St1300 Pan European coolant leak

Water pump seal failure

[@sttraveler2593]

The small hole you indicated coolant coming from is an early indicator that your water pump mechanical seal is failing. Replacing the water pump housing seal does not fix it. You will have to replace the water pump and mechanical seal assembly which involves removing the front engine case cover and opens the engine up, very indepth job that takes a service manual to complete.

[@MrImarcus]

Hi Gary, yes agreed, but there are a number of cavaties within that cover that can contribute to leakage. This one was caused by corrosion between the surfaces and subsequently fixed the leak 👍

[@mattthomson1689]

Q & C: Question, 2-part: A), Would someone share a coolant hose diagram, as viewed from riders position, with main fuel tank, air box, and throttle valves removed, looking at the hose connections to the thermostat housing? B), Two hoses come off the right side of the radiator, a small diameter hose clamped at the neck of the radiator cap, running about 16” to a ‘T’ connector, two lines then disappearing upward toward the fuel tank (Logic would have one of these connect to either the top or bottom of the reservoir; where would the other hose connect?). A middle-sized hose runs from the lower radiator hose ‘Union’ at the water pump cover, upward toward and under the fuel tank. This hose feels hard near the right engine bank and I suspect it is heat-damaged, ripe for replacement. I need to know if it connects to the thermostat housing, hopefully before I dig any deeper...all comments welcome!

[@BeavistheLizard]

Did you get anywhere with this Matt? I have just removed my failed Alternator... can see lots of crusty issues around all the hoses... I am in deep about to start cleaning up.

[@mattthomson1689]

Thanks for showing us the corrosion or precipitate found on the water pump cover. Looks not too bad, but suggest obtaining pro-experienced advice, including a possible water / deposits analysis for best practice for internal cleaning and flushing. With radiator passages very small, incorrect cleaning (products) may decrease radiator effectiveness....ouch!

[@user-pb1mu7yq6r]

Just got the same thing now. Thought it was the weep hole but it’s down the side of it. Taking a look at this video may help as having to change the coolant as service time. Thanks

[@whatchalookin429]

Thank you for the video. I have the exact same issue with mine. It sucks, but im just glad its not coming from the weephole :)

[@chubbybrown4real]

not happened, but thanks for heads up

[@kirklogan3414]

Thanks for the video mine started this, this spring when I pulled it out. Any idea where the reservoir is on this bike?

[@MrImarcus]

Hey just behind the grey panel. Not obvious to see but easy enough to find. Hope you got it sorted.

[@usarmy3111]

What did you accomplished by removing that water pump cover? Just changing the water pump cover seals and fixed the leak?

[@MrImarcus]

Yes, the seal between the cover and the engine block had been disrupted by aluminium corrosion. If you remove / clean and replace it should fix the leak - if that was the leak in the first place.

[@anaheimstcruiser2996]

Same problem and I'm not a mechanic so I was taking off the gas tank to get to the leak😂😂😂😩

[@MrImarcus]

We've all been there mate. Hope you got it sorted. 👍

[@neilgallagher6152]

Hi - did you have any issues getting that seal to fit properly. Ive put on a new seal as part of changing the water pump but its now leaking from that seal.

[@MrImarcus]

Hi Neil, I cleaned up the rubber seal and used a gasket sealer product as well. I did spend a considerable amount of time cleaning both surfaces and inside the recess that holds the seal. I was also careful to tighten the securing bolts as you would a cylinder head...

[@myz06rocks]

That’s me! Just found this same issue. Only 40,000 km

[@MrImarcus]

Good that you spotted it pal. It's an easy fix compared to a breakdown or significant overheat.

[@myz06rocks]

@@MrImarcus it was easy to spot in the sense that the bike is currently on my lift while I do the valve clearance check. 11 of 16 out of spec and the other 5 right on the tolerance limit. Don’t believe what you read on the internet, do the work. 😀

[@user-yx8np2oy4e]

Thank you your video helped

[@MrImarcus]

Very glad to be of service. Hope you get it sorted.

[@bigpicturesstudio]

Thanks for making the video. Is the thermostat inside that housing cover??

[@MrImarcus]

Hi, no it's the pump housing and transfer port. I'm not sure where the thermostat is. Hope you get sorted :)

[@bigpicturesstudio]

@@MrImarcus ok I found it, its behind the radiator, need to strip away fairing plastics and radiator out to reveal the housing for thermostat. Job done here. Bit of a pain for such a stupid part fix, but hey its supposed to be fun right hahaha. best luck :)

[@MrImarcus]

@@bigpicturesstudio great stuff, glad you got it sorted :))

[@eroom2087]

How many miles at that that time and has your valves ever been out of spec when checked

[@MrImarcus]

Hi, about 30k? Valves hadn't been checked to my knowledge but the engine ran lovely so would bet they were in spec...

[@eroom2087]

MrImarcus I just got a 2004 with 42000 and it runs good but I’m going to change all fluids, break,clutch, coolant, rear gear oil and this winter go for the valve check and a few other things while I got all the plastic off

[@MrImarcus]

@@eroom2087 smashin, coolant and rear drive oil will pay dividends in my opinion. Also brakes on my bike were night and day better than other pans I rode, I didn't change the fluid but it's gotta be a step in the right direction.

[@MrImarcus]

@@eroom2087 fantastic bike btw. 40k is barely run in and owners tend to look after them. Best bike I've prob ever owned...

[@SICKFRESH619]

I have the same problem on my 2007. Questions Sir.... Do you have the part number for the rubber seal and what is the name of the part you took off? Thank you in advance.

[@MrImarcus]

Apologies I don't have the part. Quick look on Google? I can search back in my bank statements if you can't find it, but I don't remember any hassle finding it? Think it's a dealer part only BTW...

[@usarmy3111]

My 2009 Honda st1300pa model, bike runs fine after warm but when gets hot it runs really rough and i also notice slow coolant leak.... what should i do?

[@MrImarcus]

Investigate if the problems are connected. I would invest in professional help if you aren't confident. Don't want to overheat and potentially lose an engine.

[@usarmy3111]

Do you replaced your water pump if so a easy task? And what is it mean when a slow leak from that little hole near the water pump cover?

[@MrImarcus]

@@usarmy3111 I didn't my leak was corrosion between the 2 surfaces. There are permissable amounts of losses from the pump hole so not always an indicator of a fault.

[@sttraveler2593]

@@usarmy3111 If you have a leak from the small hole near the water pump cover it is indicating a mechanical seal failure on the water pump itself and requires a water pump and mechanical seal replacement. Not an easy job, very indepth as you have to remove the front engine crank case cover.

[@usarmy3111]

@@sttraveler2593 thanks.👍🏻

[@Toyorulesitall]

Mine is leaking from the same place. Was it an easy fix?

[@MrImarcus]

Yes fairly easy and well worth the investigation. You are dealing with steel bolts through machined aluminium parts. If you are confident in cleaning, preparing and not overtightening then I would suggest it's straightforward.

[@cbis8518]

After repair was it the problem. I think i have the same problem.

[@MrImarcus]

Hi, yes it was. Problem is now sorted. :)

[@stefan7n]

MrImarcus great video.