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cr125 leaking coolant

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ok so i just rebuilt the top end on my cr125 1999, new piston, rings, gaskets the lot. kicked the bike and it started first kick however i noticed coolant leaking out the peep hole beneath the water pump. i believe this is related to a head gasket problem but the head gasket is brand new. anyone know of why the coolant is leaking and how i could possibly fix it? thanks, paddy

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The only way for coolant to exit from the weep hole on the bottom of the water pump cover is a bad seal in that area. If the head gasket was bad the coolant would make its way into the cylinder. I see you also put a new shaft in when you did the seals which is the correct thing to do. Either the seal is installed backward or its torn somehow.

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ok il check the seals but how about if a nut on the head wasnt tightened down properly? the threads are shot on one of the screws and the nut will not tighten down fully, could that cause the coolant to leak out the weep hole?

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ok il check the seals but how about if a nut on the head wasnt tightened down properly? the threads are shot on one of the screws and the nut will not tighten down fully, could that cause the coolant to leak out the weep hole?

 

No, it will not cause coolant to come out of the weep hole.  The weep hole is there to let you know you have a bad seal in the waterpump. That area is no way affected by a head gasket leak. I would suggest however, you get the head gasket problem fixed. I'd replace the bad stud, or all of them.  If the threads are only bad where the nut tightens down, you could possibly use a washer or 2 to let the nut tighten down before it goes down to the bad threads. Replacing the stud is the correct fix though

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No, it will not cause coolant to come out of the weep hole.  The weep hole is there to let you know you have a bad seal in the waterpump. That area is no way affected by a head gasket leak. I would suggest however, you get the head gasket problem fixed. I'd replace the bad stud, or all of them.  If the threads are only bad where the nut tightens down, you could possibly use a washer or 2 to let the nut tighten down before it goes down to the bad threads. Replacing the stud is the correct fix though

ok i done what u said and placed 2 washers on top of the stud and torqued down the nut, i let the bike idle to heat up and took it a run and the coolant has slowed down dramatically. it went from rushing out to literally a drop or two coming out the weep hole. i didnt have time to ride the bike for long so i dont know if it has completely stopped leaking or not but when i do run the bike for a good length of time, il get back to u and let u know. thanks for the advice bud, appreciate it

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ok i done what u said and placed 2 washers on top of the stud and torqued down the nut, i let the bike idle to heat up and took it a run and the coolant has slowed down dramatically. it went from rushing out to literally a drop or two coming out the weep hole. i didnt have time to ride the bike for long so i dont know if it has completely stopped leaking or not but when i do run the bike for a good length of time, il get back to u and let u know. thanks for the advice bud, appreciate it

 No problem, but I am still puzzled by how the head gasket affected the weep hole. So, I done some thinking, and here is what I can come up with as a possibility:

 

You have/had a headstud with bad threads at the bottom, and wouldnt allow the nut to torque down tight enough, resulting in maybe compression leaking thru that area of gasket and into cooling system. The compression pressure was enough pressure to get into the coolant passagesand push the coolant thru the waterpump seal, and out the weep hole?

   You then added washers to bad stud to raise the nut up enough to torque down before reaching the bad threads, and it inturn tightened down tight enough to almost stop pressure from reaching into the coolant passages. Now,  I believe the head gasket is bad, and you should replace it for a total seal. If it's still leaking, any amount I'd fix it.  Another possibility is that the waterpump seal is bad, needing replaced, thats why the leak is still present.  So either headgasket is bad....Or waterpump seal. IMO

 

For now, keep riding it and keep watching it. The drops can be whats left inside the weep hole area.

Edited by wykyd450r

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