OVERHEATING ON 1997 WITH C8.3 CUMMINGS ENGINE

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OVERHEATING ON 1997 WITH C8.3 CUMMINGS ENGINE

October 06, 2011, 10:46:27 pm

We just got back from Colorado and had overheating problems on Raton Pass. I have a C8.3 mechanical engine. I washed out the radiator and changed the cooling filter but did not see a whole lot of temp. difference going home. Any suggestions on checking the accuracy of the gauges or using a different way of measuring the temp?
P.S. I am pulling a 1999 Jeep Cherokee toad and downshifting to keep the rpm's around 2000
Thanks for any thoughts on this problem.

Re: OVERHEATING ON 1997 WITH C8.3 CUMMINGS ENGINE

Reply #1 – October 07, 2011, 12:45:35 am

Jim,

How about more specifics like how hot, what conditions, as much detail as you can? Any previous history?

Re: OVERHEATING ON 1997 WITH C8.3 CUMMINGS ENGINE

Reply #2 – October 07, 2011, 10:30:17 am

A motor, tranny and rear ends are going to run hotter climbing mountains. Double the work load plus thin air at elevations such as Raton pass.

Re: OVERHEATING ON 1997 WITH C8.3 CUMMINGS ENGINE

Reply #3 – October 07, 2011, 10:38:44 am

Agree with Pierce. We need the details.

What does your temperature gauge show on the flats/most of the time?

What did it read climbing?

What was ambient temperature?

How old is the thermostat (if known)?

Brett

Re: OVERHEATING ON 1997 WITH C8.3 CUMMINGS ENGINE

Reply #4 – October 07, 2011, 07:37:14 pm

We found by driving much slower at part throttle, downshifting, RPMs about 1,700, our temps stayed down going south up Raton. We also cleaned out 'tons' of stuff between rad & intercooler, like many recently talked about.

Re: OVERHEATING ON 1997 WITH C8.3 CUMMINGS ENGINE

Reply #5 – October 07, 2011, 07:44:56 pm

I have had to take my foot out off it climbing in high heat conditions. It was 105 degrees and the engine kept going up to 220. I did the same trip in the spring with a high of 45 degrees and the temps on the silverleaf showed 210 for a high with full throttle.

Re: OVERHEATING ON 1997 WITH C8.3 CUMMINGS ENGINE

Reply #6 – October 07, 2011, 08:49:20 pm

We have never had an issue with coolant or transmission temperatures rising above normal levels. However, we watch the pyrometer and start easing off the throttle if the exhaust temperature gets near 1300F.

Our only instruments are the cockpit gauges. There is no ecm on our C8.3-325.

Re: OVERHEATING ON 1997 WITH C8.3 CUMMINGS ENGINE

Reply #7 – October 07, 2011, 10:21:01 pm

First of all, thanks for the replies. The normal operating temp has been around 180 to 185 degrees. When climbing, the temp rose to around 220 with the tranny temp rising to around 200 degrees. The outside temp was cool but not sure of the actual temp. and the age of the thermostat is unknown by me. I have had the coach app. two years and this is the second time to bring it to Colorado. The first time was without a toad and the temp alarm just started chirping on Wolf Creek Pass but quickly cooled down when I topped the pass. My mileage for the trip was 7.5 mpg. and the miles on the coach is app. 65,000 miles.
J.D. I don't have a pyrometer but I may need to put that on my list of things to get.
I think I will replace the thermostat, remove the louvered panel to really clean the radiator. I think the fan is run by hydraulics and should be checked, is that right Brett? Is there anything else I should do? Again, thanks for all the help and knowledge.
Jim Monk

Re: OVERHEATING ON 1997 WITH C8.3 CUMMINGS ENGINE

Reply #8 – October 07, 2011, 11:39:01 pm

In really hot weather with toad, I have seen 220 degrees on long grades. I shift down to second (four speed) if necessary and back off the throttle a bit to bring the temp down to 200. Don't like to have it much higher than that for very long. It always cools down quickly on the flat or downgrades.

If you check the thermostat and clean the radiator and find nothing, you may want to fix up a spray system for the radiator like several others have done.

Generally, warm weather driving combined with mountains in the west require a few compromises that we don't often have to make in our passenger cars. Eliminate the possibilities in the above posts and adjust driving to conditions.

Only other suggestion is to make sure your tires are correctly inflated in hot weather. Not the time to have low pressures for a comfortable ride as they may add a little to your engine temp with increased drag.

Re: OVERHEATING ON 1997 WITH C8.3 CUMMINGS ENGINE

Reply #9 – October 08, 2011, 09:43:48 am

Jim,
I did that same pass in August north to south with a nearly identical engine, coach, and toad. Temperature never exceeded 200 with no downshifting except what the transmission did on its own in the econ mode. I'm betting you have some leaves and trash between the CAC and the engine radiator. You can check that by moving some of the rubber aside on the front edge of the radiator next to the battery compartment door and looking in there with a flash light. You can also do that from the rear, but you will need a mirror and 3 hands. I have a few leaves between mine that need removing. If it should be a thermostat problem, I believe there are two of them. If one is not opening what would the results be? I have no idea. I suspect that it would just run hotter under all conditions. My temperature is generally 180 to 190 on flat roads.

Re: OVERHEATING ON 1997 WITH C8.3 CUMMINGS ENGINE

Reply #10 – October 08, 2011, 10:07:19 am

Jerry, Good point on the C engine, there are 2 thermostats side X side, of course if one will not open when needed the temp can continue upwards for sure.
Never seen a C with one thermostat.
FWIW

Re: OVERHEATING ON 1997 WITH C8.3 CUMMINGS ENGINE

Reply #11 – October 08, 2011, 10:24:16 am

I have an Ultra Desert Supercooler on my coach that is very effective. Sadly, I believe the company is now out of business. The UDS has four nozzles about 6" apart that spray a small stream of water over the surface of the radiator. It is activated by a control unit much like an intermittent wiper switch. This allows one to adjust the amount of water that is sprayed based upon the amount of extra cooling required. This is a low pressure system that sprays small streams of water rather than an atomizing spray system.

The only system I can find on the net is Seine Systems > MPC. This appears to be a high pressure low volume mist system that uses its own water reservoir so you can use distilled water to prevent mineral buildup in the vaporizing spray nozzles. Being a high pressure misting system it doesn't appear to have an intermittent switching system, just on and off. It claims 15 o 20 degree reduction in coolant temperature. Based on experience with my system, this sounds reasonable. Cost appears to be $269.95, a bargain compared to engine damage from overheating. Installation should be pretty straightforward with the most difficult part being wiring the switch.

I hope this helps anyone with annoying heating issues in Desert (or more recently Texas and Oklahoma) and Mountain driving.

Re: OVERHEATING ON 1997 WITH C8.3 CUMMINGS ENGINE

Reply #12 – October 08, 2011, 10:57:41 am

Kent, I cobbled up a spray system for the 12V in the MCI, total cost about $25.00, worked great, I found water corroded my special spray nozzles, switched to window washer fluid, no more clogging em up, worked beautifully, easy to reduce temps by 20 deg or more with flip of switch. Everyone that looked at it laughed and copied it.
The rich folks bought the fancy commercial products. Me, picture cheap & tacky

FWIW

Re: OVERHEATING ON 1997 WITH C8.3 CUMMINGS ENGINE

Reply #13 – October 08, 2011, 11:09:55 am

Thermostats are relatively inexpensive and easy to replace. I would sure start there, particularly if you don't know their age. Thermostats ARE a wearing item.

Brett

Re: OVERHEATING ON 1997 WITH C8.3 CUMMINGS ENGINE

Reply #14 – October 08, 2011, 12:01:49 pm

You might check the condition of the water hoses, on the suction side of the system. A soft hose that partially collapses will restrict coolant flow. It all adds up.

Re: OVERHEATING ON 1997 WITH C8.3 CUMMINGS ENGINE

Reply #15 – October 08, 2011, 12:35:11 pm

Quote from: Dave M – October 08, 2011, 10:57:41 am

Kent, I cobbled up a spray system for the 12V in the MCI, total cost about $25.00, worked great, I found water corroded my special spray nozzles, switched to window washer fluid, no more clogging em up, worked beautifully, easy to reduce temps by 20 deg or more with flip of switch. Everyone that looked at it laughed and copied it.
The rich folks bought the fancy commercial products. Me, picture cheap & tacky
FWIW

Our water is full of minerals and our cooling sprayers clog like Dave's. I was at the plumbing supply store on a hot day and asked if there was any remedy. He showed me their DIY sprayers with an icemaker filter installed. No more calcium deposits. At $13, how can you go wrong? See at: OmniFilter R200 Refrigerator Icemaker Water Filter Only $13.5

Yes, thermostats are really cheap and easy to replace and along with radiator exterior cleaning, at the top of the "try first" list.

Re: OVERHEATING ON 1997 WITH C8.3 CUMMINGS ENGINE

Reply #16 – October 08, 2011, 02:35:46 pm

And yes if I have seen bad thermostats. If you put them in a pan with water and bring it to a boil, they should open smoothly and ALL the way. If they stop and then open with a series of jerks or only open half way, replace. Nice to have a candy thermometer to check temps against the temperature rating stamped somewhere on the body of the thermostat in really small print. Should go from closed to all the way open with an increase of about 5 degrees (180 degrees closed, 185 degrees full open as an example).

Thermostats stuck all the way open can also cause engine overheating as the coolant goes through the radiator too fast to be properly cooled in high horsepower conditions. Will also cause engine wear as light loading will not let the engine come up to operating temperature so the engine will not achieve designed dimensions/clearances and will allow acids from condensation to form (below about 180 degrees). Another reason NEVER to operate an engine without the thermostat installed.

Re: OVERHEATING ON 1997 WITH C8.3 CUMMINGS ENGINE

Reply #17 – October 08, 2011, 03:15:37 pm

Another point about the thermostat, if for example your using a 180 F thermostat, it will start to open at 180 and will be fully open at 195, We have been instructed that the 15 degree spread from start opening to fully open is standard design.
There may other specs for thermostats, but this is the industry standard we students are told. As of 30 yrs ago. Some things do not change too fast.

In case your wondering, the thermostat is to keep the engine at minimum temp, not max temp. The radiator needs to be large enough with proper air flow to handle the BTU the engine is producing.

Re: OVERHEATING ON 1997 WITH C8.3 CUMMINGS ENGINE

Reply #18 – October 08, 2011, 10:12:17 pm

Definitely will change the thermostat(s) and reclean the radiator the right way. Are the thermostats the same or does one open at a different temp? Checking the condition of the water hoses is a very good ideal, I have seen hoses that look good on the outside break down on the inside and restrict flows on the suction side. A lot of things can deteriorate on something that is 14 years old.

Thanks, Jim Monk

Re: OVERHEATING ON 1997 WITH C8.3 CUMMINGS ENGINE

Reply #19 – October 08, 2011, 10:44:46 pm

Jim, When you go to Cummins for the thermostats and gaskets, also check the water pump, Besure to take your engine number with you, not just the C 8.3, but the actual engine number from the data plate, Also a great time to double check your belt tensioner and belts. These parts are not expensive until your broke down, then the price seems to soar.
Nice easy job when you do it at your convience, instead of along the road or in a Wally World.
Thermostats are the same as I recall from the units we do on the generators.

Re: OVERHEATING ON 1997 WITH C8.3 CUMMINGS ENGINE

Reply #20 – October 09, 2011, 01:15:51 pm

On our road to finding a solution for overheating, we replaced our Cummins thermostat ourselves. Even though we hear that there are two thermostats, our C8.3 engine only had one thermostat. Two thermostats are probably just a way to flow more coolant where both would open at same temperatures and maybe they are smaller in diameter than our one thermostat.

We also replaced our coolant water pump, but found the original pump to look perfectly like new once it was removed. But we still left the new pump in place. I don't think the new water pump made any change.

We also did lots of other stuff like cleaning out leaves from radiator area, cleaning radiator fins, test-forcing hydraulic fans to high speed, sealing gaps around radiator shroud, flushing coolant system with acid & alkaline cleaners, changing to Cummins ES Compleat pre-mix.

We don't have an overheating problem anymore, but don't have any idea what improved the situation. Maybe everything we did helped a little and maybe we have not had to drive the same conditions that caused our high heating situation.

Re: OVERHEATING ON 1997 WITH C8.3 CUMMINGS ENGINE

Reply #21 – October 09, 2011, 08:24:48 pm

Barry, Good info, This is one big reason when you go to Cummins for parts, any parts, be sure to have your engine number with you, there are many variables, many CPL setups.
You only need the engine number, having the CPL is OK, but the engine number is the biggie.
FWIW

Re: OVERHEATING ON 1997 WITH C8.3 CUMMINGS ENGINE

Reply #22 – October 18, 2011, 12:40:18 am

What was the ambient temperature when you were experiencing the problem? I find that I have a heat problem with my 96 when temps exceed 80 degrees and I have to pull hard for a long grade but, then I am pulling a 12K trailer.
I am sure that I need to get my radiator re-cored but, have not done it yet. Just living with the problem. I want to replace my pump and both fan motors when I do the radiator and am having trouble finding the correct pump and motors at a price I can afford. Hopefully, more research will provide an affordable answer.

Regards,
Jon Twork

Re: OVERHEATING ON 1997 WITH C8.3 CUMMINGS ENGINE

Reply #23 – October 18, 2011, 09:01:35 am

Jon, it was cool outside but I don't know the actual temp. The only time it overheated was when I was climbing. Looks like it will still be a couple of weeks before I can start digging into the problem and I will repost when I finish.

Jim

Re: OVERHEATING ON 1997 WITH C8.3 CUMMINGS ENGINE

Reply #24 – May 24, 2012, 11:40:36 am

I wanted to give an update on my overheating problem on the C8.3 overheating problem. The thermostat has been changed, antifreeze drained and replaced, new belts and radiator fins cleaned again. Took our first trip this week and made it about 300 miles before noticing the temp had climbed to around 210 degrees so turned around to head home. Let it cool off and drove about an hour and all of a sudden the temp fell to 180 and stayed there. Thinking maybe it had an air bubble even though it was flushed and filled with the air bleeder valve opened.
That was my first problem, also discovered a house water leak where evidently a rat or squirrel has eaten on one of the water lines. Problem #3 the generator will only run about 15 minutes before shutting down. Looks like the belt may be a little loose.
So, instead of going to Colorado I am working on the motor home.

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