High Coolant Temp Light

[jimgoedde]

I have a 97 Safari Sahara with a Cat 3126 engine. After changing the coolant and temp sending unit I get a red light only after the engine temp comes up to about 178 degrees. The gage reads normal and my Silverleaf computer program reads 178-182. Any ideas on why the light comes on at a normal temperature would be appreciated.

Thanks

Jim

[rossboyer]

After changing the coolant, possibly there was an air bubble that caused the coolant level to appear to be normal; but after running for a while the bubble is gone and coolant needs to be added. After the engine cools down, suggest you check level again.

[ticat900]

After changing the coolant, possibly there was an air bubble that caused the coolant level to appear to be normal; but after running for a while the bubble is gone and coolant needs to be added. After the engine cools down, suggest you check level again.

How would that cause the overheat red lite to come on especially if both coolant temp gauges both show 178??? and if the coolant was that low it sure as heck would not show normal temperatures.??

unless this is a low coolant warning? and not a heat warning? then it may as others have aluded to simply need topping off

[rossboyer]

I had a the same problem after flushing and changing coolant. Topped off and the problem went away.

[jimgoedde]

I'm sorry I should have supplied more information on my original post.

I have taken the m/h on two subsequent trips. I topped off the coolant twice and the level now seems stable. I'm sure the warning light signal comes from the ECM (engine control module).

But does the ECM, and the two temperature gauges all get there input signal from the same sending unit (mounted at the thermostat housing) which I replaced at the same time as the coolant?

Thanks for the previous notes and for any additional information.

[wolfe10]

Generally chassis maker installs a separate temperature sending unit than the engine manufacturer. But, call your chassis maker with your chassis serial number to verify.

[dickandlois]

Hi Jim and Welcome to FMCA!

There have been times when the wrong temp sender or a defective one has been shipped and installed.

I'm not on top of the Cat engine spent most of my time with Cummins.

The fact that the coolant level is now stable would suggest that any air in the cooling system has been purged.

Have you experienced a power degrade issue? With the read lite coming on?

The ECM should be reading the same sensor for the reading you are getting on both the gauge and the Software program.

Silverleaf reads information directly from the ECM data buss.

See that Brett just chimed in and he is a Cat man.

Rich.

[jimgoedde]

Thanks for the inputs. I'll order another sensor and let you know the outcome.

Jim

[wolfe10]

If this occurred coincident with work in the engine room (you mention changing coolant), I would check that the connections are clean and tight, no broken or frayed wires before spending money on a sendor.

[dickandlois]

Jim, After checking with chassis / engine manufacture, see if the part number they list for the sensor matches the one you installed also. Along with Brett's thoughts.

Rich.