Battery Change / Coolant Sensor / Spark Plug Replacement Part 1

[steve2003rs6]

When you remove the old sensor. Make sure the o ring comes out with the sensor.
I wasted half hour trying to install the new sensor. Then I couldn’t get the clip to align with the groove.

Eventually realised that the old o ring was still in there. Couldn’t see it as it is submerged in the coolant.
Once the old o ring was removed, everything went back together nicely. Dropped the clip a few times trying to insert it. Thankfully the white cord I used allowed me to retrieve it very easily.

[cover99]

Okay update on where i have got to. I will add some more detail to the post when I get more time. But thanks to all regards the sensor replacement i have followed this advice closely.

1st bonnet up and a cup of tea before started anything

Removed the front carbon cover with the small depress and turn clips. Then removed the 16 T20 torx screws and removed the larger top cover.
Then using a T25 torx removed the 4 screws attaching the silver air intakes. Jubilee clips released on the corrugated connectors and pulled off the silver intakes (Actually quite tricky)

The air intakes were then gently removed by sliding outwards towards the wing 1st then pulled back in the direction of the bulkhead. This allowed them to clear the coolant hoses. All parts then carefully stored.

Took the opportunity to remove the air filter elements and clean out the supply chamber of any debris, also hoovered out the chrome mesh protector of debris.

Then removed the 10mm securing nut on either side of the air intake assembly (Will get some picks up) and removed the Allen bolt front centre of the air intake.

Then gently lifted the air intake housing upwards until the MAF sensor released from the air intakes. I have to say this was done carefully but was still awkward. The electrical connector on the drivers side MAF released quite easily. The electrical connector on the passenger side MAF was a bit of a pig. getting access was not easy. Also found the cable to the MAF quite contorted. A walk away and return, few deep breaths and eventually got it released. (Will get some pictures up). I think Audi make these things deliberately difficult to get at.

Now carefully lifted the air intake away and covered the intakes. This allowed me to see the coolant temperature sensor more easily.

It was rather nice that the electrical connector release catch was facing the bulkhead . Again with a bit of patience i removed the plastic securing tab and I was able to rotate the sensor slowly in the housing allowing access to the electrical connector which could then be released.

So at this point i was able to carefully ease out the coolant temperature sensor. As you all said only a small amount of coolant escaped. Did initially wonder though how much was going to come out . The O-ring remained in position in the housing, I managed to extract it with my finger and gave the housing a bit of a clean. Removed sensor, clip and O-ring shown below.

Wrapped a cloth around the housing to catch any coolant and then inserted the new temperature sensor into position. Also ensured i followed the advice to rotate through 90 degrees compared to the original. Providing access to the electrical connector in the future. I also found it easiest to fit the O-ring into the locating position in the housing then push the new sensor home.

Then with a thread safety cord attached to the clip carefully pushed this into position. Please note this clip slips in a slot in the housing and sits over the top of the brass ring on the sensor preventing it releasing from the housing. Thread then removed.

I have decided whilst in here to replace the plugs so I have paused until i receive them so everything remains off the car.

Appreciate this has been done by many before but thought this may help in some way for others. I will get more details and pictures added to fill in any gaps.

Thanks again for your help. Steven

[Felix2566]

Nice write up, so much easier to work out how to do a job with a few decent pictures.

Thanks

[cover99]

Plugs changed over tonight. Will continue to update the post with pictures over the next few days. Cylinder 2 was a PITA with the hard piped breather and coolant lines. Anyway still to install the air intake etc.

Does anyone apply a thin coating of silicone grease to the MAF seals to aid assembly? Thanks again. Steven

[Felix2566]

Yes, I did put some grease on the seals to help it all fit together nicely.

I found the rubber grommets between the inlet manifold and the carbon plenum were missing, after replacing then the plenum is a much more snug fit. Worth checking yours are still there.

[cover99]

Okay here we go start of the plug replacement this will need adjusted but a start.

First I sourced some NGK plugs. I got these through ECP £136

The air intake was removed for access to the coolant sensor previously so this was my starting point looking at the engine bay.

Tools required:-

10mm socket with small extension for removal of coil pack securing bolts

16mm Spark plug removal socket and extension bar to achieve just over 200mm in depth to reach the plugs in the socket. Also a Torque wrench and standard socket set.

5mm Allen key is required for loosening the hard piped coolant line and breather pipe on cylinders 1 to 4 when you get there.

I started on Cylinder 8 and then worked back to Cylinder 5 nearest the oil filler.

1st release the electrical clip connecting the wiring to the coil pack (image is from Cylinder 7)

When connector has been removed then carefully remove the coil pack securing bolts with the 10mm socket and short extension. I personally loosened then removed by my fingers encase i dropped them from the socket and stored out of the way.

With the securing bolts removed i carefully extracted the coil pack from the plug using my hand. All eight released quite easily i did not require a coil pack removal tool.

I also inspected the coil pack connector for any debris, gave them a careful blow out and then stored carefully

Using the 16mm spark socket and extension carefully loosen the plug. I was fortunate and all 8 released without issue. If very tight apply some release oil and leave before trying to remove, as a little patience now can save alot of time should you force it. After initial release of the plug I completed the extraction by hand to ensure no pick up of the threads.

Carefully extract the plug.

Insert the new plug into the Spark plug socket and by hand carefully lower into the pocket and then locate by hand into position and hand tighten. When located fully in position using the spark plug socket tighten using torque wrench. When removing my plugs they released easily, I used the torque wrench to get an idea of how tight they were set at the last change and they looked to be around the 15nm ~. I believe by the book they should be 30nm.

Carefully insert the coil pack back into position, Using the 10mm socket insert both coil pack securing bolts. Hand tighten these and then give them a little nip up.

Repeat this process for cylinders 8 through to 3. Cylinders 2 and 1 require some additional adjustments to release the coil pack and allow access to the plugs.

To get access to Cylinder 1 and 2 i found it easiest to remove all three 5mm Allen head screws securing the hard piped breather and coolant pipes.

The two 5mm Allen bolts shown below are about 300mm back towards the bulkhead from the one above

Keep these 5mm Allen bolts in safe and in the order of removal as they are different lengths.
This now allows enough movement of the hardpipe to remove the coil packs past the pipe brackets on cylinder 2 and 1.
Complete the spark plug change on cylinder 2 and 1.

Re insert the 5mm Allen screws. I would advise all are left loose on each position to enable enough play to get them all inserted before tightening up with the 5mm Allen key.

--------------------------------------------
Re-assembly

I applied a thin coating of some silicone grease for the MAF seals before starting (Appreciated the advice).

I also inspected the air inlet for the grommets that should locate the guide pins on the intake, You can see the two holes on the cast in the above image, also checked not stuck to the pins on the intake. They were not as shown below. Must get these ordered.

[cover99]

Yes, I did put some grease on the seals to help it all fit together nicely.

I found the rubber grommets between the inlet manifold and the carbon plenum were missing, after replacing then the plenum is a much more snug fit. Worth checking yours are still there.

Hi Thanks for this. Where are the rubber grommets located on the plenum ? are they on the two external pins that you remove the 10mm flanged nut from to allow removal or should they be on the two plastic spikes that position the plenum?

I can see rubber grommets on the threads for the flanged nut but nothing on the two offset plastic spikes

Cheers

[Felix2566]

I was referring to the 2 spikes on the bottom of the plenum that locate into holes in the aluminium inlet manifold. Makes a massive difference to the security of the whole thing

[cover99]

Thanks for coming back to me on this. I will look to source these as they are not present on mine!!!! Sods law i had just installed it this afternoon. I do not understand how people do not take care with such items. Before I purchased the car this had only been service by Audi and one of our most reputable independents. Will go on the hunt for N10551301 Grommets, bet they are not £3.61 anymore and may possibly be NLA if its like many other things!!!

If you know where I can source these please let me know.

Many Thanks

[Felix2566]

Yes I find it frustrating too, same as missing or wrong hardware used to put parts back together.

I might have got the grommets from LLL Parts. That's where the parts diagrams come from.