Hi

The impeller in the engine mounted waterpump has lost at least 4 blades! I am now in the process of trying to find them.
Is ther any chance that they have passed through the whole engine out in the water or is that just wishful thinking. .....The engine is a raw-water cooled 1998 502 MPI with a Bravo drive. The water passes from the pump through the power steering cooler, fuel cooler, oil cooler and then reaches the thermostat housing. from there it goes both to the engine block (via the thermostat) and to the exhaust manifolds that are aluminum ,by the way. Where shall I look?

Matt,
Do you mean your raw water pump on the starboard side of the engine? If so, the parts are most likely lodged in the oil cooler.

When that happened to me (same year and engine) we noticed the impeller rubber was a very strange 'consistency'..
It was almost as soft as childrens modeling clay ... did you notice the same thing ?

Hi
A real problem, but all is not lost. The first thing I would do before you start taking anything apart is to try and back flush the engine with a hose pipe. Also if you can put some water descaler in the engine and let it sit for a while ( like Calgon full name sodiumtripoly phosphate or water softener to you and me! .Yyou can get this for home central heating from homedepot ) this will help to decalcify the inside and create less friction or even loosen lodge impeller parts. This is a good thing to do anyway like your home central heating system.
This method assumes that if it is stuck on the way in it should be able to get back out. A trick I have learnt is to try and pulse the water going in by putting a kink in the hose then letting go. Do this several times. Try and collect all the parts to see how much you have. If most of the parts are large then you could assume that smaller parts may have passed through.
Hope this works it has for me in the past.
Good luck jules

Oh yes discontect the pump

ps This is why KPM developed that run dry pump

Hi. Yes it is the raw water pump down on the starboard side. The "consistancy" was still rather rubber-like but somewhat dissolved. However, not enough to hope that the missing blades have sort of vanished. Do I have to tear the whole engine apart?

The one that I had go bad was as hard as a rock. Those chunks will be in your cooler. Pull the cooler and back flush it with some water. Sight down it with some light behind to make sure you got all the chunks out.

Raceangel77, when back-flushing, where do you connect? At the jumper hoses on the manifolds?

Cord, you refer to the cooler, I guess you mean the oil-cooler. Are they more likely to get stuck in the oil-cooler? The water passes thropughn the power steering cooler and the fuel cooler before getting to the oil-cooler.

Mats,
I have one cooler on mine and that is where the chunks ended up. You may have to reach in with needle nose pliers to remove some pieces if they won't backflush out. The pieces should be stopped at the first cooler after the raw water pump. Any other pieces are small enough to get through the engine and out the exhaust.

I just went through this....

Disconnect the forward hose from the oil cooler and from the rear of the oil cooler. While blasting water pressure into the front of the oil cooler, put your fingers into the back of the oil cooler with the water running and feel around, can take a while to work them out, they really get lodged in there. Be sure to match all the pieces you find to your impeller to assure you get them all. You'll see on the front of the cooler that there are a lot of small holes, anything smaller than those holes will get blasted through the water system and out the exhaust.

Good luck!