TDI question

OHsnow!!!!!

I was looking at a VAG 1.9tdi and a mate said to look for pressure coming out of where you put the oil in (The lid to the top left of the VW badge on the engine cover). When I opened it with the engine running, there was pressure coming out and the lid was shaking when left on top.



Diesel engines are quite shaky and unrefined so is this normal or an issue like my mate said??

andyseadog

the shakeyness would be normal, thats just the engine vibrating.

not 100% sure by any means but shouldnt it create a vaccum and suchk your hand down rather than push against it?

OHsnow!!!!!

Not sure about the vacuum but there was a noticeable amount of pressure coming out. The lid was somewhat 'moving' or jumping (bit strong a word for it maybe) on top.

JerCotter7

A lot of older 1.9's have back pressure coming up their. Not sure exactly what it means. Just that the engine has a lot of wear and tear I suppose?

paddyp

Its called breathing, a good engine will suck in as much as it is blowing out so when you hover the cop over the filler is will go up and down in time with the engine. A bad engine will have a net positive pressure which mean the cap will be blown up contantly.

IrishMarket

Slow and steady wins the race!
:):)

sealgaire

paddyp wrote: »

Its called breathing, a good engine will suck in as much as it is blowing out so when you hover the cop over the filler is will go up and down in time with the engine. A bad engine will have a net positive pressure which mean the cap will be blown up contantly.

So there should be an equal amount of sucking and blowing?

Zubeneschamali

sealgaire wrote: »

So there should be an equal amount of sucking and blowing?

That old VAG TDi is the motor for you, so!

andyseadog

sealgaire wrote: »

So there should be an equal amount of sucking and blowing?

durty

taintabird

andyseadog wrote: »

the shakeyness would be normal, thats just the engine vibrating.

not 100% sure by any means but shouldnt it create a vaccum and suchk your hand down rather than push against it?

No it wont create a vacuum, there will always be a certain amount of blow when the engine is hot that's natural only with experience will you be able to tell if it is excessive. if there is excessive blow it can be an indicator of high levels of engine ware which could be a potential money pit.

Tea drinker

OHsnow!!!!! wrote: »

Diesel engines are quite shaky and unrefined so is this normal or an issue like my mate said??

Did your mate show you an example of an engine not exhibiting this behaviour? I'd ask him to, starting with his own.
I've never seen a 4 pot car engine not have blow-by
If it's like a hair dryer it's time to get out of dodge though! Busted seals and p1ssing oil would be other bad signs.

Nissan doctor

Pressure from the oil filler cap is perfectly normal. If there was excess pressure, often a sign of worn piston rings, the dipstick would blow out once the filler cap is closed.

I think your friend is misunderstanding something that his mates, brothers, cousins work colleague read on the Internet:rolleyes: