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Old 04-23-2016, 03:30 PM   #1
East_Bound
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Coolant leaked out of exhaust flange

What's up guys -

So today, I fixed my exhaust leak from the exhaust flange, which is great. But while I had the exhaust flange off and open, I discovered something else:

I had the first exhaust pipe separated nearest to the front of truck, and after having it off for a couple minutes, I bumped it pretty good and had some bright green coolant drip out of it. After a few pumps putting back the thread and nut for the flange, more coolant would spill out. I'd say around 8 oz of coolant. Coolant did not leak out of rear exhaust flange (nearest to firewall)

I am aware this is a sign of a blown head gasket or something internally wrong with the engine, but is there anything else that can cause this? Why would coolant be coming out of one exhaust pipe and not the other? The exhaust flange is straight up and down while the one nearest the front of truck is at a 45' degree angle, so it shouldn't have to do with gravity.

There is a small coolant hose line right above the exhaust flange that drips on top of the flange, but could the coolant seep into the exhaust overnight before being able to be burn off by a hot exhaust? Any info helps!
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Old 04-23-2016, 03:58 PM   #2
frankslagoon
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Re: Coolant leaked out of exhaust flange

seems like a lot of coolant. if it were leaken from inside the engine you should see white smoke
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Old 04-23-2016, 04:56 PM   #3
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Re: Coolant leaked out of exhaust flange

No white smoke has been seen. Runs very good and hasn't had any sign major sign on decrease in performance. But there must be a reason.

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seems like a lot of coolant. if it were leaken from inside the engine you should see white smoke
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Old 04-24-2016, 04:20 PM   #4
storm9c1
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Re: Coolant leaked out of exhaust flange

Fluids can do weird things, and follow strange paths. If you know that you are weeping coolant from places, I'd fix those issues first. Also check your freeze plugs. I've had those leak and cause coolant to drip from places that make no sense (like coolant dripping from inside the starter, lol). What engine is this? Some engines (but not SBC) have exhaust manifold bolts that go into the coolant jacket. I had a Mopar big block that was leaking coolant out the exhaust that was caused by this. The previous owner replaced the stud but did not put sealant on the threads.
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Old 04-24-2016, 08:21 PM   #5
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Re: Coolant leaked out of exhaust flange

250 block out of a 1970 Nova, original 230 heads.

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Originally Posted by storm9c1 View Post
Fluids can do weird things, and follow strange paths. If you know that you are weeping coolant from places, I'd fix those issues first. Also check your freeze plugs. I've had those leak and cause coolant to drip from places that make no sense (like coolant dripping from inside the starter, lol). What engine is this? Some engines (but not SBC) have exhaust manifold bolts that go into the coolant jacket. I had a Mopar big block that was leaking coolant out the exhaust that was caused by this. The previous owner replaced the stud but did not put sealant on the threads.
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Old 04-26-2016, 11:01 PM   #6
sixnineK5
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Re: Coolant leaked out of exhaust flange

My 69 k5 has a 250. Strangest thing is that I have noticed coolant on top of the intake/exhaust near the no.1 cylinder. Have no idea how it gets there, it runs smooth with no smoke or oil contamination-
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