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ollison · 10-11-2013, 05:39 AM

I a 1993 Safarai Continental 38' Pusher 8.3 Cummings with only 27000 on it. Drove several hundred miles to pick it up. Hooked my tow car up and off I went and then I notice my heat gauge creeping up at higher speeds. It hovered just under 225 for about 30 miles. It finally got a shade over and I decided to stop and let her idle. It immediately drops within 5 min to 200 and then makes it way to 175 in about 10 min. I could run again for about the same time and I would redo the cycle. It heats up faster 65-70. If I run 45-50 it holds ok. Its cooler now so I need a fix before summer and the mountains. Could I power wash the side radiator or what? I hope I didn't buy a lemon.. Never had a diesel pusher but love the power and what an awesome 6 speed Allison. Hope its an easy fix. Thanks for your donated knowledge.

deandec · 10-11-2013, 10:24 AM

I would assume that you have adequate coolant in the surge tank and the serpentine belt is tightened sufficiently by the belt tensioner.

I would be more concerned about the thermostat than the side radiator. (Be careful if using a power washer on the radiator. Do not want to damage the fins.) Since the side radiator sucks outside air through it, it does not usually get the oily crud caked upon it as opposed to the rear radiator blowing action causes.

If driving at highway speeds, did it run cooler in 4 gear (higher rpm) than in 5th or 6th overdrive gears?

FWIW, my C8.3L Cummins will (and has) shut down at 225 degrees to protect the engine.

ollison · 10-11-2013, 11:19 AM

I did not try lower gears. I thought less RPMs was less heat. Is the thermostat easy to change and is the procedure. I found out that the original owner just serviced the radiator flushing it. I'll check the belt. At night I'll put a light in back of radiator to see if it clogged. No shut down. Could be a bad gauge. I peaked at 228 when I voluntarily coasted to idle. It does rapidly go back down. Thanks

sswilson · 10-11-2013, 11:30 AM

I would suggest that less rpm does not mean cooler. How hard the motor is working determines the amount of heat generated. Lower rpms can lug or work the engine. Higher rpms can also pull more air thru with the fan therefore cooling better.

rdownward · 10-11-2013, 11:46 AM

You might check to make sure the fluid in your engine hydraulic system is full, clean and that the filters have been changed recently. Any of these can cause the fan to not operate at full speed and not suck sufficient air through the radiator to cool the coolant. Before you change thermostats, etc. this is something I would look into.

deandec · 10-11-2013, 01:14 PM

Quote:

Originally Posted by ollison

I did not try lower gears. I thought less RPMs was less heat. Is the thermostat easy to change and is the procedure. I found out that the original owner just serviced the radiator flushing it. I'll check the belt. At night I'll put a light in back of radiator to see if it clogged. No shut down. Could be a bad gauge. I peaked at 228 when I voluntarily coasted to idle. It does rapidly go back down. Thanks

You should not have to run at lower gears, but if it ran cooler in lower gears, I would suspect your hydraulic system or the serpentine belt.

There is/are filter(s) in your hydraulic reservoir that may need changing or oil refreshed.

If the higher rpm made no difference, then the thermostat might need changing. You will lose some coolant and have to move some piping, the coolant filter, etc to access the thermostat. Cost about $40 when I purchased it at Cummins West.

You could check your gauge accuracy by operating the rig to high temp then shooting an infrared thermometer at the hose to see if temps are similar to what the gauge reads.

ollison · 10-12-2013, 04:57 AM

Thanks guys. Hydraulic system? Where can I down load or buy a manual or buy one?. Is they hydraulic system canister looking from front of motor on the right. about 1-2 gallon? cap on top.

deandec · 10-12-2013, 09:24 AM

That is most likely the Hydraulic Reservoir.

Mine uses Dexron III or equivalent for fluid. The pump services the power steering and radiator fan on my rig. There is a Nelson filter in the bottom center of the fluid.

I just remove the cover, suck out the fluid from the tank, remove/replace the filter and refill. Takes about 20 minutes and seems to avoid getting air introduced into the system. The smaller cap is the dipstick.

Yours could be different.

ollison · 10-13-2013, 04:42 AM

What is your gas Mileage. Moving from 460 ford to this.

deandec · 10-13-2013, 10:26 AM

Calculated over 11 years, 65,000 miles and adjusted for generator use. @7.5 mpg.

Pushing 31,000# pulling 5,000# with a 4.68 rear end frequently in Western mountains.

ollison · 10-14-2013, 04:24 AM

One other situation that was annoying. I hear brake noise just driving. It brakes good. The noise dissipates when I brake. Not metal noise. kind of a A swifting noise. annoying noise. A can't tell but maybe in front. Nothings pulling and brakes seem fully released. Sorry for all question's. I'm new to this and I'm leaning.

Papa_Jim · 10-14-2013, 06:50 PM

Good advice from everyone.

Some more thoughts.

When the engine temperature is too high, if you walk around to the radiator side of the coach, the fan should be roaring.

If the fan is not roaring, then possibly the hydraulic filter is plugged, or the hydraulic oil level is low in the tank.

If the fan is roaring, then possibly one of the thermostats is stuck shut. Mine has two thermostats, I think yours will too. This is assuming that your radiator is clean, and your coolant tank is staying full.

Jim

ollison · 10-15-2013, 06:03 AM

I did walk back to check my tow car a couple times and I did not hear any roaring. I assume it pull air through and not out. I'm currently moving from 1 motor home to another but after that work will begin. My unit needs to move away from 1993 to 2013 inside. Winter project. What a job moving. Thanks for all this help.