I'm looking at a 98 Mazda 626 2 liter with an unknown coolant leak from the area in the back of the engine. Seller says a mechanic that quickly looked it over said he thinks it's either the head or the freeze plugs.
A quick history, my exam of the car and then a pic. He was driving and noticed the car was starting to heat up, pulled over and saw he was loosing coolant. Immediately took it into a shop and they saw one of the heater core hoses was leaking and replaced it. He went back out and started driving, but saw he was loosing coolant again ( quite quickly ) and it was starting to heat up again. Had it towed to a shop and they gave him the above report.
I came to look at it and started filling the rad. Noticed that it started immediately giving a light drip near the back of the engine ( I could just barely reach the spot and it was clean water ). Ran the engine a few minutes and the speed of the leak increased significantly.
Not sure what his mechanic meant by that it could be the head or plugs. There doesn't appear to be any water getting into the oil ( dipstick and under the oil fill cap didn't have anything frothy ).
That pipe is the exhaust pipe. The leak is presenting slightly left of engine rear center towards the drivers side.
IF it's the plugs, I have a theory that it's due to a sticking thermostat. If it was sticking closed that would explain why one leak developed right after another, and it sticking open would explain why I saw water start leaking way back there as soon as I started filling the rad? Could it stick closed then stick open like that?
What do you guys think?