Overheating, Dex-Cool turns from orange to red
September 19th, 2012, 2:56 PM
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Overheating, Dex-Cool turns from orange to red
OK, first post here, welcome me 
2003 Express 1500 cargo. While driving out west in the 100 degree heat, pulling a trailer, my collant temp would hit 3/4s and beyond. I'd turn the heater on to help cool it down. Without the trailer and high heat, all was a normal.
Now I'm back home, I did a complete flush and replace with new straight Prestone Dex-Cool coolant (mixed with remaining water in block). Now it's back to running hot like it did, but no trailer and it's only 70 degrees out. It does not run hot when it just sits idling.
Now, what I find odd is, the bright orange coolant I put in is now red. I changed it 3 or 4 days ago.
Yes, I checked the fan, it spins free when cold, fast when warm, faster when hot.
I do not have bubbles blowing out of the fill hole. I do not have oil in the water, nor water in the oil. I did notice my tranny fluid is almost clear pink.
I'm scraching my head on this one. I'm thinking maybe the radiator is partially clogged, but that wouldn't explain the changing color.
2003 Express 1500 cargo. While driving out west in the 100 degree heat, pulling a trailer, my collant temp would hit 3/4s and beyond. I'd turn the heater on to help cool it down. Without the trailer and high heat, all was a normal.
Now I'm back home, I did a complete flush and replace with new straight Prestone Dex-Cool coolant (mixed with remaining water in block). Now it's back to running hot like it did, but no trailer and it's only 70 degrees out. It does not run hot when it just sits idling.
Now, what I find odd is, the bright orange coolant I put in is now red. I changed it 3 or 4 days ago.
Yes, I checked the fan, it spins free when cold, fast when warm, faster when hot.
I do not have bubbles blowing out of the fill hole. I do not have oil in the water, nor water in the oil. I did notice my tranny fluid is almost clear pink.
I'm scraching my head on this one. I'm thinking maybe the radiator is partially clogged, but that wouldn't explain the changing color.
September 19th, 2012, 3:53 PM
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Seems possible from your posts you could have a radiator leak as the tranny fluid is leaking into the cooling system. That could cause overheating, also have you replaced the thermostat? Oil in the cooling system, depending on how severe it is will show (usually) as a brown slime.
September 19th, 2012, 4:13 PM
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I thought about tranny leak, but the tranny fluid level isn't down. Unless... coolant is getting into the tranny, too. What happens to tranny fluid if coolant gets into it?
No sign of oil in the coolant. It's nice and clean... just red now lol
No sign of oil in the coolant. It's nice and clean... just red now lol
September 20th, 2012, 6:47 AM
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The manual says the capacity is 11 quarts. After flushing with pure water and draining, I was able to get 7 quarts of coolant into it. So about 64%?
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September 20th, 2012, 7:50 PM
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OK, is it possible for a water pump to be bad in a way that it doesn't pump [enough] water, without making any noises like it's going bad? I picked up a Block-Chek kit today and the fluid never turned yellow. But while testing, engine idling, all of a sudden I had a rush of anti-freeze come gushing out of the filler hole, surging. I lost 1.5 gallons! Temp gauge showed only a little over normal.
I filled er up with water and drove the 98 miles home with the heater on full in order to keep it from overheating. The water pumping not moving water, or enough water, makes sense, but I've never heard of a pump going bad that way, usually the bearings go or the seal.
I filled er up with water and drove the 98 miles home with the heater on full in order to keep it from overheating. The water pumping not moving water, or enough water, makes sense, but I've never heard of a pump going bad that way, usually the bearings go or the seal.
September 22nd, 2012, 7:08 AM
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well at least head gasket is ruled out.
1.pressure test the rad cap. if the system doesn't seal and contain pressure the boiling point of the coolant is substantially lowered. it can boil-over at normal operating temps.
2.the rad could be restricted. visually inspect the front face of the rad. Is it filled with debris? I measure temperature drop at the upper rad hose and lower rad hose with a Infrad red temp gun. There should be a minimum of 10 degree celcius temp drop from inlet to outlet.
3.squeeze the upper rad hose when the thermostat opens (it will be hot), do you feel a surge of coolant flowing?
4.as was already mentioned; the thermostat may not be fully opening.
1.pressure test the rad cap. if the system doesn't seal and contain pressure the boiling point of the coolant is substantially lowered. it can boil-over at normal operating temps.
2.the rad could be restricted. visually inspect the front face of the rad. Is it filled with debris? I measure temperature drop at the upper rad hose and lower rad hose with a Infrad red temp gun. There should be a minimum of 10 degree celcius temp drop from inlet to outlet.
3.squeeze the upper rad hose when the thermostat opens (it will be hot), do you feel a surge of coolant flowing?
4.as was already mentioned; the thermostat may not be fully opening.
September 24th, 2012, 10:16 AM
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1. The cap hasn't let any coolant back into the overflow tank, so it's at least not open at too low of pressure.
2. That's what I was thinking as a possibility, too, but I've run a flush and cleaning solution through it twice now. The front is clear but for a couple of bugs. I'll have to see if I can find an infrared gun somewhere.
3. It definately gets hot, but I can't say I feel a surge.
4. I have already replaced the t-stat.
How the hell do you get the fan shroud off?? It appears to be wider, front-to-back, then the open of the hood! lol I tried, but couldn't get it out. Looks like I might have to remove the radiator? Which I'm thinking of doing just so I can do a reverse flush on it.
I just don't get how the problem would get worse AFTER flushing it!
2. That's what I was thinking as a possibility, too, but I've run a flush and cleaning solution through it twice now. The front is clear but for a couple of bugs. I'll have to see if I can find an infrared gun somewhere.
3. It definately gets hot, but I can't say I feel a surge.
4. I have already replaced the t-stat.
How the hell do you get the fan shroud off?? It appears to be wider, front-to-back, then the open of the hood! lol I tried, but couldn't get it out. Looks like I might have to remove the radiator? Which I'm thinking of doing just so I can do a reverse flush on it.
I just don't get how the problem would get worse AFTER flushing it!