View Full Version : 1.8T Oil Pressure Sender Install - Write-Up

10-19-2010, 08:12 PM
There has been some questions about this now and again, so I thought I'd finally post a little writeup of my oil pressure sender installation. The gauge I bought was a Marshall Pro Street II, full sweep electric stepper motor gauge. I got in on ebay for about $60 as I recall.

First a little explanation of what I did. There are 2 normal places to connect an oil pressure gauge on the 1.8T AWM and AMB (2001-2005). The most common is the oil pressure switch port on the rear of the oil filter housing. The other is the test port on the top. You can see both in this diagram - the test port plug is highlighted in red, and the red box shows the pressure switch:


When using the switch location, you use some sort of splitter to make it work. I didn't want a big "T" fitting hanging off the back. You could also use a relocation type splitter like 42 draft designs sells (http://store.42draftdesigns.com/VW-Oil-Pressure-Relocation-Kit_p_314.html). That is a great product, but I didn't want to find a place to mount the glob of sender/switch/fitting block in the engine bay. It just seemed a bit messy to me. So I decided I would use the test port.

*NOTE* The oil filter housing is different for the earlier AEB and ATW engines. It is angled more and the port locations are different. Here is a diagram:


For the AEB (1997-1999.5): There is no check port. You will need to use a "T" fitting, either on the oil temp sender (#11) or oil pressure switch(#10) ports. I would recommend the pressure switch, as putting the temp sender after a "T" will reduce it's accuracy.
For the ATW (2000): It has the test port in the location of the oil temp sensor (#11). For the ATW, the oil temp sensor was moved to the oil pan, so they put a plug there instead. That port is quite easy to get to, although a 45 degree adapter or extension fitting would probably still be necessary for a bulky sender.

It became apparent that the space is pretty tight there and my bulky sender wouldn't just fit in there straight. So I eyeballed it a bit and decided a 45 degree angle fitting on top of the required metric adapter would probably do it. So off to ebay I went to by me some fittings. Now on to the fun stuff:

Tools Needed:
18mm stubby wrench
5/8" wrench
3/8" drive extension, 1 foot
3/8" drive ratchet
3/8" drive universal joint
3/8" drive 5mm allen socket
1/4" drive ratchet and extension
1/4" drive 7mm socket
Philips screwdriver (not pictured)

Oil sender that comes with the gauge
M10x1.0 to 1/8" NPT adapter (Autometer #2265)
1/8" NPT 45 degree "street elbow" ("street" means it is male on one end and female on the other, in plumbing lingo)

First step was to remove the plug on the top of the oil filter housing. You can see it pretty well through the manifold runners.

It comes out pretty easy with a 5mm socket, universal and a long extension.

Then I fitted the 45 degree elbow to the m10x1 adapter. I put in a vise to make it easier to work with. Some teflon tape is required here. I made sure not to get it on the very first thread, so teflon doesn't make it into the oil. It is pipe thread so I just tightened enough to seal. I left at least a full turn to go if needed, so I could adjust the angle (clock position) for the sender.

Installed as a unit with the crush washer and tightened with a wrench from the side. At this point I had to remove the coolant reservoir and flip it to the side to get some more room (3 philips screws). I also removed the throttle body hose (two 7mm screw clamps) for better access. My m10x1 adapter used a 5/8" wrench. Tightened enough to crush the washer, but left a little to go if needed.

Now is when the clock position matters. It ended up exactly in the opposite direction, so I tightened both fittings equally to arrive at the final position. I had to mock up the sender a few times to check

Then a little teflon tape on the sender and install. I needed an 18mm wrench to tighten the sender. It had to be a "stubby" wrench as there isn't much room at that angle. To work the wrench I had to put my hand in through the back. A tight squeeze, but workable. Then I remounted the coolant reservoir and reattached the throttle body hose.

At this point the car is now driveable again so I took a break and decided to the interior guage mounting business the next weekend. The only other under-the-hood item would be the wire that runs to the pressure sender, which is pretty simple. Although my placement of the sender did require some dexterity to connect the wire to the post.

As far as oil pressure measured, they are a little higher than I expected, which is good for a 1.8T I suppose.
Cold Idle: ~80 psi
Cold 2k rpms: ~90 psi
Cold 3k rpms: ~100psi (pegs the gauge)
Hot Idle: ~24 psi
Hot 2k rpms: ~50 psi
Hot 3k rpms: ~70 psi
Hot at redline can still peg the gauge (100 psi).

Hope somebody finds this useful, or at least interesting, or something...lol.

EDIT: For content concerning fitment to AEB and ATW.

.Mad Hatter.
10-19-2010, 08:37 PM
thank you so much. I like this install a lot and the visuals make it a lot easier. finding those fittings may be a pain but i think overall this is the best route. my sender is physically smaller than the one you have pictured there and i also planned to do this with the intake manifold off so room should not be an issue. you didnt have to drain the oil to take that port cap bolt off? i guess with the car off there is no oil there?

10-19-2010, 08:44 PM
Correct, no oil draining is necessary.

The fittings weren't hard to find.
http://cgi.ebay.com/ebaymotors/Auto-Meter-2265-Fitting-Metric-Adapter-1-8-NPT-10mm-_W0QQcmdZViewItemQQhashZitem5adc580e37QQitemZ39024 3814967QQptZMotorsQ5fCarQ5fTruckQ5fPartsQ5fAccesso ries


And you could certainly find them cheaper, that was just a quick search.

.Mad Hatter.
10-19-2010, 09:00 PM
did you try anyone local or go right to ebay?

10-19-2010, 09:38 PM
Nope. I had time to wait. Even if I did find it local, I'm sure I got better prices on ebay. I did look into a local shop that makes custom hydraulic hoses. Mostly for tractors and what-not. I was going to get an m10x1.0 to 1/8 npt hose that was 18 inches long. I think the price would have been less than $15. But I opted for the direct mount in the end.

Home depot might have the 45 elbow. And autozone might have the adapter fitting. Each place may have to order it, though. Not sure.

10-19-2010, 10:02 PM
Great writeup!

One thing though, since mentioned remote mounting. I read somewhere that its better to remote mount the sender for durability. Something to do with engine vibration going directly to the sender vs engine vibration reduced/eliminated by the hose between the port and sender.

10-19-2010, 10:19 PM
I suppose the vibration is a concern. Audi mounts them on the engine, though. So it can't be too bad, eh? Even cars factory oil pressure gauges, I've never seen one with a remote mount.

03-01-2011, 03:44 PM
Walky talky, where did you run the wiring for the gauge into the interior. Ive decided I better install a oil pressure gauge on my 03 and just ordered a few things from jegs.

03-01-2011, 08:54 PM
Walky talky, where did you run the wiring for the gauge into the interior. Ive decided I better install a oil pressure gauge on my 03 and just ordered a few things from jegs.

Ran mine throught the ECU box.

03-01-2011, 09:24 PM
Yep. I ran mine along with the my boost gauge vacuum line into the cabin through the ECU box.

Good luck with your install. I think it is an important feature to have on the 1.8T.

03-01-2011, 10:20 PM
yeah i did this awhile back and was able to find the fitting at home depot, last time i was at lowes they had the same one, mine is a little different because i added an extension then an a "T" fitting so i could use the stock oil pressure switch and the aftermarket sender, total spent was around $11, great write up!

03-17-2011, 01:53 PM
Quick question regarding this procedure on an 97 AEB.
For the life of me, I cannot find the little black screw/plug (test port) on top of the oil filter housing.
I only found two entries which are already occupied by sensors...getting a "T" fitting for the switch is my last resort.

Would that plug represent bolt #3 on the diagram?
Or does the AEB simply not have a test port?



03-17-2011, 02:54 PM
AEB and ATW use the different different setup which you have shown.

- AEB has no test port
- ATW has the test port in the location of the oil temp sensor (#11). For the ATW, the oil temp sensor moved to the oil pan, so they put a plug there instead.
- The plug on the ATW is super easy to get to, making it probably the easiest 1.8T to add a pressure sender to.

For AEB cars you will need to use a "T" indeed. Either on the oil temp sender (#11) or oil pressure switch(#10) ports. I would recommend the pressure switch, as putting the temp sender after a "T" will reduce it's accuracy.

#3 is the relief valve between the housing and the block.

EDITED my write-up above to include this info. Thanks for asking.

03-17-2011, 03:05 PM
Thank you for that clear up Walky, greatly appreciated.
Will the T fitting affect the accuracy of the oil pressure gauge and the functionality of the switch by any chance?

03-17-2011, 03:19 PM
No, it won't bother the switch or the pressure sender, but it will bother the temp sender. You can imagine that the temp sender should be exposed pretty directly to the "flow" of oil through the chamber. In a "T" configuration, the oil is pushed into the "T" and just stays there: it's just a dead end. There is no way for fresh oil to be continually applied to the temp sender probe. Therefore, it is important where it is placed so it can give you an accurate representation of real oil temps in the system. That is why most aftermarket oil temp senders are often installed in the pan. In fact, that is where Audi moved it to for the 2000 model year.

The pressure switch and sender don't care about flow, just about pressure. So they are good to go.

05-17-2012, 06:06 AM
Awesome write up i just picked up a brand new electronic oil pressure gauge and sender for $9

06-08-2012, 11:13 PM
Throwing this one in there. Very easy alternative. I did mine like walky_talky20 wrote, and I have the AWM. I don't think this piece below was out when I made mine, but it will work on both 058 and 06a blocks. Simply take out the pressure sensor switch, place this t-fitting in there, then place the stock pressure switch and oil pressure sender unit with m10 to 1/8" npt adapter (if necessary) in the 2 ports that tee off.


08-06-2012, 06:38 PM
cant find that gauge setup on ebay any links thanks maybe its out dated.

08-06-2012, 06:42 PM
You want links to adapters or to an electronic gauge kit?

EDIT: Here's a 0-150psi gauge

Here's on that's 0-100psi

08-07-2012, 03:53 PM
sure that would be great thanks. Nice write up I cant wait to get this in I hate not having one.

01-04-2013, 10:52 AM
Bumping this up. Walky what gauge did you end up using, mechanical or electrical? Oops just saw in your sig you used electronic.

02-05-2013, 05:32 PM
So I'm confused. Below is a post I started for my own oil pressure switch problem, including a link to the replacement part I purchased.


Can you explain why you added the tee/adapter piece and installed the switch on top (in the vertical) when it looks like there is the one more accessible in the horizontal (all relative to the 45 offset)?

Why am I not just removing the existing oil pressure switch and replacing it with the one I just bought? Why these extra steps? Is it because your first diagrams actually show two different layouts and you have the 1999 version while my car has the 2003 setup? Except in your images it looks like I can see the slot for #10 is the same as mine.

02-05-2013, 10:09 PM
Can you explain why you added the tee/adapter piece and installed the switch on top (in the vertical) when it looks like there is the one more accessible in the horizontal (all relative to the 45 offset)?

Yes, I can. The factory item is a "switch". It's job is just to tell the cluster 1 thing: Do I have 23psi right now? This DIY guide is not related to that switch. This guide is for adding an aftermarket oil pressure "sender" - a new and separate device that gives a variable output to drive a gauge (typically 0-100 psi range). The sender cannot replace the switch: both devices must run in tandem. So you either use a "T" at the factory switch location, or use the test port. I chose the latter, and explained my choice within the DIY (cleaner install, basically).

Why am I not just removing the existing oil pressure switch and replacing it with the one I just bought? Why these extra steps?

I don't know. Why are you doing that? lol.
If you are just replacing a faulty switch, that is all you need to do. Unplug wire, remove, install, plug in wire, done.

03-21-2013, 05:12 PM
I have this set up (gauge and sending unit) in my Car AWM. I just changed the oil over to the shell T6 5w-40 from Valvoline 5w-40 syntech + new filter. At hot idle 210-215F I see 15psi with t6 with old it was about 20psi? same oil level. The bentley book says 80C (176F) 19 psi at idle and 50-60 psi at 2k. I checked my car with the t6 at 175F and it was 18-19 and 2k rpms 55psi. At that temp (about 175 F) I dont know what the syn tech was? oil pump was replaced 7k ago. Am I just being paranoid ( Audi) or should I look into this more?


03-21-2013, 05:26 PM
Rotella T6 made your pressure go down a bit? Mine never really changed between Mobil 1, Castrol, or T6.

Anyway, I don't think you have anything to worry about. The spec should be at least 1 bar at idle, so 15psi is in spec. Usually you'll see 20psi or more, and you may have some extra lifter or chain noise at 15psi, depends. Your pressure at 2k is great. If you want, keep an eye on the pressure behavior for now. Next oil change go back to what you were using before and see how it goes.

03-21-2013, 05:41 PM
Thanks walky and I will keep my eye on it If anything changes Ill post about it.

10-13-2013, 10:26 AM
So would this spot be good for oil temp, I'm running the 42dd oil pressure re location kit for oil pressure but I'm looking at picking up some new gauges for my podi p2 new vei boost gauge and vei oil temp and coolant/water temp. And does anybody know a good spot to install the probe for coolant temp thanks.. Good write up by the way.

01-01-2014, 06:11 PM
That test port plug is impossible to get out. I've been trying to an hour and a half and the 5mm allen socket wont go into the plug all but maybe .5mm. Its not enough to put any torque on it with out stripping it.

I'm trying to hook up an oil pressure gauge to check pressure. Is there any other way to hook the gauge up?

The pressure switch looks just as much of a bitch to remove as well. The coolant lines from the oil cooler keep you from getting a 24mm wrench in there.

Any other tips?

01-01-2014, 06:52 PM
for the test plug. take a pick and clean the junk out of the hole. otherwise, the switch may require a socket to get out. If lines are I the way, you could just take them out. coolant is cheaper than a new engine.