2000 2500 Losing Coolant Somewhere

[96ahs]

My 2000 2500 with 6.0L and 85K mile is still losing coolant, I replace water pump which was leaking around gasket and also replace all the hoses and belts and much to my dismay Im still losing coolant somewhere,there are no visible signs of a leak, oil looks fine, I fill to the cold line in tank and in about 400miles the low light comes on and Ihave to add more. I did a search and nothing seems to describe my problem, any idea's

[doverarjim]

Mine did the same thing until it finally blew head gasket and then my great wisdom kept driving (trying to save wrecker bill) till I spun a bearing in it. Getting junk yard motor truck has 150,000 miles yard motor only 50,000. Lots of luck. I had done the oil checked fot water and other contaminants every 20,000 miles or so and never any sign of water in oil.

[Zembonez]

I agree. The only thing I've been seeing here that causes that is a leaking head gasket. I wish I could offer an alternative answer.

[2017HD]

Also the intake manifold gasket can leak and cause problems. My 99 Tahoe had a real slow coolent leak - nothing in the oil - no puddles in the driveway. It was leaking out the back of the engine down over the transmission and boiling off while driving. I finally noticed it when I was parked overnight on a steep incline and found a small puddle under the truck the next morning. Lucky for me the leak was between the cooling jacket and the outside world and not the cylinder head.

BTW I also had an engine blow a head gasket and it had similar symptoms - the only difference was that the leak was much faster and I had some occasional steam out the pipe.

[DofD]

Had the same sort of problem on my 97 Tahoe. The intake manifold gasket was bad. Initially it was leaking right at the very back which made it hard to find.

 

I would suggest putting some radiator dye in, which should make it easier to track down the leak.

[96ahs]

I read somewhere that there is no water jackets in the intake of the 6.0 so that could not be the problem, is this true?

[Zembonez]

I read somewhere that there is no water jackets in the intake of the 6.0 so that could not be the problem, is this true?

The new generation motors 4.8/5/3/6.0 etc do not have water jackets in the intake. Older engines like the 5.7 and 4.3 did.

[pm26]

Sometimes slow coolant leaks can be really mysterious. For example, I had this issue on my '99 Mazda with about 200k miles on the clock (original radiator). I was losing coolant at the rate of about 2 quarts every month or so. The coolant overflow bottle would periodically run dry. I could not see any coolant leaks, no puddles under the car. I even replaced the radiator hoses and clamps to make sure they were tight (used screw clamps instead of spring ones). This did not help. Finally I decided to look closely at the radiator. Immediately after getting the engine to a full operating temperature, I closely checked the radiator plastic tanks and actually saw tiny droplets of coolant on the surface of the upper hose inlet. Wiped those droplets off, and new ones formed before my eyes. This means the coolant was seeping through microscopic cracks in the plastic hose neck. You could not see any cracks or deformation in the leak area. I never saw anything like this before.

 

I replaced the radiator and no more coolant loss to date.

[cbxeric]

Get a pressure test done on the cooling system.

[pennzoil29]

Get a pressure test done on the cooling system.

 

[96ahs]

Just a update, I finally found the coolant leak, it was a small leak around the upper radiator hose. I guess I didnt tighten it down enough when I replace the hoses. I found the leak by removing the stump guard under the truck and just let it run while I looked for a leak with a flashlight.