dr Jeep Wrangler gross weight 35000. Check all things mentioned above, and drop a gear or two. If you are pulling a hill you should be able to accelerate going up if you are in the proper gear. Keep you RPM 1800-2000.

Re: ‘96 U295 Engine Temps

Reply #9 –
U295 owner.  The m11 is a much lower rpm motor.  It's supposed to have a  more torquey design than rev it up and use the hp to get up hills.

I sold beaver Marquis with 3176 cat engines that in the days of 55mph would not reach 70 mph.  3.91's with a 4 speed Allison in 91.

Speed limit changed  but the Gillig chassis had the 55mph gears.

So I regeared them new to 3:21.  Mpg went up.  Coaches at 37,000 pounds combined weight went 65mph up all the interstate 6% grades with the cruise on and the jake held it back to the same 65 on cruise control 8.25 mpg

M11 does not have a much torque/hp as the Cat regardless of the respective ratings.

Cat turned up their motors for the rv manufacturers. 

IF I could turn up the m11 I would regear it lower.  3:42's?

Being as I was unable to add power I went the other way and fixed all the parasitic draws and the tires rolling resistance.

Big difference after the changes.

Still needs more power.  I know of a place that might be able to "fix" the power but it's on the other side of the country from me.

If it has more power versus lower the losses then you have more heating.  Everything relates to everything else.

TINSTAAFL,    There is no such thing as a free lunch for the Heinlein fans

Re: ‘96 U295 Engine Temps

Reply #10 –
Hi RPM keeps the coolant circulating best, keeps EGTs down, moves more of the thinner air over the radiator for better heat exchange. Not sure how 1800-2000 in a Cummins 8.3 translates to our 9.0 engine but I run close to 2000 ( 2130 fuel cutoff) unless it starts to go much over 200 degrees and then drop a gear, keeping RPM high close to fuel cutoff.

Low RPM on grades, especially high altitude grades is the opposite of what it should be.

Large engines should still keep RPM well up in the RPM range. High EGTs take a lot of responsibilities for dropped valves.

Pierce

Re: ‘96 U295 Engine Temps

Reply #11 –
And for those of you that think the 215 degrees indicated is the temperature your engine is at, think again. It's 215 where the temp sensor is, usually close to the thermostat housing. Right around the exhaust valve, the coolant is much hotter than that. The pressure cap at around 14 lbs is what keeps the coolant from vaporizing in these locations. If it does, the temps will really head up instantly in that spot and will allow the valves, cylinder head material and pistons to exceed design limits. The oil sprayers can only cool the piston crowns so much.

A listed 10,000 foot elevation pass in summer may be 13,000 feet or more with the radiator and fan loosing even more efficiency. EGTs will run even higher. Keeping the coolant circulating as rapidly as possible and the EGTs down is the best path for engine longevity.

Pierce

Re: ‘96 U295 Engine Temps

Reply #12 –
I can count on one hand the actual number of damaged Diesel engines I have seen in the rv biz since 1984. 

Customers are too frightened to drive them hard at all.

Such a shame as they are needlessly afraid.  My heavy user garbage truck fleet owners showed me how tough these really are/where.

Theirs rarely ran below 210 engine and 230 trans.  Harabiedien had 165 garbage trucks and Garrett Box had a similar amount.

Just saying.  New DEF motors dislike idling and have EGR issues. 

Re: ‘96 U295 Engine Temps

Reply #13 –
All engines dislike idling, all engine manufacturers don't recommend it and it's against the law in many places.

When accelerating from a light or onto the freeway, I usually am at full throttle and let the computer shift the transmission at maximum RPM the ECU is programmed for. In our case I frequently run it up grades at 2130 RPM unless I don't have enough cooling. This is not running the engine hard. This is what is was designed to do, day in day out. It was not designed for operators operating on myths

Lots of diesels don't make it to their B50 life. Lots from the misconception that it was designed to "torque" it up grades and lots from operators making it a habit of idling their engines for extended periods.

Pierce



Re: ‘96 U295 Engine Temps

Reply #14 –
My favorite rv drive was a n14 444hp 1850 torque Monaco signature.  Eaton economat 9 speed trans with 1 and 2 wired out.

You could not drive it revved.  Too fast.  It's the exception to the rule as was the country coach concepts with 8v92's and six speed trans.  It would double the triple nickel speed limit as would the Monaco.

The cat marquis would torque better than hp up grades that's why I was disappointed with my m11 originally.

If you tell me it will last longer downshifted and revved I feel better about it.

The Cummins people tell me the sweet spot is 1350 to 1500 rpm.

Cm fore set up his coaches for almost 70 mph to balance the power versus mpg. 

Mine seems to be not as much difference in mpg as the cat chart shows going from 65 to 70.  Maybe half.  About a half mpg difference from 63 or so to 69 or 70

Re: ‘96 U295 Engine Temps

Reply #15 –
Bob, you wrote 'Cummins said sweet spot is 1350 - 1500 rpm'.  That matches my experience.  The ISM supposedly has peak torque at 1200, but at that rpm, my engine doesn't pull at all, but wakes up at 1350 rpm.

Larry

Re: ‘96 U295 Engine Temps

Reply #16 –
You guys need EGTs installed close to one of the exhaust ports. Watch it and don't worry.

Pierce

Re: ‘96 U295 Engine Temps

Reply #17 –
Never seen  a stock Diesel engine in a motorhome get anywhere near a damaging EGT.  If memory serves me Bluebirds had gauges on both banks and the temps were always well within specs for no issues

Re: ‘96 U295 Engine Temps

Reply #18 –
Quote from: Caflashbob –
Never seen  a stock Diesel engine in a motorhome get anywhere near a damaging EGT.  If memory serves me Bluebirds had gauges on both banks and the temps were always well within specs for no issues
But Bluebirds had Detroit 8V-92TA 2-cycles that don't have the EGT problem. That's part of the reason they don't blow up. Here is a shot of a 8V-92TA on the dyno at 800 hp and 1829 Lb/Ft torque and only 383C or 721F EGT on the highest bank, less on the other. Check the numbers. 4 cycles are hundreds of degrees hotter.

Pierce

Re: ‘96 U295 Engine Temps

Reply #19 –
That bird quote was that birds were the only coaches I had seen that bothered to have an EGT gauge oem.

Only modded engines may have  benefited from EGT gauges. 

I have appraised hundreds of coaches for purchase or trade in and if engines could be an issue I would have a shop dyno the motor and a oil analysis done.  Never needed.  No idea after 96.  Was out of the biz.  Had not been in a coach until 2012. 

Must have been Karma as this 97 mid entry is exactly what we would have dreamed up if asked.