Temp Gauge Replacement

[JGriff]

My center console temp gauge is not working. I checked for current, and I have just about 12 volts feeding to it.

I'm assuming then that I can just order a new gauge and that should be it, right? Or could the sender be bad, but still send 12 volts?

If I buy a gauge, should I get an OEM unit (from PP), which does not have numbers on it, or should I order a VDO unit, which does have numbers on it? I would prefer the latter, but does that VDO unit require a different sending unit? If so, how difficult is that to replace?

Thanks.


Jim


------------------
Jim Griffin
JGriff@JGriff.com
www.JGriff.com

[John Rogers]

A couple of pretty knowledgable people told me that the console temp guage was wired in parallel with the one in the dash such that they both read low since I thought the ones on our 1974 914 never worked? I unhooked the console guage and the dash indicator reads somewhat off the lower whit line as before it almost never moved. I replaced the console guage with a large red light for oil pressure and I have seen some others put amp or head temp guages there. Good luck.

[Dave at Pelican Parts]

John, none of the cars with the oil temp gauge in the "combo gauge" had center consoles with gauges. It was an either-or proposition. I think either your console or your combo gauge was added by someone after they had bought it.

I already responded in the Yahoogroups list, but for those who missed it:

The oil temp gauge needs power when the ignition is on. Check for +12V on the red/white wire. It needs a good ground on the brown wire. The signal wire (green/black) goes to the sender, which varies resistance with its temperature. Colder = higher resistance, warmer = lower resistance. I do not remember the range, though. Check the resistance between the gauge end of the wire (unplug it from the gauge first!) and a good ground; you do not want zero and you do not want infinity.

OEM gauges may be hard to find. Aftermarket VDO ones will read wrong if you use the stock sender.

Replacement isn't that tough; drain the oil, remove the "taco plate" from the bottom of the engine (some more oil will come out most likely), unscrew the sender, install the new one with new crush washer, replace the paper gasket, bolt the taco plate on with new crush washers. About 10 lb-ft of torque on those, or the plate will bend into a taco shape and leak.

You may need to pull out the mounting plate from the hole. If so, you might consider replacing the big red O-ring around it.

--DD

------------------
Pelican Parts 914 Tech Support

A few pics of my car: http://www.pelicanparts.com/gallery/Dave_Darling

[mejulihn]

In addition to DD's comments about replacing the sender, the VDO "Cockpit" series gauges are slightly smaller than the factory center console temp gauge with no numbers. I like them better, but you will have to get a ring adapter to fit them to the factory console opening (2-1/8" vs 2-1/16" IIRC). Since there is only one wire (grn/blk) from the sender on the bottom of the engine, one of your two temp gauges should be disconnected/inoperable. If a PO wired them both to the sender, my guess is that neither will be reliable.

[John Rogers]

Dave, you of all people should know anything is possible on a Porsche, even the lowly 914! According to the original owner of Julia's car it came that way and was an order from the factory with them. He said it was requested to have an amp meter in the middle with the voltage gauge on the bottom but the temp gauge was installed! Maybe there was something lost in the english to german translation? At any rate the wiring harness behind the dash and in the tunnel has never been hacked so I tend to believe him.

[This message has been edited by john rogers (edited 08-03-2001).]

[Dave at Pelican Parts]

I think the harness on 74+ cars always has the wires for both--it's cheaper for the factory to just build one version.

But I believe you about it being original. It's very very unusual, but Karmann did all kinds of very strange things every once in a while.

--DD

------------------
Pelican Parts 914 Tech Support

A few pics of my car: http://www.pelicanparts.com/gallery/Dave_Darling

[Roland Kunz]

Hello

The instruments have 60mm diameter while the standard VDO Instruments had 52 diameter.

VDO also had 60 mm instruments used in Mercedes and Hanomag Trucks and the fuel meter from the early 308 hapend to have a similar design and the same ramge only needed the correct needle and a additional reserve light ( used the light in the Oilinstrument ).

The Oilinstruments from the 914 where made in different versions simple to indicatet by the start from the red zone. Porsche repeatet the 914/6 instrumet story again.

The 914 stock temperaturesender is a direct fit for the VDO Cockpit Oiltemperature instrument. It has some 5% tolerance at low temps.

I know a car who had a inside/outside temperatur einstrument installed fom the factory. To match it the Voltmeter and the clock with heater preset where also used in 52 mm VDO design ( like used later in the 924 ).

As this car also had partially leather and a seperate heater the middle console face was costum made with the heater control knobs from Volkswagen.

If my memory serves me right the parts where made in Zuffenhausen and send to Karmann, so the car was produced on the normal row.
But it also could have been made complete at Karmann.

Grüsse

[Dave at Pelican Parts]

> The 914 stock temperaturesender is a direct fit for the VDO Cockpit
> Oiltemperature instrument. It has some 5% tolerance at low temps.

I think that, for once, I am going to disagree with Roland. I believe pretty strongly that the original senders are a different range than the aftermarket ones. They are even labeled differently--the aftermarket one is labeled "300C" while the stocker is labeled "200C".

--DD

------------------
Pelican Parts 914 Tech Support

A few pics of my car: http://www.pelicanparts.com/gallery/Dave_Darling

[Roland Kunz]

Hello

Well no problem as my memory isn´t comperable to a spec book and I never state to know all.

I just remeber that I had a 2,0 in my 412 and hooked up a VDO Oiltemperatureinstrument and find it very acurate. And we know that changing that thing can consume time as the rubber o ring as a bit strange and sometimes fails to seal.

But I never looked into the VDO sender cataloge to check the real numbers.

The thing is that the meteres are allways working in the same resistance range and the senders are used to adopt to the enginetemperature. So using the 914 sender on a other car will give missreadings while using the instrument in a other car will show a similar range.

Maybe I do think wrong but after some years I beleive to understand how some things work normaly. But you never can be sure and some companys like to have special made things and go there own way.

VW/Audi/Porsche always proofed there construction attidtude for being simple interchangable over the last years and together with Mercedes, Behr, Bosch, Eberspächer, ATE ( would be a long list but you know what I will say ) they made the standards in german automobilindustrie.

Grüsse