So I have a new Subaru Crosstrek, 2014 model, manual transmission.  Shortly after I got the car I've noticed that it has a lot of pre detonation during steep hills or heavy accelleration. Another thing I don't like is that the engine compression on down shifting to slow the car down seems none-existant, and there is about a 2 second delay from when I let off the gas pedal to when the engine throttle actually releases.  Is this all normal behavour for these new subarus or is this unique to my car?

Sounds like a trip to the stealership for warranty work is in order.  Detonation is not normal for any engine, and can result in damaged pistons.  I have no delay in my Impreza, which has the same engine as your XV.

I had forgotten about this thread. I think I should post an update on what ended up getting this issue resolved.

 

The car always kept having the pre-detonation sounds, I had several techs go on test drives with me so I could demonstrate the sound. Finally got the car to do it with a tech in the car and they called it valve noise and said it was normal.

 

1-2 months later the oil consumption in the engine is getting worse and worse. I finally convinced them to do an oil consumption test when I mentioned I've read online that there is a recall and class action law suit in progress over the oil issue. We did the oil test, it was burning double the amount of oil allowed per their specification.

 

The dealership replaced the short block under warranty and not only is the car not consuming any oil anymore after break in, it also doesn't have that pre-detonation noise anymore. Since it still has the same valve train and heads, I bet that noise wasn't valve noise after all. I suppose bad compression could confuse sensors and the computer enough to cause pre-detonation.  That's the best theory I have on what might have caused the noise.  It's been problem free since the short block was replaced.

Man, I'm sorry about the problems you've had.  I've been lucky. . .  Glad it got resolved.

Good on the dealer, glad it eventually worked out!

 

Definitely not normal symptoms you described.

Yeah, I hear oil consumption is a normal problem however, and clearly with the short block being replaced and the noise going away afterwords, I suspect somehow the two issues are related. I'm glad it's all better. I've got about 8k on the new short block now and it's running good now. Car has about 36k on it now.  Amazingly the brakes are still at 80% front, 90% rear, I'm used to the old heavy Chrysler where it would eat a set of front brakes every 30k miles.

Edited March 18, 20179 yr by Mr. Carb