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gomi_otaku
gomi_otaku, Technician
Category: Car
Satisfied Customers: 3462
Experience:  VW Technician, VW FastTrack, VW Academy, VW Certified
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A loud knocking suddenly developed, sounds like a sticking

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A loud knocking suddenly developed
JA: Where exactly do you think the noise is coming from? And how long has this been going on?
Customer: sounds like a sticking valve being hit by the piston. Could it be an injector knock?
JA: What is the make/model/year of your car?
Customer: 2007 Holden rodeo 4jj1
JA: Are you fixing your vehicle yourself? What have you tried so far?
Customer: Yes. Nothing yet
JA: Anything else you want the mechanic to know before I connect you?
Customer: The knocking noise is very loud. At idle sometimes it doesn't make the noise and sometimes it fades in and out. When you rev the engine it gets really noisy like it's going to do damage.

I think you are going to need to look into it before you do some damage.

A "cheap and dirty" way of figuring out what cylinder is the issue is to allow it to idle, and then disconnect and reconnect the injector at each cylinder, and see if the noise comes and goes. This will allow you to narrow it down to which cylinder.

I think that maybe you have a broken valve spring- and will have to pull the valve cover to take a look, press down on each cam follower to see if any of them can be depressed easily.

Customer: replied 11 months ago.
Removed injector wires one at a time made no difference engine slowed slightly knocking disappeared for a few seconds until engine speed picked up and knocking resumed. Exactly the same on every injector.
Also pushed down on valve springs they were all the same. No weak ones. Spent the rest of the day pulling it apart trying to get the head off. I will have to go back another day as it was a big job. When it was running there was no smoke blowing out of the exhaust or excess pressure blowing out of the oil filler cap when removed.

ok, let me know what you find!

Customer: replied 11 months ago.
Forgot to mention there is a huge amount of black sludge/gunge in the throttle body some places like on the butterfly it is up to 1mm thick. Still haven't had time to get back to it.
Customer: replied 11 months ago.
Also it looks like i forgot to mention the check engine light is on.
I am hoping to get a scan later this week but engine is half pulled apart.
Customer: replied 10 months ago.
Hi I have removed the oil filter on the advice of a friend and cut it open it is full of metal particles. It appears the engine is a major rebuild. I have been offered an engine out of a*****(manual transmission) is there any difference apart from the sump. Mine is*****(manual transmission). ?

No, the engine should all be the same, the differences are all in the transaxle, little more work removing it.

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Customer: replied 10 months ago.
The guy selling the engine said he thought the timing gears were different and the timing case. I thought that seemed strange