Metal silt in radiator bottom.

billo

billo

Joined
Nov 3, 2008
Messages
220
Location
san diego, ca
Bike
'07 ST1300
Last year I did major upkeep on my ST that included a water pump rebuild. I had the pump rebuilt by Honda and the new impeller turned not as smoothly as I would have liked. 2000 miles later I have an oil leak from the pump (yes, oil - absolutely no coolant). I stuck a toothpick up the hole and got pure, clean motor oil back. So here we go again. Preparing for teardown I've found some metallic sludge in the bottom of the radiator. Will a flush clear the block of this? Or is it a non issue?
Thanks!
 
Sounds like your favorite Honda dealership either didn't replace the water pump assembly correctly (too common) or didn't bother replacing the oil seal also.
I've repaired way too many failed water pump installs, because dealerships/folks hammered in the bearing, flipped the case over, and tried to press (or use a socket and hammer) and bang stuff together etc.
The bearing MUST be supported while your pressing the impeller into the CORRECT depth. If you don't, the impeller tries to push the bearing back out of the case etc.
***Note my picture, just a good example***
PXL_20220212_165919035.jpg
 
Thanks Igofar. I’ll see if that is the case when I get it apart. The impeller didn’t spin smoothly like a wheel bearing, I felt a notch as it rotated so I suspect the rebuild was boogered somehow from the get go.
My radiator coolant below the pump hose looked a lot like used fork oil, murky with specs of metal dust. It must be from bearing wear - no other moving parts. I guess I’ll just flush and hope for the best on that one.
 
that's a very interesting discovery you made there, I can't help but wonder given the plumbing connections across the radiator if materials don't settle across the inlet of some of the lower passages; seems to me the rad on the ST has horizontal passages. Seems to me that one of the connections is upper and the other is midpoint across the radiator; doesn't really matter which since pressure drop across the rad is so low that it becomes a point where material can hang up one way or another
 
When you say you "had the pump rebuilt by Honda", was that an actual rebuild, or do you mean a Honda dealer replaced yours with a new one?

I'm asking, because I didn't know Honda would actually rebuild a part. I thought they only did service, and sold parts.

Other shops actually rebuild stuff.
 
Sidekick said:
Just started today the job of replacing the water pump on my friend Chris 2004 ST.
Oil & coolant leak and surprise, surprise!
The impeller was setup by the last owner "3mm off" the recommended gap and shaved a big hole in the pump cover near the hose connection.
The radiator must be filled with aluminum scrap, I guess. As a big concern, how to clean it, is there shavings accumulated anywhere else?!
The constant push on the impeller axle can easily explain the degradation of the seal and subsequently the oil leak.
The wrong impeller position was maybe not noticeable when tightening the cover, but not not paying attention of the drilling sound is less forgivable.
As usual @Igofar is top on!
I hate it.

It’s what I do :rofl1:

View attachment 336071
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Sadlsor said:
When you say you "had the pump rebuilt by Honda", was that an actual rebuild, or do you mean a Honda dealer replaced yours with a new one?

I'm asking, because I didn't know Honda would actually rebuild a part. I thought they only did service, and sold parts.

Other shops actually rebuild stuff.
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I brought them the front crankcase cover and all the new parts. Afterwards I measured the protrusion from the bearing surface and it seemed correct. Whether the bearing is fully seated or any damage I’ll soon see.
 
That is not where, or how, you measure the correct depth.
Looks like you were off about 3-4 mm, from the damage shown.
 
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What are the gray sections on the O-ring? Is that smashed metal from the surrounding area or some sort of goop to keep the ring in place during placement so it doesn't shift and get pinched upon reassembly? It looks like there are already places where the casing has 'bumps' on it for that...
 
billo said:
Thanks Igofar. I’ll see if that is the case when I get it apart. The impeller didn’t spin smoothly like a wheel bearing, I felt a notch as it rotated so I suspect the rebuild was boogered somehow from the get go.
My radiator coolant below the pump hose looked a lot like used fork oil, murky with specs of metal dust. It must be from bearing wear - no other moving parts. I guess I’ll just flush and hope for the best on that one.
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Not bearing wear, but shaved aluminum from the inside of the front cover!
Be sure you flush and clean the entire engine out now!
 
Igofar said:
That is not where, or how, you measure the correct depth.
Looks like you were off about 3-4 mm, from the damage shown.
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I'm just measuring the damage there.
Would the flushing procedure be run, drain and flush radiator a few times?
Gus1300 said:
What are the gray sections on the O-ring? Is that smashed metal from the surrounding area or some sort of goop to keep the ring in place during placement so it doesn't shift and get pinched upon reassembly? It looks like there are already places where the casing has 'bumps' on it for that...
Click to expand...
That's Honda goop. The bumps weren't doing it alone.
 
I picked up a used cover off EBay from a police bike for under $100 shipped. No damage, the finish could be better. No matter, I’ll take functional over pretty any day. I think this same situation, over time, has taken its toll on availability. I got while the gettin’ was good. Anaheim to San Diego - should be here soon.
 
billo said:
I'm just measuring the damage there.
Would the flushing procedure be run, drain and flush radiator a few times?
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Years ago you could buy a kit for flushing your cooling system. You cut the heater hose and inserted a T - the middle leg of the T had a cap. An angled plastic pipe was put in the radiator where the cap was fitted. You removed the cap on the T and hooked up a garden hose with a fitting provided, then you turned on the hose. The coolant flowed out of the bent pipe over the front of the radiator. Alas, that would not work on our ST's because of the oversized hoses.

Talk to Larry about flushing. I'm sure he has a way to do it safely (for the bike).
 
billo said:
I'm just measuring the damage there.
Would the flushing procedure be run, drain and flush radiator a few times?

That's Honda goop. The bumps weren't doing it alone.
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I would pull the radiator and flush it separately. Remove the thermostat and put the cover back on. Pull the two drain plugs on the block. Put the lower radiator hose on , connect a garden hose to it and let the water run.
 
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GitSum said:
I would pull the radiator and flush it separately. Remove the thermostat and put the cover back on. Pull the two drain plugs on the block. Put the lower radiator hose on , connect a garden hose to it and let the water run.
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Sounds reasonable. Will do.
Igofar said:
Be careful not to swamp your alternator.
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I think that means don't over pressurize and blow a hose up top?
Igofar said:
Call me and I will tell you how to press it in safely.
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Thanks! Will PM when time is near.
 
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