Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length

[shyboy]

I think I have worn valve stem seals on my 2001 2.6i estate. When I bought it 3 months ago I noticed a burn off of oil on starting after an overnight rest, and as there was no sign of oil being burned during normal running I concluded that it was probably worn stem seals allowing oil to seep past overnight. Seemed a bit odd at 75k I thought, but then remembered that a new HBV had been fitted shortly before I purchased.
The car developed a misfire and I had to renew the cam cover gaskets as oil and water had flooded one of the plug wells, and found that the passenger side 'Coil Per Plug' unit was cracked and looking ropey, but I re-used it after cleaning and drenching in WD40, which has done the trick. I'm now wondering whether the engine had been allowed to run without coolant when the HBV packed up, and whether this could 'cook' the stem seals, making them brittle and leaking, and cause the damage to the CPP unit. (The driver's side CPP is perfect).The oil burn off does seem to be occurring after shorter rest periods now, but still not obvious when driving, so perhaps I need to attend to this sooner than I was planning.
Can the experts give an opinion on my reasoning, please, and would it cause major problems, (eg. to the valve stems),  if I delayed the work for a while? Would the oil burning damage the cats?
The engine is running beautifully in all respects at the moment, but I don't want to take silly chances.
Bill.

[Mike Collins]

I've not yet had stem seals fail, 2.5 run to 200K, my 2.6 is at around 130K, my wife's 2.5 is over 230K, none have smoked at start yet.

Is there much smoke? Is it really oil smoke, not just condensation?

[shyboy]

Thanks for your reply Mike Collins.
It's definitely light blue oil smoke which appears approx. 5 seconds after starting, and disappears after another 5/10secs. I'm assuming the delay is just the non-contaminated air being exhausted initially. There is also plenty of water condensation when cold particularly but I think this is within normal bounds. I can't see major blue smoke when driving, and oil consumption doesn't seem to be excessive.
 Would a compression test tell me anything about the condition of the stem seals? A poor result would really only suggest poor rings or valve seats, wouldn't it, as I think the HG is OK?
Do you know how difficult a job it is to replace seals and guides if necessary? Obviously a head off job.

[Mike Collins]

A compression test can't tell you much about the guides and seals. It will show up poor valve seating or poor ring/bore seal.

I have seen somewhere an adaptor which fits in place of a spark plug and  
uses compressed air to force the valves closed while you change seals.
Might be worth a search of automotive tool suppliers

Otherwise, as you say, heads off.

[Marks DTM Calib]

There are tools that allow you to change the seals with the heads on but, not easy to source and pretty pricey.

You might be able to see carbon on the inlet valve stems with the intake out...

Does this engine have any history of snapped belts etc?

[kcl]

Known issue on 2,6 engines, the stem seals get off for some reason. They have done several ones as a guarantee job, someone told me that they make threads to stem and then fit new seals... Don't know what is the original cause for seals to come off but I know a dozen cases, mine also... Sometimes after start a small cloud of blue smoke behind the car, but not too much oil consumption. Annoying, but not dangerous I suppose...

[Tony H]

Known issue on 2,6 engines, the stem seals get off for some reason. They have done several ones as a guarantee job, someone told me that they make threads to stem and then fit new seals... Don't know what is the original cause for seals to come off but I know a dozen cases, mine also... Sometimes after start a small cloud of blue smoke behind the car, but not too much oil consumption. Annoying, but not dangerous I suppose...

A build up of burnt oil residue could have an effect on valve seating over time

[Martin_1962]

I think mine are gone too and only 100,000 miles

[shyboy]

Thanks for your comments, fellas.
Mark - no known history of broken cambelt, but as I said, the HBV was changed just before I bought. I'm still thinking of serious overheating being a possible cause, but I've got no definite evidence of that or of any other related symptoms. Perhaps I could pick your brains on Saturday, although I will be in the 2.0l so won't be able to demonstrate anything.
KCL - Thanks. Do you know if it is easy to replace the type of seal arrangement you describe? I'm capable of doing it if it doesn't involve special equipment, and I suppose it will have to be done at some time.
At the moment, there are no performance issues at all.
Thanks again.
Bill.

[kcl]

AFAIK it's a "cams-off"- job, so I will not be doing it until I really need to... Not that bad I suppose, but still, taking cams off is a bit too much to me