huntings

2004 Audi A4 1.8L +137k miles:

-It takes a long time to warmup
- when warming up it sits at 1500rpms for 5 min then comes down to 500rpms
-sometimes while stopped at a light it starts to vibrate slightly a little more and then goes back to smooth running.(also does this randomly while driving)

any thoughts???

W261w261

What is the temperature gauge doing after a cold start? It should be up to temperature within say 3 miles at moderate speed. If it takes a loooong time to come up it's probably the thermostat.

the_duke

The vibration at stop lights is caused when the SAI pump kicks in. Over the years they have smoothed it out but it was still pretty new technology in 2004. I have a 2000 Passat 1.8t and it get's warm pretty quickly when driving it. However if I just let it idle it takes forever to warm up.

huntings

I was thinking I can replace the thermometer and the SAI pump so I i can have smooth running and help reduce cold start warmup time.

Thoughts??

the_duke

That just how the SAI pump works. Replacing it won't change anything unless something is wrong with the system. However doing a coolant flush and fill with new coolant and also replacing your thermostat might help. Bleeding the air out of the system is a pain in the ***. I highly recommend a vacuum coolant fill tool. Makes a pain in the *** job easy.

https://www.ecstuning.com/Search/Sit...ill/ES2712734/

huntings

Ok so I cant change anything about the loudness of the vehicle during that warm up cycle?,
Although I will do the coolant flush.

the_duke

Ok I give up. Loudness? Where did that come from?

John535is

Is the supply air pipe from the SAI still attached?
On my Allroad the plastic pipe from the pump fell off. (its at the back of the engine on the 2.7T so not obvious and it does not have a clamp).
Real 'loudness'! sound and of course extended running as it was effectively pumping air into the engine bay, so check the hose is still attached.