OIL TEMPERATURE GAUGE RETRO-FIT

[Southernboy]

I have read any number of threads on various BMW forums where the question arises for the retro-fitting of an oil temp gauge to various BMW cars, and it would seem that it has caused consternation with all sorts of solutions including using the OBC to create a display on the satnav screen to installing separate screens as well as fitting mechanical devices with oil pipes etc etc...
This is a quick solution to retrofitting an oil temperature gauge to the Z3. This is easiest done by replacing the oil drain plug with a temperature sender. The thread size on the drain plug is M12 x 1.5. There is a sender available from VDO (Germany) which has the same thread size...so it only requires the plug to be replaced by the sender. The part # is :- 323-801-010-003K
Once this has been fitted, the rest is straight forward. The gauge will have 3 connectors at back 1. 12V power connection denoted by a "+" . 2. Earth denoted by a "-"... and 3. Line from the sender to the "S" pole on the gauge.
The power "+" will need to be from an ignition switched source, the earth "-" can be anywhere close by or linked to another earth line.

[Cooper01]

Your a legend @southernboy !

[Southernboy]

........ As in Kevin Bloody Wilson ???

[Southernboy]

UK link........
https://www.google.co.za/url?sa=t&rct=j ... SuxVLiYAUQ

[Cooper01]

Thanks, I don't want one now but who knows in the future... I would probably get a rack of gauges like outside temp, oil pressure, engine temp, and such. I am still settling into my z3 2.2 so won't be rushing into anything yet. Thankfully, everything works - no on-board computer is the most negative thing I can complain about. As you know I will be replacing the IPanel very soon! I like the guages though so will accumulate members ideas!

[lightning]

Oil temperature gauge?

Won't that just be another thing to worry about? I'd rather not know.....

[Southernboy]

Wouldn't you rather have some advance warning information before any serious damage can be done? Anyhow, mostly this info is for those who are fitting the M console to their cars which includes an oil temp gauge... and anyone who prefers to have extra gauges for track meets etc.

[lordhelpus]

That's freaky Southernboy I was thinking about adding some gauges and was looking for this very info. But the more I think about it the more problems I get.
I thought about adding three gauges Oil Temp, Oil pressure, and Volts but I don't want them in a pod on top of the dashboard (obvious place)
I want to be able to fit them in the centre dash under the heater controls the area presently occupied by the ASC switch and roof switch, all the gauges I can find are 52mm in Diameter. I have not measured up yet but looking at it I don't think there is room for three gauges there anyway...So if I go down to just 2 gauges say oil temp and oil pressure and use a flat mounting plate (you can trim the plate to fit) then 2 gauges might just fit in the place I have mentioned but..... where would I then put the ASC and Roof switch???......Also looking on various websites for gauges one site had a word of warning about VDO gauges that you must use a VDO sender with the VDO gauge other senders won't work with them. I have always been of the opinion that the Z3's should have been factory fitted with a few centre gauges anyway. nice bit of info though... Thanks

[Southernboy]

Most gauges are 52mm... including the OEM M car versions. They are also VDO brand. I doubt if it's true about the sender and gauge needing to be matched, although it is quite possible that the sender is calibrated to the gauge or visa versa.
The switches can be moved to the back of the console where the little container is situated. here is an OEM fitting which will accomodate 3 switches, and some Z3's have the roof switch located there anyhow. If you move all the switches off the console, you should be able to modify it to take a couple of gauges without too much difficulty. FYI, someone recently posted a thread about a product called SUGRU... Seems like a useful material to use in your application... have a search for it... it was on the board about 2-3 weeks back. It's like a putty which can be shaped easily, and then it hardens overnight...also seems to adhere to almost anything. Might be useful for filling in and making good. The new VDO gauges are all black bezel surrounds, but you could also do a search on eBay UK for 1963 Jag XJ6 Gauges.... there's someone on there selling these gauges for £20 each and you can buy a set of 3 on the original little mounting plate from the Jag.... Might help instead of doing 52mm cut-outs etc. They may be Smiths gauges, but that shouldn't present too many hassles since Smiths are still around, and personally I prefer their gauges - the modern ones look really good but are quite pricey... anyhow, have a look on eBay and contact the seller...

[lordhelpus]

Southernboy I have copied this from the VDO website:

Note: All Pressure sensors are designed to work with VDO gauges only, unless otherwise noted. Sensors are matched to gauges according to maximum reading on dial face. All sensors are standard ground (sensors case to common ground). Please note: VDO senders have tapered threads and DO NOT require the use of Teflon tape or pipe sealant. This will interfere with grounding causing incorrect instrument readings.

you was correct in that sensors are calibrated to the gauge.

[Southernboy]

.... I guess that makes sense to match them... although I would have thought it would be a standardised industry where gauges / senders could be inter-changed.... If you were from China, wouldn't you carefully calibrate your senders to match someone else's gauges??...

[BladeRunner919]

If you were from China, wouldn't you carefully calibrate your senders to match someone else's gauges??...

Nah, you 'd just make it as cheaply as possible, regardless!

[Southernboy]

........ are you speaking from experience, Blades...

[BladeRunner919]

........ are you speaking from experience, Blades...

No, just massively generalising about an entire, huge country without any basis to do so. But that's what the interweb's for.

[bowei001]

It is certainly possible to fit two gauges into a post facelift car depending upon how many switches you have in the centre console. There are two spare places for switches at the back of the console so if you only have two switches to relocate, they can go there simply by elongating the wires and running them under the console front to back. It is then possible to cut two 52mm holes where the switches used to be. A bit of filing and filling is needed (followed by painting) and then the gauges can be inserted, one either side of the clock. If you have more than two switches to relocate, this will not work and you will probably have to get an M console. I've attached a pic of what I did a while ago which seems to work.

[lordhelpus]

Very neat....

[bowei001]

Just to bring my post up to date: The adapter block that I purchased from the USA to fit an oil temperature and pressure sender to the boss on the oil cooler housing where the pressure switch goes wasn't really much good for the temperature as the sender sits in a "backwater", away from the oil flow (the pressure sender is fine). I recently managed to get an Z3M console with all gauges and I decided to do the job properly so that the temperature reading was accurate. The oil filter housing has 2 large torx headed plugs (T70) and the upper one opens into the chamber where the temperature sender for the ECU is located. I removed this plug (very tight!), put it in a lathe and tapped through the centre to 10.5mm and then threaded to M12 x 1.5 (which is the thread size of the Z3M sender). I then rebated the chamfer round the torx hole to a depth of 0.8mm to provide a flat surface to take an aluminium washer M12 x 20 x 1.2mm. This allowed the washer space to crush without the sender bottoming on the plug. I replaced the plug (I annealed its aluminium washer first), refitted the oil filter housing and then screwed the sender in (with the sender in first you can't insert the top right hand fixing bolt. Things are rather tight when the cable connector is fitted to the sender but it will fit. Anyone using a generic VDO gauge and sender will probably have an 1/8 NPT sender in which case you would drill the plug with a "Q" drill (0.332"), tap 1/8 -27 and leave out the aluminium washer as the sender is tapered. The whole set up works and the gauge reads accurately and gets there quickly. I understand that some early housings don't have threaded plugs but have push-in plugs with an o-ring and a circlip - I don't think I would try this with that set-up. Anyone doing this should not be tempted by the bottom plug as this covers a non-return valve and the sender won't fit!


Further update. I noticed a slight oil weep around the sender unit. When I unscrewed the sender I found that the aluminium crush washer had a slight nick in it which was allowing the weeping. Whether I missed the nick on assembly or caused it when assembling I don't know but I made the following modification: I removed the threaded plug, put it back in the lathe and machined out the washer recess to 22.5mm diameter and 1.2mm deep. Using a M12 x 22 x 1.2mm aluminium crush washer, I was able to contact the whole of the hexagonal base of the sender onto the washer and the washer contacted a larger area of the threaded plug. For "belt & braces" I put a thin film of Loctite threadlock round the first 2 threads of the sender and re-assembled everything. It does not weep now!

[Mike Fishwick]

Although replacing the sump plug with an M12 sensor is simple and attractive, it has a problem in that the sensor is positioned in the outer area of oil, adjacent to the sump and therefore cooler than that being fed to the bearings. As this cooler oil has a higher viscosity it tends to cling to the area adjacent tothe sump.

I found this problem about thirty years ago on my BMW motorcycle, after making a lovely stainless steel sump plug, threaded for a VDO 10 X 1 mm sensor as used on the early VW Golf GTI. I then experimented by moving the sensor to the centre of the oil filter cover plate it 'found' about another 20 degrees C, due to the problem of stagnant and therefore cooler oil around the sump walls.

[Southernboy]

Great job you've done, and an excellent description of the machining and fitting procedures. I love it when a mod is done as well as it could possibly be.
IMO This should be stored in the Z3 Knowledge base...