DIY: B5 A4 V6 - Oil pressure switch - Oil sending unit - Replacement

[ECS Tuning-Audi]

Disclaimer: The following DIY is intended as an aid only and is by no means a professional set of instructions. It is recommended that you use this DIY as a visual aid to assist you in replacing your ignition switch. As such ECS Tuning does not take responsibility for anything that may be damaged or broken while using this DIY on your own vehicle.

I was plagued by a bad oil pressure switch yesterday evening. I dumped all my oil all over the road. To my dismay, there was no write up on replacement. Here is a write up for the do it yourself mechanic:

Car: 1996 A4 2.8 12v Quattro Manual - Should be mostly the same for all V6's

Symptom: Oil warning light came on with three beeps and then went off.

Problem: Oil pressure switch was bad, leaked oil out all over everything at a massively fast rate. If you are driving and you get this l light quit driving! I was at a gas station and 2 miles from home so I topped off my oil and limped home slowly. I advise you tow your car.

Things you will need:

• Oil Pressure Sender - Oil Pressure Switch (Interchangeable Terms!) - ECS has them cheaper than Advance Auto! So if you can, order from us
• Flat head screw driver
• 10 mm wrench/ratchet
• 14 mm wrench/ratchet
• 24 mm SHALLOW well socket
• 22 mm SHALLOW well socket
• Channel locks or a 27mm socket

Step 1: Remove splash shield. Three 10mm nuts in rear of the splash shield, 3 platic flat head screws in the front.

Step 2: Drain oil and remove filter.

Step 3: Loosen and disconnect bottom coolant line going into oil cooler (what your filter screws into). Push hose up and out of the way.

Step 4: Loosen 14mm bolt on font side of oil pan holding the water lines that supply the oil cooler.

Step 5: Only loosen the top coolant line going into oil cooler. This is where it gets tricky.

Step 6: You will need to remove the nut on the end of the spindle that attaches your oil cooler to your oil pan. This will be a 27 mm nut. I forget exactly. This will allow you to wiggle the oil cooler.

Step 6: Pull the oil cooler off slowly while using all of your human strength to rotate it clockwise. This will remove the top coolant line and free the oil cooler so you can take it off the car.

Step 7: The oil pressure sending unit is located behind this assembly. It has a single wire running to it with a rubber boot. Remove the rubber boot and disconnect the wire.

Step 8: Using a 24mm shallow well socket and ratchet, break lose the old oil pressure sending switch. Unscrew with you hand. You will get a ton of oil and coolant all over you, but this is the only way to get the switch out. Clean the whole area with brake cleaner a few times and have a beer while it dries.

Step 9: Your new oil pressure sending switch is likely going be a 22mm nut. So work it on as much as you can by hand, then tighten with a 22mm socket and ratchet. You want it tight, but not super tight - 20nm of force was quoted somewhere when I read through a million threads on this but don't quote me on it.

Step 10: Plug in wire and push rubber boot on. Reassemble oil cooler.

Step 11: Fill with new oil and coolant. Start car to verify it doesn't leak.

Step 12: Attach belly pan.


Below is the oil cooler with filter off and bottom hose attached. Loosen the top hose and pull the cooler out a wee bit while rotating as hard as you can clockwise to remove the stubby and stubborn top hose as pictured here.


I do not know how long this picture will stay up so if someone could host that would be great