Foretravel Owners' Forum For owners and Fans of Foretravel Motorcoaches September 08, 2025 ...

engine overheating

August 11, 2010, 08:40:08 pm

I am out west and have experienced overheating on some of the hills. I had the coolant changed in July and they steamed cleaned it because of a gell substance. We climbed from 7K' to 8K' in just a few miles, dash air off, 85 temp  outside, and was in 4th at 50mph and the temp was up to 210 and climbing. We stopped at the summit and opened the rear engine door and left it running and in 5 minutes the temp had returned to 180. Any suggestions on what to check or should I bring it for a check. 450 Cummins. Thanks John

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Re: engine overheating

Reply #1 – August 11, 2010, 10:02:02 pm

Do you think going up the hill in 2nd or 3rd at about 1600 RPM would be a cooler run?

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Reply #2 – August 11, 2010, 10:38:55 pm

John,
 
Do you recall what your RPMs were?

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Reply #3 – August 11, 2010, 10:56:12 pm

First, I'm no expert, but we did do quite a bit of mountain driving this summer.  I found that a good rule of thumb with our ISL400 (2003 U295 36) was to keep the speed in the 30s in 3rd gear and 40s in 4th.  Going up hill I try to shift into a gear that maintains a fairly constant RPM.... so if the RPMs are dropping, I will shift into a lower gear and reduce my speed.  I had a similar experience to you going through Las Vegas a few weeks ago.  The temps were in the 100s and climbing out on the hill in the south end of LV pushed the engine temp to above 200 and rising.  So I just slowed down and shifted down to keep the RPMs above 1400 and the temps came back to near 180 where it normally is.  In addition to the engine temp, I also keep an eye on trans temp and intake manifold temp (Silverleaf).  Driving one of these beasts does take a lot more attention than driving a car. 

George

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Re: engine overheating

Reply #4 – August 12, 2010, 06:12:28 am

Is that 210 on the silverleaf or on the dash gauge. If it is on silver leaf and or if they both match, that should not be a problem. You have very thin air up there and the fans are not pulling as much across the fins to reduce the heat. ALso if you had your foot in it and were  WOT you are pour raw fuel that will just be burned and create extra heat.  I have hit 210 when it was very hot outside and climbing mountains in the past but when I climb the same amount of grade but at a lower altitude it does not go up as high. I think I would not start to worry till I was well over 215 and if you back your foot off and slow down a bit and gear down to keep the rpms up, you will be fine. I have driven many many miles in the mountains both on the east and west coast in three different FT. I would not worry over 210.

George, you are 100 percent correct. One of the benefits of this board is we share our knowledge. Mountain driving going up requires a skill set as well as coming down the mountain requiring another skill set or you can smoke your brakes or worse.

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Reply #5 – August 12, 2010, 07:40:37 am

In '08 our '01 U270 with 350 ISC was overheating badly when approaching Colorado from Texas. When we got to  Ratan Pass, it was obvious that we weren't going to make it and I pulled in to a Diesel shop. The mechanic said the radiator was probably clogged and removed the cover from the bottom of it. Sure enough a lot of straw was jammed in there and it appeared that a squirrel or bird had nested there. The mechanic said that at least one third of the radiator was ineffective. He powered sprayed everything (recommended that I don't ever do this) and spent about and hour and a half working on it cleaning everything. We proceded on our four month Alaska trip with no cooling (or other) problems. He said he sees this a lot with boxed in side radiators and recommended that I clean this area annually.

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Reply #6 – August 12, 2010, 10:43:03 am

Thanks to all who replied, guess I need a lesson in mtn driving. I was trying to keep the RPM's up around 1800 but probably was trying to keep my speed up as well. This is such a great reference Thanks a lot John

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Reply #7 – August 12, 2010, 03:01:50 pm

We travel the west with a 36' U270 pulling heavy 24' trailer which puts us at around 40K pounds with a C8.3 mechanical.
Long runs like from Tularosa to Ruidoso or the SR375 Loop around El Paso really put a load on the rigs cooling ability.
I have found that if I choose a gear which allows me to run the engine at 2000-2100 RPM's on a long climb my temps will stay under control.
It seems that the higher engine RPM's, provide for faster circulation of the coolant from the engine to the radiator.  I have noticed that if I am climbing and RPM's drop under 1800 the temps increase dramatically.  If its not too hot it will run well around 1800 RPM.
FWIW,
Regards,

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Reply #8 – August 12, 2010, 06:48:17 pm

We unbolted the conveyer belt material on the bottom of radiator area, removed slatted grill on outside of radiator and used a water hose with a small brass nozzle to wash out lots and lots of leaves, grass, twigs, dirt, etc from between the outer silver colored turbo cooler and the inner black radiator.
 
We now have a hardware cloth screen, just behind the grill to catch grass, etc from being sucked into the radiator area.
 
Our overheating seems to have gone away, but we also drive up mountains/hills differently now.  Yesterday, I shifted to a lower gear and drove slower just to keep our pyrometer temp lower, which also keeps coolant temp down.

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Reply #9 – August 12, 2010, 07:01:03 pm

We recently returned from our first long trip in our 1997 U295 with C8.3. I think it has a Banks Stinger (tweaked turbo) installed by the previous owner. We were at about 32,250# gross. We climbed significant grades on US-40 out of Steamboat Springs, I-70 from Dillon toward Denver, and I-25 into Raton. I set maximum engine effort based on the pyrometer. If it was above 1250F, I eased off the throttle. I selected vehicle speed and gear according to requirements to keep the exhaust temperature in range. We had no issues with water temperature.

Coming into Denver from the Eisenhower Tunnel, I controlled speed with the retarder and selection of an appropriate gear. I didn't use the brakes until the exit near Golden. The transmission temperature didn't exceed 200F according to the dash gauge.

If all systems are clean and functional, it appears that choosing an appropriate speed and gear will allow all equipment to stay in appropriate temperature ranges. That may mean slowing down a bit. What is your rush anyway?

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