loosing coolant

[Darren Parkinson]

Hi everyone , i have a really strange one here with my 250 slx 8.2 mag , its loosing coolant so i had it pressure tested and all was ok , i topped up after a day out and all was ok , came back in the morning and its gone out of the resevoir , any ideas as the mechanic says everything is ok with the cooling system as the pressure test was good , i did witness it as well , really confused

 

[CaptRonn]

Check the heat exchanger. The gaskets on the ends can leak and the coolant leaks into the raw water and goes out the exhaust.

 

[LG111]

Check the bottom of the Reservoir. There is a hose that leads from the bottom. Check the hose clamp. They tend to loosen over time. Next check the hose clamps that lead to the Heat exchanger.

Hope that's the fix. Was on mine.

 

[Thornton69]

If you topped up at the end of the day while hot, it will draw down when it cools. A system pressure check should eliminate everything to the fill cap. Do you have coolant in the bilge? It is heavier than anything else sitting in the bottom.

 

[Darren Parkinson]

Hi no i dont have any coolant in the bilge at all , i have had it all pressure tested and it tested ok , its a really strange one , pressure is fine but if i top it up when cold it still disappears overnight , i have seen some come out of the exhaust but the mechanic said this was probably due to me overfilling and it then gets pushed out of the expansion tank under pressure , really strange and frustrating , it does not overheat either

 

[CaptRonn]

Hi no i dont have any coolant in the bilge at all , i have had it all pressure tested and it tested ok , its a really strange one , pressure is fine but if i top it up when cold it still disappears overnight , i have seen some come out of the exhaust but the mechanic said this was probably due to me overfilling and it then gets pushed out of the expansion tank under pressure , really strange and frustrating , it does not overheat either

Replace both gaskets on your heat exchanger.

 

[Darren Parkinson]

Thanks for that CaptRonn , which gaskets ?

 

[dwna1a]

Captain is talking about the two end caps, they have a gasket.

mine would also be to have the heat exchanger checked out for split cooling tubes. They too will leak coolant into the raw water side and put it out the exhaust.

if there is no coolant in the bilge that leads me to Captains idea or the split tubes.
Both are easy fixes. If I had to pull the caps I’d clean the exchanger, replace the zinc, and replace the two gaskets. Don’t over tighten the caps. Good luck and keep us informed please

 

[Darren Parkinson]

hi do you have to drain the coolant to replace the end gaskets ? would a pressure test not detect if these end gaskets and split tubes have gone ? pretty new at this ,

 

[Darren Parkinson]

does anyone have a diagram of the gaskets i would have to change they could send me ?

 

[dwna1a]

You can go online and type in the heat exchanger you have to get a complete diagram. As for a pressure test I’m sure you can learn how to do it but I took mine to a shop had them tested and rebuilt.

That was over in Chesapeake VA.

 

[scoflaw]

If your losing coolant your pressure test will detect that. No way it won't

Test as a whole assembly to start

 

[Darren Parkinson]

yes i have had the pressure test done and all is ok , so at the moment it looks like the mechanic is right ,i am over filling it

 

[scoflaw]

yes i have had the pressure test done and all is ok , so at the moment it looks like the mechanic is right ,i am over filling it

It shouldn't go empty. Over filling would make it expel through the top and then level off at proper level

 

[Darren Parkinson]

well , im confused on this one , its a mystery really