FSI Diesel start up x oil viscosity

J

james.mckenzie

Member
Hello all,


Hoping to take the plunge into A2 ownership again. TDi90 last time. FSI this time. I've been around the forums a few times but just wondering what the occurrence of the proverbial diesel clatter on start-up is amongst the group here?

Is it every morning on daily use?
Is it only occasionally on start-up with daily use?
Is it only after car has sat for [period] time?
Does it happen on cold and hot starts?

And secondly, has anybody had any success with muting and or solving the startup noise? What did you try?

Would changing the oil viscosity/weight help? HAs anyone tried this?

Many thanks,

James
 
Hello,
I have not owned an FSI. 😞
I know nothing about the engine layout. 😕

My generic thoughts are, replace each and every one of the temperature sensors relating to engine management.

Then drop the sump and replace the o-ring on the oil pump pick-up tube (if there is one to be replaced).
Because the FSI operates at 90 to sometimes 110° centigrade, I would replace every seal and pipe that related to air intake and vacuum lines, as well as the spring clamps. My aim? To provide engine the best chance of running how it was designed to with all seals, gaskets, hoses, o-rings and sensors sorted.
I give myself a budget of £500 to do this.
😁👍
You can change the grade of the oil but I would like to gain some indication of the health of the engine before using thicker oil as a "cure all".
  • Service history
  • Receipts for new part stretching back over the cars history
  • Compression test
  • Colour of the oil at present
  • The emission test results at last MOT
  • VCDS scan
  • Test drive using all the revs
  • Watch and listen to the engine at tick over
  • Compare your car with other FSI cars for sale in your local area
Good luck 🤞
 
james.mckenzie said:
Hello all,


Hoping to take the plunge into A2 ownership again. TDi90 last time. FSI this time. I've been around the forums a few times but just wondering what the occurrence of the proverbial diesel clatter on start-up is amongst the group here?

Is it every morning on daily use?
Is it only occasionally on start-up with daily use?
Is it only after car has sat for [period] time?
Does it happen on cold and hot starts?

And secondly, has anybody had any success with muting and or solving the startup noise? What did you try?

Would changing the oil viscosity/weight help? HAs anyone tried this?

Many thanks,

James
Click to expand...
Mine does, and always has. I have assumed it is because the oil drains from the hydraulic lifters, when the engine is off. Only for a few seconds.
Personally, I wouldn't mess about with oil. Use the best oil you can afford, and always to spec.
I only use this.
Mac.
PXL_20240407_152029845.jpg
 
Hi

We know engines need air and fuel to get the starting mixture right.
They take that air fuel ratio depending on certain peramiters set mainly by various temperatures. The outside air, engine bay sensors and exhaust gasses.

Off the top of my head
  • Intake air temp [MAF)
  • Coolant temp
  • Radiator return flow temp
  • Fuel temp
  • Lambda temps
The ECU can read atmospheric pressure and tally it with intake manifold pressure. (MAP)

If the fuel injectors & HT leads or coil packs are new the only other factor to maintain is air.

Air management in the engine is via hoses and tubes etc.
As long as they are sealed tightly you should be running a nice healthy engine.

I would like an FSI to work on to improve my understanding and validate what I am saying here.

The FSI, is a brilliant engine. :)👍
 
PlasticMac said:
Mine does, and always has. I have assumed it is because the oil drains from the hydraulic lifters, when the engine is off. Only for a few seconds.
Personally, I wouldn't mess about with oil. Use the best oil you can afford, and always to spec.
I only use this.
Mac.
View attachment 122171
Click to expand...
Hi,

Question, do the hydraulic lifters run at twice that of the engine revolutions?

If the answer is, yes, I would expect
  • The hydraulic lifter noise to be double that of an engine at tick over
Is this what you experience @PlasticMac ?
 
PlasticMac said:
Mine does, and always has. I have assumed it is because the oil drains from the hydraulic lifters, when the engine is off. Only for a few seconds.
Personally, I wouldn't mess about with oil. Use the best oil you can afford, and always to spec.
I only use this.
Mac.
View attachment 122171
Click to expand...
What cadence is the noise Mac? Every morning? Every startup regardless on elapsed time? One every so often? How long have you had her and how many miles? How many owners before you?
 
Mine too rattles for a second or two on start up. I think it’s normal for the FSIs, there’s a number of posts on here dating back well over 10 years commenting or asking about the noise, and the consensus is that they all do it and it’s nothing to worry about.

For me, it doesn’t happen every time, but certainly the vast majority and seems to happen when the engine is hot or cold
 
Indi said:
Mine too rattles for a second or two on start up. I think it’s normal for the FSIs, there’s a number of posts on here dating back well over 10 years commenting or asking about the noise, and the consensus is that they all do it and it’s nothing to worry about
Click to expand...
yes, I've seen the old posts but just wanted to touch base and see what cadence peoples cars do it now, if anything has changed, if there's some new information and if oil viscosity plays into the mix.
 
Hi,
Can we track down a cross sectional diagram to indicate that oil in the hydraulic lifters can drain out?
Logically, it's highly likely to be caused by a componant that has worn, Audi would not have designed their FSI to perform in this way. The up side is, it must be repairable. 😉 👍
 
james.mckenzie said:
yes, I've seen the old posts but just wanted to touch base and see what cadence peoples cars do it now, if anything has changed, if there's some new information and if oil viscosity plays into the mix.
Click to expand...

Yeah fair enough!
No new info as far as I’m aware, but I had heard of the noise before getting mine so never looked into it or thought much of it.

Further background for comparison, mine is on about 115k miles, I’m the 12th owner and will do it sometimes even if the engines only been stopped for 10/15 minutes as far as I can remember
 
Hi Indi,
Is the diesel knock noise running at crank shaft speed or hydraulic lifter speed?
 
Mine was on just over 40,000 when I got it, and it did it then, still does. Just started mine, about two hours after it was out and about and the noise lasted between one, and two seconds, no more. Dropped stuff off at the tip, restarted after a couple of minutes, no noise.
It worried me at the start but once I learned that it was, or seemed to be, the norm, I worried no more.
If it is oil drain, then some sort of check valve would fix it, theoretically, but there's, probably not enough head in a gravity drain, to open a check valve, which would need to be spring loaded.
If you believe some posts, there's a lot more to worry about with an FSI. My driving licence for one!
Mac.
 
PlasticMac said:
Mine was on just over 40,000 when I got it, and it did it then, still does. Just started mine, about two hours after it was out and about and the noise lasted between one, and two seconds, no more. Dropped stuff off at the tip, restarted after a couple of minutes, no noise.
It worried me at the start but once I learned that it was, or seemed to be, the norm, I worried no more.
If it is oil drain, then some sort of check valve would fix it, theoretically, but there's, probably not enough head in a gravity drain, to open a check valve, which would need to be spring loaded.
If you believe some posts, there's a lot more to worry about with an FSI. My driving licence for one!
Mac.
Click to expand...
Thanks Mac. Agreed on other issues. Ive been reading about fuel filters, fuel pumps, CCCU , Pro Boost, Intake flaps and vacuum valves, death pipes and the kitchen sink.
 
My FSi is at 148k and has always had the intermittent diesel noise at start up. It’s run on the best fuel and oil and the noise is not getting any worse. Like you I’ve read all the strings on this and it seems to fall into the salesman’s category of, they all do that. I’ve stopped worrying about it a very long time ago.
 
They will all do it if no one knows how to or even attempts to fix the issue 😂

Unfortunately, this adds to the extensive list of documented negatives and, as a result, can put individuals off this car. This is problematic because it means that FSIs are less popular choice.
 
Last edited by a moderator:
rotifer said:
They will all do it if no one knows how to or even attempts to fix the issue 😂

Unfortunately, this adds to the extensive list of documented negatives and, as a result, can put individuals off this car. This is problematic because it means that FSIs are less popular choice.
Click to expand...
Yeah I thought I’d seen posts about it from when the cars were new, but having just looked I can’t see anything pre 2010…
That doesn’t bode well 🫤

I saw one post about another fsi engine (1.4 fsi I think) saying it was normal and said so in the manual, I’ll have a look and see if I can see anything…

The later FSI engines in the mk 5 golf and such have a rattle commonly attributed to the timing chain tensioner, but this isn’t the case for our FSIs as the BAD engine found in the A2s is belt driven, and doesn’t have a hydraulic tensioner.
 
All engines have some type of noise on start and some when running regardless of the fuel or injection type. What is more important is that the correct grade and specification of oil is used along with a quality OEM filter and that they are changed regularly.

For many years I also add treatment to the oil and my preferred choice is Lucas Oil products. In particular this is used in my A2...


www.lucasoil.co.uk

Lucas Oil UK - Pure Synthetic Oil Stabilizer

Use Lucas Synthetic Stabilizer in new equipment which requires synthetic oils or any equipment that needs enhanced performance. It can also be used to protect new and used Heavy Duty and High Performance transmissions, gear boxes and engines. Controls heat and wear in motorcycles, air-cooled...
www.lucasoil.co.uk www.lucasoil.co.uk

I have nothing to do with Lucas Oil just my experience in using this product.
 
rotifer said:
They will all do it if no one knows how to or even attempts to fix the issue 😂

Unfortunately, this adds to the extensive list of documented negatives and, as a result, can put individuals off this car. This is problematic because it means that FSIs are less popular choice.
Click to expand...
If you're after a reason not to have an FSI, there are many more, (but not, necessarily good), reasons than "the start up rattle"
FSIs are not for everyone, which is just as well, as there's not enough to go around.
Mac.
 
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