I have a 1998 500dawith Detroit Diesels. I have a starboard engine which is overheating. I shut it down and pulled the sea water impeller. It is shot. I can not seam to get the new one back in. Any advice on the proper procedure for changing an impeller?
Replacing Sea Water Impellor
- Thread starter patrickg
- Start date
- Nov 26, 2006
- 7,628
- Boat Info
- 2008 44 Sedan Bridge
- Engines
- Cummins QSC-500's
Straight Drives
Make sure it is an exact match, including the hub - I've seen exact impellers with different size/shape of opening in the middle. Grease that puppy down. Some use soap, some use grease. I used Chap Stick. Check for the alignment of the hub before inserting. They are usually round with one flat side.
You need to know the spin direction of the impeller. Start with it about 1/4 of a turn upstream from where the hub aligns. Begin to push it in while rotating it in the normal direction (as if powered by the engine). As you push it in and rotate it, the splines (is that what they're called?) will bend over to allow you to push it in with the hub aligned.
It may take a couple of attempts to get the feel for it and get it in with everything lined up. Good Luck!
You need to know the spin direction of the impeller. Start with it about 1/4 of a turn upstream from where the hub aligns. Begin to push it in while rotating it in the normal direction (as if powered by the engine). As you push it in and rotate it, the splines (is that what they're called?) will bend over to allow you to push it in with the hub aligned.
It may take a couple of attempts to get the feel for it and get it in with everything lined up. Good Luck!
osd9
New Member
I've always pre-bent the blades in the direction that they need to be and then put a few tie wraps over the impleller to hold the blades in that direction. Squirt some dish detergent into the house and and on the impeller and then push the new impeller in place. The ties wraps should slip off as you get the impeller into the housing, but if not you can snip them off with a pair of small clippers. Probably 3 or 4 tie wraps should do it.
BTW...you said the old impeller was shot....if shot means you are missing blades off the impeller, I see a little blade fishing in your future.....start by taking off the hoses downstream of the water pump until you find all the pieces...or least most of the pieces.
Oh...and change the other side while you're at it....
BTW...you said the old impeller was shot....if shot means you are missing blades off the impeller, I see a little blade fishing in your future.....start by taking off the hoses downstream of the water pump until you find all the pieces...or least most of the pieces.
Oh...and change the other side while you're at it....
DCarl320
New Member
Im going through the same thing right now, I didnt have too much luck when I tried to dry fit the impeller, but once I sprayed the housing with silicone spray it slid right in, while twisting in the proper direction.
Do you know what model water pump you have or what was the impeller part # you got?
Thanks for the response. This is great. How can I tell the proper direction of rotation? Will the direction be opposite that of the folds in the blades on the old impeller?
Before you start taking bad advice, you need to post what model of water pump or impeller you have... a spline is not the fin... for example. And I doubt you will have "one flat side" on the shaft.
DCarl320
New Member
I dont know about your particular model, but mine had a little arrow on the housing showing the direction of rotation.
Thanks for the post...very helpful.
Blade fishing! Great, just how much of the blades should one expect to recover. About half of the impellor blades are shredded. Should it be fairly easy to track down the rest of the blades? How far should one go looking for the pieces. Is it possible that they can simply evacuate out of the cooling system without fishing? I am trying to avoid disassembling more items if at all possible.
Blade fishing! Great, just how much of the blades should one expect to recover. About half of the impellor blades are shredded. Should it be fairly easy to track down the rest of the blades? How far should one go looking for the pieces. Is it possible that they can simply evacuate out of the cooling system without fishing? I am trying to avoid disassembling more items if at all possible.
HELLO?! GUYS??! An impeller change on Detroit Diesels is NOT the same as a boat with a BIII outdrive...
sheez!!!
sheez!!!
Skip
Well-Known Member
- Oct 5, 2006
- 1,085
- Boat Info
- 07 58 DB
Truly Blessed IV
2010 Nautica 12' RIB, 40HP Yamaha
- Engines
- MAN CRM 900s
What my esteemed colleague who led the Rally for Change at Port Kinsale on Sunday said.
-and-
You will need to retrieve as many of the disintegrated impeller pieces as possible. To determine how much you have retrieved, take a clean white cloth and lay it out-then lay out all the impeller chunks you have recovered, along with the old impeller hub, on the cloth. Put a new impeller next to the sad pile of rubber on the cloth. Try to piece the old impeller back together-this will give you an idea as to how much rubber is still in your cooling system. I had to do this last year on a generator impeller. it is a bit tedious, but worth the time. Any sizable rubber chunks left in your cooling system will impede the efficiency of the system-a bad thing on big diesels.
Many experts here will say this is a needless expense, but I replace my impellers every year. Last year I had one vane starting to tear after 165 hours of use-it would have let go on early into this season. Not worth the trouble to try and coax another year out of the impeller in my view.
regards
Skip
-and-
You will need to retrieve as many of the disintegrated impeller pieces as possible. To determine how much you have retrieved, take a clean white cloth and lay it out-then lay out all the impeller chunks you have recovered, along with the old impeller hub, on the cloth. Put a new impeller next to the sad pile of rubber on the cloth. Try to piece the old impeller back together-this will give you an idea as to how much rubber is still in your cooling system. I had to do this last year on a generator impeller. it is a bit tedious, but worth the time. Any sizable rubber chunks left in your cooling system will impede the efficiency of the system-a bad thing on big diesels.
Many experts here will say this is a needless expense, but I replace my impellers every year. Last year I had one vane starting to tear after 165 hours of use-it would have let go on early into this season. Not worth the trouble to try and coax another year out of the impeller in my view.
regards
Skip
Alex F
Well-Known Member
- Nov 14, 2006
- 9,166
- Boat Info
- 2005 420DB with AB 11 DLX Tender, Raymarine Electronics (2x12" MFDs) with Vesper AIS
- Engines
- Cummins 450Cs, 9KW Onan Generator, 40HP Yamaha for tender.
What do you guys think should be the reasonable average (hours or time limit) for changing impellers as a preventive measure?
Skip
Well-Known Member
- Oct 5, 2006
- 1,085
- Boat Info
- 07 58 DB
Truly Blessed IV
2010 Nautica 12' RIB, 40HP Yamaha
- Engines
- MAN CRM 900s
Alex,
I did the impeller in my BIII equipped 260DA annually. The impellers on the Sherwood pumps on the 420DA's C-Series Cummins are far simpler to change, and as indicated I change them annually as well. I have the impeller from last year on my work bench as a reminder not to press my luck with impellers.
Ditto the impeller in my generator.
regards
Skip
I did the impeller in my BIII equipped 260DA annually. The impellers on the Sherwood pumps on the 420DA's C-Series Cummins are far simpler to change, and as indicated I change them annually as well. I have the impeller from last year on my work bench as a reminder not to press my luck with impellers.
Ditto the impeller in my generator.
regards
Skip
I replace my impellers every year as well... Except last year I replaced them twice.
This is an old post you may want to read:
http://clubsearay.com/forum/showthread.php?t=935&highlight=impeller
When the impellers get really big, like the Sherwood 1800 series pumps, I don't have enough hand strength to insert them and align the shaft. Given the proper tools and setup as outlined in that post, I can do the starboard engine in 15 minutes but the port takes about an hour as I have to remove an exhaust pipe to get access.
FYI
This is an old post you may want to read:
http://clubsearay.com/forum/showthread.php?t=935&highlight=impeller
When the impellers get really big, like the Sherwood 1800 series pumps, I don't have enough hand strength to insert them and align the shaft. Given the proper tools and setup as outlined in that post, I can do the starboard engine in 15 minutes but the port takes about an hour as I have to remove an exhaust pipe to get access.
FYI
Steve36
Member
Skip, how do you replace the impeller on the starboard engine. I have a 420 as well and replaced my impellers this year. It was easy for the port engine but the starboard engine was surgery. Any helpful hints will be appreciated.
I am a trim guy but can not get a comfortable spot to do the work. Seems everything is in the way.
I am a trim guy but can not get a comfortable spot to do the work. Seems everything is in the way.
- Nov 26, 2006
- 7,628
- Boat Info
- 2008 44 Sedan Bridge
- Engines
- Cummins QSC-500's
Straight Drives
Gary's right. The fins are called fins - couldn't come up with that term. The new one should look the same as the old one once it's installed. Yes, the blades/fins will bend away from the direction of rotation just like the old one. Make sure you are considering the old one observed from the proper side (not looking at it backwards).