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Discussion Starter #1
Hi there just a quick question I have got water in my oil and have assumed this must mean head gasket has gone but is there anywhere else water could mix with oil Assuming there is no serious prob like cracked engine!

Cheers mart
 

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cristo
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Head gasket, cracked head, cracked block all come to mind. Do some models have an oil cooler?
These would all put coolant into the oil; you might be able to see the green dye in the murky mess.
Sometimes condensation in cold weather can bring a little water into the oil from the atmosphere.
 

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www.cityminicarhire*****
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9 times out of 10 the problem is with the head gasket.

Get it checked out by a garage asap, you could end snapping your con-rods/crankshaft and could result in an engine replacement.

Good luck
 

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Discussion Starter #4
cheers for replies,

decided to try the cheapest option first and have striped it down and replaced head gasket. All back together now but unfortunately same problem. Gutted as well as I re-ground valves while i was at it, cleaned all oil ways and seemed to removed the annoying tappet noise. Infact engine sounds nicest its ever sounded, unfortunately I'm losing lots of water and new oil is already light brown sludge:-(

There was no obvious sign of damage on head but i guess I prob wouldn't be able to see it anyway. How much is it to have them pressure tested?

Are garages able to test it without taking head off?
 

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As far as coolant goes, you can pressure test that system with a tool. Coolant entering oil and its not a head gasket....hmm...is it billowing white smoke out the tail pipe and overheating? You can also check condition of plugs. If lots of coolant is getting in there it will "steam clean" that plug. Too much water and it will blow the plug out and possibly bend a rod! I'm very new to Mini engines to know more about where else this could happen. Don't rule out the head gasket again, Did you get a compression or leak down test done ? Some cars the intake manifold has coolant to warm up faster, that could be a possible spot.
 

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Discussion Starter #6
nop there is no white smoke or over heating(as long as i keep the water topped up). Its is very bizare as looking at it and normal driving you would not even know there was a problem.

Will do compression tests this weekend and then think i need to get someone to leak test on head! don't suppose they can do this while it is still in car can they? Will also check plugs more closely while they are out but think they all looked ok and same!

Any ideas for a probable cause would be much appreciated.
 

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coolant pressure leak test is where they put a pump of sorts in place of the rad cap and take up to the normal operating pressure (my 04 stnd mini that's 16 lbs) and watch for leaks dripping, and see if the pressure holds or if it leaks down. Obviously you have a major problem if Oil and water are mixing.

A leak down test of the cylinder is like a compression test, but uses an air hose to provide pressure and you don't crank the starter. Just plugs into the spark plug hole at TDC and you see what sort of pressure you can get in each cylinder, write them down and see if one is messed up or not.

I'd bet you have a problem with the head being flat or block and its still got a messed up head gasket problem, but you'll find out soon. The leak down test will show if you have a head gasket seal on each one.

Don't drive it you need to get it fixed soon as water where oil goes can cause a lot of corrosion fast.

If it is leaking, one thing you could try - retorque the head bolts to spec. Some cars call for replacing the head bolts every time you dissemble. Did you do that? curious to see how this plays out.
 

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Discussion Starter #8
nah didnt replace bolts but as they are not stretch bolts i would have though they would be ok, also tightened them up to correct torque so that should be ok! Will let you know how compression test goes. As for the leak down test, is this something they need head off to do?
 

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Discussion Starter #9
right quick update, did a compression test and they all came in at 100 psi, which is good that they are all the same but seems quite low, anyone know what they should be?

Also there seems to be oil and water getting into the intercooler, so maybe this could shed some light on my problem. Maybe the water and oil could be mixing within the super charger?
 

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Boosted engines don't have high compression ratios as to help control detonation.

I'm not sure about the cooling system used for the SC, I'm guessing here but perhaps it has coolant in there, most do a have oil loop for the bearings. Sorry but I have not seen breakout picture of it, but if it does have both coolant and oil, have a test done to see if the coolant hoses/passages hold a moderate pressure (8lbs or so).
 

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Discussion Starter #11
ok cheers for reply so maybe ok then.

Having done a bit more research SC has a water feed but has its own separate oil so dont think it is this. Back to head so need to get some tests done. Oh yeah also turns out they are stretch bolts in head so perhaps should have changed them too.
 

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Oil cooler as a source of coolant contamination in oil

My 2005 s model had a similar issue of coolant in the oil. I changed the head gasket (and a valve job) but still had contamination issue. I now suspect the oil cooler which is attached to the oil filter housing. Any thoughts?
 

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My 2005 s model had a similar issue of coolant in the oil. I changed the head gasket (and a valve job) but still had contamination issue. I now suspect the oil cooler which is attached to the oil filter housing. Any thoughts?
. Same prob with my r53 leak found in heat exchanger/ oil filter housing, its a pig to remove though !
 

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I had the same problem that all of you guys had. I changed the head gasket and the bolts but the water and oil still mixed. Turns out it was the oil cooler! So that was the culprit behind my car messing up.
 

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Go to Youtube and watch the video "To all Mini Cooper S Owners Important Info about Core Plug Engine Failure" The core plugs fall out on top of the cylinder head. That fills your crankcase with water very quickly.
A good test is to take the oil filler cap off and have someone blow into the coolant filler. You will hear it if it's the core plugs.
 

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To anyone still looking for answers on why they have Coolant present in engine oil on any Mini.
There are 3 main reasons. Nr.1 will be mostly seen in N12 engines. But not uncommon in any other boosted version.

1. Seals gone in oil cooler ( Oil filter housing seals ) Most common and cheap to fix.
Mini must be in "Service position", front end off, exhaust manifold off, oil filter housing off. Drain coolant prior to working being carried out.
2. Headgasket gone or head cracked.
3. Head core plugs.

If repairing 2 or 3, both repairs 2&3 should be completed at the same time to avoid any future issues.

If vehicle was used for longer period of time with above issue, I would also strongly advise to replace the Pre-Cat Lambda/o2 sensor.
Flush intake manifold, clean crankcase breather pipe, clean crankcase breather valve.

This should be followed by good engine flush (Liqui Moly Pro Line) and Oil replacement.

Best of luck.
 
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