Looking at a car with low miles, sub 50K, 2011 R56 has blown head gasket. N18

Going in morning to look.

I'm a mechanic by trade... and familiar with common causes of this (overheat etc)... but not familar with N18.

Wondering what are some of the issues on this engine that may have caused this to happen?

Will simple OBD scan show overheat incidents in recent memory?


Any help is much appreciated.




.

 

Overheat (coolant over temperature) events are not part of the OBD2 world. Mini might log in a proprietary way coolant over temperature events.

As I'm sure you know, the engine doesn't have to experience a total or engine wide over temperature event just a localized over temperature event is sufficient.

If the cooling system can't hold pressure this can allow a pocket of steam to form in the head coolant passage and this can result in an extreme over temperature condition which can can cause the gasket to fail. In severe cases the alum head can "soften" where it gets too hot and the head bolt's torque in that overheated area reduced which lets the gasket leak. While the coolant is probably hot (212F or hotter) the coolant does not get that much if any hotter that it would normally. It is just that at the hottest spot in the engine, around an exhaust valve, the heat managed to form a pocket of steam and once formed this prevents the coolant from at least making contact with the area covered by the steam pocket. In severe cases the steam pocket can block coolant flow entirely. In these cases the head overheats, sometimes severely, but the coolant temperature can barely register an increase.

Anyhow, if there is any other head gasket failure mode unique to the N18 engine I'm not aware of it. Thus I expect the N18 engine and any failure of its head gasket can be due to the same causes of a failed head gasket for other engines.

 

What was done to determine a headgasket failure?

In the event of an over heat, the engine goes into reduced power and displays the overheat symbol. Did the owner verify this?

 

Once upon a time I had a dealer diagnose a failed engine as a "probable blown head gasket". Turned out to be a blown cylinder wall. Granted, this is "unusual" but you need to be cautious about a vague diagnosis. Try to get all the conditions leading up to the time of failure, then make your decision.

 

Was this in a Mini ? If so, how many miles?










.

 

All seller says is white smoke from the exhaust... and then the engine stopped running.
Has coolant in the cylinder but not in the oil, when a sample was drained from the pan. Checked from the pan as coolant settles.
Oil was used, and topped up when sample was taken.

No cross mixing of oil in the radiator either.











.

 

Thank you to all that have replied so far.

Sincerely appreciate the input/help !

I am a mechanic by trade... with 40 yrs experience.

I'm looking for Mini specific reasons that head gaskets have gone on N18's.




.

 

Yes, my N14, with about 90K miles. However, the engine was heavily modified and I was on a drag strip when it let go.

I just wanted to mention this "mis-diagnosis" by a pro. Knowing all the conditions and symptoms are critical in getting it right. Your latest description makes it sound more like the head gasket. I doubt that N14 or N18 engines have any new ways to blow a head gasket, but I don't have any Mini experience other than my own.

 

.



Are N28 head gasket failures common.... or rather unheard of??






.