hud "warning low oil pressure" & "stop engine immediately" cam chain tensioner

[largebeardy]

hay guys im hoping some one can help me out.
a couple of weeks ago i was driving my 2006 gti 2.0L fsi BWA and had been giving it a hard time and it was waaaay overdue for a service and i got a hud warning with beeps saying "warning low oil pressure" stop engine immediately" and the car went into limp mode straight away. i pulled over straight away (very dangerous hills road) so after a second i tryed to move it about 2 meters ahead to a safe spot but a heap of warning bells ran so i turned her off and with the help of my friends (where i was headed 200 meters away lol) pushed it off the road.
checked the oil ( there was none) and its never lost oil before so i started searching under & around the car to see no obvious signs of where it lost it.
so next morning after organizing a trailer and car to tow it home ( 2 hours drive away lol) i went down to the car and checked the oil again and it was all there which is my current concern......i started the car for 5 seconds to see if the engine was blown but apart from a waaaay louder cam it fired ...so i researched all i could and came across a " carbon build up oil catch blocked " article on another forum and the symptoms + severe lack of maintenance ( ive been building another car for a while and had planned on taking the gti off the road to bring it back up to scratch as soon as i had registered the other one. but no money and awaiting surgery to repair severed tendons in 3 of my fingers on my left hand is an issue) so i get all the stuff to change the oil and drop the sump to find the oil pick up is only slightly blocked but i found a big chunk of plastic debris in the pick up ......
so research and find info on the cam chain tensioner ...so ive pulled it all apart and it has indeed failed dramatically and after much painstaking recovery of all the pieces of plastic and aluminum to completely jigsaw the tensioner together again...
now i have limited mechanical knowledge and have spent everything and begged n borrowed to by the other tools i required to do this repair and have got a couple of other tools to help me do this.
i got the engine to tdc and the cams line up so i dont think its skipped and i bought an inspection camera to check for debris but that has just brought up other questions i have about the car and if the previous owner had mods don which would make sense cause well i dont know if all gti's go as hard as this thing dose cause ive bettered my mate in his 90k brand new worked off its head holden v8 or if they are governed ( i had it up to 280km ..it got there fast as and didnt struggle in the slightest)
so i put the inspection camera into each piston to check for any damage and the pistons are flat ( aren't they supposed to be crowned) and now my concern is should i take the head off ( i did engineer a cam locking jig) and im worried about the tensioner failing due to the low oil pressure not causing it as in what else should i look for ( and i did check the oil pump chain/and toothed wheels (all perfect) + chain tensioner.
so long of the short should i just put it back together and see how i go or is there other things i should cheak/ do while its half torn down ? ( and yes im doing cam follower and cleaning all the carbon deposits / cam chain and tensioner) as getting running is a priority so my missus can get to work (4 way half hour trips cause of split shifts and no public transport where we are she has been borrowing her dads car) and i can finish the other car.
and if anyone can recommend a none vw stealership supplier of OEM parts cause they will take half a week to get them from stealership so if i can get them cheaper it would save my fat behind.
any knowledge and help would be very much appreciated.

[Umai Naa!!]

If the cam chain tensioner has failed, I'd be pretty certain the valves have hit the pistons.

[largebeardy]

thanks for replying.
so should i take the head off and take it to get checked or replace it ? and what sort of damage should i look for?
there did seem to be impact divets on the pistons when i put the inspection cam down the spark holes.
thanks heaps for your help.

[largebeardy]

or should i pull the engine and rebuild?

[JustCruisn]

You may have nothing to worry about at all. It is possible that you had low oil, and given these 'hills' where you were likely flogging the **** out of your car the cornering forces have caused oil to move away from the pickup and caused the low oil alarm. When you came back things had cooled and the oil had then run from the engine galleries etc back to the sump, enough to show on the dipstick.
Funny about the tensioner, if it had gone totally you probably would have had a much bigger mechanical issue earlier, not this low oil pressure.
Have you actually done a simple oil change or even a top up on level ground and then started it ?

[largebeardy]

i usually keep the oil topped right up ( had checked it the day before and it was at the highest point) and when i checked it after i stopped the car it wouldn't even wet the lowest part of the dipstick and when i checked it again the following morning it was right back up the top so i kicked it over and let it run for between 5-10 seconds to see if it was blown which it did fine, just a terrible noise from what i know now was the tensioner.then towed it home bought all the stuff for oil change and to drop the sump before i did ( to check if the pickup was blocked) then found the plastic shards and went on research to find out where they would have come from.and went straight to tearing the engine down. and finding all the pieces of broken tensioner (luckily it was 3 big pieces of plastic and 1 piece of aluminum plate) so i read up on doing the tensioner and mad a cam locking tool and now have that in place with all the front end off for easier access and thought id check other possibilities before putting it back together. the big dints on a couple of the pistons is worrying me though plus they all have a real lot of small chips in them and it did have a very loud diesel sound for a long time.so im not sure if i should just do the head while its broken down this far or not. i dont have a diagnostic tool or cable for the rostech system nore a service manual and my knowledge is some what limited (i do my best to teach my self as i go) so im not sure where to go from here plus i live in the middle of butt #@$@ nowhere and there is stuff all decent mechanics up here that i know of who i could get to come out and help diagnose it with me ( couldnt enen find one outside of vw to do a dsg service al of em where like "nope to hard" so ended up doing it my self ...painfully lol) so your input is really appreciated.

[largebeardy]

update
so ive figured out how to upload photos and took a shot of the 2nd & 3rd cylinders with inspection cam and as u can see the valves from the cam closest to the firewall have obviously hit so i probably need a new head ? and is it likely that ill have to change pistons ?

[largebeardy]

so next question dose anyone know where i can get a reasonably priced new head or a reputable reconditioning group ?

[fransnz]

Are you taking about the marks on the pistons?
The marks look like machine/vale clearance slots in the pistons.
If the valves hit the piston it normally stuff the lot.
Pull the head and check, it may not be as bad as you think.

[largebeardy]

thanks fransnz im half way through removing all the elec and cooling system components and about to start removing the inlet manifold and injectors ....taking me a while though cause i am tagging and photographing it all as i go so ive got reference to put it back together lol.so maybe they r supposed to be that way? hoping

[Passat my07]

If the valves hit the pistons it will leave a mark where the carbon is scraped off the piston. If the valves are bent you just get the head reconditioned.
I'd fit the chain tensioner and time the cams. Then I'd do a leak down test or a comp test and see if the valves are leaking. Saves removing the head if it doesn't need to be removed.