hrrs01

Rough idle and vibration

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Hi, i just picked up my first subaru, its a '08 Impreza with a N/A EJ20 engine and 4EAT tranny. The mileage is around 95000 miles. It drives like a charm, but im having some minor issues with it im hoping to get rid off, both for peace of mind, and to hopefuly save some money in the long run. 

So to the symptoms:

1. The car is vibrating a little on idle (in both D, N and P) and i sometimes almost get the feeling its about to stall (never has though, might just be flashbacks to an astra i once owned). Idle seems stable at around 700-800rpm.

2. The car also has a very noticeable vibration around 2000rpm. I only notice this in N and P, at a standstill. Cannot guarantee that it isnt present while driving though.

3. And now maybe to my biggest concern.. The car has a fairly low (aka barely able to hear it while inside the car, over the fan) clacking/tacking noise. Im in a very cold country, but only hear the sound when the engine is warm, and is idling after a drive. Im sort of wondering if it is some sort of tappet noise. Ive checked the oil and its just over the max line on the dipstick while warm. 

4. Maybe related, or maybe not, but i feel like there might be coming just a tad too much white smoke from it, with a weak smell of gas. It might just be steam though (as i live in a cold area). 

 

I cant feel any blowby through the oilcap hole or the oil dipstick hole, but havent been able to compression test the actual cylinders yet. The coolant temperature is around 94C at idle. Also ive bought some new sparkplugs just to see if that will help anything (when not sure, always start with the cheapest solution, right?) 

Sorry for a long first post. Any ideas or pointers to common flaws that might be the cause is appericated! 

 

P. S. Ive read up a little, and found out that the 4th cylinder lacks something in cooling compared to the rest, any solutions to this, that might increase the lifetime of the engine?

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Wotcha and welcome.

I have the same model with slightly less miles but do not have any of the symptoms you describe. As a cheap option you could try an ECU reset - this helped the auto gear change on mine and also smoothed out the revs - I did this because I was running on super unleaded petrol and wanted to force the ecu to recognize that.

There is a cooling mod mostly aimed at the turbo models due to teh increased pressure and heat but it is simple enough to make up a kit yourself.

 

cyl4mod.thumb.jpg.774048906d2218f150f376d795d0d0cb.jpg

 

https://www.iagperformance.com/GDT-Cylinder-4-Chamber-Cooling-System-WRX-STI-p/gdt-1005.htm

https://www.blingstrom.com/modmonday-sti/2019/3/17/getadomtune-cylinder-4-cooling-mod-showing-cylinder-4-that-you-still-care

Alternate fittings

1774958224_coolantmod.jpg.f9cd2132f8b34427f6d479fcd4927ef0.jpg

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I own a WRX and before a Classic Sport and both have a pattern on tick over where it wobbles the car slightly but never stalls. It is like a stutter. Flats do not naturally balance until it has some RPM. They can be quite lumpy on tick over. On tick over they try and twist the engine on its center until revs balance it out. Both idle when warm at quite low revs, again normal for a Scooby. Maybe this is what your referring to on your point 1.

You say oil is over the max. Is it below the notch on the dip stick when warm if not then you have over filled it which would possibly explain the smoke. White smoke usually means coolant is burning. Are you losing coolant, does it smell sweet?

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Thanks for answers so far! No, the exhaust just smells like unburnt gas in my opinion. Placed my hand fairly close to the exhaust, and didnt get any grease on it either, so im kind of wierded out by it.. 

I sure hope it isnt coolant, as i picked the Ej20 mostly to avoid leaky headgaskets 🤣 will make sure to check for air escaping at idle when it gets cold after work today. 

Thanks for the cooling mod! Will look into it!👍

I Will try to post the sound im refering to also when im home. 

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Anyone able to tell me the color of this smoke? Its after a 25min drive, in 5°C so im fairly certain its not just vapor. Dosent have any particular smell, and certainly not very sweet. As mentioned the oil seemed to be just a little high, so im thinking about draining some of it very soon. 

Ive also checked the radiator for bubbles for about 2 minutes, and couldnt see any. Had to stop, because the radiator overflowed though (i suppose this is normal). No overheating issues, and the car pulls as it should afaik. 

Also! Any good ideas on how i can post the sound i mentioned? 

As said i have owned this car for just a week, and are super aware of all symptoms that may have an exspensive fix (as i used all my money on the car).. 

Screenshot_20200117_132819_com.android.gallery3d.jpg

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To me it looks like burning oil and if you have over filled it that would be a possible explanation.

Post your video on youtube and link it. Or use something like Google Drive and post the link.

Yes the coolant will overflow if you have rad cap off when its running. I would not rely on the temp gauge in the dash as they are very slow to respond. I use a OBD dongle to get exact temps.

You will get some bubbles in the overflow tank as this vapour from the Turbo cooling when you turn off the engine.

See https://oppositelock.kinja.com/random-fun-car-fact-subaru-shutdown-turbo-cooling-514111544

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I cant really tell to be honest - if you video using phone etc then upload it to a hosting platform like photobucket etc and then post the link we should be able to see it

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Just now, Siluro said:

You will get some bubbles in the overflow tank as this vapour from the Turbo cooling when you turn off the engine.

See https://oppositelock.kinja.com/random-fun-car-fact-subaru-shutdown-turbo-cooling-514111544

No turbo on this one its NA same as my RX

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Ahh yes no turbo my bad. Interesting link though and true it not really possible to be sure on the smoke/vapour from this picture.

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i detached the hose between the pcv and the inlet, and saw some minor oil grease both in the valve, and in both ends of the hose.. could the car be burning oil through this, if the pcv is going bad? I havent noticed anything in terms of performance yet though. 
 


The car had been running for almost an hour when i filmed this, and the temperature were above 0 degrees celcius.
 


And i suppose the noise could sound a bit like a diesel engine in the video, but i assure you it is not. Its a fairly metallic sound in real life - a bit clickety clackety almost. (not as deep as rod knock though).

Hope this makes it easier to help me do guesswork! 😛

Thanks in advance!

 

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The pcv valves are cheap for my car they are a little over a tenner from ICP probably the same for you. Ive been looking up pcv failure symptoms and it sounds to me that could be your issue. I am NOT a mechanic though so pinch of salt and all that.
Good luck mate I have a bit of vibration at idle aswell I thought it could be my crank pulley giving up on life but I too have found oil seapage around the pcv valve on the breather hoses. So im just going to replace mine and the the hose set and see its ancient on mine anyway. Taking it off and cleaning it is also an option though

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Tricky vids don't help much. Not easy capturing that in a video, sound and smoke. The smoke looks like steam but hard to tell.

PVC being all blocked would stop it breathing and as ROSSCOSM said could be the cause, I would clean it out and see what happens. Sounds like it needs a clean anyway so worth doing anyway.

Possible cause for a sound could be the belt tensioner if it hydraulic like WRX. These start to fail and make a knocking sound.

 

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The noise could also be the injectors, i can hear them ticking away slightly on my wrx 

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