2006 mercruiser 4.3l overheating possible head gasket

[MCFAM]

Well my 2006 4.3l mercruiser overheating problem took a turn for the worst. The overheating alarm was disconnected and I did not know that or that it is only suppose to run about 175. So I checked the oil and it looked fine but was over filled for some reason so I pulled the plug and sure enough the bottom was all water. So does anybody know a good video for replacing the head gasket and what all should I check for damage? I just ordered the seloc repair manual but I want to start working on it and seeing how much damage their is and it won't be here for a week.Any advice would be greatly appreciated? I spun the motor by hand and everything seems okay, it only ran about 200 for maybe 30mins and I shut it off, and haven't restarted yet. it was running okay when I shut it off.

 

[tpenfield]

Don't just assume head gasket until you have run a cylinder leak test and even a cooling system pressure test. You can probably Google your way to some videos on tearing down the 4.3. Either do Mercruiser or GM 4.3 . . . same base engine

 

[r.j.dawg]

One of these should help.
http://boatinfo.no/lib/mercruiser/manuals/mercruiser32.html#/0

http://boatinfo.no/lib/mercruiser/manuals/mercruiser25.html#/0

 

[MCFAM]

I planned on a doing the cylinder tests, do you know what they should be ? How do you do a cooling test on a fresh water system like that? I found out the last owner put in a 180 thermostat for some reason so that it explains at throttle why it ran a little hot , but he said he put a new impeller in it last season so I will check that but I think a hose must be clogged for it to overheat at idle every time how can I flush the hole system or do I need to do it hose by hose? If it is not the head gasket where else should I check for where the water in the oil pan came from?

 

[Bondo]

I planned on a doing the cylinder tests, do you know what they should be ? How do you do a cooling test on a fresh water system like that? I found out the last owner put in a 180 thermostat for some reason so that it explains at throttle why it ran a little hot , but he said he put a new impeller in it last season so I will check that but I think a hose must be clogged for it to overheat at idle every time how can I flush the hole system or do I need to do it hose by hose? If it is not the head gasket where else should I check for where the water in the oil pan came from?

Ayuh,.... Welcome Aboard,.... How long has it been Yer boat,..?? How much have ya Run it,..??

To do an air pressure test on the motor, Drain it, 'n isolate the Block, from the in-comin', at the T-stat housin', 'n the exhaust manifolds, the out-goin',...
Add 'bout 15psi, 'n Listen, then follow the Hissin' sounds,...

 

[MCFAM]

This is my 1st season with it. I have only had It out twice so maybe 40 hrs. By doing that will it tell me I have an exhaust gasket bad only or will it tell me if I have a head gasket bad also?

 

[tpenfield]

This is my 1st season with it. I have only had It out twice so maybe 40 hrs. By doing that will it tell me I have an exhaust gasket bad only or will it tell me if I have a head gasket bad also?

It will tell you where water may be escaping from the cooling system, which could be anywhere . . . cylinder heads, engine block, exhaust, etc.

 

[MCFAM]

Could you possibly give me a little more instruction or point me towards a video on doing the air test? I think by doing it and a cylinder test it my just point me in the right direction for finding which gasket is leaking water.

 

[MCFAM]

I pulled my thermostat housing off and was wondering what the bolt with the ball on it on. The exhaust hoses attach to it. i couldn't find it in my repair manual, is there a certain setting it is suppose to be at?