I have a 1999 Honda CR-V EX 4x4 Automatic. I bought it from a guy with a bad tranny. The motor ran fine when I bought it. No issues or engine lights. I ran the motor over the winter many times to make sure seals didn't dry out. Started every time with no problems.

This spring I pulled the tranny out and sent it in to be rebuilt. While it was out I also pulled the motor out and changed all the exterior seals and a few other items I could. From memory I did:
cam shaft
rear main
main
water pump seal (water pump was changed about 10,000 before I bought it)
pcv valve
thermostat
thermostat seal
valve cover gasket and sparkplug housing gaskets seals

When I put the motor and tranny back in I started it up and it started within a few cracks. After running it for 20 sec it was running rough. I stopped it and looked under the car for leaks. The entire underside was covered with water that came out of the exhaust manifold which I have not hooked up to the cat or exhaust pipe. I ran it one more time for 20 sec and it did the same thing. I drained the oil and it had water in it. Not mixed really bad but you could tell it had water in it.

Then I filled up the engine with 4 quarts of oil and topped off the radiator. I did a pressure test and found the radiator had a crack in the plastic. I changed out the radiator with one from a junk yard and did the pressure test again and held 15lbs. Then attempted to start it. No spark. Odd. It was fine up to the point.

Tested the coil and the coil was bad. I put a new coil on it started with a few cranks. Engine still running rough. Water still coming out the exhaust. Dip stick had cloudy oil, guessing thats from water mixing. While it was running and water coming out the exhaust I put the pressure tester on and it held 15lbs. Put the cap back on and started it again and squeezed the upper hose after running for 10 sec and there was no pressure in the hose.

I have looked over the motor to see if I put a water line on a vacuum line or something like that. Can't seem to find anything wrong.

Friends have been telling me its the head gasket. I'm not a mechanic so I'm looking for some advice. I seems strange to me the head gasket can go right at the time I'm changing the tranny and replacing seals on the motor. (also seemed strange the coil could go bad but it did) And seems strange it holds 15lbs of pressure when running and when off. It would seem to me the gasket would allow pressure through when I test it running or off.

I do have history working on cars and my training has been years working with my dad on his cars, trucks and tractors and years working on my own. I put a new motor in my Accord and had no problems at all. I put a rebuilt tranny in my Chevy K1500 and runs strong. Yet I am not a mechanic so I am always looking for advice from people who know.

Anyone have any ideas?

 

So I drained the oil again, filled the water back up and started it. No water came out the exhaust. Checked the oil, no water. Let it run for 2 min, no water from the exhaust or in the oil.

All seems to be running. Strange.

 

Try to have a compression and leak down test just to be sure about the health of your engine.

 

Do a pressure test to check the condition of the head gasket.

 

Yes that's also a good idea. Or have test like this.