I am in need of some advice about what I should do with my Car. I was about to trade it in, in June this year, but I have had 4 major issues with the car since then and all that is happening is that I am losing money and I still cannot trade in my Car. I am not sure what my next step should be and I am pretty much out of cash. I currently own a Holden VE Calais V8. I purchased brand new in April 2010.
I passed 100,000kms in March 2013. This is when the Warranty expired. Please excuse my technical knowledge. I will try my best.

Issue #1
On May 16th this year, my gearbox failed. Cut a long story short, it needed to be replaced. I had it replaced at a local gearbox specialist rather than at Holden. Same gearbox from both places, but Holden quoted 12k to replace. The Gearbox mechanic did it for 4k. This took about a month as there was a delay in sourcing the gearbox initially. The mechanic said it was due to the gearbox being out of oil and from poor servicing.

Issue # 2
The day after getting the car back with a new gearbox, the Engine failed. The #1 chamber in the engine was not firing. After investigating the faulty chamber, it was found that there was the end off a compression gun screwed in where the spark plug is meant to go. Then because the thread on the compression gun piece is the same as the thread on the spark plug, the spark plug was simply screwed on top of the gun piece.
There have only been 4 other occasions where the car has been touched since I brought it. 3 times being serviced at a Holden dealership (1st, 2nd & 4th service) and once at a mechanic (3rd service). So common sense would say one of the 2 places has left the end of their compression gun in my engine. Somehow it has held compression and the engine has worked (even though everyone has told me it should have been impossible). I called the Holden dealership since they serviced it last, and the person I spoke to may as well have told me to F..Off.
This took a while to diagnose & fix. Because the car has active fuel management, it was a unique issue and hard for them to find the cause. In the end, I needed to have all of the lifters replaced (+ a few other bits n pieces). This cost $5000.

Issue # 3
After collecting the car from having the lifters replaced, the car worked for about 2 days before Alerts regarding Oil pressure kept appearing. The engine would struggle to start, but it would be OK once the revs were up.
The issue was that I needed a new Oil pump. Another $1500.

Issue # 4
After replacing the oil pump, the car worked fine for approx 3 weeks until (last week) the Engine decided to fail once again. This time with all new alerts and symptoms. I have it towed again to the mechanic and this time it is another new totally unrelated issue. The Pistons in the Number 2 chamber have Cracked/Broken. And some other major stuff. Basically the engine is that messed up now that it is going to cost less to buy a 2nd hand one.

I am unsure what to do now. I cannot afford to spend another 10k after already spending 10k on the work done so far in the last 4 months. I especially cannot considering it looks like I will have to pay for my wife�s father�s funeral next week.
After the 2nd issue happened I contacted Holden customer service to discuss potentially considering this issue under warranty as it all happened within weeks of the 1st issue happening. They said I had to take it to a Holden dealership to be fixed and then assessed. I issue was that my car was in pieces being fixed already. I would have had to ask the mechanic to put it back together, pay then for the work they had done, have it towed to Holden, pay for them to fix it, only for them to maybe reimburse some of the costs. I saw that as a lose/lose decision for me and decided to wear the cost of the repair. The rep I spoke to said that they would only reimburse any factory related issues, and didn�t like my chances since things had already been fixed.
After this latest issue, I decided to contact the cust assistance team again. They again asked me to take to a dealership to have it assessed. However, I was again told that my chances would be slim to nothing as there had been so much work done to it outside of holden and that it would be near impossible to prove that an issue is factory related or related to the mechanics working on it.
As mentioned in the start, I was days/weeks away from trading in for a new VF Calais. I am/was a fan of the car and I have always owned Holden�s since I was old enough to Drive. It�s now 4-5 months later and I am even further away from trading in than I was after the 1st issue. I�m just in a financial mess now because of this car and Holden are not really providing me any guidance on my options.
Just wondering if others can give me some advice? I can�t imagine any normal person in the world accepting the fact that they needed to buy a new engine after 3 years! I purchased a semi prestige car in the hope it would be more reliable and worth the extra cost. So far I am not seeing that.
I also let my insurance expire in May because I did not expect to have the car for more than a few more days at the time. I am in a real pickle here. Would appreciate any suggestions.

You hit the nail on the head. How do I prove it... As mentioned I do know much about cars, so I wont pretend to know what a compression test does, So I have no idea why it was done. But I guess I need to find out who did it any why if it is not a standard practice. I assumed it was something that happens every service.

In the end I think I am just fighting a losing battle, but I was hoping someone might have some advice about what I should so next. I am living in hope that Holden will come to the party and help me out and possibly look at covering some of the costs under warranty. But I think the fact that I have taken it to non Holden places to have it fixed is gonna come back to bite me. Holden is just going to say that too much work has been done to prove any factory faults. Even though its pretty much a no brainer that the car is a dud.

I think I really only have 2 decisions:
1. Buy 2nd hand engine (+labour will be 10-12k. WIll probably need to get a loan) & then I can sell the car for hopefully 30k.
2. Trade in as is (not working and in need of new engine). I'm only guessing here, but I assume a car that needs a new engine is not going to give me much on the trade in. I would assume less than 10k?

I only have 6 months of repayments on it left, but because it was expensive to start with, the residual payment is 18k. So I still owe about 24-25k in total. So with option 2, Id need to get a loan anyway to pay out the remainder.

If the car has over 100000k's (as you said), it should of had at a minimum 7 log book services done (at 15000k's intervals which I consider is still too long). Have you had all them done? Did the Holden dealer do them? The first mechanic said the gearbox failed due to poor servicing. What did he mean? Poor servicing by whom? Was the box serviced at the specified log book time? I think issue 2, 3 and 4 are related. Why, if the problem was something screwed into the spark plug hole (issue 2), did this call for the replacement of the lifters? Did you keep driving the car when you have oil pressure problems as in issue 3? By saying when you revved the car it was ok, I assume you kept driving it. If the alert comes on, it's for a reason. I really don't think you telling us everything here, I'm sorry to say. Hope it works out for you.

What about statuary warranty ? these part would be designed to last more than 3 years?