8 replies to this topic

[Bluecray]

Mini 1000
1986


I'd had a strange water leak that appeared only to manifest sometimes and I looked at the usual culprits, bypass hose and water pump but they appeared ok.

I'd travelled from JNC 10 to JNC 13 on M1 and back Friday night without loss of water.

On Saturday I travelled to JNC 14 and then enroute home........pitch black enroute home

I was on the 50 mph restricted section, with no hard shoulder when I noticed temp gauge pointing too high, also what I thought was steam pouring off the back of the car.

Oh ******* do I stop or not, I had to, engine was hot, stopped best as I could and with some water I'd been carrying I poured it in as fast as I could, it bubbled immediately as it was that hot. Got moving straight away to get off slow lane.......

It was Bl**dy dangerous stopping there, trucks were thundering down upon me and had to change lane to overtake.........

Carried on to Toddington service station, temp gauge went down but smoke/steam pouring out of back.

Got breakdown to take me home.

This morning, I poured water in and it came straight out of the bypass hose, its one of those stupid concertina ones, started car to see what the smoke/steam? was and it blowing blue smoke out...... oh not good methinks.....

so the bypass hose has gone, but why have I got blue smoke coming out of exhaust???????

With my limited knowledge I can only think the valve stem seals perished in the heat and oil is getting past going in bores???

I was supposed to be watching temp gauge but think I wasn't just prior to when I saw it so have no idea really how long temp was high.

Obviously something is damaged in engine but what?????

The head is coming off anyway in the next few weeks for a cam change, and to change springs and now this has happened.................

Edited by Bluecray, 06 February 2011 - 02:16 PM.

[Merlin-Mini]

quite possibly the head gasket.. blue smoke is an indication of burning oil. check underneath your oil filler cap. if there is white gunk under there then the head gasket has almost defiantly gone. lost any power at all??

[Bluecray]

Just been out and looked at cap, it looks perfectly normal.

So overheating can blow a headgasket I presume?? Just trying to work out how the oil gets past....................which blows out as the blue smoke.

Not sure about the power lost as I was driving gently to service station, but I dont THINK there was any loss, it went at 50 to get there.....

Edited by Bluecray, 06 February 2011 - 02:36 PM.

[bmcecosse]

If the engine was roasting hot - the rings could be ruined.

[Bluecray]

Just been out and checked oil level, it was at the top and now dropped to the bottom level mark.

Can a headgasket let oil get in the piston bores? I always thought if a headgasket blows it effects the water......................

[1984mini25]

From when I looked at it yesterday, there was a lot of oil/water round the water pump end of the engine, but it wasn’t obvious of were it was coming from.

What it sounds like to me is, the bypass hose has failed, instant coolant loss, overheated and then taken the head gasket witch might have already been leaking with it.

Head gaskets can fail in a number of ways, between adjacent cylinders or between a cylinder and oil/coolant ways.

The mayo under the rocker cap is never 100% accurate for telling when a head gasket has failed. If for instance an engine is only used for very short trips and never gets up to temperature, then the condensation that builds up inside the rocker cover never gets fully burnt off. So what one would assume would be a head gasket, would in fact just be the car needing a good run up to temperature.

I’ve also personally had a head gasket fail between a cylinder and coolant waterway; it didn’t however lose any coolant. But instead was pressurising the cooling system till it boiled over out of the radiator.

You could try and remove each of the spark plugs and noting witch one/s are oily, so then you should be able to tell if its just the one cylinder or all of them.

[Bluecray]

Well the head was taken off today and we awaited with abated breath to see what we found....

There was a place on the head gasket that looked iffy BUT when it came to cleaning the head, taking the old gasket off that the source of the blue smoke was found.........

There was a small hole going through the whole head, daylight could be seen looking through it !!!!!!! see attached picture..........




Now I'd like to know how it got there? my only thought were that there was a weakness in the head at that point and the overheating just finally finished it off?????


Any thoughts anyone please??????????

Attached Files

•  12022011176.jpg   1.17MB   52 downloads

[1984mini25]

If it turns out the head ‘had’ been skimmed along with the larger valves (look close to standard to me) I don’t think it would have helped, could have already bee a weak casting to start with? But for any ones else’s opinions, the other side of that hole is the hole for that main oil feed into the rockers.

Still at least there’s another head on there now and its all running, just have to treat it gently for everything to settle before giving it the full beans.

Ps. if it’s still idling a little high once warmed up, just back the idle screw off a quarter to half a turn.

[Bluecray]

I was wondering if maybe the cast iron head had a small "blow hole" or "air pocket" at that point in the head, someone else I was talking to, said the oil way clears the top of the head by around 1/4 of an inch, assuming it had a "air pocket" there and the overheat weakened it, and it then blew through forming the hole????

For anyone else's interest we added a Kent 276 cam (fast road/rally) to what I thought was a modified head (bigger valves) but that appeared not to be the case (we think) and anyway its got the hole now ( so another head was put on.

Only driven the car gently so far, need the parts to bed in, then I will check the tappets gap again, and then give it some welly and see what it does.

The tickover now is slightly lumpy, should be interesting to see what difference the cam makes.