450G engine coolant temp warning

[BigYellowjeep1331]

5 min after operating my 450g the engine coolant temp warning lights comes on. I replaced the radiator cap and the lid for the overflow tank. Is there a way to test the water pump? I started it with the radiater cap removed thinking I'd be able to see the coolant circulating but it didn't after idling for 10-15min. Also could a plugged fuel filter cause it to overheat?

[Jim B]

Welcome to the Boards.

Your 450G is on the new side of most here so only a few actually have one of those. In general, I will say 5 minutes of idling wouldn't start to warm it up, so it is not likely you would see any circulation anyway. It sounds like an electrical issue to me. I would use a handheld temp gun and check the thermostat housing and the water pump inlet as it warms up, watching to see how the temps change as it warms.

I do not see a plugged fuel filter causing the light to come on, unless the same light covers coolant, fuel and other systems on the crawler. Does it? What does your Operator's Manual tell you? Do you have an Operator's Manual? Do you have the Technical Manual set for it? TM1403 is the Operations and Test Manual which will have the recommended operating parameters and tests to check and diagnose systems. TM1404 is the Repair Manual with the wrenching info related to repairs.

[njoldiron]

What about the thermostat? When it is open the coolant should be circulating around easy enough to see through the radiator. If it is not opening the engine will overheat.

[BigYellowjeep1331]

What about the thermostat? When it is open the coolant should be circulating around easy enough to see through the radiator. If it is not opening the engine will overheat.

That's what I was thinking as well and i never physically see any circulation of the coolant. But the coolant in the radiator does eventuslly get really hot. Hot enough to crack the lid on the overflow jug.

[dtoots1]

you never did say whether you checked the fan belts to see if possibile slipping...that too will cause overheat...
i generally pull the thermostat and heat it on stove in water....watch temp with cooking thermometer and see if opens around 180 degrees...else start looking at water pump itself...i like to see reality

[BigYellowjeep1331]

Sorry. The belts are not slipping. After a few min of operation the right side radiator hose and radiator are hot but the radiator hose on the left side is cold.

[BigYellowjeep1331]

I also found coolant around the cap for the radiator

[Jim B]

Hot water from the engine passes through the thermostat and through the hose to the top of the radiator at the right top inlet connection. cold/cool water is pulled into the engine by the water pump through the left hose hooked to the outlet of the radiator. If the radiator is doing what it is supposed to the coolant temperature will be lower at the bottom left. It takes more than a few minutes to make a good assessment.

Use a temp gun/infra-red thermometer to check the radiator core to look at the temperature across and down it the temp should spread out at the top and get coolers as it goes to the bottom. Did you use the temp gun as I suggested to get some actual temperatures? If the thermostat is opening the top of the radiator will be about the same temperature as the hose side of the thermostat housing. (It is best to shot temperatures on metal not on the hoses, as hoses can skew the readings.) If you are going by touch most people find 120 degrees uncomfortable and can't touch 140 for long. Your engine will run 190 to 210 degrees depending on ambient temperature and engine load. Get some actual temperatures at several locations as it warms up.

When was the radiator core last cleaned externally? Can you easily see through it if you put a light on the engine side and look through it from the grill side?

Coolant around the cap can be a worn cap that is not holding the pressure it should. do you know anyone with a cooling system pressure testor? Those can test radiator caps.

It is possible to have a loose or bad impeller on a water pump. Try to rule other things out before tearing the water pump off.

[BigYellowjeep1331]

I had the bulldozer up to operating temp and the engine temp warning Light was on with the bottom hose cold to the touch and top hose was untouchable. I don't own a thermal thermometer. I'll see if I can rent 1. I dont know the history of the dozer ive owned it for a 2 years and most of that time its been in the shop being fixed. I'll order a new cap and flush the cooling system too. Thanks for everyone's input and help. It's very much appreciated

[Jim B]

If you have a Harbor Freight near you, they have at least 3, ranging from about $11 to about $50. I have the $25 one and for the general needs it works fine and is handy for temperature checks many places, not just an engine. You can scan the radiator core with it running to see if there is flow going down through the entire core or it seems to be narrow trails indicating blockage. Again, look from front to back with a light on the fan side to be sure the fins haven't plugged externally so it is not passing air through it correctly. Does it have a puller or pusher fan?

[jimmydiesel]

Replace the thermostat and retest.
The water pump not pumping is possible but unusual.

[BigYellowjeep1331]

I removed the 2 thermostats so I could test to see if they were working. While I was waiting for my water to boil I put the thermostat housing back togeather without the thermos. Started the dozer and took off the radiator cap and could see coolant flowing through the radiator. So the water pump is good. Both thermostats opened when placed in the boiling water. So that really narrows it down to someone putting the thermostats in backwards right?

[Jim B]

Were the thermostats in backwards when you took them out? When you removed the thermostats were the pellet and spring ends towards the engine? The fact that you said the top of the radiator was untouchable would indicate the thermostats had opened and were passing coolant. Did you check temperatures with thermometer? Did you scan the radiator with a thermometer to see if it was hot at the top and cooled evenly to the bottom? Going by touch is not a good check. It is possible the warning light or its sender are bad.

[BigYellowjeep1331]

My friend removed the 2 thermostats for me and didn't pay attention to there orientation. Is it possible to install the thermostats backwards? I used a thermal camera to see the temp difference between the upper and lower hose.

[Jim B]

Were you able to track coolant flow down through the radiator? You should the hot coolant spread across the radiator, then down as it cools. That should show across most of the radiator. Going down the radiator in a narrow area could indicate a blockage in the radiator.