My 2000 Isuzu Rodeo runs out of coolant after several hundred miles. The hoses, radiator cap and thermostat are new and it has been put under pressure and shows no sign of a leak. I can’t see any evidence of water having come out of the overflow and there is no water in the oil. There is no coolant coming out of the heater core and fogging the windshield. I have heard that it is possible that a cracked head is allowing water to escape through the exhaust. Any thoughts?
Morning warm up moisture from a tailpipe is normal.
That said, after the engine is up to operating temp is there still visible moisture dripping from the pipe?
Have a helper step on the throttle a few times while you watch the pipe. Does the water smell sweet like hot coolant?
If there is definitely no visible leak and a coolant pressure test doesn’t show an intake manifold gasket leak then what you suggested may well be the fault.
UNless, there is a manifold gasket leak allowing a small but continuous amount of coolant to leak out and is being heat dissipated before it hits the ground.
Thanks Roadrunner. I found some more info on another site and they suggested running the engine at 3000 rpm’s for a while and then look at the tailpipe. Sure enough, there is water on the ground under the tailpipe. A mechanic has suggested using a block sealant called K&W rather than going through the expense of removing the head. I’m going to give it a try first.