Small oil leak from just above the oil filler plug

If the spark plug is oil fouled, you either have leaking valve seals, or bad piston rings. Bad rings would be accompanied by excessive blow-by. With the engine running, remove your oil filler cap. If there is air pulsing out of the filler tube, it your rings. If not, it is your valve seals.

Use more pressure, more elbow grease, put more force on it, use a bigger wrench or ratchet. Make sure its indeed the filler plug.

There's a check valve in the air line between the compressor and tank that sounds like it's failed.

Why do you want to add it? Wipe the dipstick on clean white paper towel or cloth. If there are no leaks and the colour is still fairly bright it should be ok. If there are no leaks and the transmission is slipping it needs to go to a dealer or tranny shop.

Sounds like it could be the oil pressure sensor. Very common for them to leak on older vehicles.

I’m happy to assist further over the phone at https://www.6ya.com/expert/jeremy_d728a59f986299fa

there is a small filler neck in frt. of the trany , with red cap on it. Brake the cap , there will be a plug under.
Proccedure : engine on idle , take of plug at the bottom of trany oil pan(with engine on idle!!!!! , if engine off , fluid will leak out) , use transfering pump to pump oil in to filler neck untill it starts leaking from bottom plug , wiat till it only drips , put bottom plug back in and torque it. Now you can shut engine off and seal filler neck.
Use only approved trany fluid .This trany takes syntetic fluid.

Hi,

Just checking.... it is a manual gearbox?

You may need a special tool for the drain plug and a 17mm allen key for the filler (some use the special drain tool for the filler as well)

The drain plug is located under the diff housing.

The filler plug is located on the left (nearside) off the gearbox (look to the left of the hole and you can see the 17mm hex filler bung).

Check you can undo the filler bung, then drain the gearbox oil.

Refit drain bung and fill gearbox through filler/level ********* until gearbox oil is up to the level of the filler bung.

Refit, test drive, check for leaks and retest level again when cold.

Cheers,

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hi,not a hard job to do,take the bike for a ride to warm the oil up before you drain it,it makes it a lot easier draining the oil as cold diff oil is quite thick and the hondas only have a small drain hole,get the bke sitting level i normally use a small car jack under each side of the bike just to hold it level,undo the lower drain bolt(about a 10 or 12mm from memory)drain all the oil out into a clean container,inspect the oil for any shiny bits,you shouldnt see any foreign bits on a bike this age though,if you do get the bike looked at straight away,there are a lot of bits and pieces inside that diff and they are very expensive to repair,once you have drained all the oil out replace the drain plug making sure it is tight(but dont strip the thread by over tightening it)undo the filler bolt(large plug type bolt above the drain plug)and fill with a good gear oil(from memory honda use a 80/90w oil)fill the diff to the bottom of the filler plug just untill the oil starts to dribble out of the filler hole,this is the correct level and i think from memory they hold about 280-300mls,a 1 litre bottle does 3 changes..dont forget to put the filler plug back in and tighten it...hope this helps...cheers ian

Transmision oil for 2001 Audi A4 1.8 l turbo:
Manual gearbox (5 speed):
- Capacity = 2,25 liters
- Specification: Gear oil SAE 75 W 90 (synthetic oil)
Part number G 052 145 S2 (1 liter)
- To check oil level, unscrew oil filler plug placed on the left side of the gearbox in front and near of transmission axle, using an Allen 17 mm key.
- Check oil level with locally manufactured tool, e.g. a piece of angled wire.
- Specification: oil level 7 mm below bottom edge of oil filler hole.
- Install oil filler plug, tightening torque = 25 Nm.
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possibly the oil pressure sending unit- looks like a small spark plug screwed into the engine with one wire going to it