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Old 01-08-2018, 03:31 AM
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mccutter mccutter is offline
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Thumbs up Old tool brought back to life and fitting extraganza!

I have a 2001 VW Passat 1.8t I'm working on. It has an "information center" in the center of the instrument panel. Imagine my alarm when it said something to the effect of "NO OIL PRESSURE--STOP ENGINE NOW!" There is/was no knocking or rattling that would indicate lack of oil...

So I check the oil level (fine) and pressure sender and discover it has oil inside the electrical connection. OK easy fix, pick up a new sending unit for $16 and put it in. Same issue with the message above.

Next step is to verify oil pressure with a mechanical gauge. I have a transmission line pressure gauge that I used to use to also check oil pressure. The problem with it is that I've owned it for about 30 years but haven't used it in about 25...

The gauge came with a number of adapters but none of them metric. So I gather up the necessary fittings from a couple of sources. O'Reilly's had a M10x1.00 to 3/16 brake line flare adapter I picked up but no other useful fittings. That fitting was about $5. I had to grind it down about 1/4" but it had a shoulder like the sending unit from which I transferred the aluminum sealing gasket/washer.

Now off to my local ACE Hardware to see what I could come up with in order to mate to the 1/8" male pipe end of the gauge hose. The youngish guy working at ACE set me up with a piece of copper tube, a 3/16" flare nut and 3/16" compression fitting to 1/8 pipe adapter. He even single-flared the tube for me. I ended up shortening the tube and double-flaring it because that's how I roll. That was another $5 but I had to go back because he shorted me the ferrule for the compression fitting, (I had none in stock that I could find ) and returned the flare nut as I had about 6 of them in stock.

While getting ready to attach the hose from the gauge, about 2/3 of its 6' was rock hard from sitting for 25 years and split open when trying to straighten it. The last time I had used it I put a plug in the end to keep the residual oil from leaking all over the tool box and coiled it into a drawer. I ended up cutting the barb fitting off the end of the ultra hard hose and attached it to the remaining flexible portion. While doing this, I noticed a good deal of petrified oil smegma in the hose so I removed it from the gauge and flushed the gauge and hose and blew out with air.

I installed the fitting menagerie in place and tried spinning the hose male pipe fitting into place into the 1/8" pipe coupler (F-to-F) that came with the gauge. Not having success, I added a 90 M-to-F elbow that came with the gauge. No success there so I removed the barb fitting from the hose and attached to the elbow. Then slid the hose over the barb fitting and clamped with a hose clamp.

The fitting tally is as follows: M10x1.00 straight (M)-to-3/16" flare (F), 3/16" flare nut (M) and tube, 3/16" compression-to-1/8" pipe (M), 1/8" pipe-to-1/8" pipe connector (both F), 1/8" pipe "street" elbow (M-to-F), and 1/8" pipe (M) to 3/16" barb. In hindsight, I should have just gutted the old sender and welded a barb to it--DONE!

Results were as expected: plenty of oil pressure and surprisingly no leaks from the fittings!

PS: and yes, it looks as miserable as it actually was getting the fittings into place...
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Last edited by mccutter; 01-08-2018 at 03:58 AM.
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Old 01-08-2018, 05:38 AM
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LW Hiway LW Hiway is offline
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So, is there some way to clear the code/alarm it has thrown at you?

I'm so old school, that electrical senders leave me less than satisfied that most everything that uses one, has a tee added with an analog gage added to the system, sitting oddly just within eyesight under the rim of the dash.
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Old 01-08-2018, 12:06 PM
Samcord Samcord is online now
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Good job on the plumbing exercise. Now it's time to exercise the electrical.

Use a volt meter, one probe on ground, other probe stuck into back of sender wire connector (back probe). You should see voltage with no pressure, and voltage drop as pressure builds.

If no voltage, find other end of sender wire - probably at ECM. Repeat test from this end of the wire. If results are different, look for break in wire.
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Old 01-08-2018, 05:28 PM
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Is that right there at the oil cooler? The black rubber hoses are the coolant side of the heat exchanger and the oil filter is just visible? Yours is very clean compared to mine.

Scott
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Old 01-09-2018, 08:54 AM
bigb bigb is offline
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Quote:
Originally Posted by Samcord View Post
Good job on the plumbing exercise. Now it's time to exercise the electrical.

Use a volt meter, one probe on ground, other probe stuck into back of sender wire connector (back probe). You should see voltage with no pressure, and voltage drop as pressure builds.

If no voltage, find other end of sender wire - probably at ECM. Repeat test from this end of the wire. If results are different, look for break in wire.
Is there a chance the voltage is always present and the warning light is triggered by a ground signal? I have had equipment like that where a ground wire got pinched and completed the circuit.
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Old 01-09-2018, 01:59 PM
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mccutter mccutter is offline
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Quote:
Originally Posted by LW Hiway View Post
So, is there some way to clear the code/alarm it has thrown at you?
I'm pretty sure this is just an "on demand" system that relays/interprets info as received from various sensors such as oil pressure, coolant tank and windshield washer system as well as the engine computer.

Quote:
Originally Posted by Samcord View Post
Good job on the plumbing exercise. Now it's time to exercise the electrical.
Thanks for the tip. This is a single-wire sensor so it should be an easy diagnosis. Getting to it is the hard part and there is not much "extra" wire to speak of...

Quote:
Originally Posted by Scotts View Post
Is that right there at the oil cooler? The black rubber hoses are the coolant side of the heat exchanger and the oil filter is just visible?
Yup, that is the oil cooler. These take an "oversize" filter, above that is the liquid-to-liquid oil cooler (the silver box), then the oil filter adapter that the sender is mounted to. You can also see the banjo bolt which is the turbo oil supply. And a bunch of various hoses that like to get in the way. It is clean because I cleaned it--it certainly was NOT before I began...

This is a longitudinal engine so access is a tiny bit easier than the engine as mounted tranversely such as in a Mk4 Jetta, for example. In that case, there is a turbo control module vacuum "assembly" in the way as well as a number of vacuum and PCV vent hoses. In this case, I was able to remove the recirc. hose from top of the expansion tank and pivot the tank out of the way for access.

Quote:
Originally Posted by bigb View Post
Is there a chance the voltage is always present and the warning light is triggered by a ground signal? I have had equipment like that where a ground wire got pinched and completed the circuit.
As it is one wire, I'm thinking I can rig a jumper and ground it and the message will go away. I'm guessing the connector has become loose and combined with a coating of oil, is not sending a ground signal to the message center.

I'll be running this car until warm to check the oil pressure on the gauge and to verify it still has some. Then I'll dick around with repairing the connector which is barely visible just under the fittings.
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TA Arcmaster 185 w/tig/stick kit
MillerMatic 252 w/3rd gen 30A
MM140 w/o AS, w/CO2
Hobart (Miller) 625 plasma
Hobart 250ci plasma
Victor O/A (always ready, but bored)
Lincoln Patriot autodark (freebie)
45ACP Black Talons for those stubborn jobs...

Last edited by mccutter; 01-09-2018 at 02:14 PM.
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