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2013 2.5i rattle on cold starts

8.1K views 6 replies 4 participants last post by  johnnyarma  
#1 ·
2013 2.5i 160,000 miles, recently bought the car.
Every cold start I hear metallic rattles / clacking that last 3-5 seconds. Something like Trrrrrr.

Some points worth noting:
  • The engine is not consuming oil
  • The idle is very smooth
  • There are no visible oil leaks in the engine bay
Is the noise something I should address and if so, how?
 
#2 ·
What brand of oil filter is installed?

It sounds like your oil filter may be losing its pressure and it therefore needs to be re-filled by the oil pump after the engine starts.

If you start the engine and let it rev normally until the rattling stops (don’t touch the accelerator pedal), there is likely to be little or no damage being done.

Seagrass
 
#4 ·
What brand of oil filter is installed?

It sounds like your oil filter may be losing its pressure and it therefore needs to be re-filled by the oil pump after the engine starts.

If you start the engine and let it rev normally until the rattling stops (don’t touch the accelerator pedal), there is likely to be little or no damage being done.

Seagrass
You can try changing the grade of oil used. Consult your manual and try the heaviest grade appropriate for the temperatures in your area.
Seagrass, it makes sense what you say regarding the oil pressure.

When I bought the car, it had:
  • Synthetic 5W-30 and original Subaru filter
I changed it to:
  • Repsol Synthetic 0W-30 and Hyundai/Kia filter (It is blue and looks like the original Subaru, can't tell if the size is 100%, can't compare it here. But if it was a bit smaller it would help the pressure, right?)
I live in a place where you have around 80-90F every day. I read in the Subaru manual that 0W-20 is for naturally aspirated 2.5i and 5W-30 is for turbocharged engines.

At first I wanted to replace the filter for Subaru original but it was doing the same or similar noise before the change so I didn't rush with it.

I thought about using some higher grade oil too, it was recommended to me on my 1989 Mercedes 500 SE by a mechanic, the engine got quieter after changing to a honey-like 20W-50 (which is what the manual back then recommended). But that was different and addressed noisy lifters which is a constant noise.
 
#7 ·
Found this document:


Subaru models from the 2000 model year and later, equipped with 2.2 and 2.5 liter engines, are more fuel efficient, more powerful and have a flatter, more usable torque curve than in previous years. To achieve these objectives, it was necessary to make several internal engine improvements and modifications.
These modifications include:
â–  Mechanical valve lash adjusters (reduced friction)
â–  Lightweight pistons (reduced inertia)
â–  Short skirt, Molybdenum coated pistons (reduced
friction)
â–  Increased compression ratio (improved power out-
put)
â–  Improved cylinder head design (improved cooling)
â–  Improved induction system (improved breathing)

As a result of these enhancements, some engines may exhibit some engine noise during the warm-up period after a cold start-up.This noise is a consequence of the engine improvements and is not, in any way, an indica- tion of any engine problem. A light engine knock, after cold start, that gradually dissipates as the engine warms up and is virtually undetectable (from inside the vehicle) once the engine has reached operating temperature, is a normal characteristic of these engines. Repair attempts to reduce this type noise are generally unsuccessful.
If you are diagnosing an engine for noises other than those that have been described above, be sure to take the time to check all possible causes prior to condemning the internal components of the engine. Before replacing parts in an attempt to eliminate engine noise, the engine should be inspected externally and internally for anoth- er source of noise.A look at the engine oil is a good place to start.Another area to look at would be the timing belt tensioner and the belt and sprockets. Noises coming from under the belt covers and from external components can sound like a deep internal knock.