Engine Temp In Hot Weather w/ Trailer Behind

[Kelly Bluebaugh]

Newbie here  Just bought a 99 Patriot 425 hp w/ C-12. We plan to run cross country racing with a 28 foot stacker trailer in tow. Yesterday, we were headed down a flat highway w/loaded trailer and noticed the engine seemed a bit hot at 219 on the Silverleaf. The outside air temp was was in the high 90's. dry air. We live here in the AZ desert and it is normal for engine temps to rise 10 even 20 degrees in the summer. Is this however normal for the C-12 given the condition? The engine later ran 194 when the air temp was down and the engine had cooled. The previous owner said he upgraded the cooling system with an aluminum recovery tank. Is this engine temp just normal, which may be? Does the cooling system perhaps need to be burped? How hot is of concern? Thoughts? Thanks!!

[Steve Huber Co-Admin]

Kelly,
Normally a C12 will run at about 185F. 219F is too hot IMHO when running on flats. The check engine light will illuminate around 220-225 (if I remember correctly). I could pull the Black Canyon to Sunset Point Hill on I17 in the summer with the same engine (pulling a Jeep Liberty) and temp would max out at around 200F. Since you were running on the flats, I'd check a number of things; coolant level, weight of trailer, were you fighting a strong head wind, were you really lugging engine, etc. Also, you may have a faulty thermostat or wax valve.
Steve

[Kelly Bluebaugh]

We were fighting a little bit of a head wind. The stacker trailer is a good bit heavier but that is also why we looked for the 425 hp. Here is a picture of one for perspective. We also made sure we had a side mount radiator for plenty of air. Thanks 

[Joel Ashley]

That triple axle trailer looks like quite a load, perhaps better handled by a 500 horse than a 425, esp. if the coach itself is of any size, and if either or both are fully loaded.  It’s critical that the loaded status of the combination doesn’t exceed the GCWR provided on the coach and it’s documentation.

Joel

[Steve Huber Co-Admin]

Kelly,
That looks like a lot of wind resistance. In addition to the items I mentioned previously, consider running the coach with and without the trailer on the same route and day. That will give you an indication of the temperature load the trailer is adding. Also as Joel noted, the hitch is rated at only 5K lbs. You may need to have the hitch reinforced in addition to addressing the cooling issue.
Steve

[Dave Atherton]

Kelly, yes your trailer is putting a lot wind resistant. Before you start repairing or stopping at
Service shops and spending money. Would suggest dropping your transmission down one gear
To fifth gear and see how engine will operate. Remember it takes a big engine just to push a
Flat front motorhome down the road now putting load and a head wind you are working the
caterpillar 425 pretty good. You will use more fuel but there has to be a spin off to get your
Trailer down the road with you also. Dave Atherton Retired Cat Mechanic

[Jerry Emert]

Kelly, I have driven in the summer in Florida 95+ temps.  My C-12 almost never gets hotter than 186.  The hottest I've seen is about 195 going up a steep hill in the summer in Arizona.  My transmission now stays in the 250 range in the hot summer.  Not todays issue.  Good luck.
Jerry

[Mike Tomas]

Kelly. I have a 2000 C-12 Patriot 425 and live in Phoenix also.

Before we purchased our coach I performed a coolant analysis. in my case, I know the cooling system is -pristine- But the two dealers that had it previously, just topped it off using tap water.(Only coolant issue). We changed to CAT ELC Pre-mixed immediately before any corrosion could be done.

That being said, With ambient temperatures around 90 degrees, we took our first run up to Sunset Point last month, and again last weekend. Both times We climbed that hill at approx 185 degrees never dropping below 55 MPH. But by experience (especially on THAT hill) I shifted down to 5th and shot up it PASSING CARS along the way (I was seriously verklempt .

This may help you with a baseline expectation with your coach without a trailer going up to the top of Black Mesa. Temperatures here in Phoenix will be in triple digits the next few weeks (months). I'd expect your engine temperature to be just slightly higher, but no where close to 200 (assuming 5th gear used).

I am no engine expert, and no where near "Gerald Farris" master of all,  but I've read a lot of posts during my research phase. I'd recommend Googling the following string:    c-12 side radiator overheating site:beaveramb.org

I'm close by, feel free to PM me if needed. I hope I've been of some help.

[Kelly Bluebaugh]

Thanks Everyone 

Today, We had a Diesel mechanic take a look and run some tests. He thinks it may be the Hydraulic Fan Motor and plans to run a few more tests tomorrow. All in All, it seems that 219 under any circumstance is too hot. It also seems the trailer is having some impact. Being that we just got the unit, we do not have enough road time to really make ample before an after comparison except to say we noticed the problem clearly with the trailer in tow in the head wind with higher outside temps. We may have well been lugging the motor.

My new question is, what are the most likely candidates for causing the fan not to function? The mechanic brought the engine to temperature and the fan did not turn on? I did read in another post here a good point that perhaps the static test did not bring the engine temp high enough to trip the fan start? I just don't want to get stuck for a motor if its a common relay or simple fix. Thoughts?

[Kelly Bluebaugh]

Kelly, yes your trailer is putting a lot wind resistant. Before you start repairing or stopping at
Service shops and spending money. Would suggest dropping your transmission down one gear
To fifth gear and see how engine will operate. Remember it takes a big engine just to push a
Flat front motorhome down the road now putting load and a head wind you are working the
caterpillar 425 pretty good. You will use more fuel but there has to be a spin off to get your
Trailer down the road with you also. Dave Atherton Retired Cat Mechanic

Dave, We were considering a Nose Cone for the trailer- Thoughts?  Thanks

[David T. Richelderfer]

I have read about a "wax valve."  Is this valve something that would be pertinent to this discussion?

I entered "wax valve" into the search routine and got back many posts to look at.  This one seemed maybe too obvious but still worthy of consideration.

http://beaveramb.org/forum/index.php/topic,6764.msg48705.html#msg48705

[Fred Cook]

I see some are saying their C12 hovers at around 185 degrees. Mine hovers at 189-192 and sometimes 194 pulling a long hill in hot weather.  I am hoping that is not too far out of the ordinary.

[Steve Huber Co-Admin]

Fred,
Those temps are OK. You may have a 190 thermostat.
Steve

[Michael Rump]

All,

I changed the thermostat on our C12 and the new one is rated at 194.  The one I removed was rated at 185.
CAT made this change.

The coolant temperature now cycles between 188/194 until the engine gets really hot and then it stabilizes at 192/194.
On a steep hill, it will rise to 201/203 and then settle in at 194/197.

Regards,