Who HASN'T done the IMS Retrofit (and why not)?

[vijen6]

My 2c .. copied and pasted from another thread ..

Common wisdom on this board for new owners is do the IMS .. its cheap insurance.

I had a IMS scare about a month ago when my water pump went and I thought it was IMS, but after fixing the water pump, it made me really think about getting the fix done.

Here's my take on that ... this is mostly personal opinion with some math .. so make your own conclusion.

First, some estimated cost.

Cost of the IMS upgrade ( parts + labor ) ~= $1500 if done at my local shop.

Cost of a newly used engine installed ( parts + labor ) ~= $9000 based on ebay prices.

Cost of a new reman 3.6 engine installed with warranty ( parts + labor ) = $16500 ( from Roock )

Second, I assume that IMS fail in 1 out of 10 cars ( correct me if I'm wrong but I remember reading somewhere that this was Flat6's ratio ). This gives you a 10% chance of failure.

Third, I assume that there are no fortune tellers among us and no one knows exactly when their IMS will give out. If you just know for sure you're one of the unlucky ones, then by all mean, get your IMS done.

...

To make 'insurance' worth buying .. it has to give me better odds of saving $ than if I didn't buy it. In another word, a $1500 insurance for a part that has a 10% failure rate only starts to make sense if the cost to fix when the part fails is over $15000. In this case, it is not. If your IMS goes, restoring your car to "as good as before" with a used engine cost $9000. That's gives you about a 1 / 6 ratio of IMS upgrade cost to potential saving in case of engine failure .. about 16%.

In another word, you're pre-paying 16% of the repair cost to guard against a 10% chance of failure.

So for me .. mathematically .. it only makes sense to do IMS upgrade when you can reduce the labor cost. Such as when you're already doing something in that area already so you can save on labor .. like changing clutch.

Doing IMS upgrade for the sake of IMS upgrade is not the best way to spend your money.