TheSamba.com :: View topic - Installing Gauges (Temp, Volt & Oil pressure) 2.1

Wed Mar 22, 2017 8:54 am

So, I have purchased Temp, Volt and Oil pressure gauges for installation in my 89 Vanagon with 2.1 engine.

-Temp gauge; where is the best place to "tap" the cooling system (safely) to install the sensor? (photos appreciated)

-Volt gauge; really no question there. But, if there are bad places to access for measuring voltage, where are they? Should I just run a wire directly to the battery positive cable?

-Oil Pressure; I'm doing a mechanical gauge. So, I suspect a T needs to be installed at the sending unit location of the left side of the engine, with either type gauge. Also, the 1/8 tube should be protected .... debatable subject in of itself.

As for the Oil Pressure Gauge, I've really liked my LED electric gauge on the '84. But, those things can be very problematic... loss of ground, being subject to vibrations destroys the sending unit, LED lights burn out, etc.

Thoughts, suggestions?

Wed Mar 22, 2017 10:00 am

You'll want to connect the voltmeter to a switched source of 12v + unless you add a toggle; otherwise you're just adding a voltage drain when the engine is off. Personally, I'd be leery of running an oil tube all the way to the front of the car, not only for the concerns about leaking but also accuracy. I've had very good luck with VDO electric gauges on many different vehicles.

Just curious, why are you adding a coolant temp gauge...or did you mean oil temp?

Wed Mar 22, 2017 10:08 am

Here's my install just for reference....

https://www.thesamba.com/vw/forum/viewtopic.php?t=642686

Wed Mar 22, 2017 11:03 am

Zeitgeist 13 wrote: You'll want to connect the voltmeter to a switched source of 12v + unless you add a toggle; otherwise you're just adding a voltage drain when the engine is off. Personally, I'd be leery of running an oil tube all the way to the front of the car, not only for the concerns about leaking but also accuracy. I've had very good luck with VDO electric gauges on many different vehicles.

Just curious, why are you adding a coolant temp gauge...or did you mean oil temp?

Yep, good point on the Volt Gauge.... and, actually, that's how I have the Volt Gauge in my 84. But, seems the "actual" volts shown with just the key ON is lower than what's shown on my Scan Gauge. Engine running, they are almost identical.

In my 84, I ran a lot of wires forward via three separate 3/8" inside diameter vinyl tubes (from the local Home Depot). I'll probably run the 1/8" tube inside something protective as well. Yeah, there is a pretty good lag with mechanical gauges.

VDO, New Old Stock (NOS) gauges, made in Germany or the USA, are high quality. I've not had good luck with the China and India made versions.

I was able to get a NOS VDO Coolant Temp and Volt Gauge off eBay at good prices, made in Germany. I could not find anything NOS VDO for the Oil Pressure Gauge. I purchased a Stewart Warner NOS made in USA mechanical at a decent price.

In my 84 (with TDI engine), the Oil Pressure Sending Units would last about 6 weeks to a month. So, I purchased a 24" long grease gun hose and routed it from the pressure hole forward above the Vanagon Transmission. There, I "hung' the sending unit on a spring so it would not be subjected to all the vibes. I had to provide a ground wire. It's been working well for almost three years now. The grease gun fitting on each end fits perfect... seems it is 27 NPT..... whatever, it works fine.

As for coolant Temp, I just like to monitor those three engine parameters. My OE coolant Temp gauge appears to work fine though.

I'm curious if the black plastic housing that holds the T-stat on the left head could be tapped for the Coolant Temp Sending unit. Seems that is where all the coolant exits the engine and is close to the OE Temp Sender location.

Wed Mar 22, 2017 11:24 am

I wonder if you could piggy back onto the stock temp gauge sending unit for both gauges. I also used old school VDO gauges/sendor for my oil pressure and voltmeter. I'm adding newer VDO units for my ALH install (pyrometer, boost and engine/trans oil temp--toggled).

Where are you mounting the gauges?

Wed Mar 22, 2017 11:37 am

Andy:

FWIW, the first gauge we attempted wiring was the oil pressure, and it was immediately clear we needed the extender to clear the valve tubes. Didn't have it (then), so got one from Van Cafe and proceeded to not wire any of our VDO gauges yet. :D

Apologies for brief OT, but anyone know when VDO stopped local manufacture?

Wed Mar 22, 2017 11:40 am

Below are pics of the gauges in my TDI 84 Tin-top.

Top, Left to Right >> Combo EGT/Coolant temp, Turbo Boost and Oil Temp (the gauge in the pic at top right was replaced since this pic was taken)

Bottom, Left to Right >>> Coolant System Pressure, Vacuum System Gauge, Volt and Oil Pressure.

The bottom 4-gauge Pod is for over head use. It has the gauge holes pointing toward the driver. I used a small piece of black plastic to fill the long hole across the top, above and behind the gauges. (kind hard to see in the pic, but it does look natural)

In top pic, the small hole that can be seen below the bottom 4 gauges was made by a previous owner...

In my 89 Carat, I plan to use a 3-gauge overhead Pod like the 4-gauge above and mount it in the same location.

Wed Mar 22, 2017 3:22 pm

Those gauge locations are much closer to the line of sight than mine, which are two up in the A/C plenum and three down just under where your group of four reside.

Wed Mar 22, 2017 4:25 pm

AndyBees wrote: So, I have purchased Temp, Volt and Oil pressure gauges for installation in my 89 Vanagon with 2.1 engine.

-Temp gauge; where is the best place to "tap" the cooling system (safely) to install the sensor? (photos appreciated)

-Volt gauge; really no question there. But, if there are bad places to access for measuring voltage, where are they? Should I just run a wire directly to the battery positive cable?

-Oil Pressure; I'm doing a mechanical gauge. So, I suspect a T needs to be installed at the sending unit location of the left side of the engine, with either type gauge. Also, the 1/8 tube should be protected .... debatable subject in of itself.

As for the Oil Pressure Gauge, I've really liked my LED electric gauge on the '84. But, those things can be very problematic... loss of ground, being subject to vibrations destroys the sending unit, LED lights burn out, etc.

Thoughts, suggestions?

for water temperature, the stock sender is in a good spot, at the temperature control valve, ie thermostat. try to use that one. why are you adding a second water temperature gage?

oil pressure can be picked up off the stock oil sender port(s). of course doing so on an engine with the dynamic warning system would diable that system, unless you rigged a tee, or a dual sender but space can be tight.

I added an oil temp sender in the very tight spot of the rearmost pressure sender, and ran a hose to the sender ,ocation on the side of motor, and then made a three port manifold, mounted near the top of bell house, connected to the hose other end. then both stock oil sender switches and my gage sender had plenty of room.

an electric gage is prefered, specially in the vanagon, as the run is very long to gage, and that can greatly reduce response time on the gage to the point where you miss seeing intermittant loss of pressure caused by say low oil level on a winding road and sloshing. you think a broken ground an an electric gage is bad, how about a blown tube or hose spraying oil all over! Go modern, go electric, specially with such a long run from motor to gage. the only way to improve response time on the gage is too use a very large diameter tube to connect to motor, you may need 3/8 inch id or more to get response time like electric gages, it will be worse in winter. a busted hose of that size, will gush oil out quickly. I tiny 1/16 inch id hose will have a huge lag in response, and you miss good data. In fact it may not fully register pressure until you have driven around the block! reading will be very temperature dependent, changing with viscosity of the oil, as viscosity and tube diameter are the primary things effecting the response time, in addition to the length of the run of tube.

at anyrate a mechanjcal gage is more appropriate when runs are short, as found in a front engined car, not a rear engined long van.

good luck

Wed Mar 22, 2017 4:39 pm

I used two Mercedes 124 front brake hoses combined together to tap into the oil circuit in between cyls #3 and #4--the brake hoses use the same exact thread pitch as the oil sending unit, unlike most SAE grease gun hoses. I installed the gauge and WBX sending units above #3 cylinder with an Audi splitter.

Wed Mar 22, 2017 5:22 pm

Zeitgeist 13 wrote: I used two Mercedes 124 front brake hoses combined together to tap into the oil circuit in between cyls #3 and #4--the brake hoses use the same exact thread pitch as the oil sending unit, unlike most SAE grease gun hoses. I installed the gauge and WBX sending units above #3 cylinder with an Audi splitter.

What is this "Audi splitter"?

-Rob

Wed Mar 22, 2017 5:50 pm

Robw_z wrote: Zeitgeist 13 wrote: I used two Mercedes 124 front brake hoses combined together to tap into the oil circuit in between cyls #3 and #4--the brake hoses use the same exact thread pitch as the oil sending unit, unlike most SAE grease gun hoses. I installed the gauge and WBX sending units above #3 cylinder with an Audi splitter.

What is this "Audi splitter"?

-Rob

Steel post that Audi stikes becuase unintended acceleration..

Wed Mar 22, 2017 6:25 pm

bluebus86 wrote: ...oil pressure can be picked up off the stock oil sender port(s). of course doing so on an engine with the dynamic warning system would diable that system, unless you rigged a tee, or a dual sender but space can be tight...

42 Design makes a splitter that accepts the input hose and up to 3 other connections [stock sender(s) and VDO sender]:

Wed Mar 22, 2017 7:21 pm

Robw_z wrote: Zeitgeist 13 wrote: I used two Mercedes 124 front brake hoses combined together to tap into the oil circuit in between cyls #3 and #4--the brake hoses use the same exact thread pitch as the oil sending unit, unlike most SAE grease gun hoses. I installed the gauge and WBX sending units above #3 cylinder with an Audi splitter.

What is this "Audi splitter"?

-Rob

Audi used them on their 2.8L twelve valve V6 engines for the exact same purpose; to split between the oil pressure gauge sender and idiot light switch.

Wed Mar 22, 2017 8:11 pm

Thanks for all the responses....

Well, without attempting to respond by quotes, I'll just do a general response.

I've seen comments in other Threads that a long small tube for the Mechanical Gauge would be less responsive, especially during the colder season.

So, I need to go back shopping... for an electric gauge! Question: Digital or Sweep?

As for the rear Oil Pressure Sending Unit, after changing that thing out about 8 months ago, I gave some thought to plugging it. Of course, I'd need to do a T off the other Oil Pressure Sending unit hole to maintain the Dynamic system.

Now, to tie all this together, where do I get one of those splitters?

Side note: Seems the Grease Gun Hose has the NPT pitch and I am using it with a brass T on my 84. So, I guess that explains why it works okay without a leak, etc.

Wed Mar 22, 2017 9:27 pm

https://www.thesamba.com/vw/classifieds/detail.php?id=1381302

No affiliation, just good stuff from a good guy... 8)

- Dave

Thu Mar 23, 2017 8:02 am

AndyBees wrote: ...
Now, to tie all this together, where do I get one of those splitters?...

What I used:

http://www.42draftdesigns.com/vw-audi-oil-pressure-relocation-kit/

[img]http://cdn3.bigcommerce.com/s-79qhm1/products/3500/images/1337/oprk_001__38649.1446580622.1280.1280.jpg?c=2[/img]

They also have senders though I could no longer find the VDO gauge (analog, 80 psi) that I got from them..

http://www.42draftdesigns.com/150psi-oil-pressure-sender-m10x1/

Thu Mar 23, 2017 12:52 pm

I installed the van cafe oil press gauge kit. I disabled the factory "high" warn circuit by grounding the wire, & I move the low pressure warn switch wire from the factory switch below the left head to the new VDO sender (which has 2 outputs: 1 variable signal, & 1 low press on-off).

I did this because it will turn on the low pressure warning light a little sooner than the OEM switch

Thu Mar 23, 2017 1:40 pm

I'm pretty sure the low pressure switch on the VDO oil pressure gauge is set to trigger at a higher pressure than the stock WBX unit.

Thu Mar 23, 2017 1:45 pm

Zeitgeist 13 wrote: I'm pretty sure the low pressure switch on the VDO oil pressure gauge is set to trigger at a higher pressure than the stock WBX unit.

....which will turn on the warning light a little sooner.... :D