I had my 2011 Clubman S's Timing chain replaced by a GM Mechanic and now the car will not start. Mechanic is saying that I need new ECU but I have done some research and that seems confusing unless I am missing something. He said that my ECU connectors were corroded from steam from before I had my Thermostat/Housing replaced. That would make this 3 seemingly-unrelated issues one after another.

Here is chronology:

1 - had Mini Dealer check computer and found Thermostat issue

2 - had GM Dealer replace Thermostat Unit and Mount.

3 - Got check engine light after and codes pointed to Timing (death rattle).

4 - Had Timing Chain completely replaced.

5 - Mechanic can not start after reassembly with new timing chain.

6 - Mechanic says I need new ECU as 'it's corroded from steam' (Thermostat)

Any thoughts?

 

The DME does not "corrode due to steam" from the thermostat. I've seen DME connectors corrode due to people powerwashing the engine bay, as well as oil ingress into the DME from the oil pressure control solenoid that causes major problems.

Did they use the proper timing tools as well as a torque wrench that reads torque + angle?
If not, they fixed your car wrong, and even still the chance of the exhaust valves being bent is possible if they haven't done the job before.

Have a compression test done.

If the thermostat is properly connected and all the electrical connectors are in place then you have a mechanical fault, of which this dealership is on the hook for fixing. It started before they touched it, it should start and run better after they touch it.

Good luck, post back with any information they provide you with.

 

Find another mechanic as this doesn't sound right at all.

Steam? I don't think so. If your car made that much steam it would have melted down.