Diesel noise while starting

[Lepr]

Hello everyone, I just recently bought an Audi A4 B6 1.8 T with 62k km.Initially the engine was very quiet but when I changed oil with Mobil1 ESP Formula M 5W40 and Mann 950/4 filter (we all know sludge problems of this car) engine started doing a "diesel engine" noise for the first second after cold starting.I traveled only 800 km with new oil and it all returns to normality after one or two seconds.What can the problem be? I apologize for any errors writing in english. Greetings from Italy.

 

[Olas]

I'd guess at sticky lifters tbh, if a hot flush/drain doesn't fix it they probably need replacing

 

[Lepr]

The strange thing is that all started coinciding with oil change

 

[tcp71]

Try to find a filter with a silicone anti-drain back valve. Not sure if the Mann you quoted has that.

 

[Olas]

Theres no need for an adbv even though the filter has one. In this application the filter sits 'right way up' and gravity keeps it full..
If the noise started when you changed the oil, change it again. Even within the same viscosity engines can show a preference for one fluid over another.

 

[yvon_la]

Might be filter didnt charge up .might want to go to your car mechanic and tell him or her to charge oil filter .normally it should but in some case it doesnt .hence the reason why it is preferable to precharge the oil filter .check online maybe your car have a specific way to bleed system to make sure oil filter thingy is charged up of oil.usually it is the adbv sticking or what pass for adbv.

 

[bigjl]

Similar problems used to occur with VAG engines back in the 90s if you used a non OE oil filter.

I would only consider it wear related if it had always done it.

I would only consider it oil related if i was using an OE filter.

I would change the filter to an OE VAG one.

Hydaulic tappets don't wear out during an oil change.

 

[Nick R]

Interesting. My focus (and my mazda for that matter) both sound like diesels at cold start. My understanding is it's due to the thinner exhaust manifolds, and late ignition timing right at startup, to light off the catalytic converters. I don't know if this is the same phenomenon that happens with your Audi, but it's worth considering.

 

[Clevy]

Originally Posted By: Nick R
Interesting. My focus (and my mazda for that matter) both sound like diesels at cold start. My understanding is it's due to the thinner exhaust manifolds, and late ignition timing right at startup, to light off the catalytic converters. I don't know if this is the same phenomenon that happens with your Audi, but it's worth considering.




Interesting.

 

[chrisri]

Originally Posted By: Lepr
Hello everyone, I just recently bought an Audi A4 B6 1.8 T with 62k km.Initially the engine was very quiet but when I changed oil with Mobil1 ESP Formula M 5W40 and Mann 950/4 filter (we all know sludge problems of this car) engine started doing a "diesel engine" noise for the first second after cold starting.I traveled only 800 km with new oil and it all returns to normality after one or two seconds.What can the problem be? I apologize for any errors writing in english. Greetings from Italy.

Is this belt driven engine.Maybe hydraulic tensioner?

 

[Lepr]

Originally Posted By: bigjl
Similar problems used to occur with VAG engines back in the 90s if you used a non OE oil filter.
I would change the filter to an OE VAG one.


This is possibile but many people use mann filters for their Audi without any issues,they have the same technical data of the oe vag ones

 

[Lepr]

Originally Posted By: chrisri
Originally Posted By: Lepr
Hello everyone, I just recently bought an Audi A4 B6 1.8 T with 62k km.Initially the engine was very quiet but when I changed oil with Mobil1 ESP Formula M 5W40 and Mann 950/4 filter (we all know sludge problems of this car) engine started doing a "diesel engine" noise for the first second after cold starting.I traveled only 800 km with new oil and it all returns to normality after one or two seconds.What can the problem be? I apologize for any errors writing in english. Greetings from Italy.

Is this belt driven engine.Maybe hydraulic tensioner?

This is an interesting point of view (belt was replaced also) but i can hear the noise from valve cover

 

[Olas]

You sure its not the injectors? They make a distinct ticking noise on the 20vt

 

[Lepr]

I don't think broken injectors tick only after cold starts...comparing the mann 950/4 and 940/25 filters the only difference is the "g" :
http://catalog.mann-filter.com/EU/eng/catalog/MANN-FILTER%20Katalog%20Europa/Vehicles/CARS%20+%20TRANSPORTERS/SEAT/Terra/1.4%20D%201%20W%20%28T1089%29/Oil%20Filter/W%20940~25;jsessionid=24239B647C7A9789B0DF3ED770C8EA2F

http://catalog.mann-filter.com/EU/eng/catalog/MANN-FILTER%20Katalog%20Europa/Hydraulics,%20Hydr.%20steering,%20Oil%20Filter/W%20940~5

What is this specification?

 

[aquariuscsm]

I wonder what oil was in your car before you changed it out? If you can find out,change it out with that (plus the filter that was previously on it) and see what happens.

 

[Lepr]

There were castrol edge 5w40 (I don't like it) and original oem filter (very small,it caused sludge in some cases). I went to the mechanic, he said that new oil is thinner,so it can cause ticking after cold starts (the old oil was very thick). He said it's not a problem,I can use the car whatever I want.

 

[aquariuscsm]

How come you don't like Edge? Sounds like it worked very well (experienced no startup noise with it). I'd go back to the Edge and OEM filter.

 

[Lepr]

Some people here in Italy experienced sludge on their VWs using castrol,old oil in my car was very thick due to contamination...the oem filter did't work well.Next oil change I'll switch to another oil,if startup noise continues I'll use another filter (Mann 940/25)

 

[Lepr]

Yesterday I changed the oil after 1500 km...it was fake.Now the engine is running very well with Fuchs TITAN GT1 5W40