VW Pathfinder 50 marine diesel questions

[RobertPA]

Thanks Ryan. I've been through that threat previously. I'm surprised I didn't see Tzara's post re the Pathfinder Engine Manual 65 MF previously (or maybe I had a download problem and aborted????). In any event, I've downloaded it now, and at first glance, it appears to be very useful. Thanks for pointing me in that direction. Also, thanks to Tzara for scanning and posting!

[hirondeller]

One caution about timing. With both timing tools in place, (1) cam lock (2) pump pin you can still be exactly 180 degrees 'out of time' on the #1 piston. The sympton will be a difficult to diagnose 'no start' condition. Make sure you are at #1 TDC 'firing position', not the 'exhaust TDC'. The cam lobes will tell you where you are with respect to timing. The next valve to open after 'Firing TDC' should be the exhaust valve. You can see that happening by turning the engine. This matter is hard to visualize and describe in words, if my statement is confusing leave a message and I will explain further.

[RobertPA]

This is the tachometer sensor that screws into the flywheel housing on my Pathfinder Marine diesel. I have no idea what the brand name of this sensor is but it once connected to a Sea Ray Marine Boat Console Engine Motor Tachometer 4000 RPM gauge. The connector is missing.

Do any of you know what brand this sensor is, or can you recommend a replacement one that will fit the flywheel housing on this engine? Thanks.

[ryangalliford]

Pathfinder typically used a Motorola 7ep2005; might be different depending on your housing, but it looks correct to me. Connections to the tach are via two wires with ring terminals mounted to the posts on top.


It is 3/4-16 UNF thread, and any pickup that matches your tach gauge will work. The current one doesnt look broken, but if its known to not work correctly, Id recommend Datcon for a replacement.


- Ryan

[RobertPA]

That's helpful, Ryan. Thanks.

[RobertPA]

I'm into it now, working on changing the timing belt. Of course, nothing ever goes in a straight line. In order to change the timing belt, I have to remove the crankshaft pulley assembly (connected to the sea water pump and alternator) that is bolted to the crankshaft sprocket. One of the 6 mm hex bolts stripped. How to get it out? The other three came out with a lot of torque. Why pathfinder chose hex bolts is beyond me.

The Pathfinder service bulletin I have (in the Owner's Engine Manual) says "Do not remove sprocket bolt." Hmmm. How do I to get the pulley off the crankshaft sprocket unless I remove this bolt?

Lots of fun!

[ryangalliford]

Some have luck with soaking bolts with a little kroil for quite some time, some like heat; either way it sounds like youll need a good pair of vice-grips to get any amount of torque on the bolt if its stripped. You can replace it with a socket head cap screw if you want.


There is no need to remove the sprocket bolt to remove the crank pulley. Remove the 4 M8 cap screws and carefully pull/pry it off; the crank pulley has a large hole in the middle to slide over the crank bolt washers, and is not held on by that bolt. VW changed those crank bolts because they were prone to breaking...


Sounds like youre in the final stretch!



- Ryan

[osprey877]

Originally Posted by ryangalliford

Some have luck with soaking bolts with a little kroil for quite some time, some like heat; either way it sounds like youll need a good pair of vice-grips to get any amount of torque on the bolt if its stripped. You can replace it with a socket head cap screw if you want.


There is no need to remove the sprocket bolt to remove the crank pulley. Remove the 4 M8 cap screws and carefully pull/pry it off; the crank pulley has a large hole in the middle to slide over the crank bolt washers, and is not held on by that bolt. VW changed those crank bolts because they were prone to breaking...


Sounds like youre in the final stretch!

- Ryan

I agree there is no need to remove the crankshaft sprocket in order to change the timing belt, at least not on my version of the engine. I did have to use a gear puller though to get the alternator/water pump pulley off once the four m8 cap screws are removed.

[IOM]

Hit the bolt with a hammer. It will do two things, first it loosens the bolt because it deforms the metal on the head, and if the threads are corroded helps loosen them as well, and second it will close the hole for the hex. You can now try hammer a hex socket back into the hole and loosen it, or better yet, hammer a 6mm spline socket into the hole and it will come out. Its a common problem on many VW's. Mostly caused by over tightening (in your case, probably corrosion as well). Hex bolts are usually stronger bolts , and easier to work with.


If you still don't get it out, drill the head off with a 8mm drill, just until the head can be knocked off the bolt. You can now remove the pulley, and have more space to work at extracting the bolt. As a very last resort , take the pully off the front and drill out the bolt from the back. If it starts to loosen it will thread the bolt out without any extra effort.



Refit the new cap screws with grease. They will never fall out, and you have a better chance of working with them easier in the future.

[IOM]

A word of advice.
Take the water pump pulley off before you take out your last bolt on the crank pulley. Makes life a little easier if you can use the belt to stop the water pump from turning.



Looking at the water pump bolts, they dont look too happy either. You may need a LARGE adjustable pliers to grab across the two bolt you not loosening, while loosening the third. Do not take any all the way out until ALL three are loose.
The water pump bolts are supposed to be the same cap screws as the crank pulley.

[RobertPA]

Thanks to Ryan, Osprey877 and IOM for your helpful replies. I'm going to try a drive impact bolt remover first, and will let you know how it goes. Agree re water pump bolts. https://www.canadiantire.ca/en/pdp/m...1207p.html#srp

[RobertPA]

On another note, I am still uncertain as to whether I have a 1.5 or 1.6 litre engine. Parts Place Inc. tells me it's a 1.6 l engine, based on the serial number I provided. Hmmmm. It seems that Pathfinder had 4 versions of the 4 cylinder engine (ref Pathfinder Owner's Engine Manual, issue M3118, Pathfinder Model 65MF):

Model 50 - 1.5 l 1977-1983
Model 50MF - 1981-2001 size?
Model 55MF - 1981-2001 size?
Model 65MF - years? size?

A buddy of mine here in Newfoundland showed me a couple of old VW diesel blocks that have the engine size embossed on the blocks on the exhaust manifold side, e.g., 1.5 in large font. My engine has no such embossing. I do have a mechanical cylinder head (single oil return hole), with 6 point hex head bolts (probably 11 mm).

The aforementioned buddy is of the view that the 1.5 l engine had mechanical cylinder heads, while the 1.6 l version had hydraulic heads, but I don't think this is accurate. From what I can tell, VW Rabbit 1.6 l diesels made in North America also had mechanical cylinder heads.

Buddy is also of the view that the 1.5 l engines are prone to overheating because they have only the single oil return hole.

See cylinder head shape on my engine with single oil return hole.

[RobertPA]

A number of you have replied to my previous inquiry about the timing mark on the flywheel, visible through a hole in the bell housing. Thanks again!

The TDC mark on my flywheel is a 'O' symbol.

At TDC and with the cam locking plate and injection pump locking pin in place, this 'O' should be aligned in the centre of the bell housing hole. However, in my case, this 'O' is off by about 1 cm. What do you make of this?

Also, the instructions in the Pathfinder Owner's Manual (Model 65MF) re timing belt change say, "Lock camshaft in position with locking bar....When in correct position, bar slides into groove without force." Pathfinder then asks us to use a feeler gauge. "Turn camshaft until one end of locking bar touches the cylinder head. Measure gap at the other end with feelers. Take half of the measurement and insert feeler of this thickness between bar and head. Now turn camshaft so that bar rests on feelers. Insert second feeler of the same thickness between the other end of bar and head."

I've reviewed timing belt change method on a number of YouTube videos, and the VWVortex forum and I don't recall anyone talking about the need to use a feeler gauge. What's your take on this?

[RobertPA]

Good morning Hirondeller. See appended photo re TDC #1. I take it that 'firing position' is when valve lobe #1 depresses the valve, and 'exhaust position' is when lobe #2 depresses the valve. #1 valve is on engine front side (camshaft pulley side).

Originally Posted by hirondeller

One caution about timing. With both timing tools in place, (1) cam lock (2) pump pin you can still be exactly 180 degrees 'out of time' on the #1 piston. The sympton will be a difficult to diagnose 'no start' condition. Make sure you are at #1 TDC 'firing position', not the 'exhaust TDC'. The cam lobes will tell you where you are with respect to timing. The next valve to open after 'Firing TDC' should be the exhaust valve. You can see that happening by turning the engine. This matter is hard to visualize and describe in words, if my statement is confusing leave a message and I will explain further.

[RobertPA]

The stripped hex bolt came off with relative ease using a drive impact bolt remover, and the pulley popped off as stated above. Now it's on to the timing belt change tomorrow. Thanks again to those above who gave advice.