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Raw water mixing with closed coolant. 7.4l model350

S

skpr44

New member
Just replaced head gaskets, planed heads, hot tanked complete exhaust system and magnafluxed all pieces. On startup I have anatifreeze coming out the exhaust. Engine runs ok.
 
bondo said:
Ayuh,...... My 1st WAGuess is the heat exchanger's got a crack in it,....
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Yes, how old is the HE? I've seen 'em with corrosion in the tubes cause the leak too.
So, do a pressure test with 10 psi into the HE, and detach both exh. hoses to home in on the pathway out.
I think I would have the plugs out too. You don't want bend rods adding to issue.
 
skpr44 said:
Heat exchanger is 2 years old. New from Anthony Keats. There were no issues last season.
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The other common issue is loose bolts on the riser to elbow joint. The gasket that has coolant on one side and raw water/exhaust on the other. When new, that gasket settles and bolts become loose.
 
I was going to ask what gaskets were used to reassemble the exhaust riser/elbow???

not much else if it happens right at startup...
 
Heat exchanger is 2 years old. New from Anthony Keats. There were no issues last season.
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Ayuh,.... If it had any raw water left in it over winter, you've found the problem,....
 
Seems straightforward. You know you have to fix it, and to do so you will need to drain the coolant. Do that first, then pressurize the coolant system with air (as suggested by Dave) and listen for the leak. No point speculating.
 
Since the entire exhaust system was apart, might look hardat the elbow/manifold connection. Should consist of a solid stainless steel plate sandwiched between two gaskets to preventany coolant from passing to the exhaust. If that connection is sound another possibility is coolant getting into one or more cylinders. This is not likely since some degree of hydraulic lock would be present and heavy steam would be coming out the exhaust with an intense coolant smell. A failed HE is unlikely since it is relatively new. Might temporarily replace the HE-to-elbow hoses with clear plastic segments and note the color of the water. This would for sure determine if the coolant is coming from the HE or exhaust manifold. Interesting problem. Good Luck
FL Panhandle
 
diver_dave said:
The other common issue is loose bolts on the riser to elbow joint. The gasket that has coolant on one side and raw water/exhaust on the other. When new, that gasket settles and bolts become loose.
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Mulletwagon said:
Since the entire exhaust system was apart, might look hardat the elbow/manifold connection. Should consist of a solid stainless steel plate sandwiched between two gaskets to preventany coolant from passing to the exhaust........................
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This may apply if Skpr44 has a 7.4L model 350 with a "Full" Closed Cooling System.
If he has a "Half" system, this would not apply.



Skpr44....... which closed cooling system is your engine fitted with .... Half or Full?



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