Bike overheating

[GG221]

My bike is overheating easily. Radiator will be smoking after even a mellow hill climb. I let the bike cool down and check the radiator is full, but I can see a thin film of what I think might be oil on top, but not positive. It is not very milky like heavily contaminated oil, but maybe there is a small amount. When I change my transmission oil it does not look very milky at all.

Any ideas?

2018 XC 300

[TGM_OFFROAD]

Originally Posted by GG221

My bike is overheating easily. Radiator will be smoking after even a mellow hill climb. I let the bike cool down and check the radiator is full, but I can see a thin film of what I think might be oil on top, but not positive. It is not very milky like heavily contaminated oil, but maybe there is a small amount. When I change my transmission oil it does not look very milky at all.

Any ideas?

2018 XC 300

Your water pump shaft seal may be leaking. Pull the impeller off and inspect the seal and shaft

[GG221]

Originally Posted by TGM_OFFROAD

Your water pump shaft seal may be leaking. Pull the impeller off and inspect the seal and shaft

I will check that out. Would that cause overheating?

[(F5)]

Is the pump working?

[Doc Brown]

Originally Posted by GG221

I will check that out. Would that cause overheating?

No, that would not cause overheating. Very often the culprit is the rad cap or better the over pressure valve in it. Could also be a lose impeller.

[Laszlo ervin]

Do you have a fan?doaes not start? Chech the radiators if its clogged or something..

[GG221]

Today I looked in the radiator and it looks dry. I added about 1 cup of coolant and it was full again started the bike and I can see that the pump is working. It looks to me like the steam or smoke is coming off the header pipe. Maybe it is just a leak somewhere?

[swazi_matt]

is this a new issue? or is it a new bike? If it is a new bike it could be jetted too lean.

[GG221]

It is a new issue. I think jetting is good.
Sounds to me like i should replace the head o-rings and the water pump shaft seal.
Any other parts I need to order along with the pump shaft seal?

[(F5)]

If the gear oil is not milky then pump seal should be fine. If you do have to replace the seal check the shaft. Mine got a groove in it. Was quite cheap.

I have a bung with a shrader (tyre) valve in it. You could glue one into a piece of plastic or drill and tap. This bung is radiator hose size. Put a plain bung in other hose and put a radiator in a bucket of water and a couple pumps with a bicycle pump. You'll quickly find a leak or prove it as a good part.

If they both prove fine and you swap a cap over then yeah I'd replace the head o-rings.