My 3GM, 27HP narune diesel engine looses cooling water (fresh water). There are no leaks in any of the hoses, no water in the bilges or engine cooling oil. Does anyone have an idea as to what is going on, and how can I fix it. I am loosing out on lots of sailing.
3gm cooling problem
- Thread starter Leigh14353
- Start date
- Status
Heat exchanger leaking
The fresh water is leaking out of the heat exchanger and being discharged with the raw water in the exhaust.
The fresh water is leaking out of the heat exchanger and being discharged with the raw water in the exhaust.
Need more info
You start the engine and than what does it run do you see water coming out exhaust and does it over heat what is happening to tell losing water
You start the engine and than what does it run do you see water coming out exhaust and does it over heat what is happening to tell losing water
If you are really out of luck there could even be a blown head gasket and the water is finding its way into the cylinders when the engine is running.
With the engine cold try taking the filler cap off and then start up to see if there are any bubbles coming up in the coolant as it circulates.
Unless you are very experienced DON'T take the cap off if the engine is hot as this is likely to spray scalding coolant water over you.
With the engine cold try taking the filler cap off and then start up to see if there are any bubbles coming up in the coolant as it circulates.
Unless you are very experienced DON'T take the cap off if the engine is hot as this is likely to spray scalding coolant water over you.
Re: Need more info
Water is coming out of the exhaust. Engine overheats after about 15 minutes. Shuting engine off and waiting 15 minutes, then open coolant cap - no fluid inside.
Water is coming out of the exhaust. Engine overheats after about 15 minutes. Shuting engine off and waiting 15 minutes, then open coolant cap - no fluid inside.
That is massive leaking
If it was a head gasket it would hydro lock (very very bad) the engine with a leak that bad. I'm betting the only way that much FRESH water (anti) could leak out that fast is a hole in the FRESH to RAW water heat exchanger. If you where loosing all your water elsewhere it would be seen in the engine compartment some where. If it is getting dumped overboard with the raw water in the exhaust you would not notice.
To test get some of the cooks red food coloring and put it in the FRESH water side, fill the engine, put the pressure cap on and run it. Watch the exhaust for red water
If it was a head gasket it would hydro lock (very very bad) the engine with a leak that bad. I'm betting the only way that much FRESH water (anti) could leak out that fast is a hole in the FRESH to RAW water heat exchanger. If you where loosing all your water elsewhere it would be seen in the engine compartment some where. If it is getting dumped overboard with the raw water in the exhaust you would not notice.
To test get some of the cooks red food coloring and put it in the FRESH water side, fill the engine, put the pressure cap on and run it. Watch the exhaust for red water
Gasket
I believe that the heat exchanger on the 3GM has a total of 4 gaskets that seperate the water flow, two on each end of the exchanger. Would not be hard to believe that one is defective and allowing the coolant to mix with the raw water through the exaust.
I believe that the heat exchanger on the 3GM has a total of 4 gaskets that seperate the water flow, two on each end of the exchanger. Would not be hard to believe that one is defective and allowing the coolant to mix with the raw water through the exaust.
if you've never changed/cleaned out that heat exchanger- now is the time and its relatively inexpensive and a DIY (at least on a 2GMF) - I'd order the gaskets and when you pull the exchanger take it to a radiator shop and have them flush out all the tubes & cleaned up. You will probably find that your issues will be solved once reassembled.
- Status