Yanmar 1GM cooling pump

[Brian Hickson]

Have any of you CD25D owners replaced the cooling pump impeller? I always thought this would be a simple procedure, but the clearance is so small, it appears to me that the cooling water pump cover cannot be removed unless the crankshaft pulley is removed first. I know I'm missing something here. Thanks.

[Bob]

Have any of you CD25D owners replaced the cooling pump impeller? I always thought this would be a simple procedure, but the clearance is so small, it appears to me that the cooling water pump cover cannot be removed unless the crankshaft pulley is removed first. I know I'm missing something here. Thanks.

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Brian:

You will have to remove the pulley to access the water pump. Use a hub puller so you don't damage anything, also when you reassemble make
sure to use neverseize on all screws so you can get it apart the next time.

Bob
S/V Ranger #144
CD25D



rmalinka@spec.net

[Bill]

I replaced my impeller last summer. It was very difficult and the screw behind the belt pulley was indeed difficult to remove. At the time I got a 1/4" box wrench and had a phillips head screw tip welded into it, then ground down the back side so it would fit behind the pulley. Knowing that this would take forever in a true need to situation, I changed the bolts to hex head machine screws and got another wrench just for them (either a 7 or 8 mm box end). While it is still somewhat of a chore to get at the screw behind the pulley, I am no longer worried about stripping the head of the phillips screw. IMHO removing the pulley involves considerably more effort (alternator et al..). But I have not tried it either.

The email address below will hit about 1/2 dozen owners of CD25Ds cd25d@onelist.com

Bill

Have any of you CD25D owners replaced the cooling pump impeller? I always thought this would be a simple procedure, but the clearance is so small, it appears to me that the cooling water pump cover cannot be removed unless the crankshaft pulley is removed first. I know I'm missing something here. Thanks.

cd25d@clnk.com

[Jerry]

Have any of you CD25D owners replaced the cooling pump impeller? I always thought this would be a simple procedure, but the clearance is so small, it appears to me that the cooling water pump cover cannot be removed unless the crankshaft pulley is removed first. I know I'm missing something here. Thanks.

The impeller is better accessed by removeing the housing to which the impeller is attached. This is the one that has three hex head bolts and the hoses also attach to it. The hoses have enough slack so that you can swing the impeller housing cover out to get at the screw behind the pulley. some of the housings have a gasket and some use an "O" ring that should be replaced just like your cover gasket. I have had two impeller failures where the impeller was intact but the bond between the rubber and the metal bushing on the shaft had failed. Removing the housing makes it a quick and simple job.



jlecocq@milehigh.net

[jim jamieson]

You have two options. You can pull the pump itself as is suggested. There are 3 bolts securing it and it comes out and goes in without pulling the pulley. I did it last year when I had to replace the pump because of seal leaks. You may have to remove the clamps around the rubber hoses to get free access to the pump. BTW, replace those iron bolts with SS bolts that won't rust out. Any hardware store that sells metrics has them.
The other option is to cut a slit between the bolt hole and the outside of the pump cover so that all you have to do is remove the two accessible screws from the pump cover and loosen but not remove the screw that holds the pump cover behind the pulley. All you do is pull it out sideways. Cut a slit in the gasket so it slips around the screw behind the pulley. Use SS screws with hex heads so you can loosen and tighten with a small metric wrench. The Yanmar originals are steel and will rust. These modification work fine. I know, I had to change another impeller that slipped on its shaft after 6 hours today when the water temp light came on. I had the same thing happen with a new impeller last year after 18 hours which lost bonding between the impeller and the shaft insert. This is really quite common and I would like to know if Yanmar has found a decent manufacturer. It took about 5 minutes to change the impeller and get going again with the slotted cover. Call me if you want more details.
jim
203-785-4317
CD25D Hull #99 "CYLAN II" in Guilford, CT



james.jamieson@yale.edu

[SteveZ]

I change the impellor on my 1GM every couple of years.
I use an angle phillips screwdriver made for getting into tight places. The one I have ratchets making it an easy job.