VW cooling system question

I am preparing two 1,9TD Volkswagen engines for a marine life.
Can somebody please tell me why the waterpump is so complicated? There are 3 outlets (or inlets?) plus a flange that connects to the engine block. Also the cylinder head has hoses at the side and back. I bought the Brooklands VW T4 transporter shop manual, but that was a waste of money. It only provides a symbolic diagram of the cooling system, showing two pumps(?) and two heat exchangers.

 

you have a car engine with outlets it would seem for heaters and perhaps the turbo, and maybe aftercooler, hard to say without seeing it,, maybe you could take a big resolution photo

 

A photo doesn't clarify anything in this case. With VW, the pump is mounted just above the oil pan, hidden from view by an enormous bracket that holds the alternator. The only things visible are three perpendicular 1" pipes with cut off hoses and clamps on them.
The lowest one has a thermostat inside, so that probably went to (or from) the radiator. The other ones come straight from the pump.

The Brooklands book mentions 2 pumps, one is called water pump, the other one "circulation pump". The engine has only one pump of course. There is also a 1th heat exchanger and 2nd one, plus something called "additional heating" and then of course the radiator and the oil cooler.
For its 2nd life as a marine engine, there is only a Bowman exhaust manifold/ heat exchanger with expansion tank, that - I suppose - should be connected where the radiator was. Connected like that, I have 2 unused pipes from the pump and a total of 4 hoses from the cylinderhead that go nowhere. I could use one pump outlet and one cyl. head hose to connect the oil cooler, which is only a small alloy box on top of the oil filter.

 

Cooling diagram with a bit of text

Hi CDK,
I'm no great expert on the 1.9 TD but I've got a 1.6TD in my VW Bus witch forces me to deal with it. As the 1.9 TD and the 1.6 TD are very similar, maybe I can help you.

Check this: http://www.kerschhofer.net/t3/kuehlung.htm

This page shows a good diagram of the engines cooling system if the thing in mounted in a bus. You're right, the pump looks complicated.
In general, the pump has three hose connections. One connection comes in from the side, this is the return connection from the radiator. This connection must have the thermostatic valve under a plastic flanged hose connector. If possible, replace the plastic connector by a alumineum one. The plastic is crap and tends to leak. Second main connection is next to the first one but facing in longitudinal direction to the engine. This is the radiator bypass witch feeds uncooled water into the pump. The thermostatic valve will mix cooled and uncooled water to hold the correct temperature. The third connection (between the second and the engine) is the common return from the heatings and the expansion vessel. The pump will take water from all three hose connectors and force it into the engine via the flange at the engine block. I hope you have the rubber hosing witch connects the engine return connection with the expansion vessel, electric pump and heating returns. This item makes things easier.
To adapt the cooling system to a boat, you must replace the radiator with a water/water heat exchanger or surface cooling or something.
VW Bus turbo diesels have a small electric pump to circulate the coolant after the engine is stopped while hot(>107°c). This is to avoid "heat nests" in the cylinder head. My electric pump has died due to 21 years of uselessness and I guess it's not really needed. You can simplyfie your system by not installing such a pump.....to make things more simple, you can also plug the heating connections as the heatings in a VW are shut off by closing the water valves to the heaters. My bus doesen't die when I turn the heatings off.

Hope to have helped a little. By the way, what are you building? Sounds interesting to me.

Regards,
Frank

 

Frank, thanks a lot for supplying all the answers.
The 1,9TD's come from T4's from around 2001, but are almost identical to the earlier 1,6 engines. They have a multi-V belt for the alternator, one longdrink glass more capacity and a few extra horses, that's all.
Because the engines come from a recycler, they were very crudely dismantled, all hoses and cables cut off. I even don't know if they are in a usable condition and have no means to find out. First I have to build bell housings to mount the starter motor and complete the cooling circuit. I had hoped I could use old gearboxes from a Golf and cut off everything I do not need, but they do not fit because the flywheel is larger. Another option would be to use Passat parts, but then I'd need new starters and flywheels, so I decided to make the housings from steel plate. Lots of work, but not impossible. Where I live, it is very difficult to get technical stuff, look at: http://www.puntakriza.com

Another question: The Bosch injection pump has a cold starting device. Do I really need that in the meditteranean or can it be secured in off position? Otherwise I need another pair of bowden cables.

As for my project, look at the surface drive forum on this site: "from sterndrives to jets to surface drives".

 

Cold starting device

Hi there,
about the cold starting device, you mean the small leaver in the gap between the pump and the engine? If you pull the leaver it will move the injection timing a little forward. The pump automatically pulls injection forward at rising engine speed so that the effect of the pulled leaver is overrun at about 1200 rpm witch is about 1/4 of the engines max. speed. According to propeller law, you can't load the engine constantly with very much torque at such low speed so I wouldn't worry about the cold starter and just fix it in the pulled position. Make sure the fixing can be removed easily becuase you can't time the injection pump with the cold starting device in pulled position. For some reason, the VW turbos don't like to start from cold without the cold starter pulled, regardless of the ambient conditions (although, the non turbos don't care). On my bus, I don't notice any difference in engine sound, performance or vibrations if the thing is pulled or not. It just won't start without....

Best regards,
Frank