Valve stems

[Jonny3777]

Hi all, hoping someone can shed some light on this issue. I've been getting a catalyst converter fault on my 2006 2.0 e85 for a while now, also she idles shaky on the needle.

(Code P0420 stands for “Catalyst System Efficiency Below Threshold Bank 1)

Been in and out of the indie a few times but nothing was reported as out of the ordinary. Got the same answer about airflow, idler motor, maybe a disa vavle etc.

However new indie same issue, new answer theres a small oil leak nothing major. Oil gathered at the bottom of the engine and I'm getting a little blue smoke from the exhaust on a rev.

Indie says that oil is being burnt and reckons it may be the valve stems. This would explain why its idling shaky as he showed me the values in the cylinders and two of them where much higher than the others.

He said that because the engine is aluminium once they are opened they never go back together right when torqued???

He also said this would be a heavy bill to pay North of €2k? I'm not sure what to make of this?

 

[Rockhopper]

Find another garage, this one hasn’t got a clue. Aluminium heads, blocks etc are the norm these days and cause no issues when they are properly rebuilt.
Does it smoke when you start it up after it’s been standing for a while? That’s usually a good sign of worn valve guides.
You need to do much more diagnostic work to find out what the P0420 code means (looking at fuel trims etc). Could be lambda sensors, contaminated cat or any one of a long list of other possible issues.

 

[Jonny3777]

Find another garage, this one hasn’t got a clue. Aluminium heads, blocks etc are the norm these days and cause no issues when they are properly rebuilt.
Does it smoke when you start it up after it’s been standing for a while? That’s usually a good sign of worn valve guides.
You need to do much more diagnostic work to find out what the P0420 code means (looking at fuel trims etc). Could be lambda sensors, contaminated cat or any one of a long list of other possible issues.

Hi Rock hopper, thank you for the reply, it smokes s little on startup but usually until it warms like condensation.

It's only done 185000km. Would Worn valve guides be an issue with that kind of milage? It's worth mentioning I use it as my daily driver so she gets plenty of use, never left parked up.

What kind of price should I expect to pay for a valve stem replacement?

 

[Rockhopper]

A very quick Google suggests that your particular engine is prone to valve guide wear if low quality oil is used. Do you mean 185k km? That’s a lot!

 

[Jonny3777]

Yeah it's 185k, I use castrol 5-30 oil it's maybe not the best but it's good quality oil. If it is the guides, is that an expensive fix? Thanks

 

[Rockhopper]

Yes it’s fairly expensive usually, head off, strip, press in new guides, ream, skim head and rebuild with a new cam belt etc. £2k at a very rough guess so what you’ve been quoted probably isnt far off.
I just question their diagnosis, I think you need to look further before spending that kind of money.

 

[enuff_zed]

Just a thought?
Haven't other people on here had similar issues with the CCV system being blocked up?

 

[Zulu4]

A very quick Google suggests that your particular engine is prone to valve guide wear if low quality oil is used. Do you mean 185k km? That’s a lot!

It's only 115,000 miles.

 

[Jonny3777]

Yes it’s fairly expensive usually, head off, strip, press in new guides, ream, skim head and rebuild with a new cam belt etc. £2k at a very rough guess so what you’ve been quoted probably isnt far off.
I just question their diagnosis, I think you need to look further before spending that kind of money.

that's what I was afraid of, it's back to investigating I think. 2k is a fair wack to fork out.

 

[Jonny3777]

Just a thought?
Haven't other people on here had similar issues with the CCV system being blocked up?

Would that cause my engine to idle shaky and have blue smoke from the exhaust every now and then?

 

[enuff_zed]

Just a thought?
Haven't other people on here had similar issues with the CCV system being blocked up?

Would that cause my engine to idle shaky and have blue smoke from the exhaust every now and then?

I'm not 100% certain, especially the shaky idle, but a search on here, plus a bit of googling may enlighten you.
TBH, I'd also missed the fact it's a 2 litre and was basing my thoughts on the straight 6.

 

[Mr Tidy]

My 2nd Coupe threw an EML for P0420 and P0430 - post-cat 02 sensors bank 1 and bank 2.

Admittedly that was a 3.0si, but it turned out they were the random warning lights BMWs tend to throw up when the battery was dying as it died while my Indy was running the diagnostics!

Might be worth checking the battery, although the rough idling could well be something else.

I'd want to take it to a specialist BMW Indy before getting involved in that sort of work! If you don't know of any locally I'm sure someone will be able to help if you say where you are.

Good luck getting a proper diagnosis and a fix.

 

[colb]

How about switching to 5W-40 oil thats reccomended for higher mileage cars, also try some oil seal additive that rejuvenates oil seals that have gone hard and lost their sealing ability. Got to be worth a try before spending out replacing the valve stem seals if you can't do it yourself. If you go down the road of replacing the seals there are some good videos on Youtube detailing how to on an E46 engine which is a good guide on how to do it without taking the head off for most BMW models.
https://www.youtube.com/watch?v=Xv1mRlr_GF8 Camshaft removal
https://www.youtube.com/watch?v=pM9KXEw_Wd8 Seal removal

 

[Mike6]

Check the spark plugs . If the tips are black and oily then it's a sign that oil is getting into the combustion chamber and could be the stem seals.

 

[grumps]

Indie says that oil is being burnt and reckons it may be the valve stems. This would explain why its idling shaky as he showed me the values in the cylinders and two of them where much higher than the others.

What values? Is it a variation in compression pressures? If so, worn valve guides is a red herring!

 

[tug]

Mate, in all honesty your worrying over nothing. The fault code is common on the N46. Just get a cheap code reader & clear it. As for the valve stem seals, if i leave mine idling for say 20 mins then rev the engine i also get blue smoke and have done for about 4 years now, it clears quickly and dont get any smoke during normal conditions.

I also have the slightly lumpy idle, its also common on the 4 potter & well documented.

To keep the fault code away you need to thrash it more often so as to "keep it clear" so to speak. After my engine gets up to temperature i always where possible take it up to at least 4000 revs through the gears, especially up to 4th. And rarely get the pesky code. I have had mine for over 6 years now & is my daily with 135,000 on the clock.

It gets serviced regularly and well looked after. These engines are not a patch on the 6 potters but this 4 potter is probably the best car i've ever owned and at my age i've had a few. :lol:

Hope this helps a bit. Cheers, tug.

 

[enuff_zed]

Mate, in all honesty your worrying over nothing. The fault code is common on the N46. Just get a cheap code reader & clear it. As for the valve stem seals, if i leave mine idling for say 20 mins then rev the engine i also get blue smoke and have done for about 4 years now, it clears quickly and dont get any smoke during normal conditions.

I also have the slightly lumpy idle, its also common on the 4 potter & well documented.

To keep the fault code away you need to thrash it more often so as to "keep it clear" so to speak. After my engine gets up to temperature i always where possible take it up to at least 4000 revs through the gears, especially up to 4th. And rarely get the pesky code. I have had mine for over 6 years now & is my daily with 135,000 on the clock.

It gets serviced regularly and well looked after. These engines are not a patch on the 6 potters but this 4 potter is probably the best car i've ever owned and at my age i've had a few. :lol:

Hope this helps a bit. Cheers, tug.

There seem to be a lot less 4-pot owners on here than sixes. The 4-pots get a bad press but I wonder if some of that is cast down from the lofty 'must have a six pot sound' mentality.
I'm pleased the OP has had some sensible feedback from someone who owns and runs one.
Hopefully a reset and the knowledge that 'they all do that' will mean more stress free driving from now on.

 

[Jfgoldfish]

I'm with Tug on this one; reset the codes and drive it fairly hard regularly. The 2.0 regularly throws emmisions codes if it is babied.

Some folks here have advised that the valve guides are a 2k+ job to replace... They are in the right ball park. However, the guides probably aren't excessively worn. Certainly not at 115k miles.
The seals are the only bit that generally fail prematurely on these engines. There are garages around that will replace the seals for less than 800 quid. The head doesn't need to come off to do them. There is a place in Nuneaton that do it at a fixed rate. I forget the name of the place, could probably dig it up if you were really interested.

Try the forte seal conditioner. It will get you a few more years out of them.
I wouldn't bother replacing them until you're burning more than 1 litre per 1000 miles and I can almost guarantee the oil consumption isn't causing your shakey idle.