stuck valve

[paul cable]

hi all,

ive got a 1999 clk 230 kompressor sport.2 months ago car was mis firing but cleared itself.now,mis fires and seems to be stuck in 3rd gear.took it to a friend of mine who owns a garage,changed coil packsx2 plugs and leads and was still mis firing on pot 2.i had it read and iam told the valve is stuck open,hes tried to free the valve and has had no luck.ive been quoted £500 pound which is way way out of my bank balance.is their any way of freeing said valve that i could try myself.
when i say friend i mean an a aquaintance.if their isnt a way round this problem it looks like ive got to scrap the car,although for the year its in excellent condition and dont know wheather anyone would buy the car has a going concern and what price i could expect to ask.i paid £2,400 1 year ago,car has 80 000 miles..
thanks

 

[GordonTarling]

I think that perhaps you need to expand on exactly which valve is stuck before anyone is able to correctly advise you.

 

[Sp!ke]

Didnt you refurb the block recently with new valves piston rings etc?

If so, I'd be looking to speak to whoever did the job if indeed you have a stuck valve.

 

[BlackC55]

Do a compression check first.

 

[grumpyoldgit]

If it is just a sticking valve, I would try Redex (upper cylinder lubricant) fuel additive initially. It could just be sticky carbon built up of the valve stem.

Or if you've had new valves fitted recently as Sp!ke thinks, forget the Redex and wait for more advice.

 

[SJX]

Is this hydraulic tappets? I have had engines in the past that have been rebuilt (head) and the buckets have got swapped round, causing a valve to stick. Dont know enough about C230 lump to comment further but someone will know.

 

[paul cable]

about 10
months ago i had new stem seals,head gasket fitted.new piston rings also.
its been running ok since.mechanic is reporting that this fault has nothing to do with previous work done and me not knowing anything about cars has to take him to his word..do you pour the reddex down the plug holes or straight into the engine..silly question i know...

 

[paul cable]

yes,had compression test and pot 2 is low and stays low..its not looking good is it ???

 

[SJX]

Mix off the shelf accessory shop RedEx with the fuel in tank to specified mix amounts (on tin/bottle) run car for a week or so and 'see the results' - or not.

Years ago when RedEx was thick oily and blood red, came in tins and stained everything in the garage red, when it was teaspooned into your petrol tank with scientific care (before the premixed bottle of pee you buy now) it was stirling stuff!

It described the 'stage 1 RedEx' full decoke technique thus:

First drive out to the country, and find a secluded lay-by.
Keep your engine running and remove the air cleaner.
Rev the engine to about half throttle and pour in 5ml (teaspoon) of 'devils blood' straight down the carb intake. Repeat again.
Hold the revs constantly until smoke clears - About an hour, the resemblence to a Hiroshima mushroom cloud against the rural landcape was I admit uncanny.
Release throttle and refit air cleaner and drive home with smile. (a suggestion better left until dark due to the pungent smog cloud that would be following you homeward)
After about three weeks, the smoke eventually cleared from the combustion components of your car and your engine was like new... Ehmm

OK to try with 1959 Morris Minors with side valve engines and simple exhausts - not for use in this manner within the world of fuel injection and catalytic coverters as it would more than probably bugle everything it set out to mend! Plus the environment police may home in on the gas plume of your chosen rid-out location.

I still have half a tin of the original potion in the garage for when I take onboard more practical classics - not.

 

[grumpyoldgit]

Redex should be added to the fuel (petrol or diesel), but make sure to get the right one. Amount to add is shown on the bottle. You could also pour a small amount into number 2 cylinder through the plug hole, but if you do choose to try that, don't be concerned about the smoke from the exhaust when you start it up...... it will soon clear.

I had a similar problem many years ago on a normally aspirated (Carburetor) engine and as well as adding Redex to the fuel I was advised to pour some down the carb (with the engine running at quite high revs) so a small amount down the plug hole would do the same. Misfiring was cured after driving a few-ish miles. (Can't remember how many).

You say compression is low on No. 2, you haven't heard a knock at all prior to the problem have you? Did it suddenly and noticeably start misfiring or has it gradually got worse? Have you checked for water loss and water in the oil and/or oil in the water.

 

[SJX]

For nothing more than slightly informative babble, and I admit its slightly off topic (so I do apologise) the best way to decoke/steam clean the internals of an old style engine (Crowns, valves and ports) was not to use redex, but to teaspoon water in very small amounts down through the carb at half chat on the revs. The effect was to superheat the water vapour in the combustion chambers which in turn steam-cleaned the insides without all the smoke and days of oily fog. Anyone that has ever had a head gasket blow 'water-to-pot' will know exactly how clean it all is inside once its stripped! Only ever done this on single pot motorcycles myself and the occasional lawnmower - I wouldnt recommend anyone tries it on their new MB but its a ye olde mechanics trick of years gone by and if nothing else an interesting method !

 

[paul cable]

thanx all for advice..i ll let you know whether it worked or not.no grumpy,no water loss,water in oil,knocking sound..was hoping full change of coils,plugs ,leads would do it.did mis fire about 1 month ago for a day then rectified itself.now it s mis firing all the time...