Still running hot

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Still running hot

June 02, 2018, 11:01:56 am

We are presently in Mammoth Lakes, Ca (8,000') where we have vacation house. There is a long steady grade that gains 4,000' from Bishop, that has always been a problem for us in a motorhome. This time we detached the Jeep and my coolant temps. reached 221 degrees. Last year I replaced the radiator and transmission cooler (and hoses) and put in an exhaust resonator. With the ISM engine, I don't expect to have this problem. When approaching a long grade, I drop to 5th gear and keep the rpm's in the 1700-1800 range going about 50 mph, dropping down to 45 mph as needed. There doesn't seem to be a problem with the power, if I ignore the temps. The weight of the coach is just over 30,000# so this should not be a problem.
Any suggestions?

Re: Still running hot

Reply #1 – June 02, 2018, 11:40:39 am

In the archives I read about Barry's problem that seemed to be caused by the fans not working at high speed. Can't tell when the fan changes from one speed to the other. Shortly after I changed out the radiator, I had difficulty maintaining the proper coolant level. On one occasion, the overflow tank spewed coolant onto my toad, leaving white residue. That doesn't seem to be a problem now, but I find that I have to refill my reservoir frequently. I considered the problem of air in the system, considering the radiator change out, but had hoped the air would have worked its way out by now.

Re: Still running hot

Reply #2 – June 02, 2018, 11:47:17 am

Boil over is 265. Driven up countless grades up to 230+ since 1984 including Sherwin grade you mentioned.

Your motor has an electric cooling fan temp control on it to trigger a front mounted engine cooling fan on a truck.

It's turn on point is 210 degrees F.

I spent lots of hours discussing this exact scenario with owners long ago.

All were concerned if the temp gauge moved.

My customers who ran fleets of garbage trucks mentioned their trucks ran 230 a lot and the trans at 275 continuously.

If you pass 230 much and the gauge continues to climb a load reduction and a gear down might be helpful.

At 220 sounds like it's working perfectly. No coolant loss I presume?

Not possible to put a big enough radiator to never have the gauge move.

Foretravel original Unihome had the same radiator for the u280 with the cat and the u300 with the Detroit.

Factory had to block off part of the radiators on the u280's as the cat never warmed up completely.

Passed a lot of rv's on grades because of this.

The Detroit's may not like being hotter over long run according to some here.

Delivered dozens on u300's up baker grade going to Vegas for out of state deliveries at 100 degrees plus and demonstrated that the gauge stopped climbing at 230-235 F to the future owners.

Versus drive in the middle of the night to not have the temp gauge move like a lot of customers were doing I demonstrated no damage or coolant loss occurred.

I hit 230 or so on a lot of western grades in the summer. No issues.

I can almost see the raised eyebrows out there reading this.

Go slow if you are not comfortable with what I post.

I thought it was more dangerous to pull over on grades and then try to blend back in up hill into traffic slowly which is why I researched this. Then tested it a hundred times. Then demonstrated this to customers.

On my dime ,in my m11 coach, I would have and have passed a zillIon coaches up grades in the West in the summer heat

Sounds like yours is perfect to me.

If the gauge stops at 230 or so everything's fine IMO.

Drove beavers, country coaches, monaco's, blue birds and prevosts exactly this way without issues

Re: Still running hot

Reply #3 – June 02, 2018, 11:58:00 am

Going up hills, if I don't like the temps I see, I drop down another gear and go from there.

Re: Still running hot

Reply #4 – June 02, 2018, 12:07:44 pm

Try the same hill in 4th going a bit slower with more RPMs to reduce coolant temp. I have done a fiair amount of mountain driving in our coach and I an not sure if I have seen coolant temps over 210. It might not hurt to get hotter but it doesn't hurt to stay cooler.

Re: Still running hot

Reply #5 – June 02, 2018, 12:16:37 pm

I have run that grade a bunch, no higher than 220 ever. Just drop a gear and enjoy life. If you continue to have to add coolant you have a leak or air in the system.

Re: Still running hot

Reply #6 – June 02, 2018, 12:24:00 pm

Is your trans cooler disc installed? We consistently blew out coolant until finding out ours was missing. Haven't lost a drop in two years.

Re: Still running hot

Reply #7 – June 02, 2018, 01:39:56 pm

We go up Sherwin and Conway all the time did it again a couple of weeks ago. Put a test light on the fan switch to see if your fan goes into the high speed mode. Run it up into the bedroom and have someone watch it. You could also use one of the extra wires that goes up to the front and put a light on your dash to indicate the high speed position.

Your Cummins and our Detroit both have wet liners. They don't tolerate high temps as well as parent bore engines like the smaller Cummins and some CATs. I let the temp gauge go two needle widths above 212 max.

Summer temps make a big difference. We can charge up out of Death Valley in winter without a problem but in summer, I've had to go down into first gear.

You might check your pressure cap to make sure it's working OK.

The effects of overheat are cumulative so it pays to be on the conservative side.

Pierce

Re: Still running hot

Reply #8 – June 02, 2018, 01:48:12 pm

If your temps get to hot for the setup wont the computer shut it down? I have climbed Baker grade in the heat of the summer and I think it was 222- 223 area.. I think at 225 the computer starts complaining.. I think?

Re: Still running hot

Reply #9 – June 02, 2018, 02:24:32 pm

David,

That's like the idiot light for low oil pressure. Use it too often and ...

When the ECU goes into shut down mode, you have partial power for 30 seconds then the engine shuts off. If you are in a place where you can't pull off, your personal safety is at risk.

There is an override switch on the dash. One Detroit owner lost a hydraulic belt just before entering an uphill tunnel. He used the override but it shut down again after a few seconds. Not to be deterred, he used it again and again. He got to the far side of the tunnel but the toll charge was almost $30,000 for a new engine. The block was too distorted to rebuild.

Pierce

Re: Still running hot

Reply #10 – June 02, 2018, 02:28:16 pm

Quote from: DavidS – June 02, 2018, 01:48:12 pm

If your temps get to hot for the setup wont the computer shut it down? I have climbed Baker grade in the heat of the summer and I think it was 222- 223 area.. I think at 225 the computer starts complaining.. I think?

ISM Engine Protection Theory of Operation - Cummins Engines

Re: Still running hot

Reply #11 – June 02, 2018, 03:54:29 pm

Go slower. . . Certainly go slower until you figure if you have a problem. Why push it. Wonder what exhaust gas (pyrometer) temps are.

Re: Still running hot

Reply #12 – June 02, 2018, 05:07:42 pm

Quote from: Bob Rozek – June 02, 2018, 12:24:00 pm

Is your trans cooler disc installed? We consistently blew out coolant until finding out ours was missing. Haven't lost a drop in two years.

Transmission cooler disc? My cooler is pretty straight forward. Four portals, two for coolant and two for trans. fluid. The transmission temps have been good and I have not detected leaks anywhere.

Re: Still running hot

Reply #13 – June 02, 2018, 05:22:48 pm

I did go slower and did drop two gears. Third was the next one down and that over rev-ed. Should I expect to go 40mph in fourth gear without a toad to avoid over heating? I could have done better than that with my Safari with small CAT. After spending the money on the ISM and replacing radiator, etc, I expect more, and from what I've heard and read, others aren't experiencing this problem. I don't want to have to stress every time I go up a long grade or have to disconnect the car. For those that suggested dropping a gear and running up the RPMs, which gear and how many RPMs?

I'm interested in knowing more about the trans. cooler disc, where it is located and about its function. The test light sounds like a good idea, once I figure out where to attach it.

Re: Still running hot

Reply #14 – June 02, 2018, 05:42:21 pm

"I hit 230 or so on a lot of western grades in the summer. No issues."

Caflashbob, the only time I hit 230 and trans temps in excess, my engine check light came on and the engine de-tuned (lost power), almost before I could find a safe place to pull over. It was after this experience I changed out the radiator. Your M11 may be different than the ISM.

Re: Still running hot

Reply #15 – June 02, 2018, 05:53:43 pm

Quote from: Sven and Kristi – June 02, 2018, 05:22:48 pm

I did go slower and did drop two gears. Third was the next one down and that over rev-ed. Should I expect to go 40mph in fourth gear without a toad to avoid over heating? I could have done better than that with my Safari with small CAT.

Your Safari was much, much lighter and the small CAT was a parent bore engine. DPs get no ram air to aid cooling. Just an inefficient hydraulic system that has to move all the air on it's own.

Some members have installed radiator sprayers to keep temp down. You need to use RO water to avoid the white calcium deposits. I think this is a good idea but have not had the time to do it.

I even turn the heater on with the fan on high. The engine temperature gauge reads higher with the heater fan on by about 15 degrees. The heater does work to reduce temps. I just hate to think about the work it will take to bring larger hoses up to the front.

Check your 12V schematic for where to put a test light to see if you are getting high RPM.

I drive in the gear and RPM to keep the temp at bay and don't worry about the speed. I have plans to put a couple of big aluminum radiators up front but that's not an option for you with the bus style front end.

Pierce

Re: Still running hot

Reply #16 – June 02, 2018, 06:43:19 pm

The Safari was about 2000# lighter and had a rear radiator, which worked to contain the heat in the engine compartment, but don't want to spend time with the comparisons. The FT has many more features that I prefer. I won't put down the Safari, because I believe it was a fine RV and well made.
Back to the issue: I use distilled water for the radiator, which should be better than RO. As far as I remember, it is as pure as water can get, devoid of all minerals which are precipitated out in the distilling process (we did this in chem lab back in the "college days").
I always use the dash heater in these situations and the ambient temperature was under 80. The only remedial action that I didn't take was opening the cowling (engine compartment door). I also base my driving on RPMs and temps. How fast I am going is indicative of the engine performance.
Sorry if my frustration comes through. The only thing that has made sense so far, is the fan speed, it might not be kicking into high.

Re: Still running hot

Reply #17 – June 02, 2018, 07:42:29 pm

Sven,

Sorry, I know I should have been clearer. The RO water was for the sprayer that some have made to spray water onto the front of the radiator to aid in cooling. Since RO water is free (if you have an RO system) that's the reason I suggested it. Usually, schedule 40 is used with brass misters and a 12V pump to supply the pressure needed. misting nozzles | eBay

12V 1 GPM/100 PSI high pressure pump for misting system: New Solid 100PSI DC 12V 1GAL/Min Diaphragm Water Self Priming Pump High...

Pierce

Re: Still running hot

Reply #18 – June 02, 2018, 10:10:09 pm

I vote for the mister. I did the redneck version. 1/4" plastic tubing zip tied to flat stock double stick taped to the radiator, 1/4" NC solenoid tee'd into the pressure side of the fresh water pump, and a switch to the solenoid on the dash. I used it a least a dozen times just coming across southern Tennessee (Hwy 64 E) today. Temps were high 80º low 90ºs. I never hit 190º. This is in a coach that fires on every stroke, is overloaded (fulltimer), dash air on, towing a 4600lb car, and the drivers foot gets heavier as the day goes on.

This simple cheap hack is one of the best things I've done to my coach. It does require more involvement by me driving as I have to decide when to use it and how long to leave it on. My goal usually is to never have the fan kick into high speed mode. I did as Pierce suggested above and ran a light to my dash for a visual aid. On mine when the light is on it's in low speed mode. Light off it's high speed.

If I don't do anything high speed mode comes on at 185-187º reverts back to low speed at about 184º. YMMV

The cheapest easiest solution is Barry suggestion. Relax slow down. Go to 4th. The mountains have the best scenery!

Edit: to change NO to NC!

see ya
ken

Re: Still running hot

Reply #19 – June 02, 2018, 10:51:27 pm

Mister on 94 6v92, works great on 2 Alaska trips

Re: Still running hot

Reply #20 – June 02, 2018, 11:38:27 pm

Pictures

Re: Still running hot

Reply #21 – June 03, 2018, 12:32:40 am

The early coaches had low/high electrical switched fan controllers

Later coaches went to a variable speed hydraulic fan controller.

Foretravel used a 165-180 way too conservative fan controller.

The rest of the industry used a 185-199 unit.

I and bob rozen both changed our coaches to the 199 degree unit.

In the posts here there is a mention of a disk in the thermostat to divert antifreeze for the trans cooler if memory serves me.

Some engines had the disk. Some did not it seems.

Thermostats do not open fully until 195

I personally convinced the Gillig rep to reprogram the beavers coaches engine shutdown settings as they were ridiculously low.

Don admitted they were way off finally.

We were in the edge of the desert and you had to go uphill to get out of so cal.

Bad in the summer,

Customers leaving at 4am to avoid unnecessary warning lights and power downs.

I had long talks with all the motor guys. And all the chassis guys and the Allison guys. And my garbage truck fleet/owner customers,

I actually rode along with Garrett Box's guys to see how hot their garbage trucks ran.

Oshkosh sent two engineers to me in Ca and the cat guy showed up and we instrumented coaches to test things in the desert summer heat.

Late 80's time frame.

James T should remember this stuff. Ask him.

My local Cummins shop manager/owner laughed when I asked a few years ago if running current engines at 220-230 would damage them. No.

Re: Still running hot

Reply #22 – June 03, 2018, 12:44:04 am

I just came up that grade out of Bishop yesterday towing my Grand Cherokee. Left the trans in economy and watched the VMSpc trans. got to 220 engine to 210, most of the time it was in 4th shifted to 5th a couple of times. 47 mph lowest speed reached at Deadmans summit.

Re: Still running hot

Reply #23 – June 03, 2018, 06:51:55 am

Sven and Kristi,

When I look at your problem I am making the assumption that the M11 and ISM cooling systems are similar as we use the same radiator. With that in mind is there any possibility that the deaerator box & bypass hoses are reversed?

Are you certain the coolant overflow is coming from the overflow tank and not the deaerator box cap. Our overflow tank was empty and the deaerator box 1/2 full when we purchased our coach 10 years ago. After filling both several times I started looking at other possibilities. Head gasket? Nope. After going through countless gallons of coolant I finally made the connection. The transmission cooler was starved for coolant, when the engine thermostat closed off, going down hill. The coolant pressure was apparently suddenly rising , under the right conditions, that it would force coolant past the cap gasket. I was able to reduce the amount of leakage by bending the ears on the cap to get a tighter connection. This did not solve the problem but greatly reduced the frequency. Fortunately, finally I saw a post from prevostart about a orificed disc. Suddenly everything made sense. This disc would force flow to the cooler solving the low flow condition. Cummins verified that it should be there. Mine was missing. PROBLEM SOLVED!!!!!!!!!!!!!!!!!!!!

Re: Still running hot

Reply #24 – June 03, 2018, 07:09:42 am

Caflashbob,
Just arrived in Sioux Falls SD.
2332 Miles/ 9.6 MPG/ 60-65 MPH Highway
I have recovered the entire cost of the replacement temperature control valve.

Thanks for the valve advice,
Bob

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