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VZ Oil Pressure

Tamkat

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Hi all,
Need help with a problem with my 05 VZ V6 Alloytec. Just had timing chain and guides replaced and now I have no oil pressure. No oil seems to be getting to top of motor. Been at the mechanics for 2 months and they can't find the problem.
The pick up works ok.
Pump is ok.
Lifters are ok.
When started it will run ok but then a loud tapping at the top starts. It then runs like ****.

Any thoughts?????
 

greenacc

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Is pump new or reused the old one?
 

Tamkat

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The old one
 

Sean880

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1. IF the engine ran ok for a bit as you suggest in your post ,and then became noisy, that is odd because the claimed zero oil pressure should produce engine noise right away from lack of normal lubrication. It is also odd that you apparently had no oil pressure problem before but after work is done on your car you are told there is an issue.

2. If the timing change job has been botched I would expect the noise you complain of and the engine to be running badly.

3. You had no oil pressure issue before the work was done apparently. What is the indication of low oil pressure now? You say the pump is fine and there is nothing wrong with the oil pick up. Has a mechanical gauge been fitted to the engine to verify that there is low oil pressure (rather than the pressure sender unit on your car having failed or their being a problem with the wiring)?

4. If low oil pressure has been confirmed with an independent gauge (but you had normal oil pressure previously) then I would suspect:
A. Sludge build up in the oil pick up tube that has not been identified and is heavily restricting or now totally blocking the ability of the pump to suck up the oil. If your car has been subjected to 15000 km oil change intervals, or has missed services or both, and has typical kms for its age there will be lots of nasty oil sludge in the engine.
B. If the integrated oil pressure relief valve is stuck open because debris is stuck in there you will get very low oil pressure.

5. Oil pressure in your engine is produced by resistance to flow (not by the pump which produces the flow and not the pressure). If you have a high km and very worn engine there will likely be large tolerances between critical moving parts, especially worn main and rod bearings, and you will consequently get very oil low pressure no matter how good the oil pump is. Excessive clearances elsewhere in the engine can also reduce oil pressure. This includes wear in the lifter bores, excessive clearances between the camshaft journals and cam bearings, and excessive end play in the cam. Any cracks in the oil galleys, leaking galley plugs, or leakage between the oil pump and block can also reduce pressure.
 

Tamkat

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Before the timing chain was replaced it was coming up with low oil. The mechanic that worked on it claims it has low oil pressure from him using the gauge. He claims he put a camera in the sump and found no problems. It did have a sludge problem when we bought it but was apparently cleaned out when we took it back. It has all Services since we have had it at correct intervals.
 

Big Red VF-SII Go-kart

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2 months!!?
Strewth, the shop would have test run the engine after chain replacement to check for vacuum leaks (gasket),firing and oil flow. It comes to me as mighty strange that oil would not be flowing to a critical part of the engine. After two months, I'd be looking at getting some money back rather than throwing more money at them. Have you other options for dealers?

Besides that, I am very keen to know how [Alloytec] engines become so sludged up here and there; I have heard of this multiple times on this forum, and a recent picture I saw was quite horrifying. Is it missed oil changes, or obstructed needle ...or what?
 

Sean880

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Besides that, I am very keen to know how [Alloytec] engines become so sludged up here and there; I have heard of this multiple times on this forum, and a recent picture I saw was quite horrifying. Is it missed oil changes, or obstructed needle ...or what?

It applies to all engines. If you don't change the oil and oil filter as frequently as required you will get sludge build up (combination of oxidized oil and contaminants) in your engine.

The type of driving most people do requires more frequent oil changes than the basic service book coupons show and if you read the finer details in Holden service documents (few do I suspect) they normally make this very clear. Most need to be changing their oil every 7500 kms at least to keep the engine running at optimum and clean. 10 - 15000 km oil change intervals are too long for the type of driving most cars are subjected to if you want to keep the engine clean and running on oil not over contaminated.
But this is what many people do and they get sludge build up in the engine which will eventually block the oil pick up screen, oil pick up tube and oil passages in the engine so the oil pump cannot do it's job. Components will be coated with sludge and where the oil goes so does the sludge. Once the lubrication system fails because of the sludge build up you will get very excessive wear and overheating of components and that's often the end of your engine.

It's a lot cheaper to change your engine oil and filter more frequently than to allow sludge to develop and build up and cause destruction of your engine in worst cases. Once you have sludge problem in there it is also very time consuming and hence expensive to have it removed properly.
 

Big Red VF-SII Go-kart

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Most need to be changing their oil every 7500 kms at least to keep the engine running at optimum and clean. 10 - 15000 km oil change intervals are too long for the type of driving most cars are subjected to if you want to keep the engine clean and running on oil not over contaminated.

Hmmm. That 7,500km interval applied to my very old Toyota Lexcen (VP-Commodore-cross) wagon, traded in around July 2010. It was initially a very dirty engine when I took delivery of it (off a fleet) iin 1995 where it was serviced by them, seemingly on a whim, around 20,000km intervals (!!). They were just plain lazy! So it was cleaned up and changes done at 7,000-7,500km and at the time of trading it was a pristine engine, but it did suffer fuel pump failures that left me stranded a couple of times. But the engine was a stand out at 388,655km.

But Alloytecs — I'm not so sure that short interval is right; it certainly hasn't been said to me by the techies who service the car (engine flushes each change) at 15,000km intervals. But 95% of my driving is at high speed on freeways over very long distances, and nothing untoward has been observed or spoken at oil changes. If there was something akimbo, the boys would tell me so. Possibly shorter changes would be in order for cars that do not reach warm-up or are driven very short distances repeatedly. I don't know.
 

gungazza

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I change mine every 5000 ks peace of mind
 

hallb82

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I had a similar issue with my VZ. One day i was cruising on the highway and noticed the engine sounded i bit off but wasnt enough for me to stop right away. About 20 minutes later my speed started decreasing then the engine shut down and i rolled to a stop. Got towed home even though it did start again on side of the highway.

Long story short im pretty sure it stopped because of sludge build up which blocked the pump or some oil passages etc. I got some advice and (this is going to sound completely crazy. it sounded crazy to me anyway) was told to drain the oil then get cheap oil and mix 50/50 oil and diesel and put that in the engine. Also use a new filter for the 50/50 mix. Run it for 5 minutes at a time and rest for a few minutes between, do this 6 or so times over. Then drain it again and fill with your usual oil and another fresh filter. This actually worked. I didnt take anything apart, just did what i was advised to do and iv done another 30000Ks since without any problems. Apparently the diesel thins out the sludge and gives the engines oil passages a clean as well. Cost around $100 all up.

Note: after my engine stopped on the highway it had a knock which seemed to be coming from the top passenger side. this disappeared during the oil diesel mix treatment.

I realise you were having your dramas 6 months ago but thought id share that anyway. Hope you got it sorted.
 
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