Coolant Leak - Blown Gasket?

[wood47]

Hi all. Assuming the worst, but figured I would ask here before I start ordering parts and tearing the engine apart. Recently rebuilt the carb and while I was working on the idle speed, noticed a steady leak under the driver's side exhaust manifold. Blown head gasket? Worse?

Video is under the left side of the vehicle, looking up https://drive.google.com/file/d/1JD76ZETSGuD4yzu6nLlmyI4cLMzfEjqS/view?usp=share_link

- Oil looks fine, not milky
- Loud hissing sound when engine is turned off
- No leaks above manifold
- White smoke leaking out of an exhaust joint
- Oddly enough, at normal operating temperature and after a drive, coolant is cool to the touch. Basically room temperature, as opposed to the heat above.
- I can see corrosion around the exhaust manifold

Appreciate the help.

 

[Broncobowsher]

Did you just remove the carb, or did you take more apart (like remove the intake manifold).

Coolant flows down, that is how gravity works. Start following the coolant up. Gaskets can fail. Hoses can leak.
My guess, your heater control valve is right by the carb. It could have been borderline and you bumping it around make it start leaking. Following gravity, it will run to the back of the intake and down the back is the engine.

 

[wood47]

Did you just remove the carb, or did you take more apart (like remove the intake manifold).

Coolant flows down, that is how gravity works. Start following the coolant up. Gaskets can fail. Hoses can leak.
My guess, your heater control valve is right by the carb. It could have been borderline and you bumping it around make it start leaking. Following gravity, it will run to the back of the intake and down the back is the engine.

Thanks for the reply. I just removed the carb for the rebuild.

I’m sure a lot of things are borderline on that thing But my heater hoses aren’t currently connected. They’re just dangling off to the side and the coolant is in a closed loop to the engine.

 

[Broncobowsher]

Borrow a tool from the local parts store. Cooling system pressure checker. It is a hand pump that pressurizes the cooling system with the engine off and cold. Need a full cooling system (so it isn't just blowing air out the leak). Easier to follow the leak when it isn't shaking, fan blowing, and trying to burn you.

 

[B RON CO]

Hi, check the freeze out plugs too. Good luck

 

[pcf_mark]

I had an Escape with a blown head gasket it drank coolant and overheated but held pressure on the tool when cold. Pull your plugs on the white smoke side - if you have a leaking head gasket it will steam clean the spark plug(s) where the leak is.\.

 

[wood47]

Took Broncobowsher's suggestion and grabbed a pressure checker, but having a bit of trouble with getting it to seal and build pressure. Yanked the driver's side exhaust manifold; freeze plug right above the mount (thanks B RON CO). Will still pressure test while I have the tool, but I think this is the main issue. How painful is it to change one of these with the engine still in the vehicle?

 

[73azbronco]

problem is getting tools there, big punch on one side would knock it off or push it into the block, no big deal if it does go into block. Other method using drill, and screw into side of plug and try prying it out. neither easy in the truck. Although, with any 90 degree battery drill it should be easy to drill and put a screw in, a big screw. You'll want to spray some BP blaster or such.

 

[Oldtimer]

And very seldom does only one rust thru, sorry to say.

 

[Broncobowsher]

If one is bad, they are all bad. Every time I thought I could get away with just doing one I have been wrong and spent even more time and lost coolant. Even lost one engine because that hard to get one looked good enough.

 

[73azbronco]

Brass is your friend.

Here is an easy install kit for less than long term use I would say.

https://www.amazon.com/dp/B09DD87M2V/?tag=classicbroncos-20

I will add, if one is bad, they all are, and if so, whats the rest of the motor inside look like? That said, this might be the time to pull the engine and fix them the easy way. Out of the bronco.

 

[B RON CO]

Hi, that is one of the worst freeze out plugs I have ever seen. O'Reilly's has a set of brass freeze out plugs. I choose to fix them one at a time, but yours looks really rotted, so I might change all you can reach. You can't reach the back of the cylinder head. You need to wire brush down to good clean metal. I use Indian Head shellac around the plug, and tap it in with a large socket. Good luck

 

[wood47]

Poked it with a flathead and it went straight through. It's the center plug right above the motor mount and in its current condition, there's really no hope getting it out with the engine remaining in the vehicle. So the engine comes out. Frankly it's so rusted, its looks like it will be hard to replace even with the engine on a stand. Surprisingly, the others look to be holding up well, but might as well replace them while I have the chance.

 

[Broncobowsher]

Yes, just get the kit and replace them all. And while it is out look over the oil pan gasket, intake gaskets, valve cover gaskets...