05 ambassador cummins engine temp hot

Sounds like a typical Monaco ground issue. Remove the panel over your instrument cluster and add another ground wire to the gauges. There is a big chink of frame back there that you can tap as another ground.

Mark2005 wrote:
I have an 04 Knight and the temp gauge would read very hot when we turned on the lights while traveling at night or any time for that matter....turn off the headlights and temp would instantly show a 30 to 40 degree drop

We traced the issue to a bad ground on the gauge cluster and once we resolved the grounding problem we had no other issues.

Also some of the other gauges would read erratically although the tach would read correctly.

Hope it is that easy a fix for you!!

Mark

Mine does the same thing

Randy,

Agree, there should be a bleed line from highest point on the engine/thermostat housing to reservoir. But many do NOT. I know for a fact that our last coach did not have one, and you had to crack open the coolant line from thermostat housing to air compressor to bleed the air from the thermostat housing. Fail to do that and you can crack a head, as hot air will NOT open the thermostat.

Hope there is one, but VERIFY.

I must address the "burp" the cooling system fallacy. All of the modern engines have a pressurized expansion tank. This tank should sit higher than the highest point in the engine. If it does not the RV manufacturer screwed up. There are usually 3 hoses to the tank: the main feed (my Cummins went to the lower rad. hose), the overflow and the bleed hose. The bleed hose attaches to the highest point in the engine cooling system so any air will travel to the expansion tank. Any vehicle equipped with an expansion tank, not an overflow tank, requires that you fill the system, pressure test it, put the cap on and run the engine. As air moves to the ET the level may fall but if you pressurized the system this will not occur. When you pressure test the system you will feel, the amount of time it takes to reach pressure, any air in the system. When you release the pressure any air will usually move to the ET. Top off the ET and let it run. Make sure you have the heater valve open.
Randy

I have an 04 Knight and the temp gauge would read very hot when we turned on the lights while traveling at night or any time for that matter....turn off the headlights and temp would instantly show a 30 to 40 degree drop

We traced the issue to a bad ground on the gauge cluster and once we resolved the grounding problem we had no other issues.

Also some of the other gauges would read erratically although the tach would read correctly.

Hope it is that easy a fix for you!!

Mark

I would not stress that engine with climbing some of the grades in the mountains until I located and fixed the problem. You're going to find yourself on the side of the road somewhere where it's either not safe or inconvenient..Murphy's Law demands it. IR guns are everywhere..Home Depot, Lowes, Harbor Freight. Determine IF you have a problem first, then fix it before heading into the mountains...Also, when they changed the fan clutch, I assume they put new coolant in at the same time. Maybe you have an air bubble in the cooling system, and it simply needs to be burped.....just my 2 cents worth.....Dennis

does your alladin system agree with the gauge?

If you have a side mounted radiator stop and get the radiator cleaned. It is most likely plugged with dirt not permitting enough air flow thru the fins to cool the water.

When we were having overheating issues with our 330 ISC it was because of a very blocked radiator that eventually had to be removed and cleaned. The check engine light should light up as you get around 220, I was able to monitor it pretty well with the Scan Gauge D. I would bet on a dirty radiator, best of luck!

Don't count on the engines electronics to keep it from destroying itself.
You can ruin that engine.