TheSamba.com :: View topic - Routing of Oil Temp Gauge with Capillary Tube

Tue Apr 15, 2025 9:44 am

Guys,

While I have a decent amount of experience with our cars, I have zero experience with the oil temp gauges that use a capillary tube to measure the oil temperature, an example would be the Stork gauge. How does one route the wiring from the gauge back to the engine compartment with that tube in place, or is the tube removable? I cannot tell from any images I have seen. I am building an Old Speed '57 with an Okrasa engine and want to install a period oil temp gauge.

Many thanks in advance.

Tue Apr 15, 2025 9:53 am

Oil "temperature' that uses a capillary tube? I wonder if you mean oil-pressure?

Temperature sensors with some type of thermistor/ resistance based signal have been available for ...forever. At least since before VW tuning happened. I know some capillary gauges exist, I was using a Stweart warner /motometer temp gauge that had one- it was flexible copper tubing, and a huge hassle to route that front to rear. I ran the tube sort of tucked up under the running board, drivers side, up under the fender to the dash.

It's either that or inside, maybe next to the hard brake line, neither is super satisfying. I Eventually removed and went with a 40mm electric Motometer oil temp gauge.
If it's a really cool gauge, it can be worth the effort.

Tue Apr 15, 2025 10:00 am

Bub wrote: Oil "temperature' that uses a capillary tube? I wonder if you mean oil-pressure?

Temperature sensors with some type of thermistor/ resistance based signal have been available for ...forever. At least since before VW tuning happened. I know some capillary gauges exist, I was using a Stweart warner /motometer temp gauge that had one- it was flexible copper tubing, and a huge hassle to route that front to rear. I ran the tube sort of tucked up under the running board, drivers side, up under the fender to the dash.

It's either that or inside, maybe next to the hard brake line, neither is super satisfying. I Eventually removed and went with a 40mm electric Motometer oil temp gauge.
If it's a really cool gauge, it can be worth the effort.

Thanks Bub, I appreciate the quick response. I am sure the early Stork oil temp gauges use a capillary tube, several of my friends with very early 356s have them but alas did not do the installation so could not help.

While the cool factor is extremely high, it sounds like a pain to route properly and I worry about damaging such a rare piece so perhaps I can look for an electric gauge. The Koch temp gauge is electric and was the gauge of choice for Okrasa so perhaps that is the route I should go.

Many thanks again Bub.

PS I like the car in your avatar, I've been a Registry member for 35 years.

Sat Apr 19, 2025 6:47 am

Quote: I've been a Registry member for 35 years.

Hello,

is it correct, you "have been" member of 356 registry? (I have many older magazins, but I´m no member)

Capillary Tube Instrument:

There were more than the Stoerk for 356 pre A.

To find a possible routing, you must know and start with the lengh of the tube of your instrument. The sender for VW Beetles replaces normally the oil level dipstick. (one unit)

It makes a difference, whether you want to install the gauge inside the dash, routing the tube throuh the front trunk, compare with choke cable, or

mounting the gauge for ex, under dash, routing the tube along the tunnel or (right) heater channel.

The sender normally replaces the oil level dipstick, so the right side of car, body is probably easier.

In the old book, early edition of "Jetzt mache ich ihn schneller", there are hints about old style gauges, if I´m remembering right. In old magazins like "Gute Fahrt", there is also some info.

On my attic I have a capillary gauge oil temp, I got along original Okrasa parts.

Mon Apr 21, 2025 5:33 pm

wagen19 wrote: Quote: I've been a Registry member for 35 years.

Hello,

is it correct, you "have been" member of 356 registry? (I have many older magazins, but I´m no member)

Capillary Tube Instrument:

There were more than the Stoerk for 356 pre A.

To find a possible routing, you must know and start with the lengh of the tube of your instrument. The sender for VW Beetles replaces normally the oil level dipstick. (one unit)

It makes a difference, whether you want to install the gauge inside the dash, routing the tube throuh the front trunk, compare with choke cable, or

mounting the gauge for ex, under dash, routing the tube along the tunnel or (right) heater channel.

The sender normally replaces the oil level dipstick, so the right side of car, body is probably easier.

In the old book, early edition of "Jetzt mache ich ihn schneller", there are hints about old style gauges, if I´m remembering right. In old magazins like "Gute Fahrt", there is also some info.

On my attic I have a capillary gauge oil temp, I got along original Okrasa parts.

Thanks as always w19, I appreciate your insight. To answer your questions, yes, I have been and still am a Registry member over the last 35 years!

If I understand you correctly, are you saying the capillary tube can be routed alongside the choke cable through the tunnel? I would love to use one of these gauges but the routing seems difficult; any help is greatly appreciated.

Tue Apr 22, 2025 4:10 am

Sebastian Gaeta wrote: wagen19 wrote: Quote: I've been a Registry member for 35 years.

Hello,

is it correct, you "have been" member of 356 registry? (I have many older magazins, but I´m no member)

Capillary Tube Instrument:

There were more than the Stoerk for 356 pre A.

To find a possible routing, you must know and start with the lengh of the tube of your instrument. The sender for VW Beetles replaces normally the oil level dipstick. (one unit)

It makes a difference, whether you want to install the gauge inside the dash, routing the tube throuh the front trunk, compare with choke cable, or

mounting the gauge for ex, under dash, routing the tube along the tunnel or (right) heater channel.

The sender normally replaces the oil level dipstick, so the right side of car, body is probably easier.

In the old book, early edition of "Jetzt mache ich ihn schneller", there are hints about old style gauges, if I´m remembering right. In old magazins like "Gute Fahrt", there is also some info.

On my attic I have a capillary gauge oil temp, I got along original Okrasa parts.

Thanks as always w19, I appreciate your insight. To answer your questions, yes, I have been and still am a Registry member over the last 35 years!

If I understand you correctly, are you saying the capillary tube can be routed alongside the choke cable through the tunnel? I would love to use one of these gauges but the routing seems difficult; any help is greatly appreciated.

Thanks for your answer.

Routing the capillary tube: I have not ment, "inside the tunnel", more similar as the long brake line, alongside the tunnel, but on the right side.
On bulkhead area upwards (under the carpet) and then:
a) directly to the gauge under dash,
b) through the sheet upwards to front trunk (eventually through the same hole as choke cable) and to the in dash mounted gauge.

Rear: idea: through the same hole as plus-wire

An alternative can be, routing the capillary tube alongside the right heater channel, similar the main wiring on later beetles (on the left side)

Good fixing and isolating against electrical plus-wires (starter area) is important.

(mine for beetle is made by Stoerk, but it has a different design as for 356)
(there were gauges with "Oettinger" on the face, but not on mine)

Also an idea is, to transform a old defective gauge (broken or missing tube) to electrical sender.

Tue Apr 22, 2025 7:57 am

wagen19 wrote:

Thanks for your answer.

Routing the capillary tube: I have not ment, "inside the tunnel", more similar as the long brake line, alongside the tunnel, but on the right side.
On bulkhead area upwards (under the carpet) and then:
a) directly to the gauge under dash,
b) through the sheet upwards to front trunk (eventually through the same hole as choke cable) and to the in dash mounted gauge.

Rear: idea: through the same hole as plus-wire

An alternative can be, routing the capillary tube alongside the right heater channel, similar the main wiring on later beetles (on the left side)

Good fixing and isolating against electrical plus-wires (starter area) is important.

(mine for beetle is made by Stoerk, but it has a different design as for 356)
(there were gauges with "Oettinger" on the face, but not on mine)

Also an idea is, to transform a old defective gauge (broken or missing tube) to electrical sender.

Great info wagen19, I will investigate these and determine which will work best for me. Thanks so much for your insight.

Fri Apr 25, 2025 3:55 am

would the oil not be cold by the time it got to the dash?

Sat Apr 26, 2025 1:09 pm

An oil temperature capillary tube is a thin tube that connects a sensing bulb (located within the engine) to a gauge or display. This tube transmits temperature changes from the bulb to the gauge, allowing you to monitor oil temperature. The bulb is placed in the oil flow or at a location where it can accurately measure the oil's temperature. Capillary Tube is filled with a fluid that expands and contracts in response to temperature changes. As the oil temperature changes, the fluid inside the tube expands or contracts, causing a change in pressure or volume. The gauge uses this pressure or volume change to indicate the oil temperature.

Fri May 02, 2025 12:48 pm

I would like to jump in with a related comment and question. I have a Stork oil temp gauge as well, but it has a different end. Any ideas on where this could be mounted in a 36hp motor?

As for routing, my plan was to mount the gauge on my column and either run it one of two ways:

1. Run the cable from the column into the trunk area via the same hole as the turn signal wiring and then back down through the area where the vent hose is located and out of the small factory hole at the bottom of the front quarter panel. I would then run it under the carpet along the heater channel, under the back seat, and through the small factory hole in the luggage area to the engine compartment.

2. The alternative would be to run the cable along the column to the firewall carpet area and then hide/run it along the tunnel to the same hole in the luggage area.

The goal in either approach is to have the cleanest routing without cutting any new holes, while also making sure there is enough cable to reach the engine.

Fri May 02, 2025 2:43 pm

jbannon wrote: I would like to jump in with a related comment and question. I have a Stork oil temp gauge as well, but it has a different end. Any ideas on where this could be mounted in a 36hp motor?

As for routing, my plan was to mount the gauge on my column and either run it one of two ways:

1. Run the cable from the column into the trunk area via the same hole as the turn signal wiring and then back down through the area where the vent hose is located and out of the small factory hole at the bottom of the front quarter panel. I would then run it under the carpet along the heater channel, under the back seat, and through the small factory hole in the luggage area to the engine compartment.

2. The alternative would be to run the cable along the column to the firewall carpet area and then hide/run it along the tunnel to the same hole in the luggage area.

The goal in either approach is to have the cleanest routing without cutting any new holes, while also making sure there is enough cable to reach the engine.

First, more input please:
> Pic of instrument (original for 356?)
> Lengh of capilary
> type of thread of sender (evt. M 14 x 1,5) ???

The "slim end", the hexagon sender has to pass through any holes from front to back, to engine. (much larger holes as for a electrical wire are needed)

As the lengh is fix, (under normal circumstances), it´s up to you to find out, what routing and direction is possible, if at all.

Affixing the sender on engine, first idea:

Have a look for a 356 adapter of a 3-piece engine. With luck, your sender have the same thread M14 x 1,5 as for the later PTC or NTC electric senders on 3 piece 356 cases.
My idea is, machining this part, or a part like that, to make usable for VW engine and also use some 356 parts. (screws, gaskets, etc.), (evtl. have a look on Porsche website, spares till 356 A, 1959.

Take a stiff steel wire, for ex., for tensioning a fence or something like that and cut it in the same lengh as the lengh of your capilary. So you can find out, what way, direction or routing is possible. (356 has wheel base 2100 mm, Beetle has 2400 mm.

(my Okrasa sender has no thread, it´s designed similar as a oil level dipstick)

Wed May 14, 2025 8:48 pm

im running the stork gauge in my ova and run the capillary line up though the top like the wiring cables. the line was long enough to make it front to back no problem, its hidden an not in a position to be damaged