Hey guys, I've got a 1990 ZX6 that has just been running way too hot. Originally I would be riding maybe 45 mins, hit a streak of red lights, and the bike would be extremely hot and start leaking the coolant out the back of the reservoir. This was in 50 degree weather tops. I've now replaced the thermostat, the radiator cap, flushed out the radiator and put new coolant in. Now it's a little better, but far from solved. I just rode home, about a 25 minute commute in a ton of traffic, 60 degrees out, and it wouldn't have lasted much longer. I havent noticed anything leaking out the pump, so I figured the pump should be ok. I also know that the fan is running because I've hooked up a manual switch for it. The bike seems to do ok as long as I'm moving pretty fast, its just the traffic and idling that kills it. Don't know what to do next, any ideas?

 

When was the last coolant flush? Are you 100% sure that the pump impeller is actually moving coolant? Possibly a combination of both of these issues if you have already tested the others. Keep us posted

Welcome to KF.

 

I think that theres nothing wrong with the pump because it's not leaking, but I wouldn't say I'm 100% sure, and the coolant was flushed last week.

 

right on, just checking. And when you pulled the rad cap to bleed off air, you noticed the coolant moving?

 

Right, that too.

 

So I just found out that there's an air bleeder bolt on the water pump as well. I'll give that a shot and let you know how it goes.

 

Sounds like a candidate for a head gasket. If you're puking coolant out of your reservoir and the bike seems to get stupid hot for no good reason, I'd say it's time for a gasket job. Make sure you clean the mating area (acetone), take a medium 3M scrubby and lightly scour the insides of the cylinders, use the best gasket sealer you can (actually, Suzuki makes some excellent stuff: Suzuki-bond) and take your time.
Let me know if I can help guide you through.

 

I sure as hell hope it's not the head gasket.

 

Ah; not that bad of a job, really. (Don't try to solve the problem by removing the thermostat.) I think it's time to get your hands dirty. Do you have a decent set of tools; sockets, wrenches, torque wrench, etc? You can do this! Yes, it's moderately "invasive" but you'll appreciate your engine when you're done.

 

hey jeff, I know that nothing mechanical is perfect, but a head gasket on a 1990 is not what I have heard as being an issue. But I need to stick with basics.....lol