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dloneal68 · 06-15-2019, 09:47 AM

I have a 2004 Holiday Rambler Ambassador with a 330 Cummins and I have just replaced the radiator and cooling pack with a copper brass instead of aluminum. So we just came back home from a 2000 mile trip pulling a toad and on the last 200 miles of our journey it was hot like 90 degree weather. Lots of mountains to climb. It was the same climbing on our way starting the trip with the exception of the temperature was in the 60's. There is almost 39 thousand miles on the engine now. O.K. on our way home the temp gauge began rising past the 200 degree mark then into the red and then 250 degrees and the check engine light came on. As soon as I got to the peak of the climb it went down to about 220 and the check engine light went off. The check engine light would go off as soon as the gauge started dropping off the 250 mark. I know all the things to do when a motor overheats so first I turned off the dash air, then I cranked up the heater to as high as it would go and that helped. I down shifted to keep the rpm up 1500 or more. It seemed like I was loosing pulling power after a while and that was due to the engine was probably derating I think. All in all I got us to our home base and when I stopped and went back to check the radiator the temp had already went back to the normal range. There was no water or steam coming out and the water level was perfect. I have an appointment with Cummins to check this out but I am totally confused as to why all the overheating and check engine light but no steam, no water loss, does not compute. Any ideas?

Skiddy · 06-15-2019, 09:55 AM

sounds like the temp sending issue, the gauge isn't reading accurate

Outbound · 06-15-2019, 11:26 AM

If you were losing power I would say motor was getting hot, I would also check cooling fan for high speed operation to confirm it is ramping up.

oscarvan · 06-15-2019, 11:53 AM

Food for thought for others..... at 230 I slow down, at 235 get off the road.... Taking it to 250 would make me very unhappy.

BeenThereB4 · 06-15-2019, 01:04 PM

Sometimes it is necessary to "burp" cooling system to be certain any air bubbles are purged and eliminated (once components have been replaced/reinstalled) you can find info on doing that procedure by google search if needed.. This could be very important because air pockets can prevent your system from cooling adequately, I have seen it happen. . The net result from that being that the coolant level in radiator could actually be low, although it could appear correct with rad. cap removed as fully warmed up engine idles.. Coolant levels below a certain point will show up for sure when you're climbing an upgrade out on the road.. keep an eye on that temp gauge..
Then I d double check (cooling system related) electrical connectors are clean and tight for connectivity, basically a "double check" that all is in good order, nothing overlooked during reassembly after your recent Radiator swap. make sure your cooling fan is getting a good ground and such.
If electrical cooling fan is not consistently kicking on when the sending unit calls upon it to run, this could indicate poor connectivity or a bad sending unit, for example..
I see you mentioned very low miles on your engine, but I'm wondering how many miles total on the vehicle, and are the cooling system components now in use all original to the vehicle ? (cooling fans, sending unit, thermostat, basically everything except the new radiator)
Making certain the coolant is filled to proper level with proper coolant type, and definitely no air pockets (as above) give it a good road test, and see what happens.
If your overheating situation is still there, just normal troubleshooting sequence should lead you to the cause and solution.. Heck, I even have seen one situation where they put a thermostat in backwards.. Took em the longest time to figure that one out, because nobody was expecting that.. (LOL)
Let us know what you found out, we might learn something new (thanks)

Mtn. Lion · 06-15-2019, 01:49 PM

Keep driving it up a grade with coolant at 250F and above? Run it into the ground why don't you

BTW, the head gasket(s) may go soon.

Journey cat · 06-15-2019, 01:59 PM

Maybe due to the temperature changes .
It may have been beneficial to select a lower gear climbing the hills ?

nathaniel · 06-15-2019, 02:02 PM

Could you hear if the cooling fan kicked on in HIGH I have a 40 ft and I can hear when mine comes on at 220 and drops temp back to 187 in about 8 seconds. Sounds like you fan clutch is not working. When ever you get running hot like that you should slow down to a crawl let it cool off. You pop a head gasket or worse it will cost a whole lot more than your time to slow it down

Kodiakan · 06-15-2019, 02:04 PM

For next time keep in mind my Cummins 330 manual says running over 212 degrees for any length of time is a no-no.
1500 rpm wont get you cooled down. On mine at least it takes about 1800 rpm. Yes, ambient temperature makes a huge difference after 85 degrees or so on a flawed system. I would have Cummins check to see if the original hoses are still on or if they R&Rd them when you replaced the radiator. You could also just check your bill as they would be charged on it. One might be restricted. Best of luck.

oscarvan · 06-15-2019, 02:12 PM

I want to second the filling procedure. There's a big yellow sticker in the back of mine with the procedure. RE-doing that and making SURE there's no air in there is not a bad idea since the system was drained.

I can't hear my fan kicking in..... it's 40' away, but I CAN watch the gauge and SEE it kicking in as it has an immediate effect on the temperature.

BTW, my 6.7 ISB340 lists the max coolant temp at 220ºF. Now to be fair, I also know that some of the temperature limitations are not necessarily to avoid damage to the engine as they are to prevent breakdown of the coolant. Mine has additives (OEM) that don't like getting hot. But that's another story.

DamonCamper · 06-17-2019, 10:45 AM

Quote:

Originally Posted by oscarvan

I want to second the filling procedure. There's a big yellow sticker in the back of mine with the procedure. RE-doing that and making SURE there's no air in there is not a bad idea since the system was drained.

I can't hear my fan kicking in..... it's 40' away, but I CAN watch the gauge and SEE it kicking in as it has an immediate effect on the temperature.

BTW, my 6.7 ISB340 lists the max coolant temp at 220ºF. Now to be fair, I also know that some of the temperature limitations are not necessarily to avoid damage to the engine as they are to prevent breakdown of the coolant. Mine has additives (OEM) that don't like getting hot. But that's another story.

Not to highjack but on the same line.....

With a ISL 400 Cummins ours runs about 180-190 or so. No markings on the gauge (but it is below 200(, what is the normal temp running on flat land?

koda59 · 06-17-2019, 07:13 PM

We have the ISL 400 and our temps run 180 to 190 all the time. When it ran at 175 Freightliner said that was to cold. Found the fan control module bad. It was running on high all the time.

A Traveler · 06-17-2019, 08:27 PM

Quote:

Originally Posted by dloneal68

...I down shifted to keep the rpm up 1500 or more....Any ideas?

Yes, I have an idea.

1,500 RPM is WAY TOO LOW when climbing a grade and working the engine hard. You should shift down to keep the RPM up around 2,000, not lugging badly at 1,500. At 2,000 RPM the engine is up near its horsepower peak (where you want it when climbing a grade) and you are running the water pump faster. This could be your entire problem.

RiverBurt · 06-17-2019, 08:53 PM

The faster you go, the more horsepower you need. The more horsepower you’re using, the hotter the engine gets. 1,500 or 1,800, or 2,000 rpm, you still need more horsepower to climb faster.

SLOW DOWN, drop a gear, keep the engine at peak horsepower, and something (probably turbo PSI) will drop. The exhaust and coolant temperature will drop along with it.

It’s simple math. Well, algebra, akshully...