Losing oil pressure in Engine

[Davies1992]

Audi A3 2.0TFSI 2009 - Engine Code CCZA

I was driving home one night when suddenly EPC light flickered on and stayed off mainly then noticed a weird noise coming from the engine bay area, got home and left it until morning.

Took the car into my local garage and he put it on his diagnostic machine and got a code from chain/cams I was told. So he opened the engine area up and noticed my chain was loose so advised I should get it done witch I did and got a full new chain kit with tensioners etc he took it for a test drive and said it was nice and quiet and on the 4th test the original noise came back and he also noticed the ECP light flashed quick and just stayed off. Mechanic then said his next step would be to do an oil pressure test witch on my vehicle was told the idle pressure should be between 17-30 PSI and mine was idling at 55 PSI and then at 2000 revs should be between 39-65 PSI and mine was 55PSI the same but then started to decrease and went down to 45PSI and he switched it off and it was losing oil pressure. 
 

He then said that there’s a problem with the engine as it’s losing oil pressure meaning the chain and tensioner is not keeping tension. I was then told that it could be either the oil pump in the sump or inlet cams, I bought the oil pump as was a bit of a cheaper option had it fitted and new oil back in etc and same thing again on the test ride after about 3-4 miles he said the noise came back again!! The only thing he can advise now is to do the inlet cams witch are expensive and I have already spent £720 on parts & labour already. 
 

Has anyone else ever had a similar issue or anything? 
 

Thanks Luke 

[cliffcoggin]

Luke.

I am having a hard time understanding a connection between a loose camchain and low oil pressure. I suspect these are two different unrelated problems.

If we assume the new camchain is fitted correctly yet you still have a noise and low oil pressure then the problem must lie elsewhere. My first thought would be worn big end bearings or main crankshaft bearings, which rarely fail nowadays unless the oil and filter changes have been neglected.

The oil pressure figures you quoted are puzzling. The high pressure at idling speed suggests a pressure relief valve fault or a blockage in one of the oil galleries. That the pressure drops away at higher engine speeds is worrying. One explanation for that would be worn bearings as I mentioned above, though I have to stress that is only speculation at the moment.

Some more information might help. What is the mileage of the car? Have the oil and filter been changed at the right intervals? Have you used cheap or substandard oil filters? (The oil filter often contains the pressure relief valve.)

[Magnet]

Hello Luke,

To try to keep this as brief as possible. 
Was the engine oil up to operating temperature when the oil pressure was checked? I.e. after a run of at least 5 miles. If not, all the readings are really meaningless. Pressures will drop as the oil heats up - that is normal, but as said, the readings will only be meaningful if carried out on an oil-is-hot engine.

Get them to take the car on at least a 5 mile run then do the pressure test again. Please do not assume that the engine oil is up to temperature once the coolant reaches normal - this is a totally incorrect assumption.

Perhaps you would let us know how you get on.

Kind regards,

Gareth. 

[Stevey Y]

1 hour ago, cliffcoggin said:

Luke.

I am having a hard time understanding a connection between a loose camchain and low oil pressure. I suspect these are two different unrelated problems.

If we assume the new camchain is fitted correctly yet you still have a noise and low oil pressure then the problem must lie elsewhere. My first thought would be worn big end bearings or main crankshaft bearings, which rarely fail nowadays unless the oil and filter changes have been neglected.

The oil pressure figures you quoted are puzzling. The high pressure at idling speed suggests a pressure relief valve fault or a blockage in one of the oil galleries. That the pressure drops away at higher engine speeds is worrying. One explanation for that would be worn bearings as I mentioned above, though I have to stress that is only speculation at the moment.

Some more information might help. What is the mileage of the car? Have the oil and filter been changed at the right intervals? Have you used cheap or substandard oil filters? (The oil filter often contains the pressure relief valve.)

Hi Clifford, a lot of the petrol engines have Hydraulic cam chain tensioners, which when the oil pressure starts to slide down is what causes the chain to rattle, my guess is that the cams are not holding the pressure and if its creeping down that fast on a warming engine it would be stupid to run it until the cam chain jumped a tooth, then its game over.

Steve.

[cliffcoggin]

3 hours ago, Stevey Y said:

Hi Clifford, a lot of the petrol engines have Hydraulic cam chain tensioners, which when the oil pressure starts to slide down is what causes the chain to rattle, my guess is that the cams are not holding the pressure and if its creeping down that fast on a warming engine it would be stupid to run it until the cam chain jumped a tooth, then its game over.

Steve.

Thank you Steve, I was unaware of that. It's an innovation that has passed me by in the years since I regularly took engines apart. (Having recently changed to an electric car I doubt I shall ever see a big end or a gudgeon pin again.) Am I right in assuming a hydraulic tensioner is supposed to take up the slack as the chain stretches?

[Stevey Y]

18 hours ago, cliffcoggin said:

Thank you Steve, I was unaware of that. It's an innovation that has passed me by in the years since I regularly took engines apart. (Having recently changed to an electric car I doubt I shall ever see a big end or a gudgeon pin again.) Am I right in assuming a hydraulic tensioner is supposed to take up the slack as the chain stretches?

My god Cliff I can't believe you have gone over to the Dark Side what bought that on, were you bitten by a technophobe when you went shopping. and yes the oil pressure keeps the chain tensioned and accommodates the slack as the chain wears, I only became aware of this when a friend did his Polo oil change and left it to drain overnight when he tried to start it the engine just turned and kept firing past an exhaust valve or two, turns out the tensioner only holds pressure for about an hour whilst draining the oil and the cam timing had slipped.

Steve.

[cliffcoggin]

The answer is far more mundane Steve, it was a matter of simple economics. My wife found the A3 uncomfortable so all journeys together were in her Yeti. That left me running a moderately powerful 5 seater with me as the only occupant, doing individual journeys of less than 50 miles that totalled less than 2000 miles per year. With a possibly expensive gearbox repair in the offing it made no sense to retain it any longer.

So I now drive what I call a Noddy car (Smart EQ). It's not very comfortable and it looks ludicrous, but it's great fun to drive. No road tax, insurance is two thirds of the A3, and only 3 pence per mile fuel cost if recharged overnight on cheap rate electricity. In the light of recent events in Ukraine it looks to have been a good choice.

Edited March 4, 2022 by cliffcoggin
double word

[JRHILL1]

I've just had this on my A4. The non return valve (apparently a spring and ball bearing)was leaking very slowly and released pressure on the timing tensioner. Local garage drained oil to do another job involving oil cooler, left it standing over weekend and when they started it up after completion, the timing jumped 3 notches and the subsequent repair (for which they deny all liability) was in excess of £2k. 

This can apparently happen if the car is not started for a while, allowing oil to leak and de-pressurize the valve. Of course, there's no way of knowing if you have a worn valve, so imagine parking at an airport for a couple of weeks, turning your engine over and immediately needing a rebuild.

Hope this makes sense...I'm not a mechanic. 

[Stevey Y]

8 hours ago, JRHILL1 said:

I've just had this on my A4. The non return valve (apparently a spring and ball bearing)was leaking very slowly and released pressure on the timing tensioner. Local garage drained oil to do another job involving oil cooler, left it standing over weekend and when they started it up after completion, the timing jumped 3 notches and the subsequent repair (for which they deny all liability) was in excess of £2k. 

This can apparently happen if the car is not started for a while, allowing oil to leak and de-pressurize the valve. Of course, there's no way of knowing if you have a worn valve, so imagine parking at an airport for a couple of weeks, turning your engine over and immediately needing a rebuild.

Hope this makes sense...I'm not a mechanic. 

Its not a leaking valve problem they all do it if you let them sit for to long the oil in the valve syphons back.

[geoffrey]

2 hours ago, Stevey Y said:

Its not a leaking valve problem they all do it if you let them sit for to long the oil in the valve syphons back.

Hi Steve,

if as you suggest the oil naturally syphons back after a period of time are you implying that they automatically self prime?

it would seem a reasonable assumption to believe that they self prime.

to  take that assumption one step further requires the oil pressure on the said valves  to be instantaneous.

any lag would leave the cam chain lacking tension allowing tooth jump and the resulting consequencies.

Does Audi have a procedure to deal with draing of oil and restart after refilling with oil?

my usage leaves me with my car standing in the garage up to a week at a time should i be worried, i cannot afford a £2 k bill.

JRHILL1 has my sympathies

[Stevey Y]

19 hours ago, geoffrey said:

Hi Steve,

if as you suggest the oil naturally syphons back after a period of time are you implying that they automatically self prime?

it would seem a reasonable assumption to believe that they self prime.

to  take that assumption one step further requires the oil pressure on the said valves  to be instantaneous.

any lag would leave the cam chain lacking tension allowing tooth jump and the resulting consequencies.

Does Audi have a procedure to deal with draing of oil and restart after refilling with oil?

my usage leaves me with my car standing in the garage up to a week at a time should i be worried, i cannot afford a £2 k bill.

JRHILL1 has my sympathies

Hi oil pressure is virtually instant it has to be or the big ends will knock, I don't know what milage you have done but if you have never changed the chain/tensioner it is of the old variety, most hydraulic tensioners have a spring inside which holds the position of the piston against the chain for a couple of seconds until the pressure from the oil arrives, VAG in their infinite wisdom chose to use another design which uses a ratchet system similar to a rack on steering, the idea is that the ridges on the piston when the oil pressure drops engage with a small male ridged pawl that sits above it and stop the piston moving back maintaining the pistons position against the chain mechanically, my guess is the pawl on your unit has failed and stripped its teeth away allowing the piston absent oil pressure to go further into the tensioner housing therefore making the distance to engaging with the chain far greater than normal and allowing it to jump, apparently this is quite a common problem and guess what VAG now do an upgraded version with a spring in it.

Steve.

[geoffrey]

18 hours ago, Stevey Y said:

Hi oil pressure is virtually instant it has to be or the big ends will knock, I don't know what milage you have done but if you have never changed the chain/tensioner it is of the old variety, most hydraulic tensioners have a spring inside which holds the position of the piston against the chain for a couple of seconds until the pressure from the oil arrives, VAG in their infinite wisdom chose to use another design which uses a ratchet system similar to a rack on steering, the idea is that the ridges on the piston when the oil pressure drops engage with a small male ridged pawl that sits above it and stop the piston moving back maintaining the pistons position against the chain mechanically, my guess is the pawl on your unit has failed and stripped its teeth away allowing the piston absent oil pressure to go further into the tensioner housing therefore making the distance to engaging with the chain far greater than normal and allowing it to jump, apparently this is quite a common problem and guess what VAG now do an upgraded version with a spring in it.

Steve.

thanks for that reply Steve.

so this original idea of oil draining back under non usage is a non starter as the chain is kept in tension under the back up systems .

1/ spring valve

or

2/ ratchet system.

that removes my worries about non usage.

sorry if i seem pedantic

KEN

 

[Stevey Y]

4 hours ago, geoffrey said:

thanks for that reply Steve.

so this original idea of oil draining back under non usage is a non starter as the chain is kept in tension under the back up systems .

1/ spring valve

or

2/ ratchet system.

that removes my worries about non usage.

sorry if i seem pedantic

KEN

 

Hi Ken, totally correct as unfortunately this seems to be an ongoing problem with VAG engines from late 2007-2014 they really should have done a recall but were just content to keep selling the new and improved tensioner, I am going to see the garage I use for cam belts and clutches he has over forty years knowledge of dealing with this type of thing and will no doubt give me his honest no nonsense opinion on what happened in your case.

Steve. 

[JRHILL1]

My garage told me that the tensioner is oil pressurized and the pressure is maintained by a non return valve when the engine is not running. If the valve is worn or damaged (my engine has covered 160k miles) then oil can/will leak and therefore lose pressure...how much and over what time scale being dependent on the severity of the leak, which seems plausible. My initial problem was oil in cooling water, suspected during service as oil cooler leaking but could not fit me in to do the job before a planned trip, so to be on the safe side I trusted another outfit to do it. I drove it there performing perfectly. They completed the job and after a few seconds running it went BANG! My usual garage, whom I've trusted for 30 odd years, towed it in and sorted it, but I had some sleepless nights wondering if it was new engine or scrap time.