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I have coolant in the oil & oil in the coolant but didn't overheat & compression fine
Stock Problems/IssuesDiscussions related to warranty related issues and repairs, or other problems with the OEM parts and software for MINI Clubman (R55), Cooper and Cooper S(R56), and Cabrio (R57).
I have coolant in the oil & oil in the coolant but didn't overheat & compression fine
I've got a 2012 Clubman non-turbo. 138k miles.
As the title says, I have coolant in the oil and oil in the coolant but it didn't overheat and compression is great (180 or more) on all cylinders.
I can get it towed to the shop and have them do diagnostics (like a camera in the cylinder and all that type of stuff), but that will cost me towing both ways and diag costs.
So I am trying to avoid that.
I know it's impossible to tell any issue on any car without personally looking/testing, but what does your gut tell you?
Is this a heat exchanger which has cracked internally, or possibly heat exchanger gaskets? Does the non-turbo have a heat exchanger?
Or is this a part of the head gasket that separates oil and coolant flows but does not come into contact with a cylinder? Mini shop is saying they have never seen a head gasket failure of this type (all have been of the overheating/bad compression variety).
is there a third place on this vehicle where oil and coolant are separated by a gasket?
I am thinking/hoping that it's the heat exchanger and I'm thinking I will start by pulling it and checking it. What do you guys think?
Does this symptom ring any bells? I don't have a ton of money so I am trying to do the repair myself if possible. I do have a lot of experience working on cars but never a Mini before.
Thanks in advance!
Last edited by shipbreaker; 07-12-2019 at 11:18 AM.
I'm not familiar with the Non-S engines, but if you do have a heat exchanger, and provided that you're sure your head gasket still holds, then yeah, I'd say the heat exchanger is likely where the cross contamination is taking place. Just also keep in mind that the oil-filter-housing is probably the site where the heat exchanging is happening. I see that in a lot of other BMW motors. For the MCS models, heat exchanger is a direct peripheral add-on to the oil filter housing. So yeah, take a look at that and you may find something.
Shipbreaker, I"ve been down this road; I have the N12 engine, and you have the N16; they are similar with the main difference being the volume optimized oil pump in the N16. In my case my cylinder head was warped, but I caught it before it became catastrophic. You don't have an intercooler (heat exchanger) like the turbo engines, and you don't have an oil cooler either. Most intercoolers and oil coolers are air over oil, so engine coolant isn't a factor, but I've heard that the N14 & N18 engines have coolant lines that run to the oil filter housing.
Last summer I detected a black oil film on the inside of my coolant recovery tank. The car had about 125K miles on it at that time. The car started consuming oil between my 7,500 mile oil changes right about the 100K mile point.
These were my compression and leak down numbers; engine was hot; throttle valve full open during the test. Your next step would be to perform the leak down test.
As you can see my dry compression numbers were good for a car with this many miles, but the leak-down in cylinder #1 was much higher than the other cylinders. So, I pulled the cylinder head, and it was warped; the machine shop had to take .006" off the head to correct the problem. Like you, the car had never been overheated, and I performed a complete cooling system refresh (all new hoses, coolant recovery tank, coolant, water pump, etc) at the 10 year point. There was a thermostat failure at 85K, but that was for the mapping portion of the thermostat (engine running too cold).
In your case, you say you have 180 PSI in each cylinder or "more". How much more? Post all the cylinder numbers; you are looking for a 10% (or more) difference between cylinders. So let say you have one cylinder at 180, and another at 200; that means you should consider a leak-down test.
OBTW, when I did the leak-down test, I didn't see any bubbles in the coolant recovery tank, and when I sent an oil sample to Blackstone labs they didn't detect any coolant in the oil, but I could still see a black oily substance on the inside of the coolant recovery tank.
1 year later after the repairs, the car is running well. The engine still consumes oil (I'm at 135K miles now), about 1 quart every 3K miles, but that's to be expected at this point.
If I had to do it all over again, I would have found a salvage MINI with low engine miles and swapped the engine. For the money I paid on tooling alone, I could have purchased a low-mileage engine.
Wow guys thanks so much for the detailed and helpful responses. To answer one question above, the compression numbers were all in the 180-185 range, so fairly tight I guess. Because this engine does not have the heat exchanger it sounds to me like this indeed might be a cylinder head issue. Even if it's not, however, more and more I'm thinking it's best to just sell this and move on. I might try to get $2k or so for it as-is on eBay or something like that and just move on with my life. The car is in fantastic shape otherwise and it is a 2012 (that is running) so hopefully I can squeeze $2k out of it. I don't know. Unfortunately I have a lot of things going on right now and not a lot of time to take this apart. If I do end up getting into this I will certainly report back with my findings. If I have some time in the next week or two, I will possibly do a leakdown test and pull the valve cover. I will report back with what I find in that case. Thanks again guys I really appreciate it.
Did you check leakage in the oil filter housing connection to the coolant, even though it has no oil cooler it plugs the coolant like a dummy plate on the upper portion and coolant can still seep into the oil past those gaskets like in the post below.
How do you check for leakage? You'd have to remove the oil filter assembly from the block. On the non-turbo engines where exactly does the coolant enter and leave the assembly? Please post an updated picture to identify the coolant path. Where would we see the seep? What plugs the coolant like a dummy plate, the cooler (he doesn't have)? That's the way your sentence was structured.
Updated the sentence a little more. It does not enter and leave more or less the engine block is the same and the path the coolant usually takes is blocked. You have to pull the filter, change the gaskets or look at the old gasket for deterioration.
Pretty much if you have some mileage on that car, it's best to replace the gaskets anyways. Those gaskets get brittle after repeated heat cycles, it's common to have leaks through those. It's a simple and cheap replacement, so you're not really throwing money at the problem. But for your NA motor, that's pretty much the common point where oil/coolant can cross-contaminate. The less common point would be what MiniTobe has mentioned, the freeze plug inside the valvecover housing. And judging from your compression readings, I highly doubt it has to do with the head gasket in this case.
Updated the sentence a little more. It does not enter and leave more or less the engine block is the same and the path the coolant usually takes is blocked. You have to pull the filter, change the gaskets or look at the old gasket for deterioration.
So in the picture above (cooler for N14/N18 engines), I see an external cooler where the water enters an leaves. The ports on this assembly that are blocked off on the N12/N16 engines are for the oil to flow into an out of the cooler. So, the only place the oil and water can mix is if the cooler fails internally. I don't see any water inside the engine block at this point, so how can a gasket failure where the filter assembly attaches to the block allow oil to mix with the water? Anyone have a schematic? Here's what I think (correct me if I'm wrong) is going on.
Can the oil cooler fail internally? Sure. I see heat exchangers fail all the time in industrial facilities. The fastest way to tell is to pull an oil sample and tell Blackstone you suspect water in your oil. I've attached a sample report. Cost is $28.00.
See the oil stain that is oil. See the no stain that is coolant in that top right hole, when i did my gaskets thats what i saw and changed both oil and coolant as some residue mixed. I drain booth before i did the gasket change.
Thank you for sharing! MINI doesn't do a very good job of showing cooling system flow in a formal schematic of the system. It may be out there, but I haven't found it yet.
Now the questions (sorry, but I'm trying to understand the flow). If the water comes in from the block, goes through the cooler, and then re-enters the block. What are the external cooling hoses for? If the coolant enters the heat exchanger from the block and then flows to the radiator, why are there two coolant hoses?
If the two ports (without the stain are coolant, how does oil get into the heat exchanger?
If you pour water into the two ports without the stain, where does it come out?
Perhaps it works like this with the oil and coolant flowing through separate paths in the heat exchanger before it exits.
Wow! I don't like this design if this is how MINI did it! But I'll bet their engineers are smarter than I am. The good part is that two gaskets have to fail before coolant and oil can mix.
Mkov608, in regards to the coolant flow design, I can tell you that on the oil filter housing for the N14 and N18 engines, those filter housings are routed with the heat exchanger. On the N12 and N16 motors, those filter housings look similar to the ones on the turbo engines, except there aren't any heat exchanger. Then to answer your question as to why those two hole (without stains) are even there, well this originates all the way back to whence they made this engine and it's peripheral component designations. MINI/BMW's goal when they made this N-series engines was to make a single engine and utilize as less parts as possible to serve both turbo and NA platform vehicles. The N-series engines actually did what they aimed at and therefore you see what you see today.
On the N14 and N18 motors, heat exchanger is there that during cold start, the coolant gets heated up quickly and therefore it can serve as an oil warmer in the heat exchanger to expedite the oil lubrication efficacy and delivery when starting up cold, this helps lubricate the engine faster, and more importantly it helps getting the turbo bearings all primed up asap. Then once the engine is warm and you drive the car hard, the heat exchanger acts as an extra cooler to help cool the oil down so that it won't coke up the oil and turn it into hard carbonized deposits. This is also very critical for turbo cars because the turbo's bearing lubrication holes are quite small and any deposit or coke build up in that channel will cause bearing failure. On N12 and N16 motors, there isn't a turbo to care for, so they removed the heat exchanger. For the oil filter housing without the heat exchanger, and to produce the oil filter housing using the same mold cast, all they need to do is block out the channel to the heat exchanger and let the water by pass. It saves manufacturing cost of having to make two separate casts for the oil filter housing.
Think yuptec already got it for you. Pretty much PSA base designed and them BMW worked with the design to find an engine that was a good fit for MINI and did meet the efficiency standards. Vanos i think was re-engineered a little by BMW group themselves. When i talked to BMW/MINIUSA group about it once I was actaully there for the launch of the N18 2011+ engine on MTTS 2010.
Yes that was my hand and watch in the pictures from Motoringfile when took when i was talking to the MINUSA people about PSA engine design.
They stated that at first, they chose the engine as it did not compete with anyone in the USA(No other US car manufacturer was using it) or a large part of others globally, it was not shared.
I pulled the valve cover. It turns out it was a freeze plug. The freeze plug between the two cam gears. It popped out and was lodged down between the timing chain/timing chain guides. So that is what caused this. Unfortunately the head still has to come off and be sent to the machine shop but I thought I would share what I found out. Also good luck to anyone who ever has to change an exhaust manifold on this car. Whoo-boy. The front clip setup where pretty much everything fits together like a puzzle and you can't take any one item out without taking out another 10 items? Soooooo much fun. FFS I would like to wring the neck of whoever designed the front end of this car. Never seen anything like it.
Also add to that the freeze plugs fitted on the cylinder head. take the valve cover off and you should be able to see them..
another easy way to test, is blow some air in the coolant reservoir and listen to where the sound is coming from.
check those before towing, very simple
This was my problem with my 2010 Clubman . . . freeze plugs blew allowing coolant to get into the internals of the engine. $7,300 later, used engine put in and I'm back on the road. Working with MINI US to try to get them to cover the cost. I am 67 years old and have never, ever heard of freeze plugs failing on any car. Mine failed in April in Michigan so no freezing going on at that time.
07-12-2019, 09:22 AM
