wolfe10 wrote:
Scott,
I agree, I personally would not continue without addressing the overheating at 230 degrees F. Will it do permanent damage-- probably not, but certainly is not as good as running with it lower.
Things you can do before facing that situation:
1. As you did, clean the CAC/radiator-- mostly from the front where the dirt is deposited. Needs to be done at least once a year on a rear radiator chassis.
2. If the crankcase breather has not been extended to behind the fan shroud, do so immediately-- cost under $10. If anyone needs information, let us know. If your chassis maker did not extend it, you WILL have lots of oily dirt deposited on the front of the CAC blocking air flow through the CAC and radiator.
3. If your engine has a separate belt for the water pump (as do the Caterpillar 3116, 3126 and C7) make sure it is properly tensioned-- it does NOT have an automatic tensioner.
4. Make sure your coolant is "current"-- i.e. changed per the coolant manufacturer's recommendation, pressure cap is good, thermostat(s) are good, etc.
4. When really hot daytime temperatures are forecast, we change our schedule and drive in pre-dawn and morning. Particularly if heading east where the windshield will get all that solar heating.
Once on the road and experiencing overheating:
1. Turn off dash A/C. At a minimum, that is a 5 HP load on the engine. And, if the condenser is in the cooling package's air flow there is an additional heat load. Use roof A/C for cooling.
2. Gear down, running the engine at higher RPM's/lighter throttle. Climbing a grade at a certain speed takes XX HP. If in a lower gear/higher RPM/lighter throttle, the heat load produced by the engine is roughly the same, but the fan is turning faster, the water pump is turning faster, so more BTU's can be dissipated. For the 3126 or C7, that means around 2000 RPM.
3. Before overheating becomes excessive, pull over and run the engine at high idle until is cools back down.
4. If you are overheating and there is no place to pull over, turn on the dash heater with fan on HIGH. Yes, you will be uncomfortable for a few minutes, but the pain will be less than doing major engine damage. The heater is nothing more or less than an additional "radiator".
Brett
Brett,
Roger all that Sir. I have done EXACTLY everything you've listed there. That includes leaving our home in the San Diego area and heading for the Bishop CA area (about a 350-400 mile run) at exactly midnight. Coolest temps, and NO TRAFFIC WHAT SO EVER! Now, again, mine has never hit the 230 mark and I wouldn't even let it come close before I'd head it off at the pass, so to speak.
Our C-7 runs great. I runs at 190 for 99.99% of the time. It will climb in temp, on the grades, if certain conditions prevail. But, it does not get out of hand. If others, who have the same exact coach, can climb the same exact grades and towing the same weighted toad, at the same exact outside temps, and have the same gearing, DON'T have any rise in engine temp, then I envy the heck out of them.
I watch my RPMs and keep them up for additional fan cooling and better gearing, the tires are up, and all precautions have been taken. About the only thing I've not done is pull the thermostat and replace it. The coolant is brand new. Thanks for your additional support here.
Scott
Passin Thru wrote:
FIRE UP You need to talk to CAT. 212 is not hot. You should be running CAT long life antifreeze (Red) and you can run in temps in CA as high as 230 degrees I believe because you are running it under 15 lb pressure.
Passin Thru,
I surely appreciate your advice here. I am running the Red CAT anti-freeze. And, this coach normally, for about 99.9% of it's travels, hovers around 190. As stated, it will climb on grades and especially if the outside temp is hanging around 90-100 degrees. Our first adventure with this rig was a couple of years ago and we were heading towards Vegas on the Baker grade. The outside temp was right at 104. Right close to the Hallorin Summit off ramp, the alarm system alerted me of "High heat threshold". I glanced at my Medallion Info screen and if I recall, the temp of the coach was around 217-220, (again, I think) and that screen said "High heat threshold". So I pulled off the freeway at that off ramp and, let it idle for a few minutes with a bit higher RPMs. All was well within about 5-6 minutes and the temp of the engine was around 201.
Now, I'm not sure how many others run at higher temps in that same situation but, I've since removed the radiator and the CAC and thoroughly cleaned every square inch of both. But, 230 degrees, that seems seriously high to me.
Scott
n4hwl wrote:
I know there are a lot of motorhomes out there with the cat 7.2 liter. I have had a few problems with mine. I have lost 2 injectors and had a wiring harness for the injectors inside the valve cover dropped down and shorted out on the rocker arms. That was expensive. I also recently had an oil leak around the plate that holds the oil filter where it attaches to the block. This has happened over about a 4 year period and about 30k miles. What kind of luck are others having with their cat c7 engines?
Ken
n4hwl,
Knocking on my head here (wood), we've had pretty darn good service out our '07 Itasca Horizon 36GD with the C-7. It's ran down the road with great dependability. The only time it's had any issues is, when I'm on a long grade and, it's warm outside. The temp will climb to anywhere from 205-212, plus or minus. And yes, I've done all the radiator/CAC cleaning etc. way more thoroughly than most. But, that engine sure seems to work great.
I've changed the oil each time myself and the fuel filters too. While I had the radiator and CAC out for maintenance and replacement, I replaced as many of the front bearings (serpentine tensioner and idler) (could not get the fan bearing off to replace it, grrrrr). Anyway, I think it's a good engine. Of all of the C-7s made, and, especially the ones in Motor homes, (no other service) I don't know how many have had any issues. You read of some issues that some on this forum have had but, not everyone who drives a motor home, especially one with a C-7, resides on this or other forums. So I don't know the ratio of the ones with say, serious issues, like the HEUI pump failure, is to the ones with no issues what so ever, in the time frame of ownership and long distance mileage.
Scott
