VW Pathfinder 50 marine diesel questions

[osprey877]

Attached is a photo of the back end of the block of my engine and also a diagram I had made showing the fresh water routing. I wish I’d found these earlier as I realized after looking at them that the water temp sensor is t capped but actually has a small hose to the heat exchanger. I think this is needed so there is flow past the temp sensor. The main fresh water supply and return lines to the heat exchanger are 1” welded aluminum tubes. I will send you a pic in a separate email of these tubes. So the hose that has the wooden plug in it should be connected to the top of the heat exchanger, not capped off, otherwise there won’t be any flow past the sensor.

[Little John]

Hallo Robert,

for a manual possibly look there:
https://www.marinedieselbasics.com/d...ngine-manuals/

[RobertPA]

Hello Little John. Thanks for that link, which I have explored previously. The manual is not available there. The cover looks like the appended.

I spoke to a parts person at Parts Place Inc. in Michigan who said that even they do not have a copy of this rare manual!

If there is anyone in the world who has this manual, they would be doing a number of us a great service by having it scanned and posting a digital version to the manuals section on the Cruisers Forum. I'd be happy to cover the cost of having the manual scanned by a commercial operation (many print shops provide bulk scanning services).

[RobertPA]

Good morning osprey877. Thanks for the diagram and photo. Helpful. As one Cruisers Forum participant told me in separate email, "there's more than one way to skin the cooling system cat" (paraphrase). Here's some observations concerning the difference between your set-up and mine.

1. I don't have a reservoir. Your reservoir must function like the coolant expansion chamber in a VW Rabbit diesel. For me, your #1 line connects directly to the expansion tank on the Bowman heat exchanger.
2. I have hoses going between the block/head and heat exchanger like your #3,4 & 5.
3. Your 2 & 7 were connected directly on my engine but have been cut and plugged (see appended photo showing hose connection to the water pump. The diameter of this hose is the same as the one on the coolant temp sender at the back of the cylinder head.
4. It seems not to matter if there is coolant flow past this sender, as long as the sensors in the sender are exposed to the coolant. You see in the photos of the sender posted previously, in the delmarrey "clean engine" pics that there is no hose on the sender.

BTW, your oil pressure sender looks to be identical to mine.

[RobertPA]

osprey877, as for specialized tools for changing the timing belt, etc, I see that Parts Place Inc. is sold out on the Injection Pump Dial Indicator but this appears to be fairly generic as long as it fits into the Bosch fuel injector pump.

Also, in various on-line discussions and YouTube videos related to the VW Rabbit diesel 1.5/1.6 l, I get the sense that you can remove the injectors using a 27mm deep socket on your wrench or maybe a 27mm ring spanner. However, I note the specialized Diesel Injector Socket that Parts Place Inc. sells.

COOLANT: Also, according to Haynes, the VW Rabbit diesel takes 6.5 litres of coolant. How much does your marinized version take?

[AndyEss]

Originally Posted by RobertPA

Hello Little John. Thanks for that link, which I have explored previously. The manual is not available there. The cover looks like the appended.

I spoke to a parts person at Parts Place Inc. in Michigan who said that even they do not have a copy of this rare manual!

If there is anyone in the world who has this manual, they would be doing a number of us a great service by having it scanned and posting a digital version to the manuals section on the Cruisers Forum. I'd be happy to cover the cost of having the manual scanned by a commercial operation (many print shops provide bulk scanning services).

I have the Pathfinder engine in my boat and have several original manuals.

[IOM]

The temperature sensor should be compatible with whatever gauge you are using. I would forget about what VW used and get a new sender gauge combination. That way you know the gauge is reading a close approximation of what the head temperature is.

It would also be good to remove the pipe and sensor housing, and just make an aluminum plate to cover the hole in the head, then fit the temperature sensor to that plate. This will give a better indication of the head temperature, even when the water runs out.



It would be good to check what type, or if the water pump has a thermostat. The vw thermostat is a double acting unit, and can't just be removed without carefully reworking the water flow. In the oem format the water circulates in the engine alone, not the radiator/ heat exchanger in your case. This makes it warm up faster and more evenly.

[RobertPA]

Thank you for your helpful reply, IOM. I have the marinized version of the VW diesel. I will check the water pump thermostat, as you recommend.

Apart from that, are you or anyone else reading this thread able to identify the temperature sender on the cylinder head of the Pathfinder engine that a user by the name of delmarrey used to own? See appended. He posted photos of the engine back in ~2011 not long after he sold the boat, I believe. I don't know if he's still participating in the Cruisers Forum. Thanks!

[NorthCoastJoe]

Back in the 1980s I rebuild and worked on VW rabbit diesels. All the gauges were VDO you can buy the oil pressure sender with a output for gauge and light/alarm. I have a bucket full of gauges and senders if you are interested in them. I have now use for them.

The one thing I want to warn you about is if you overheat one of these engines plan on pulling the head and getting it surfaced. Just replacing the head gasket will not last. I went through this process many times where someone replaced the head gasket only it have it blow out again.

That is the only thing I really do not like about VW diesels of that age. Overheat it once and you need to pull the head. I would have a alarm to be sure that it never comes close to overheating if I ran one in a boat.

The timing belt is easy to change and you do not need anything special. The injector pump timing range is so small you can do it by ear. Like it sounds right it is good. We tried messing with injection timing and the engine never cared.

Get a Bentley manual it is what we used in the shop.

[IOM]

Judging by the common ( probably gnd) wire from the oil to the water sensors, he is using a water temperature switch as well as oil switch for a warning buzzer (quite possibly sharing the same buzzer) as well as what looks like a mechanical type temperature gauge. I am not a fan of the mechanical gauges, but mostly because of the inconvenienceand limitations of the installation and they are a lot more susceptible to mechanical vibration failure. . Because of the internal size, of the part on the engine, they are also not as easy to fit as a electric sensor. In the picture you posted, the sensor will quite easily be long enough to actually protrude into the cylinder head. The only advantage there is for the mechanical over the electric sensor, is it needs no power, which in some applications is not optional. In your case, that's shouldn't be a deciding factor.

[osprey877]

Originally Posted by RobertPA

Good morning osprey877. Thanks for the diagram and photo. Helpful. As one Cruisers Forum participant told me in separate email, "there's more than one way to skin the cooling system cat" (paraphrase). Here's some observations concerning the difference between your set-up and mine.

1. I don't have a reservoir. Your reservoir must function like the coolant expansion chamber in a VW Rabbit diesel. For me, your #1 line connects directly to the expansion tank on the Bowman heat exchanger.
2. I have hoses going between the block/head and heat exchanger like your #3,4 & 5.
3. Your 2 & 7 were connected directly on my engine but have been cut and plugged (see appended photo showing hose connection to the water pump. The diameter of this hose is the same as the one on the coolant temp sender at the back of the cylinder head.
4. It seems not to matter if there is coolant flow past this sender, as long as the sensors in the sender are exposed to the coolant. You see in the photos of the sender posted previously, in the delmarrey "clean engine" pics that there is no hose on the sender.

BTW, your oil pressure sender looks to be identical to mine.

As you note, there is more than one way to skin a cat. Having thought some about it I think my hose number 2 from the water temp sensor to the heat exchanger is a safety measure to make sure there is not an airlock in the blocks cooling system if the engine is installed on an angle with the rear end higher than the front. That is the purpose of hose number 1, which removes any trapped air when the engine is installed in the usual manner with the front end higher. I rebuilt my engine with a standard VW block and had to drill and tap a hole for an NPT fitting to fit hose #1. When installed in a car the engine is level so it doesn't need hose #1 or #2. You shouldn't need hose #2 unless you are mounting the engine with the rear higher than the front.
The benefit of the plastic reservoir tank is that its easy to check the level and you can easily see if there is any oil or other contaminants in the coolant, but you can always add this later if you get it running.
And yes, you will need a dial gauge that you can screw into the back of the injector pump in order to set the injector timing.
Good luck

[RobertPA]

Thanks for your replies. The collective experience and skill brought to this forum by past and present owners of VW Pathfinder engines, and VW diesel mechanics is invaluable. And thanks to AndyEss for bringing the existence of his Pathfinder manuals to our attention.

Part of my learning curve here has been vocabulary. I need it not just to communicate with the rest of you but also to identify and purchase parts. E.g., the broken fitting in the appended photo is a VDO tee adapter. This screws in to the cylinder head and holds two senders related to oil pressure, with a connect to the engine hours counter I imagine.

[CaptainLen]

I have this as the original engine in my 1981 C&C40. I wouldn't think of replacing it because it runs great with routine care. I am a Florida snow bird and my boat (and engine manual) are in New England so I don't think can help you much with your specific questions. Except for one thing: have you contacted Pathfinder Marine in Canada? Their phone number, that last time I talked to them, was (514) 695-6676.
Good luck with your engine.

[RobertPA]

Thank you CaptainLen for that message. I saw discussion about the company on this forum dating to 2010. The Canadian government's business registry (that I just searched) indicates that the company is dissolved. https://beta.canadasbusinessregistri...=QC&status=All

[Coltrek]

There is a fellow on the C&C List with one of these on a C&C 35.
He would probably be willing to discuss with you,
shawngwright@gmail.com