Not joined yet? Register for free and enjoy features such as alerts, private messaging and viewing latest posts and topics.

Valve stems

Discuss problems you have had or are having with your Z4
User avatar
Jonny3777
Member
Member
Posts: 50
Joined: Sat Oct 26, 2019 10:39 pm

Valve stems

Post by Jonny3777 » Fri Jul 23, 2021 12:15 am

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?
Bmw Z4 E85

User avatar
Rockhopper
Senior Member
Senior Member
Posts: 1098
Joined: Fri Mar 06, 2020 7:05 pm
Location: Mansfield

Valve stems

Post by Rockhopper » Fri Jul 23, 2021 6:12 am

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.

User avatar
Jonny3777
Member
Member
Posts: 50
Joined: Sat Oct 26, 2019 10:39 pm

Valve stems

Post by Jonny3777 » Fri Jul 23, 2021 10:05 am

Rockhopper wrote: Fri Jul 23, 2021 6:12 am 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?
Bmw Z4 E85

User avatar
Rockhopper
Senior Member
Senior Member
Posts: 1098
Joined: Fri Mar 06, 2020 7:05 pm
Location: Mansfield

Valve stems

Post by Rockhopper » Fri Jul 23, 2021 1:12 pm

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!

User avatar
Jonny3777
Member
Member
Posts: 50
Joined: Sat Oct 26, 2019 10:39 pm

Valve stems

Post by Jonny3777 » Fri Jul 23, 2021 1:17 pm

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
Bmw Z4 E85

User avatar
Rockhopper
Senior Member
Senior Member
Posts: 1098
Joined: Fri Mar 06, 2020 7:05 pm
Location: Mansfield

Valve stems

Post by Rockhopper » Fri Jul 23, 2021 2:58 pm

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.

User avatar
enuff_zed
Lifer
Lifer
Posts: 14382
Joined: Wed Oct 26, 2016 11:05 am
Location: Attleborough, Norfolk

Valve stems

Post by enuff_zed » Fri Jul 23, 2021 3:10 pm

Just a thought?
Haven't other people on here had similar issues with the CCV system being blocked up?
HQ of 'Norfolk Zed Rescue'.
Always happy to help if I can.

If the forum helped you, why not help the forum back. Thats the Z4 way! :thumbsup:
Image

User avatar
Zulu4
Member
Member
Posts: 836
Joined: Tue Mar 16, 2021 1:22 pm
Location: Lincolnshire

Valve stems

Post by Zulu4 » Fri Jul 23, 2021 4:29 pm

Rockhopper wrote: Fri Jul 23, 2021 1:12 pm 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.
2007 3.0si Auto Sport Roadster. Whippy.
Previous:
2003 3.0i SE Roadster. Whippy.

User avatar
Jonny3777
Member
Member
Posts: 50
Joined: Sat Oct 26, 2019 10:39 pm

Valve stems

Post by Jonny3777 » Fri Jul 23, 2021 6:19 pm

Rockhopper wrote: Fri Jul 23, 2021 2:58 pm 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.
:cry: that's what I was afraid of, it's back to investigating I think. 2k is a fair wack to fork out.
Bmw Z4 E85

User avatar
Jonny3777
Member
Member
Posts: 50
Joined: Sat Oct 26, 2019 10:39 pm

Valve stems

Post by Jonny3777 » Fri Jul 23, 2021 6:20 pm

enuff_zed wrote: Fri Jul 23, 2021 3:10 pm 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?
Bmw Z4 E85

User avatar
enuff_zed
Lifer
Lifer
Posts: 14382
Joined: Wed Oct 26, 2016 11:05 am
Location: Attleborough, Norfolk

Valve stems

Post by enuff_zed » Fri Jul 23, 2021 9:22 pm

Jonny3777 wrote: Fri Jul 23, 2021 6:20 pm
enuff_zed wrote: Fri Jul 23, 2021 3:10 pm 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.
HQ of 'Norfolk Zed Rescue'.
Always happy to help if I can.

If the forum helped you, why not help the forum back. Thats the Z4 way! :thumbsup:
Image

User avatar
Mr Tidy
Legend
Legend
Posts: 23608
Joined: Wed Jul 02, 2014 12:18 pm
Location: North West Surrey

Valve stems

Post by Mr Tidy » Fri Jul 23, 2021 9:47 pm

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. :thumbsup:
Coupes because stunning!
Current - Silver Grey MC, Imola Red heated Nappa & carbon trim. Aeros, H & R Coil-overs, 224s, OE Strut brace, Nav, cup-holders, DSP Hi-Fi, pdc, cruise, MFSW, no CDV! E90 330i daily
Gone - Montego Blue
Gone - Ruby Black

User avatar
colb
Senior Member
Senior Member
Posts: 1621
Joined: Wed Nov 13, 2019 9:45 pm
Location: Newport, South Wales UK

Valve stems

Post by colb » Sat Jul 24, 2021 2:41 pm

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
Z Shed Cymru member
1999 1.8 Z3
2003 2.5 Z4
1998 Honda Deauville 650
If the forum helped you, why not help the forum back. Thats the Z4 way! :thumbsup:
https://www.paypal.com/cgi-bin/webscr?c ... source=url

Mike6
Senior Member
Senior Member
Posts: 1073
Joined: Thu Aug 20, 2015 1:17 pm

Valve stems

Post by Mike6 » Sat Jul 24, 2021 6:10 pm

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
Member
Member
Posts: 107
Joined: Tue Jul 02, 2013 5:07 pm
Location: Bridge of Weir

Valve stems

Post by grumps » Sat Jul 24, 2021 6:59 pm

Jonny3777 wrote: Fri Jul 23, 2021 12:15 am 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!
Start the day with a smile, get it over with.

Bog standard 2007 3.0si manual E86 in Montego blue with black leather, currently fitted with MV2s

Post Reply