Hydraulic tappets will not pressurise

[yorky19640]

Have recently replaced a faulty oil cooler on my VW Passat TDI (ATJ Engine) ever since this has been done the engine is breathing heavily and hydraulic tappets are not pressurising. The head has recently been reconditioned so I know it is not a fault with the head gasket or oil ways as these have all been cleaned, but can anyone explain what can stop the oil from getting to the hydraulic tappets and cam shaft bearings. Many thanks.

[yorky19640]

Have recently replaced a faulty oil cooler on my VW Passat TDI (ATJ Engine) ever since this has been done the engine is breathing heavily and hydraulic tappets are not pressurising. The head has recently been reconditioned so I know it is not a fault with the head gasket or oil ways as these have all been cleaned, but can anyone explain what can stop the oil from getting to the hydraulic tappets and cam shaft bearings. Many thanks.

[kenney]

Have you measured the oil pressure? Was the head gasket done the same time as the oil cooler?

[passing]

were the hydaulics in the head replaced as part of the reconditioning ? It would be normal.

[Crasher]

Oil must be getting to the cam bearings otherwise the cam would seize within minuets. Were the tappets replaced? How long ago was the head off? If it has only just been done and you have no oil feed, then I suspect the head gasket is on upside down.

[kenney]

( then I suspect the head gasket is on upside down) WHAT WHAT WHAT have we been down that road too?;)

[Crasher]

It was 20 years ago the last time, on a 1976 Passat 1.6.

[kenney]

And i bet you only did it once.The thought struck me,because i can't understand how the oil cooler can affect the pressure. yorky has another post with the same subject,which he has not replied to.I thought it a bit to ridiculous to mention it, before he replied

[Crasher]

Too right once and once only, I can even remember it was yellow and a YN engine. At least in those days lifting the head off to slip another gasket in only cost me a gasket and 10 head bolts plus about an hour and a half to do it. Make that mistake on a modern PD and you have lost a day and a whole pile of parts.

[yorky19640]

Oil cooler went first, with Head Gasket diagnosed soon after by local garage, but after having head refurbished by specialists and re installed, still have the same problem. Blowing badly from valve cover, and tappets not pressurising. Tappets were getting very noisy before the head job was started. Oil pressure was measured and is okay. There does appear to be oil in the head. But not a happy bunny, after paying alot of money to get it sorted.

[yorky19640]

Head gasket is on the right way, made that mistake once before. never again.. Hydraulic tappets all changed when head was reworked at a cost of £300. Engine still blowing like a pig with noisy tappets.

[kenney]

Suggest,removing the oil filter housing,and one of the camshaft caps,put some air pressure in the oil channel and take it from there.You should not run the engine any more,before the fault is rectified

[Sam]

Threads merged for easier reading

[yorky19640]

Thanks for the advice. Will have another look at the weekend. Any idea what would cause the engine to breath so heavily. All seems to have gone wrong since oil cooler replaced

[kenney]

What does the engine oil look like?One thing which causes breathing is worn oil rings

[yorky19640]

Recently changed oil and is very clean. Always had a little bit of smoke from dipstick, but hardly noticeable, but now its blowing very badly. it just seems odd that its only started happening since the oil cooler problem

[kenney]

What happened with the head gasket,what symptoms had the engine then.When the oil cooler is at fault,usually you get oil in the coolant.When the head gasket blows you usually get coolant in the oil,(depending where the leak is).Iam thinking that the piston rings can somehow have been damaged (overheating)? What say Ye did the engine overheat?when the head gasket blew.:confused:

[yorky19640]

The engine never overheated, the expansion tank filled with oil, so i checked the oil cooler and found it at fault so i replaced it. Ever since I have had the heavy blowing from valve cover and noisy tappets. I took it to my local garage,they checked it over found a little sludge in the filler cap and said definately head gasket. Job was done including head skimmed valve guides reworked new cam bearing shells fitted and head replaced. And after all this the same problem

[martin1810]

Yorky. silly question time but are you sure the timing is correct after the head was done.

[yorky19640]

Timings has been double checked and is all okay. Have checked oil pressure again and all is okay so might just run the engine up and see if tappets will pressurise.

[martin1810]

Try it with oil cap left off to relieve pressure. There should be a pressure relief valve built into the cam cover that goes out to the turbo. If this is blocked... no pressure relief.

[yorky19640]

The relief valve has been checked and is clear. Have double checked oil pressure and ranges between 35psi on tick over and nearly 80psi on revs, so I think I will just let it run for an hour I think that should sort it. Have had cars in the garage before take anything up to 3 hours to pressurise. Don,t think theres alot to worry about. Many Thanks for the advice