Hi,
This is my first post so bear with me. I have a 2004 Cadilac CTS 3.6l engine. My problem occurs only once or twice every ten start-ups. It sounds like a grinding noise when I crank the engine. The engine struggles to start, sometimes it starts, sometimes it doesn't. When it doesn't I wait about 5 seconds and turn key and it fires right up. No engine codes. Slight coolant leak from mid engine. I add about 1/2 quart of dexcool every 3 days. I have included a video on YouTube of the problem. Any help would be appreciated. Thanks.

 

I haven't done a lot of engine works on these cars but it might be that the mid engine coolant leak is a blown head gasket. If the coolant is getting into the pistons it could cause the car not to want to fire on that piston(s) on the first crank. it could possibly be a faulty CPS also. Does the car not want to start when it's warm or is it just when it's cold? Just because the CEL doesn't come on doesn't mean the car isn't throwing codes.

 

have you checked the engine oil level. its it fine? When you change it last time? and what is the the routine miles distance of you oil change.? I feel its due to the poor oil. Check the levels first.

 

When you change it last time?

 

I have checked oil levels and they are good. I changed the oil about 2 months ago. I used 5 quarts of Mobil 1 5w-30 extended life synthetic with Mobil 1 oil filter. I'm now due for an oil change in about 1500 miles. The car leaks about a quart of coolant every 3 days and I always keep topped off with Gm dexcool. The starting problem occurs day or night, hot or cold. I will post a video of the engine running and see if that can determine anything. Thanks for everyone's help.

 

I have made of 2 videos of a pulley wobble I discovered. I dont not know what this controls. Also, if anyone can tell me the full extent of this repair. This is also where all the coolant was leaking from the earlier post. Any help would be appreciated.
BEFORE BELT WAS REMOVED:
AFTER BELT REMOVED

 

Like I said before, not all that familiar with these engines yet and I don't have a service manual but That pulley is right above your power steering pump. I'm going to guess it's just an idler pulley. Hopefully if someone with more knowledge reads this they'll chime in. Also being it's the idler pulley I doubt that has anything to do with your losing coolant, but if that pulley went bad, I'd be checking all the others and I'd especially be looking at the water pump for leakage.