Help! my cooling system has me confused

Beezle

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2003 mazda protege ES 2.0L (FS)
Hello all, I have a bit of a problem. My car, a 2003 Mazda Protege ES with a 2.0L engine, started overheating. The first thing I did was throw on the heater to try to bleed some of the heat off the engine, however, little to no heat came out of the vents. Since I was about about 1/2 block from my house I got it home let it cool down and checked the radiator. I noticed the radiator was low on coolant/water.

As I filled the radiator with distilled water, I thought to myself I've almost put 5/8th of a gallon in and its still not full. So I looked under the car to see if it was leaking out somewhere and low and behold it was. Now this is the confusing part, the coolant/water is dripping from the cross member that goes directly under my engine. So I figured that it must be dripping from above and running down some how, naturally I start looking at hoses feeling for any wetness, I found nothing. At this point I have inspected my radiator, all hoses connecting to/from the radiator, the heater hoses, freeze plugs, thermostat housing, the cooling hose for my intake manifold, checked my oil to make sure no water was in it, checked my trans fluid to make sure no water was in it, and I have come up with nothing. The car is still overheating and still leaking, the radiator will go from full to about 7/8ths quickly, then will slowly drain down till it takes about 3/4 of a gallon to fill back up.

Since I was trying to do this alone and at night, I called a friend over the next night we jacked the car up, got under it and tried to pinpoint the leak once again. The only thing we were able to determine is the water is leaking from about the center of the engine slightly closer to the driver's side through a hole that is about a fingertip deep and runs from the front of the car towards the back. Since my water pump is on the passenger side of the vehicle and impossible to get to could Mazda have put a drainage system into the car? I am wondering if anyone that knows if there is some sort of drain that runs from the timing belt cover/housing to the bottom of the engine to drain out or any other ideas where to look.

Thank you in advance.
 
Can you describe this "hole" in the engine a little more? Front side, back side, closer to top or bottom, on the actual engine block itself?

Just off your description of a hole near the middle of the engine, and how quickly coolant drains out as you fill it, it sounds like a freeze plug that rusted through and/or popped out. The FS has several freeze plugs along the front & back sides of the engine.

EDIT: Does the hole look something like what these arrows are pointing at?

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When I was under the car, it wasn't a freeze plug that I saw, but it was dripping from where the oil pan slopes on this picture. I'm pretty sure its not a freeze plug at least on the exhaust side because I inspected those, It could be on the intake side because I cant see them, but would it leak from a freeze plug without the engine on and no circulation? Also would the cooling system still build pressure with a freeze plug leaking/blown out while the car is running?

I will try to take a picture of what I'm talking about later today, I'm having the car towed to my father in law's where I have access to more tools and can tear it apart better.
 
Rent a radiator compression tester and adapter and have someone pressurize the system from the top of the radiator, then get under it and get a picture of where its coming from. This way you dont have to run the car to find where its coming from and get the picture.
 
Found the leak, its coming from the transmission bell housing. I have no idea where its originating but there is a lot of water inside the bell housing you can stick your finger in and feel the flywheel. Does anyone know of a failure point in that area, checked freeze plugs front and back of engine neither leaking, sending unit isint leaking either. Any other idea's on where I should check?
 
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Yes, there is a freeze plug behind the bell housing. That's not going to be a fun one to replace :(
 
Well, Ive never pulled an engine on a front wheel drive car. Would any of the mechanic in a can solutions work such as Steel Seal, Bars, Alumiseal. Or would you guys just recommend biting the bullet and having a mechanic either drop the trans or pull the engine to replace it?
 
If you're leaking coolant from a freeze plug, it's almost certainly corroded through, and the whole plug is probably weakened. Even if you could stop the leak with something like Bars Leaks, I'd bet dollars to donuts that it would be a very short term fix.

Pulling the engine should not be necessary. However, if one plug has corroded through to the point of leaking, it's not unreasonable to think that the rest could be in rough shape as well. So depending on how reliable you need the car to be, it might be a good idea to take this downtime and replace all the plugs--there are several altogether behind the intake and exhaust manifolds.
 
called a mechanic today, he said he'd drop the trans to do it and would be looking at 250-350. The guy only charges 35/hr with $45 initial charge said it'd take 5-6 hours with 2 guys and he's a mobile mechanic. Does this sound pretty reasonable?
 
I would say that's pretty reasonable. You may also want to look at replacing the clutch and transmission output seals while the transmission is off.
 
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