6.2L cooling issue
 

So I finally got around to replacing the oil pressure sensor today and when I cranked her up, everything seemed fine for the first several minutes. My temp started rising like it should and then after about 10 mins. I noticed that the temp gauge suddenly dropped to 100. After 5 seconds or so, it then jumped to about 160 for about 5 secs, then back down to 100 again. So I shut her down. I then felt the risers...here is the odd part...the starboard was warm( I could keep my hand on it for about 4-5 secs) but the port wasn't warm at all!

Ay ideas?

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I forgot to mention...I do not have a closed cooling system. I am running off a garden hose. I do not connect thru the outdrive but I have a T on my raw water pickup line next to the water pump.


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Re: 6.2L cooling issue
 

Hey cst ,
from what I understand a broken flapper can cause this type of grief. Might be worth a shot to check them both.

Just a thought :)

Larry

Are you talking about my exhaust flappers? I did just have them replaced late last year when I had my risers replaced, but I will check them to make sure. But doesn't that keep water from flowing back into the engine from the outdrive?


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Re: 6.2L cooling issue
 

Yes , ain't them then I doubt.
One other thing is there are 3-4 different riser to manifold gaskets according to mercruiser.

Larry

Re: 6.2L cooling issue
 

I have replaced my temp sensor on the thermostat housing. Come to find out that I have a second temp sensor that is located directly across from the first one. According to Merc, I should only have one and it is the regular sender that has one wire that slides onto the threaded end. So does anyone know what this is and why?

Re: 6.2L cooling issue
 

Here is second pic of mystery item...

Re: 6.2L cooling issue
 

I also have two on my 4.3 Chris.
The one your talking about on mine is a sensor for the engine alarm system. :)

Would that be the over temp alarm? I guess then that would not be the cause of my temp gauge going crazy. i guess I will start chasing ground wires and see if that is the issue. I also can't find that item in the parts diagram. I even called our local Merc dealer and they didn't know either. Maybe I'll look under electrical instead of cooling...


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Re: 6.2L cooling issue
 

Yes Chris.
Here is a pic:

http://www.mercruiserparts.com/Show_...Point+Drain%29

#6 is the sensor. If you look up your serial # it will give you the exact one but I think they are all the same for the 6.2L