I've spent the last month or so installing my new motor. The good news is I'm done. The bad news is the very last step I was pouring coolant in the radiator when coolant starting leaking out of the block near the back of the block and passenger side.

This really hurts because I've spent the last month or so putting the rest of this motor together and installing. Not easy when you work 60+ hours a week on top of wife, kids, bills etc.

Keep in mind the shortblock was professionally built as were the heads were installed by the same shop.

Please tell me its something silly and not a head gasket!!

 

it's something silly and not a headgasket. sorry man, i had to. you have a couple of possibilities here
1. coolant plug at rear of head (the small block)
2. freeze plugs that are in each head
3. cracked head
4. cracked block
5. head gasket
try to see exactly where it's comming from

 

I don't think its the head or the block thats cracked as they are both brand new.

Missing plugs in the head are a possibility though. Shouldn't have the engine builder done this though?

Also, is there an overflow hose somewhere in the back of the engine that I don't know about??

It's a pretty good leak also. Another words, a gusher. I have a hard time believing that its the head gasket leaking at this point since the gaskets, heads, and everything are new. Since the motor has never been fired, I would think that if it where leaking out of the head gasket it would be a slow leak.

Any other ideas are welcome.

 

You need to find out exactly where it's leaking from. More than likely it's the freeze plug located on the rear passenger side cylinder head. Check that first. If it's in place and not leaking, it's the head gasket.

 

Also check the coolant plugs on the top of the head. In the front of the block you have the coolant crossover pipe that goes from one head to another. In the back it uses plugs instead of a crossover pipe...you may want to check to make sure they are there and/or if they used gaskets on them. I'm with these guys as well, get under the car and find the highest point where its coming from.

 

I think its this here^^^

I forgot to put gaskets on the rear coolant plugs. Dooh!! Details...details...

Its leaking directly down the back of the block and over the starter. I'm 98% sure its the plugs. Easily fixed...

Thanks guys

 

Update: It's not the coolant plugs. I removed the plugs and the gaskets/o-rings are present and appear to be in good condition.

But I found where the leak is coming from. It was a missing plug where the temp sender goes. Problem is solved.