Where to purchase MK-1 Caddy Diesel Sending unit, hoses, and gravity valve?

[southernman]

Guys, I'm sure this has been covered here in the past, but my search doesn't answer the above question. I've got an '82 VW Caddy (pickup) diesel; 4 spd; 1.6 IDI.

Evidently, when I took my tank to the radiator shop for a refresh, they lost my sending unit, so I'm now trying to locate someone who sells a replacement unit.

Also, does anyone know now many years and body styles will cross-over using the same sending unit assy - and are gas and diesel senders compatible with each other ?

My unit has a small vent that goes to the 'gravity valve' and then to an expansion tank, I'm assuming to contain fumes. When I look at the Jetta diesel unit, it appears that sender does not have the same small vent line on it. I guess I could drill and add it, if necessary, assuming I could also use a Jetta unit...

In summary, a contact for the complete sending unit assy; the gravity valve (check valve) and there's one hose that runs through the frame and connects between the filler neck and tank that's got an inner coil - I'm unable to locate that as well.

Thanks in advance for any assistance !

Southernman

[southernman]

OK guys, since no one seems to have any suggestions for replacement parts, how about this:

Does anyone know the resistance value of the sending units ? I've checked the Bentley manual from A-Z and the closest they get to any kind of troubleshooting is to simply ground the wires to see if the gauge moves to full...indicating the gauge is OK, and the sender is bad.

In truth, I'm terribly disappointed in the Bentley manual since, the more I work on this thing, the more I realize how much technical data is missing.

I'd measure mine, if I had it, so I'm hoping one of you techies out there can tell me the resistance values for our sending units.

Thanks for any help.

Southernman

[rs899]

I can't answer your question, but I do recall the sender in the tank of my pickup mounts very differently that the one in a gas ( and presumably diesel) Rabbit sedan. I would guess that the sedan would have the same electrical specs.  You may find a way to mount one of those if you can find one.

[92EcoDiesel Jetta]

On my Jetta diesel, the small line is not a vent line, it is a return line from the IP. The check valve is not really needed if you keep your fuel tank level above the lowest point of the return line in the tank. Your caddy may be set up differently but I doubt it. I'd suggest going after the radiator shop for the lost sender. Have you tried the dealer? Look for a used one one Ebay?

[Toby]

I do not think that diesels had the "upside down valve" or the extra "expansion tank" in pickups. That kind of stuff is usually reserved for EVAPorative emissions equipment in gas vehicles. I suspect that these are remnants of its original gas engine.

[southernman]

Hey guys, thanks for the feedback here, and I did find the comment about the 'gravity' valve interesting, since mine does have the valve, which is nothing more than a check valve, but there is no evap tank mounted on the truck. You could be correct and my truck may be a 'conversion', so I'm gonna check out the VIN to verify.

On the sender, I've tried everything to get the radiator shop to dig my unit up - to no avail, so here's what I've decided to do:

It appears the resistance of the original units is somewhere between 35 and 285 ohms, full to empty, respectively.

Since I've had absolutely no luck with the parts suppliers, and the OEM want's ~$200 for a replacement unit, I've decided to take a rodders approach, and update this function with readily available parts.

After measuring up the tank and required functionality, the bulk of the tank works out to about 9" deep - minus the small sump area in the bottom.

I've located a sending unit from Moeller Marine that has the same values as the stock unit, however, it's a reed type unit that is much more accurate than the swing-arm type units; it's made of stainless steel; and it's designed to work with a 9" tank.

I'd share more information, but the SCROLL feature on this reply function STOPS SCROLLING AT THE BOTTOM OF THE WINDOW, and won't let me see things as I type them and it's pissing me off -sorry.

If, possibly, a mod can get that addressed, I'll post up a how-to convert from the stock sending units, but if the reply function isn't fixed, I'm not going to "fight" the function. However, I will keep you guys posted of the progress. Thanks again for the feedback.

Southernman

[92EcoDiesel Jetta]

I do not think that diesels had the "upside down valve" or the extra "expansion tank" in pickups. That kind of stuff is usually reserved for EVAPorative emissions equipment in gas vehicles. I suspect that these are remnants of its original gas engine.

Not sure what upside down valve your're speaking of. My diesel has a valve that is on the side of the filler neck. When the fuel cap is screwed on tight, that valve is opened. It's black plastic, on the left side of the filler neck while you're looking into it. AFAIK my tank is a diesel tank (92 Ecodiesel) and not a gasoline conversion. I think the gasoline tanks are basically the same as the diesel tanks since VW like to use common parts between models but I am not 100% sure on that since I've never owned a gasoline MKII.

His Caddy may be different but if it's a diesel, it should be similar as far as venting is concerned.

[rabbitman]

I'd share more information, but the SCROLL feature on this reply function STOPS SCROLLING AT THE BOTTOM OF THE WINDOW, and won't let me see things as I type them and it's pissing me off -sorry.

If, possibly, a mod can get that addressed, I'll post up a how-to convert from the stock sending units, but if the reply function isn't fixed, I'm not going to "fight" the function.

Southernman

Mine does that intermittantly too, drives me crazy, I've PM'd some of the mods but I don't think it's in there power to mess with it.

[92EcoDiesel Jetta]

I'd share more information, but the SCROLL feature on this reply function STOPS SCROLLING AT THE BOTTOM OF THE WINDOW, and won't let me see things as I type them and it's pissing me off -sorry.

If, possibly, a mod can get that addressed, I'll post up a how-to convert from the stock sending units, but if the reply function isn't fixed, I'm not going to "fight" the function.

Southernman

Mine does that intermittantly too, drives me crazy, I've PM'd some of the mods but I don't think it's in there power to mess with it.

The reply window is too small! One way around it is to copy what you have quoted, paste it into notepad, word whatever, then write your reply,then paste it back into the reply window.

[Toby]

Not sure what upside down valve your're speaking of. My diesel has a valve that is on the side of the filler neck. When the fuel cap is screwed on tight, that valve is opened. It's black plastic, on the left side of the filler neck while you're looking into it. AFAIK my tank is a diesel tank (92 Ecodiesel) and not a gasoline conversion.

His Caddy may be different but if it's a diesel, it should be similar as far as venting is concerned.

The pickups are Mk1s and they definitely do not have any such vent valve in the filler. Its got to be a Mk2 and later thing. I will have to find a Mk2 to scope out.

[GEE-BEE]

MK1 caddy sending units will be stock soon at MK1autohaus

I did new tubing for the filler from mcmaster carr

Intake pipe hose was flurosilicone from ebay

I relocated the filler where the old gas puel pump was , much better than the engine compartment locatin for me

GB