Leaking Coolant

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me66dartgt

me66dartgt

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While I very rarely ever post, I use FABO constantly as a "search tool" to learn. But this time I have a real problem and would appreciate some feedback and recommendations. The engine is a 318 and was built by a local person here in the SD area. It is a 318 block with 273 heads that have been ported etc.... by the engine builder. I think many of you know him and most seemed to respect his input concerning Small block engines. That is why I choose him.

The issue is that I was very close to breaking in this motor. Two days ago I added the Coolant/Water to the radiator. One day I added the first two gallons of mixture but didn't have enough, so the next day I added the rest to fill it up. Yesterday when I went out to the garage I noticed the floor was wet under the left side of the engine, about mid way back and under the starter area, or back corner of engine. Also about a 1/2 cup came out of the oil drain hole. It didn't leak until the radiator was full.

Now I'm very worried and have no local support to come through the issue and hope this forum can point me in the right direction. Do I add more water and attempt to detect where leak is from? Do I break it down and see if it is intake gasket? Go deeper and see if heads are torqued correctly. I also have Dougs that were installed by a local exhaust shop but I checked around these studs and all seemed to be dry. If a exhaust stud was leaking would it allow coolant to get to the base pan? Is the engine being damaged because it has coolant leaking through to the base? I really could use some solid input so I can correct the issue and move forward. Thanks.
 
I would go to your local parts store to get their radiator pressure tester that should be available in their tool loan program. I would leave the oil plug out and pressure up the cooling system. It might be a good idea to remove the spark plugs also. Hopefully that will lead you to the leak instead of just guessing so you will know what area you need to fix.

There are a lot of places the leak could be coming from. One of the commonly overlooked places is the timing cover housing.
 
If you had it built by someone and it has a leak somewhere in the engine, take it back to the builder.
 
Bad Sport said:
If you had it built by someone and it has a leak somewhere in the engine, take it back to the builder.
Click to expand...

^^^^^ This
If you mess with it yourself they can void any warantee on thier work.
 
What type of intake gaskets used would be the first thing I'm looking at.
If he used the OEM metal ones... I'm betting on those being the problem.
 
I'm really in a tough spot here and it has proven out that I made a huge mistake on who I picked to be my engine builder. It was 1wild&crazyguy (whom I'm sure some of you remember). I was impressed with his input and the feedback that he seemed to garner when he offered up advise. But he is now out of the picture and unwilling to help. So I can't go there. This choice is really coming back to haunt me now. Rather than members telling me how stupid I was for making this choice I need to move on. I bought a Felpro gasket kit so I assume that he used that for the intake gasket. I know he put some thought into the head gasket to match the work he did on the heads. I kind of double checked what he told me was doing against what I read on this site and it all checked out. I'm really bummed and didn't expect this to be the end result but I can't make him want to help me. So.... I either have to find a reputable builder in San Diego area or attempt to get to the bottom of this by myself. I appreciate all your input.
 
Well, that kinda changes things a bit. Can you post a pic of where the leak is, and what do you mean "oil drain hole". In the oil pan??
 
well i wwould do what oklacarcollector said,seeing how you cant take it back to the builder.
 
Very first thig I would do is take a good look at the back of the engine behind the intake where it meets the heads.
(might only be intake gaskets) but it's a little scary that it leaks without even any pressure on the cooling system yet.

The porting part is a little scary also (if he went into a cooling jacket)

Both of these could allow coolant into the block itself and come out the drain.
 
I did mean the oil pan plug. I'm having a hard time pin pointing the leak because it happened after I filled the radiator up. One day I added a couple of gallons but it wasn't enough to fill it. There was no leak. The next day I filled it up the rest of the way to top. I didn't notice the leak until the next afternoon. The floor was wet under where the starter connects.I've checked all hose connections, water pump, etc.... and they were all dry. The top of the starter was wet. I also checked freeze plugs but I don't think fluid would leak into the pan if a freeze plug leaked but am by no way a mechanic. I'm learning everyday. And this lesson has been the most painful so far. Should I be draining out the radiator? Am I hurting motor now that antifreeze has leaked through to oil pan?
 
What ever you do, do not start it with coolant in the oil pan. I would pressurize the cooling system as suggested and see if you can find the leak that way.
 
You may also want to consider buying some food coloring from the grocery store and putting it in some water and filling the cooling system with the colored water. No sense wasting good expensive anti freeze and just use water and coloring to trace the leak.

Then when it leaks, you can trace it from the stains/coloring to find where it's coming from.

It may be a slow leak that gradually drips a little at a time, but accumulates after a while.


I would figure out where the leak is coming from. The intake gasket seal, the rear cup plugs in the block, or hopefully not a cracked block. Then proceed from there.
 
if its dripping off the plug itself and not out of the hole where the plug belongs... Maybe you shouldn't have mentioned it. But anyway...
This could be a common manifold mounting stud leaking. Those at the 4 ends of the heads are drilled into water jackets.
 
I removed the intake today to see what I could see. First thing I found was that all bolts were only tightened to around 20#'s. The next thing I found was that the bolts had no sealant on them. I also found the holes reamed with a grinder on the intake. I have no idea why. These were 1966 273 heads going on a Performer intake. I remember the builder saying that the intake was not well made and out of flatness. I also found gasket sealer on each end and some was also into the water jackets and even under the gasket. I'll add pics if possible.
 

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There should be sealant on the end ports and around the gasket, those are water passages.

It looks like the hole was ground a bit to accommodate the bolt lining up.
 
A few more......
 

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Well if this looks good then I guess it is back to the drawing board. There was water laying in the valleys so I thought I had found the issue. What should the bolts be torqued to on alum intake? Should washers be used? Thanks
 
If there was water in the valley, you might be on the right track. Do the gaskets appear wet anywhere? Was there any sealant on the intake bolts?
 
Could the coolant in the block valley have come from removing the intake. Sometimes the coolant spills when you break the intake free and a little can puddle in the lifter valley. Just wipe it out with a rag and go.


If it isn't from removing the intake, then you need to find out where it's coming from.
 
Just another thought: Was the block decked at some point, and the intake not milled to fit the lower head positions? If the bolt holes were ground downward for bolt fit, that could be the reason. Man, that looks like a awful lot of sealant....
 
flat washers would be nice if there was a flat and squared surface on the intake for them. Someone else will need to provide a torque spec for the aluminum intake. Maybe the intake mfgr states it on their website.
 
If the holes are hogged, the heads might be milled at the limits of intake fit without having it milled. Any evidence of coolant in the cylinders?

Your photos are OK but hard to see detail at the ports. How do they look on the head /intake mating? Any sign of (coolant) port overlap?

We had one member on here ended up with a cracked intake, or so he claimed. That thread got so far out of this solar system, hard to say.
 
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