I have a very slow leak where the timing chain cover bolts to the engine block ("71" 302) When I drive it doesn't spray or leak however when it sits it will seep out after about 5-6 days there is enough coolant in the little pocket below the intake neck to fill the pocket about 1-2 oz. Do you think BAR or another brand sealant will work.
Thanks in advance

 

I think you already know the answer. BAR will work as a temporary fix but you or your mechanic will eventually have to dig into it. It does't sound like a real serious issue but might become one. Hard to tell how many times your '71 has been worked on and if good quality gaskets and new bolts used. Welcome to world of maintenance.

 

I figured I needed to put a new gasket on the timing cover; I just tore the top end down a few months ago to put on better heads, if only it was leaking before then...it's just to much work for such a small problem however, I'll get it done before the summer.

 

If you've got a leaky gasket, you'll be far better off to replace the gasket and cure the problem than to try putting a band-aid on a broken arm. If you see water on top of the timing chain cover, it's more likely coming from the water neck on the front of the intake. It could be a weepy gasket there, (very common) or a leaky hose. You might double check the clamps for tightness. The only place there's water between the timing cover and block is two small passages where the water passes from the water pump. The water pump itself is the other likely leak spot. Both of those are very easy fixes and can be done in an hour. Make sure you really know where the water is coming from before you tear into anything.

 

+1, been there done that. That 90-deg bypass hose is a prime suspect.

 

The motor I am using is a 302 out of a 78. I had a drip which was hard to find. My ended up being at the water pump. The pump had two gaskets. The front gasket was leaking making the coolant hard to tell where it was coming from. The pump has a plate in it with a gasket which seals it to the pump itself, then there's the gasket which seals the pump to the motor.

 

I don't think stop leak will help. Your timing cover could be leaking where you suspect it is. If you have to remove the timing cover don't be surprised if you break a bolt or two. Corrosion between the metal bolts and aluminum timing cover can be a real pain. Good luck.

 

I had an chromed aftermarket thermostat housing one time that I couldn't stop from leaking. It turned out that the flat surface were the gasket goes was warped from new.

 

Bar's Leaks works really well in my experience. It holds up for a long time. Put a few drops of fluorescent dye into the cooling system also then when you get time do a teardown use an inexpensive black light bulb in your drop light (available in most Halloween or novelty shops). It will make it easier to see where a small leak is.

http://science.howstuffworks.com/innovation/everyday-innovations/black-light2.htm

 

I went back and searched for the source of the leak and it turned out to the coming from the bottom of the thermostat housing (chrome). It was really difficult to get to one bolt I had to move the distributor. Also had difficulties getting it back on ruined one gasket and went for another and used nonharding sealant, it took a while but I got it all back together. I haven't went for a drive yet due to rain I'll get to it on Monday.

Thanks to everyone for giving me some ideas, I really didn't want to pull the timing cover & pulley.

 

Thanks for the warning. I have to do that task yet. I'm suspicious as I found two thermostats in the glove box.

 

I'm glad you discovered the cause of the leak. After I posted my experience I thought...naw, he'll think I'm nuts. I have one of those chromed housings and even new I couldn't get it to stop leaking. I was warped. It now sits on the shelf above my bench as a garage nicknack...lol.

 

Mervy49 if it's still leaking when I test drive it I'm going to toss the chrome thermostat housing and go back with the original one.

 

I have a chrome thermostat housing that seals with an o ring, instead of a gasket ,and I have not had a leak during the 6 years its been on. I may have used a littel gasket sealer for insurance.