Significant Engineering Design flaws with timing chains, tensioners and sensors. Timing chain replacement at 65,000 miles. Causing outrageous repair bills. GM engines built 40 years ago never had these problems. Major failures! I have only purchased GM my entire life. I will never buy another new GM vehicle again.

Update from Jul 19, 2017: Timing chain was replaced at 65,000 miles. Huge repair billes now it needs to be replaced again at 135,000 miles. this is a huge failure by GM engineers. They should all be fired. AWFUL situation! Never buy a new GM vehicle. I have 50 year old GM cars that have hundreds of thousands of miles that never needed this type of repair. Customers are getting royally screwed.

I used the original date that the problem became a check engine light. The timing chains are on plastic tension rollers, which is a major problem in this engine. I paid the deductible of $535, and it was an approx 3 wk repair. The engine and transmission were pulled. Immediately after the repair, my Catalytic converter went bad, and I paid the deductible for that repair. The timing chains are error coding again, the ECM has fried, which has caused a loss of power to several other sensors, and because I was just about 2 WEEKS out of the 1 year warranty on the repair it is not covered. They only want to give me a deal on a new car, and not accept responsibility for their poor engineering design. This engine was in the 2008-2010 Cadillac and there was a recall on it. My dealer told me they are repairing these timing chain issues to the tune of 1 a month, and as late as the 2011 model year. They will not repair mine again, because the parts are the same, and the repair is one temporary. HOW IS THIS OK??????? Has anyone one else had the timing chain issue with their sport?

I have had to replace the shifter assembly, due to an electronic switch that failed to allow the key to be removed, and am on my 3 vapor lock Engine Hot sensor.

Any suggestions would be greatly appreciated.

Update from Mar 18, 2016: After getting no where with dealer honoring the 12 mo, 12,000 warranty on the timing chain repair, I paid to repair again for $2300.00. 2 days after completion, broke down due to low oil pressure, and had to have towed back to dealer. I am being told now that the engine is full of sludge, due to neglect. I have every service record on the vehicle, and all oil changes have been done at the dealer and went not more than 5,000 between changes, even tho dealer told me I did not have to do so frequently. They now want more than $800 for this repair, and have advised me that the timing chains are not going to last, and I should get rid of the car. How is that a reasonable answer????