engine coolant impeller

[SKYCHENEY]

I'd also like to know what can go wrong.

I just replaced the coolant circulation pump on my Webasto diesel heater. It's a minature centrifugal. (The boiler was getting hot, but ten feet away the hose was luke warm via hand so I figure there must be a water circulation problem.) Before installing the new one, I compared output pressure by running each in a pail of water and putting a finger over the outlet.. Sure enough the old one had a lot lower pressure than the new...and it had trouble picking up water to develop suction.....so it appeared "worn"...these are magnetic driven, sealed in an outer covering, so I did not bother cutting the old one apart to see what was inside... besides, I was too busy cursing having to work in a very awkward (naturally, it's a boat!!) position...

The biggest problem I've had with Webastos is getting the air out of the system. Once you get it bled they seem to pump fine, but that little pump is just not strong enough to force the air through the whole system. A well designed system will have all of the runs slope up to the expansion tank so that the air collects there, but it's hard to do that especially on a boat.

What do you have hooked up the it? I put one in a bus conversion and we used it for interior zoned heat, domestic hot water, and engine block heating. Those are pretty neat little boilers.

[Nonchalant1]

Thats why the tell tale weep hole is there; to see the leak and reduce coolant / bearing contact. ws

The genius of the weep hole is also that if either seal wears out, it can't cross contaminate oil into coolant or vice-versa. It just dribbles out.

Doug

[Traveler 45C]

And dribble mine does...

I'll have another look at my DD manual.

[REBrueckner]

Webastos: "...The biggest problem I've had with Webastos is getting the air out of the system..."
I have not had that problem; mine seems to purge air well, but it's a common problem...A local mechanic who works with them suggests a "tee" at a low spot for connection to pressure water supply...let the external water pressure push through the hoses/radiators/appliances etc. I guess you could also pump an antifreeze/water mix this way via an impeller pump from a bucket...

If the boiler is relatively low or at the level of other appliances and the expansion tank higher thanother components, the air should move through more easily...

My webasto is for heating the boat interior only..via car like fan heaters..I did not want to go the added mile to heat engines/genny/domestic water because I would have used a heat exchanger for each....and more pumps... but's it's a real nice set up, especially in cold weather... When I run my genny for battery charging, I also run electric block heaters and the electric water tank coil to give the genny some load...

[doc g]

As far as I have seen ,the coolant pumps on DD's almost never fail . When there is a problem it's leaking from the weep hole but I've never seen a temperature change when I changed one. They still pump fine even when they're leaking....................................Pat

[Traveler 45C]

From what I gather after taking a look at my DD Manual there are 3 pumps discussed: a former (old), a current (DD changed the driven gear) and a high capacity pump (this one has the larger in/outlets).

If I’m reading this correctly, the former pump is discontinued. The current pump has a different driven gear than the former, so replacement of the drive gear on the cam is necessary to use this pump.

When I rip the old pump off my eng and take it to the DD guys, what am I gonna’ get as a replacement, a former or a current pump? Is the current pump the high capacity pump discussed?

What’s involved with RR the drive gear? Is that something I can do while sitting in front of the eng?

The pump comes off tomorrow… please straighten me out on this…