Please help / antifreeze leak

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my66fish

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I hope some one can give me some solid direction and advise with this problem I now face with my engine. I just had my 273 with steel heads rebuilt by a professional engine builder and we fired it up and found that we have a antifreeze leak in the back of the engine and it is dripping off the corner of the drivers side head. I'm having a very difficult time seeing where this leak is coming from.
Here are the facts so far. From what I can see is it don't seem like the freeze out plug on the head is leaking, and there is no antifreeze in the oil and there is no white smoke coming from the exhaust. The end stud for the exhaust manifold is in there solid. The leak is right on the corner of the head where it meets the block. It's very difficult to see the leak, but it seems it is getting worse.
I was told to retork the heads but I don't think this is the case. Some one told me to use the Barr's stop leak, and I really don't want to go down this path being it's a complete rebuild and I have heard alot of mixed reviews. The thing is the person who told me to use this stuff has been building mopar engines for forty years and well respected but I'm really nervous about this.
 
The first thing you need to do is look at it with an inspection mirror to determine exactly where it's coming from. If it is coming from between the head and block that's not good. You can try re-torqueing the head but it still may not seal. What brand of head gaskets did you use and was the head and block mating surfaces checked for flattness?
 
First thing I wouldn't recommend putting any sealer in unless its a road side last resort. The only things I can think of that may be leaking are 1. Freeze plug 2. head gasket 3. exhaust end stud 4. Back intake gasket. I mostly use UV dye and a mirror to check for hard to find leaks. If you can't see back there with a mirror then I would get a paper towel and fold it to say a 3''x3'' then hold it behind there to find the leak. On a cold started engine work from the top down, when the towel comes up wet then there is your leak.
 
I'd do like fishy68 says & really try to determine where the leak is. Re-torqueing the heads might help. It might also be leaking from the rear of the intake & running along the bottom edge of the head & just dripping off of the lowest point where you see it. You could try re-torqueing the intake manifold bolts too. Maybe you'll get lucky. I had a shop teacher in the early 1970's who had me try Bars-Leaks to stop a head gasket leak on a fresh rebuild. Didn't work.
 
Is it possible that the head bolts are not in the correct holes? Each head requires 20 bolts; 5 short, 4 long, 1 extra long. The shorts go in the bottom. The extra long goes in the second hole from the left on the top row. The other long bolts go in the remaining top row holes. I was such a klutz at this, I made a cardboard engine mock up so that every bolt goes back in the hole it came out of.

Torque the heads sequentially. In order, torque to 30#; then to 60#. In the same order torque to 85# for 273 & 318, 90# for 340 & 360.

There are core plugs at each end of the head. If rusted out or not installed properly, they will leak. The exhaust manifold studs have already been mentioned.
 
Thank you for your replies. To answer the questions I did not build the motor, I had it done my a Mopar pro, and he has a very good rep. I don't think its the stud in the exhaust manifold. I really don't want to put any sealer in a freshly built motor.When I got the motor back, all I had to do was put the carb, water pump and so on back on before putting the motor back in. I figured at this point in my life I wanted a professional motor built for my car. The motor sounds and runs awesome, its just this leak that is freaking me out. I went and bought a mirror but it's alittle to large and I can not get back there to see. I know it could only be one of a few things. If I pressure test the motor cold is there any chance of finding this leak? I know what your going to say, why not just take it back to the builder. The thing is he is a couple of hours away and I guess I will have to flat bed the car. I was just trying to see if it was something I could fix, like if it was the intake manifold or a freeze out plug before I would pay to have the car trailered back to the builders shop.
 
Did you put the manifolds on or did he? Is it a stud on the back hole or a bolt?
 
Small block; both heads, front and rear exhaust, are open into the water jacket. That is one of the reasons studs where installed at the factory (and makes it easier to install manifold by yourself.
It had sealer on the threads from the factory, not on the whole bolt, but just in the block. That is what they have to have. FACTORY. Maybe a Chebby guy was involved? lol. All 4 bolts need sealant in the block; rtv, teflon paste pipe dope, teflon tape... pipe dope or hi-temp red rtv is best.
 
Ok,
I got myself a really good mirror that extends and put light under the car and along side the engine, and found that there is no antifreeze coming from the back of the engine, nor from the stud for the exhaust manifold. The drip is coming from the bottom edge of the head where it meets the block. It looks like it is right near the last head bolt. But again no white smoke in the exhaust no antifreeze in the oil and no oil in the antifreeze. There is no fluid coming from the side of the head, just at the bottom in the corner, and its a drip every five to eight seconds. Is it possible the head bolt needs sealant? Could it be that simple of a fix? If this is not the case then the head I guess needs to be pulled again.
 
It is possible the exhaust manifold bolt is seeping, running down the head and dripping off. I would pull the rear bolt add sealant and replace. To me that would be the simplest place to start.
 
badsport said:
It is possible the exhaust manifold bolt is seeping, running down the head and dripping off. I would pull the rear bolt add sealant and replace. To me that would be the simplest place to start.
Click to expand...

I agree. Since it's a small leak it could be running down from the exhaust stud and you just can't see it. I've seen that happen a number of times. Pressure testing it while cold is a good idea. I've found more stubborn leaks with my Stant radiator pressure tester than I can shake a stick at. I would be surprised if it is leaking from a head bolt unless it wasn't properly torqued.
 
Where you see the leak and where the leak starts are 2 TOTALLY different things.

I once thought my rear end was leaking but in reality is was a power steering hose and the fluid was just blowing back when driving at speed.

Like mentioned..... Pull the exhaust studs and apply a good sealant. If the leak is still there you will have a much bigger job ahead.

This is why you try the easy things first......and pray.
 
I had the exact same leak about 2000 miles ago and was dripping on my header right below the oil filter not all the time but especially if the car sat for a day or two you could see the moisture on the header. It was either tear the head off and regasket or add a bottle of Bars stop leak. I decided to go with the Bars leak and that stopped the leak. I have no heating issues at all, car runs between 180 - 185 degree on a hot and humid day. I ran my car until the leak stopped then I drained the old antifreeze and refilled with fresh anti. and still no leak...
 
Gator said:
I had the exact same leak about 2000 miles ago and was dripping on my header right below the oil filter not all the time but especially if the car sat for a day or two you could see the moisture on the header. It was either tear the head off and regasket or add a bottle of Bars stop leak. I decided to go with the Bars leak and that stopped the leak. I have no heating issues at all, car runs between 180 - 185 degree on a hot and humid day. I ran my car until the leak stopped then I drained the old antifreeze and refilled with fresh anti. and still no leak...
Click to expand...

I too have this exact leak that drips down onto my headers making a rusty water mess all over my pretty headers and back on to my pipes. I have tried new bolts, numerous types of high temp thread sealers and it still happily drips away. Strange that we all have this problem on the same corner!

I am getting a spare set of heads that I have ready for a swap and then I can take a really close look and hopefully find out what this problem is.
 
Thanks for all the input and information. I just got my computer working again. I'll tell you if it not one thing or another lately, but I wanted to thank you all and give you an update on this.
I spoke with the engine builder who backed what he built and told me to drop off the car and he would stand by his work. He has re torqued the head and the leak has stopped. I picked up the car today and drove it home from where his shop is which was about fifty miles from my home and when I pulled it into the garage and looked under the car it was dry without leak. Problem solved. Hopefully I will be driving the car to the Rockingham Mopar show here in NC next week. 8)
P.S. Does anyone know where I can get a set of gears for my 7 1/4? I'm looking for 3:23 or 3:55, and to find a sure grip unit for it.
 
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