louder *CLACKING* when hot

[evangelos]

hello all,

i must first mention this engine has been running on veg all year round for close to 2 years. this setup is very good and veg temp is on the money.

when hot between 1k-2k there is a clacking sound as if when its first started in the winter. the sound goes away above 2k.

i have very strict veg procedures such as switching to veg when engine is hot, purge for 90 seconds driving and about 2 minutes driving on desiel before turning off engine - to be on the safe side i usualy turn on the ILH in the morning to heat the fuel a bit before injection. setup is tank in engine bay, VegMax filter, FPHE, vegtherm, Injection Line Heaters ; there is no weakness in the system that can allow coolant to mix in with the veg.

there is no air in the lines, timing is at .94mm , diesel oil freshly changed.

asside that the engine runs great but the noise is present on veg as well as diesel; is this a sign of injection or nozzles change?


TIA

Evan

[madmedix]

I've got this too. Usually after a run of 20 to 60 km or so..(no S/WVO, just petro-dino)..So I'll lurk here for an answer too  

[jtanguay]

i've got this problem too.  sounds like something is banging around in the head.  goes away at approx 2k rpm... i'm not worried as it's been doing it for a long time now and no issues.  goes away when the engine is hot.  i'm hoping its just a sticky lifter or something like that.  .94mm timing is pretty retarded... i'm running about 1.06mm right now and she starts so good!  although it does sound pretty loud at this setting  :lol:

switching to a single grade 40w oil would probably get rid of the noise, but on a really cold day the motor probably wouldn't start right.  my guess is just the really thin oil film between parts in the head, etc.  

do any of you have any oil pressure gauges to measure readings?  i have yet to install mine...  :oops:  :roll:

[Black Smokin' Diesel]

I have one injector knocking from idle to about 2500rpm then it goes away. Sometimes (read: very rarely) it doesn't even knock.

[evangelos]

mine is not excessively loud at startup but i think its because i warm the fuel with the inj line heaters.

i was not able to increase the timing past .94 ;  not that this means anything but the engine is from the early passat's without the LDR so i dont know if these had any limitations.

i forgot to mention that it misfired once while coming to a stop; but only once.

i will monitor it as the weather temperature drops.

thanks for all the input.

evan

[madmedix]

Not trying to hijack your thread Evan, but:

I installed a good oil pressure guage last week:

Cold idle - 80
warm idle - 20/25
5th gear @ 100km/h: 40 psi.

This is at an outside temp of 14c. I'm sure that cold idle pressure will climb when it drops to about 0c or so. I only get this "clack" after a good highway run (15w40 GTX) and I'm thinkin' #4 injector may be leaky..I dribbled simple clean around the injector seats to clean this previously (hate to say it: neglected) engine to clean out crap and after a drying spell I noticed what may have been bubbles-but-not-really around the 5 o'clock position of injector #4.
Evan, any of your injectors do this?

Andy

[evangelos]

hi andy,

i have not tried this but all injectors look dry but that can be decieving.

the #4 injector is the one furthest from the timing belt right?

i guess can add some soap around the injectors and see what happens.

thanks

[madmedix]

Yeah, that's #4. She's got over 400k on her and I don't think she's been touched other than the timing belt. I've been eyeing Vince's how-to on injector work....hopefully she'll get me through the winter as I don't have a garage.

Good luck
Andy

[evangelos]

can post a link to Vince's how to because i do not spend much time one this or any other forum. i shamefully visit this forum when i have problems as i dont have much experience on mechanics or vw's just running my vws on veg.

thanks,

evan