Recently I have had to put a lot of oil in my 00/W BMW 523 Touring but it doesn't seem to leak from anywhere. There is also a clattering noise on start-up which disappears after a few seconds.
Now I discover that on unscrewing the coolant filler cap OIL comes out. My immediate thought is the cylinder head gasket, are there any other likely causes?
If this is the problem, am I better off going to a BMW dealer, a non-franchised BMW specialist or an engine rebuilder, and does anyone have any recommendations in the Cambridge/Huntingon area?
TIA
|
Unless your engine has an water/oil heat exchanger ('oil cooler') fitted then head gasket failure is the most likely cause.
There is a specialist BMW engine rebuilder located (I think) in Essex - someone else will advise. They deal nationally.
|
Is it an automatic? if so, also check the radiator side tanks if you can, see if they have thin metal oil pipes going to it, fastened on with banjo bolts, if so it may be the ATF cooler built into the radiator on some if not all auto models.
|
|
|
Thanks to all who offered suggestions!
The car does not have an oil cooler so I investigated further and drained the radiator (blue plastic plug) and got 3 litres of liquid out. It was ALL oil (it looks and feels like oil and does not mix with water, or with coolant taken from another car).
There is no evidence that there has ever been water in the cooling system (no rust or oxide sludge), there is not a trace in the drain bowl I used.
I have only put about 2 litres of oil in total in the engine since buying the car 9 months and 8k miles ago so it must have been there when I bought the car.
Can someone offer an explanation for what is going on??? Yes I have even checked with the manual that I know which the coolant filler cap is!
TIA
|
Possibly Same or similar prob I had with a rover. I know. as person who bought the car informed me of reason. Cracked head ie oilway into waterway. oil pressure greater than water and so water was replaced with oil.it seems it also had faulty oil pressure valve.
--
Was mech1
|
|
|
Thanks to all who offered suggestions! The car does not have an oil cooler so I investigated further and drained the radiator (blue plastic plug) and got 3 litres of liquid out. It was ALL oil (it looks and feels like oil and does not mix with water, or with coolant taken from another car). There is no evidence that there has ever been water in the cooling system (no rust or oxide sludge), there is not a trace in the drain bowl I used. I have only put about 2 litres of oil in total in the engine since buying the car 9 months and 8k miles ago so it must have been there when I bought the car. Can someone offer an explanation for what is going on??? Yes I have even checked with the manual that I know which the coolant filler cap is! TIA
That's really wierd. I cannot believe that you can really have been running around with a cooling system full of oil for the past 9 months. All the hoses and seals would have disintegrated.
I think it must be a water/oil emulsion, cause by a cracked head or similar - as others have said.
Whatever, you have a heck of a job on your hands because you need to flush out the entire cooling system and then find out where the oil is getting in. The system must be thoroughly cleaned of all the oil otherwise all the hoses and seals in the system will deteriorate and you'll have leaks all over the place with overheating etc etc.
|
|
|
|
|
There is also a clattering noise on start-up which disappears after a few seconds.
Hydraulic valve lifters, probably.
|
|
I can recommend a couple of dissolved dishwasher tablets poured into the system filled with water and 15% coolant, run for 30 min trip, drain, refill, run, drain refill with coolant.
|
|
When the heads go on Merc. M103 engines you get a certain amount of oil in the coolant. I've used caustic soda in water to clean them out (probably the same a dishwasher tablets ??). I then replace all the hoses and keep an eye out for waterpump leaks.
|
|
|
|
I hope that a BMW expert like Aprilia will see this but of course any source of advice welcome!
I have a 4 yr old (E39) BMW 523 SE Touring which I recently discovered had a cooling system entirely full of OIL. The local dealer has now had the head off, and reports as follows:
\"On removal we have observed that there was a polished area of
the cylinder head gasket which prompted us to check the cylinder head and engine block for distortion.
Cylinder head distortion allowance
0.038 mm / actual 0.051 mm
Engine block distortion allowance
0.038 mm / actual 0.076 mm
From our observations we can only recommend a replacement engine.\"
These tolerances mean a worst-case gap of .005 inches (in old money), which is not a lot. I wouldn\'t be at all surprised if you took the head off _any_ engine and found this amount of distortion after 75000 miles.
I have asked and they say the distortion in over the whole face, there is no local dishing or pitting. Are BMW and/or the dealer being over-cautious in saying a recon engine (at GBP 6000 for parts and labour) is the only solution?
[ The full saga can be viewed at www.bmwland.co.uk/talker/viewtopic.php?t=9426 ]
TIA chris
|
Sorry, realise this should have been posted as a continuation of an earlier thread, www.honestjohn.co.uk/forum/post/index.htm?t=24925&...f, but can\'t see how to edit postings, maybe Mods will oblige?
ChrisJ
{Done. DD}
|
First off, Chris, I wouldn't believe anything your BMW dealer tells you without getting a second opinion - not when £6k is at stake!
Check out good BMW dealers on this website:
www.unixnerd.demon.co.uk/garages.html
As you'll see, a lot of dealers aren't that well rated and some may recommend expensive but uneccesary work. It may be worth contacting one of the higher-rated ones for a second opinion.
Back to your problem - It is obvious that you have a problem with distortion of the head and block (not unusual on BMWs) but I think I would be consulting a local engine rebuilding specialist, or maybe a good independent BMW workshop. I would think a bit of machining of the block and head would be worth a try - certainly that's what I would do, rather than dive in with a £6k factory replacement. I know your BMW is stuck in bits at the dealers, so be prepared to have it trailored away rather than let them hold on to it and land you with a big bill.
|
I would agree with the advice given by Aprilia.
Further to that, I would be interested to see how they measured the block surface in-situ to such accuracy.
However, I think both surfaces would probably clean up without having to take more than a few thou off each.
While the head is off, it may be worth getting it pressure tested to make sure there are no hidden cracks. Are these engine prone to cracks Aprilia?
I imagine, the dealer is saying that you should put a new engine in purely to cover himself. If there is a problem with the new engine, he can get BMW to shell out for any repairs. If he gets the machining done, he doesn't have that recourse if the fault turns out to be elsewhere.
number_cruncher
|
Completely agree with the above - a few thou' off each would probably do the trick. But have it pressure tested (only about £60 at most).
BMW head castings have traditionally been prone to cracking because of air inclusions (i.e. bubbles) in the casting. But this is a recent head and you should be OK.
The BMW dealer is probably pushing you down the new engine route because it is safest, least hassle and by far the most profitable for him.
|
|
|
Thanks both.
Can you machine the block in situ? otherwise it will have to come out, breaking e.g. all the aircon connections and incurring most of the labour anyway (but not the parts cost).
My own inclination (and as suggested in the BMWLand link above) is to
i) check the measurement method in person, they say they have a special straightedge (without seeing it IMHO it would need to be an I-beam to have 1 thou accuracy over that length) and verify there is no local dishing or erosion
ii) get them to send the head out for pressure testing and skimming. If this brings the head flatness to zero then the worst case gap will be .076mm (3 thou) which is the max allowable (head and block)
iii) hope a new gasket will get the car back on the road, maybe permanently.
If not I can start again with a specialist engine rebuilder, anyone got any suggestions (pref within 50 miles of Cambridge)?
ChrisJ
|
Hi Chris,
I think you have outlined a very sensible approach to the situation - FWIW I would be doing similarly.
As you are considering the possibility of not following the BMW dealer's advice, you should be careful over how the garage will guarantee, or warranty their work. I'm not a legal eagle myself, but I can see potential concerns.
number_cruncher
|
|
Three friends at work with 5 series BMW's all had head gasket failures (one car three times!) caused by the head bolts slowly 'pulling' the aluminium threads in the block. They all required 'helicoils' (thread repairs). BMW now has steel inserts cast into the block to prevent this problem. It is my guess this is the problem in this case.
|
GIM,
That's very interesting - it really doesn't take much 'pull out' on threads like this to relax the tension on a stiff cylinder head bolt.
For example, I would estimate that typical cylinder head bolts only stretch by about 0.2 mm during tightening. Strech bolts obviously go further, but that doesn't give you any more freedom on relaxation. (They relax down a line parallel to the elastic modulus line, rather than the plastic)
Helicoils are very good for this kind of problem - they move the thread stress out to a larger diameter, hence larger area. While it probably isn't a problem on longer bolts like cylinder head bolts, getting helicoils in straight, normal to the fastener axis, is vital. If they go in at an angle, the bolt gets a fluctuating bending stress as well as tensile stress - this shortens the fatigue life of short bolts significantly.
Well fitted heli-coils are a worth considering if you find thread pull out in the block.
number_cruncher
|
My local ind BMW specialist also told me that there have been broken bolts on this engine and BMW have changed the spec to ones that stretch more.
Plastic failure or creep in the aluminium would to me suggest that the threads were undersize in dia or length. They seem to have cut out too much weight when they introduced the M52 engine! Shades also of the Nikasil cylinder bores and plastic water pump impeller.
I have just re-read some of the earlier comments, surely caustic soda is not a good idea for cleaning an aluminium cooling system? As I recall Al dissolves in NaOH to form sodium aluminate. I was doubtful about dishwasher tablets also but their caustic action comes from the silicates in them so is presumably not as alkaline, they don't seem to do any damage to (comparatively pure) Al saucepans although I'm not sure what it would do to castings with their higher alloy content.
BTW Sainsbury's seem to have changed their supplier this year and the surface finish you get is now much less dull and tarnished (not entirely sure this is a good idea, depends what is being removed, if it is the oxide layer it will re-form each time so it is taking some Al with it)
ChrisJ
|
|
|
|
|
www.pumaracing.co.uk if he is not too busy.
|
|
|
|
|
|
