coolant leak very strange

[Ronald D.]

This one has me really puzzled, this is a 1971 LT-1 I am doing a body off restoration, the body is back on the frame, its about 6 weeks away from starting the engine, the engine was completely rebuilt at a good engine shop, never be started yet, I installed all the cooling hoses, radiator and today filled the system with coolant, I leave for 5 hours come back and lift the car up to make sure nothing drips, I have a two post lift so up it goes I see a puddle 3 inches round on the ground, looking up on the right side of the car water is slowly dripping out of the 3rd air injector fitting from the front where the bolt into the exhaust manifold, I see no other leaks, this is very odd, I guess tomorrow the passenger side exhaust manifold comes off, the thought of an engine problem before I ever ran it is not making me feel real good, any ideas?, thanks Ron

[Michael G.]

Re: coolant leak very strange

Not all of the bolt holes in your block are "blind" and will need to have the bolts sealed on installation to avoid leaks. Pull the bolt, seal the threads, and you should be good to go.

[John H.]

Re: coolant leak very strange

water is lowly dripping out of the 3rd air injector fitting from the front where the bolt into the exhaust manifold, I see no other leaks, this is very odd, I guess tomorrow the passenger side exhaust manifold comes off, the thought of an engine problem before I ever ran it is not making me feel real good, any ideas?, thanks Ron

Ron -

Remove that spark plug and see what comes out. If you have water dripping from the air manifold tube nut where it screws into the exhaust manifold, that cylinder's exhaust valve is open and the cylinder is full of water.

[Ronald D.]

Re: coolant leak very strange

I will try that tomorrow removing the spark plug, it is sounding like a bad seal on the intake manifold at this point, thanks for the tips

[Paul D.]

Re: coolant leak very strange

Ronald, before you start taking things apart, lower the car back down and look it over from the top. Had you pressurized the system to check for leaks? If not, I'm having a hard time understanding how coolant would get pushed out of the injector fitting. Actually, even if it were pressurized I would find that odd. I would expect the coolant to follow the path of least resistance and exit the manifold through the pipe or outlet. Make sure nothing is dripping coolant on the manifold from the outside. Please let us know what you find. Chip.

[Ronald D.]

Re: coolant leak very strange

I went back out to look again, this time it is leaking from the exhaust manifold donut gasket area where it connects to the pipe, it is starting to look like the intake manifold gasket is leaking, I will pull the spark plugs and look, I suspect the intake is coming off tomorrow to me, there is nothing that one can see that is a leak, its internal

[Edward J.]

Re: coolant leak very strange

Roger, Do not pull the intake yet, the best steps are to remove the plugs on that side and look for coolant in a cylinder on that side that has coolant. next do a pressure test of the cooling system.if that is possible (is engine together with all hoses?), fluid in one of the cylinders may be from a cylinder head gasket not sealing around the combustion area (without staring the engine and the cooling system is not pressurized) or worse a cracked in exhaust port area cylinder head.anti freeze leaks from the intake will either leak at the corners of the intake ports or internally into block and mix with the engine oil.

[Ronald D.]

Re: coolant leak very strange

I just went out this morning to look again, there is a puddle a foot round under the engine, the radiator is level at about half way up the same elevation as the cylinder head, who knows how much is in the exhaust pipe, the engine oil levey looks a tad high, the oil is new I will open the drain plug slightly and let any water drip out if there is any, this leak is to large for a crack or head gasket, I also have a hard time knowing this shop that this could happen, so today I will pull the intake and so what is what, I first will pull all the spark plugs on the right side to see what cylinder has water in it then get the water out somehow with a vac hand pump, and I will also pull the right valve cover to confirm what exhaust valve is open, thanks again for the ideas, Ron

[Jack H.]

Re: coolant leak very strange

I'm following this thread with great interest. I noticed coolant leaking out of my right side sidepipe as the car ('67 327/350) was sitting on a slight incline (front end up). I'm recovering from a back injury so I can't do much right now, but I did remove the radiator cap, and it continued to leak. So I assume it's a cracked head since coolant cannot flow uphill in a non-pressurized system and I can't think of another reasonable explanation off hand. Not happy.

Ronald, good luck with the troubleshooting and hopefully it turns out to be something minor somehow, and hopefully I can learn from what you find out.

[Ronald D.]

Re: coolant leak very strange

OK here is my update on the coolant leak, I pulled the intake, everything looked fine, I pulled the spark plugs on the right side, I then removed the valve cover, then the right exhaust manifold completely, the first exhaust port on the right side was soaking wet, I looked inside with a light and a mirror, nothing visible, but there is still coolant in the head leaking into that first port, so at this point it is the right head, everything was done to this head when they rebuilt it, I then drove over to the machine shop and talked to them, they are perplexed as am I, the end result is they want both the heads removed and delivered to there shop so they can re pressure check them and fix the problem, if the head, or heads are not repairable he said he would locate one with the same casting number and rebuild it like the bad one, this is a lot of work, the shop has been in business for 50 years and done thousands of engines, I enjoy working on my Corvette, just not redoing stuff, I still don't have a clue how you can test a head and then it leaks

[Michael F.]

Re: coolant leak very strange

keep us updated on what is found....good luck and sorry for your misfortune.

[Edward J.]

Re: coolant leak very strange

OK here is my update on the coolant leak, I pulled the intake, everything looked fine, I pulled the spark plugs on the right side, I then removed the valve cover, then the right exhaust manifold completely, the first exhaust port on the right side was soaking wet, I looked inside with a light and a mirror, nothing visible, but there is still coolant in the head leaking into that first port, so at this point it is the right head, everything was done to this head when they rebuilt it, I then drove over to the machine shop and talked to them, they are perplexed as am I, the end result is they want both the heads removed and delivered to there shop so they can re pressure check them and fix the problem, if the head, or heads are not repairable he said he would locate one with the same casting number and rebuild it like the bad one, this is a lot of work, the shop has been in business for 50 years and done thousands of engines, I enjoy working on my Corvette, just not redoing stuff, I still don't have a clue how you can test a head and then it leaks

Ron, If you have no history on the engine before you took apart its possible that it may have a cracked head. or something happened when and if the valve guide (s) where replaced it maybe possible when drilling out the guide (s) it maybe close to a water port?? and when pressing in a new guide a crack may have occurred. If you do run into this, my advice is to find a donor head, there are many around. It may not be dated correctly. but you have a 6 mon. window.

[Michael H.]

Re: coolant leak very strange

OK here is my update on the coolant leak, I pulled the intake, everything looked fine, I pulled the spark plugs on the right side, I then removed the valve cover, then the right exhaust manifold completely, the first exhaust port on the right side was soaking wet, I looked inside with a light and a mirror, nothing visible, but there is still coolant in the head leaking into that first port, so at this point it is the right head, everything was done to this head when they rebuilt it, I then drove over to the machine shop and talked to them, they are perplexed as am I, the end result is they want both the heads removed and delivered to there shop so they can re pressure check them and fix the problem, if the head, or heads are not repairable he said he would locate one with the same casting number and rebuild it like the bad one, this is a lot of work, the shop has been in business for 50 years and done thousands of engines, I enjoy working on my Corvette, just not redoing stuff, I still don't have a clue how you can test a head and then it leaks

Ron,

Is it possible that the intake gasket was leaking as there is a water passage right where your getting water into that head. Maybe the intake is cracked around that area. Also did you have sealer on the intake bolts where they screw into the water jack area ?

Mike

[Ronald D.]

Re: coolant leak very strange

Thanks that is my plan, as for dating the one I remover has a code H200, and that is correct for this car built in Jan 1971, but that date is located on the casting under the valve cover, is there a date somewhere else, no Judge can see that location, I would think there looking for the casting marks on the front and rear of the head, just curious, Ron

[Jack H.]

Re: coolant leak very strange

Thanks that is my plan, as for dating the one I remover has a code H200, and that is correct for this car built in Jan 1971, but that date is located on the casting under the valve cover, is there a date somewhere else, no Judge can see that location, I would think there looking for the casting marks on the front and rear of the head, just curious, Ron

Inside the valve cover is the only date location, so it's not judged per se. If/when selling the prospective buyer would probably want to see it though. Plus you will know if its not right if you care about such things. There are plenty of heads available with the same or close date, so that shouldn't be a problem to get one in range if it comes to that.

BTW, H200 sounds a bit early, which is fine since its within the generalized 6 month window, but you'll want to check the other head for its date too. If it's later, I'd match that date instead. Just IMHO. Hopefully its something more minor than replacing the head, but that's my suspicion at this point for both of us.