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Discussion Starter · #1 ·
Hi guys just joined the forum. I’m trying to return a mini to a dealer I bought it from a week ago. It has leaky valve stem oil seals that have damaged the o2 sensors. My question is this. If I’m not successful returning the Cooper how much would I be looking at to get it fixed? It’s a 2009 Mini Cooper Clubman and I believe it’s driven quite a few miles with this problem, is guzzling oil not smoking so you would notice and other than that drives great.
 

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they do use oil anyway but what i do with them when using to much oil i run them for 50 miles with a can of seafoam in the engine oil this will clean any crud causing piston rings hold off the bores etc its one of those it will cure a engine that uses oil because of dirty crankcase etc it wont fix a worn out engine,,, i had honda 2.2cdti one with 200k on it had very dirty oil i stuck a can on that run it around for 100 miles,, before ei used it the oil filler cap hole was like a steam train of oil vapour and ring blow past, after it was prettymuch all gone , worth a punt might find its dirt that is holding the seals off the stems,, that said more likely will need seals doing,,
its possible to do them without removing the head ie feed strings inside the bore . and push piston in to closed valves to hold them while make a special tool up to push the valve springs from the top and remove the collets.
down side is if its a valve worn out you wont know,, also will need to remove the timing chain and cam shafts big job still,, sometimes worth the extra few hours and do the whole job right in first place rather than need to do it again,, on a over 100k engine personally i would pull head do a engine refresh ie sump off new piston rings and big ends head gasket timing chain etc while its all off to water pump and thermostat housing , think on ebay there is a kit £177 includes it all
 

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Discussion Starter · #3 ·
Mike thanks for your reply. It’s a garage that has diagnosed the faults. Engine management light came on day after I picked it up showing a faulty o2 sensor. They said it’s burning oil and advised it’s probably the valves. Cars done 125 k I won’t be doing a lot of miles in it and will look after it but shouldn’t have to really pay all this when only picked it up a week ago. Unfortunately I’m not mechanically minded and anything that would need doing would need to be done at a garage.
 

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not knocking the garage in anyway as on most cars a 02 sensor fault is just that,, but on a prince engine its never that straightforward will explain the chain of events,,
timing chains stretch rule of thumb is around 60.000 miles replace it this ensures dont have the outcome you are having at present,
so what happens is the chain stretches some might do 100k before snapping off top guide or chain slips around worn out bottom sprocket and tension cant cope with the length of the chain,, trouble is the engine has now run with a retarded timing and this causes a lot more heat and pressure it also effects the overlap on exhaust valves and inlet valves as well,, ie overlap is how car designers add power to a engine by using opening the exhaust valves and inlet valves at same time briefly this causes a low suction effect within exhaust and inlet tracks and suck more clean air in to the cylinder as such, this must be set to within a few degrees, trouble is timing stretches in such a way as its got twin cam sprockets it plays hell with it and drops unburnt petrol on to 02 sensor ie upstream one, this also causes massive heat within the cat and exhaust ports this will melt 02 sensors and valve stem seals even melt the cat in sides,, on some cars more so turbo cars will melt and crack valves also head gaskets as well,, and very bad ones will do same to piston rings, piston rings are made to with stand the heat of normal running but those engines driven for 40k with timing retarded and a bi-product would also be the driver would be making up the power short fall with pressing the throttle even more and thus giving more fuel to the problem,
also at 127.000 miles on a car driven for a fair while with timing issues i would fear the worst case and you would be so gutted to spend out the money for stem seals and not do the chain ie the real issue to find within a 10k the same issue is back again as so many have, ironically i have over the years turned my back on a lot of work from people who say just do the stem seals to later find out another workshop had just done that to find it snapped a chain shortly after doing it,
hence why would try the seafoam it see what you have got after a couple of weeks driving it around then rather use 5/30w engine oil use a fully synthetic 5/40w see what that brings you worth a punt,, but still you need to know what state the timing chain is in,,
another thing to think about there is a revised thermostat housing that reduces the coolant temps this could also help oil burning ie engine oil is tested to 100c prince engines are 109c on pre update housings as its a piloted thermostat on them its controlled my the cars mev17.4 ecu,, very complicated design of a engine and then add the short coming of psa and bmw and mini a lot of garages turn their back on them or slate them,, i know from years of dealing with them its all preventing the bad stuff ie chains and heat control etc,
 

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Discussion Starter · #5 ·
Thanks for your reply. Diagnostic said a faulty 02 sensor was logged at 101k and it’s now done 127k. I think they’re basically saying with it also burning oil there’s a high chance it’s the seals that are leaking obviously won’t know until it’s looked into. I was told the chain had been replaced but no paperwork to back it up. No knocking engine nice and quiet. Can be a bit apprehensive or jerky from cold start but fine when warming up. Has full service history and twelve months mot. Think the dealer has removed the fault light prior to me purchasing. Trying to return it with help of trading standards.
 

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Discussion Starter · #6 ·
You just don’t expect this from a car dealer do you selling it with these issues. If I cannot return it even though trading standards say I have the right to do you think it’s worth spending on it to do these jobs and timing belt? I’m assuming it would be well over a grand to fix.
 

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at 127k it prob at it next chain change point i have seen them at 40.000 miles snapped many times then i have seen some at 100.000 and sound ok but drive horrid etc, would deffo be worth asking them to check if chain is ok either measure the trow on tensioner or pop rocker cover off and lock it all off see where the camshaft locks sit, or if doing stem seals it will need to be re timed anyway i would deffo at that point fit a timing chain kit no extra labour really below link good value chain kit this seller specialise in bmw saab mini stuff so good gear as well, would if you buy it and give it to the garage to fit to car when they do the rest of it will save a few quid
 

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Good advice if I get them to fix it I will get the chain changed too.
you will also need two camshaft bolts and crankshaft bolt as well they are cheap from main agents £4 each ish I know what your saying is getting up on miles wont be a cheap job sometimes its worth cutting your losses and move on from it
 

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I have always gone for low mileage cars but fell in love and thought with a full mini dealership history it must have been motorway miles and hoped I would get a good few years out of her.
always a gamble
 

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Discussion Starter · #12 ·
I’ve been looking at buying sensors online. It’s saying pre cat or post cat. I’m not sure if my car is pre or post? It doesn’t look like too big a job and I’m considering doing it myself. Any advice on the best make?
 

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below link appears to be genuine be careful there are Chinese copies around, genuine sensors normally have bosch stamped on them not just on the box, link beloew i believe to be genuine
upstream ie pre cat sensor
or try the link below give reg number etc

just dont bother with cheap ones they dont last, will also need a special socket link below
above link not bad kit better to buy the kit rather than just one size as such as somewhere in future you will own a car with a different size then have to buy a few times rather than just once
 

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Discussion Starter · #15 ·
Hi mike
Replaced 02 sensor and removed fault code with obi. Mini is running so much better!! Faster and smoother and light has thankfully stayed off. I have a question. When I bought the car it had hardly any oil in. When I mentioned this to garage they put 2 and 2 together and assumed oil was leaking from valves and that’s why sensor needed replacing. I put plenty of oil in and am checking levels weekly. No changes in levels. Can I assume it’s not leaking and was just really low on oil? Is there a way of finding out if they are leaking without going into engine?
 

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they use oil from new main dealers say 1 litre to 300 miles is good end of it all a bit different i guess based on how hard driven, i would also be very suspect of chain stretched even more so on a engine low on oil, as even cars that have been checked every 300 miles and topped up so oil never get to low stiff do the chains, low oil cars tend to do it earlier it would seem, i live by the 60,000 miles with them ie on or around this the chain will be stretched worth changing it like a cam belt then they stay good, a faulty or fault code for a upstream 02 sensor always gives me alarm bells to timing chain on the prince engines. ie car can be running but will eat fuel and will not rev all way to red line without a holding back feeling in 3rd gear if chain stretched and running retarded also this increases the amount of time fuel is being sprayed in to the engine this increases the heat build up and all adds up to more pain with running to hot for to much of its time,
now you have new 02 sensor it needs a good long run to reset adaptations ie ecu to relearn the settings when driven harder than normal is what i do ie a good 20 miles hit motorway speeds 4000 revs most of it this should clean out the cat that would of been effected by faulty 02 sensors, also worth sticking can of cataclean in it as well
 

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Discussion Starter · #17 ·
Thanks for your advice mike.
I have put a cat clean in when changed sensor. Haven’t given it a good motorway blast though so will do that today. Am thinking I will get it in for an oil seal replacement and a new chain while they are in the engine. And will try a cat clean every three months to keep on top of it. I was quoted £825 for oil seals doing is a chain replacement as expensive do you know?
 

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Thanks for your advice mike.
I have put a cat clean in when changed sensor. Haven’t given it a good motorway blast though so will do that today. Am thinking I will get it in for an oil seal replacement and a new chain while they are in the engine. And will try a cat clean every three months to keep on top of it. I was quoted £825 for oil seals doing is a chain replacement as expensive do you know?
if were my car would bite the bullet do the job once and right, ie pull the head fit new stem seals this also gives you chance to see if valve inserts are worn out or not ie the steal pressed in inserts the valves run in new gasket and new head bolts and throw a chain kit on it at same time as to remove the head the chain needs to come off anyway,,
if your car was a ultra low 60k engine then i would say leave head on do the stem seals with rope on the cylinders and special tool to undo the spring collects, i would ask who ever is doing it would they do a fixed price deal, for some cash maybe should save a whole load of extra costs then, chain kit mini £100 head gasket £40 head bolts £21 stem seals £15 cam and crankbolts £20 tops plus oil and filter change etc, shame your not closer might of been able to work something out
 

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cornwal/devon border
 
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