hey i have a 1996 isuzu trooper v6 3.2l dohc and my problem is that its wasting the coolant n i have check the pipes from the radiator n there are no leaks. i have also checked the radiator for leaks but its fine. like i would fill up the overflow tank and in two days it would be in the middle. i checked the oil to see if it has a milkshake color but it was normal. i also checked the spark plugs for residues but they r clean. its running fine n no smoke coming out of the tail pipe. but one thing that is very strange is that in the overflow tank its looks like the water is boiling n the radiator is sending a lot of air to the overflow tank its like its getting rid off the air inside the cooling system. i mean thats normal when its cold but it happens when the engine is hot..... doesn't anyone have any suggestion???

 

I am by no means a mechanic.......and just purchased a 97 trooper about a month ago......I've had the same problem than my water pump started to leak. My best guest and googled a ton was that the water pump is done.