Most common failure for overheating on these , is the water pump . The impeller comes lose on the shaft and stops working. You’ll need the cambelt done at the same time.

That's a terrific accolade for german design and production engineering isn't it?

Despite their enormous engineering resources they can't design a water pump where the impeller remains attached to it's drive shaft.

I've had a similar experience in the past - BMW 520i E34 water pump impeller disintegrated resulting in instant overheat. Fished the bits out, slapped a BMW recon pump on it and sold it.

As I mentioned in another parallel thread, it seems to be a specifically German ting, and the local British mechanic here in Taiwan (where these issues allegedly tend to come on sooner, possibly due to the elevated temperatures) theorised this was due to degradability constraints imposed on the plastics for environmental reasons.

So the enormous German engineering resources have...er...been harnessed to the cause of destruction. (DMZV moment)

I don't know if there's any actual documented evidence for that, but it seems almost daft enough to be true

Edited by edlithgow on 05/11/2024 at 08:55

Most common failure for overheating on these , is the water pump . The impeller comes lose on the shaft and stops working. You’ll need the cambelt done at the same time.

That's a terrific accolade for german design and production engineering isn't it?

Despite their enormous engineering resources they can't design a water pump where the impeller remains attached to it's drive shaft.

I've had a similar experience in the past - BMW 520i E34 water pump impeller disintegrated resulting in instant overheat. Fished the bits out, slapped a BMW recon pump on it and sold it.

I think the water pump has done a great job, lasting 100,000 miles.

No moving parts on a car are built to last forever.

And unfortunately, plastic is everywhere on cars nowadays.

With the engine idling and the temperature gauge pointing straight up at 90 degrees I can't see any sign of "swirling" -- the coolant just seems to be sitting there unruffled.

So your engine will be working in the ancient convection way, which is inadequate for more modern cars. Pumping is necessary to remove the engine's heat fast enough, and the thermostat helps it to run at about the optimum temperature.

Though I doubt I'll ever have another car, there's a current possibility of a small Yanmar seawater-cooled marine diesel, in which apparently the thermostast helps them run at a very sub-optimal temperature, because otherwise they clog up with salt.

I'm wondering if I could modify it to use a keel-cooling. pipe, containing c onventional coolant, so I can avoid the nasty salt and run a hotter Tstat.

Not sure the geometry will work though.

Havn't even got it yet, much less got it to run, and already I'm planning to break it

I was thinking the first option, but on this hull its likely not possible to arrange the pipe without it being an excessively vulnerable source of drag.

Edited by edlithgow on 06/11/2024 at 00:42