39 replies to this topic

[pdaykin]

Is it actually loosing water ?

Is the heater valve open ?

Did you check the head for cracks ?

[The Matt]

Possibly just the heater rad filling up after being empty??

[Beej123]

Possibly just the heater rad filling up after being empty??

I doubt the heater was drained though? Bit of a faf getting it empty.

OP, did you totally drain the system or did you just pop the bottom rad hose off to remove?
If you just popped the rad off then once refilled you shouldn't add much more than a couple of litres once it has run. If you totally drained the system, heater matrix and all then you can spend ages and litre after litre of coolant getting all the air out.
I have a nagging in the back of head that thinks the block has gone but if it didn't over heat then that's pretty unlikely. A compression test will be VERY useful to do now!

[minimissionary]

I took the temp sender plug off, and the head was skimmed and hot washed, so it was completely dry up top.
I'm not ruling out cracked block/head, but there was no overheating at any point.

Went for a run before, drove it 1/2 mile round the block and it got up to temperature worryingly quick. Opened the rad to check for bubbles etc. It pushed a fair bit of coolant out, then settled at a level with a bit of foam on top and some steam (don't think it was exhaust gas).
Also feels a bit sluggish. Oil is clean though.

Am I just avoiding the inevitable fact that it's blown again?

Edited by minimissionary, 26 February 2012 - 01:08 PM.

[puggered]

If it pushed coolant out then that sounds like its air locked, let it cool down for a wee bit then fill the system up again with the engine running and heater turned on. Leave the rad cap off to let all the air out. If it still does it again I would suspect the head if gubbed

[minimissionary]

Ran it again. Got up to full operating temp, then as soon as I turned it off, it pushed the coolant out again. Bit of foam around the top. It's only water, not coolant, but I doubt that makes a difference.
I've now come to the conclusion that something is very wrong. The block must be warped, as it's apparently blown on a coolant feed, rather than a coolant and oil last time. Horrible. Engine out time I suppose. Good old daily drivers

[Blatherskite]

Had an issue with a head gasket a while ago - chinese qiality. The giveaway was that the stampings "front" and "top" didn't match (if one was right the other wasn't). Blew, naturally, just after fitting. Was recommended to get a Cooper 1275one, that was ok. So - watch out for sub-standard components...:-(

The chinese gasket blew all the coolant out of the (open) rad cap as soon as the thermostat opened. Its not sp bad to change them, just a royal pain to get a new one.

Edited by Blatherskite, 26 February 2012 - 05:29 PM.

[minimissionary]

The gasket I used the first time was Payen, the second a Unipart one stamped with 'AF470' and 'Made in England'. The 'Top' stamp was on the wrong side though. Ended up nearest me, but all the holes matched up. Looks like I'll be changing my 3rd head gasket very soon.

[Pauly]

Does sound like the coolant system is under excess pressure, which is usually caused by head gasket or cracks in the head casting which lead into the water gallerys. I would fill the rad right up to the top of the neck. Run the engine up to temp with the rad cap off, squeezing all the hoses. Leave the heater valve open because 9/10 this is how bad air locks occur. Once happy that theres no air in the system pop the rad cap back on and try that. If theres any excess water it will just trickle down the overlow.

Edited by Pauly, 26 February 2012 - 06:42 PM.

[Beej123]

Have you done a comp test yet?

[kitroxin]

What coolant did you use?

[bmcecosse]

Sounds like cracked head to me.

[finch661]

may seem like a daft question, but are you torqing the nuts in the correct order?

[Dan]

There is a lot of unhelpful nonsense and misdirection in this thread. Will people please only post things they know about, the OP is answering questions that don't help anything.

Of course the head was empty, you can't keep coolant in a lifted head it's full of holes. You can't put 4 or 5 litres or litre after litre into a Mini cooling system, or if you can then most of it is coming straight back out somewhere obvious, the system capacity is around 3.5 litres with the heater. The most you would usually need to top up after running having refilled the system is around 3/4 of a litre. Please everyone think more before posting.

Odd way to creep up on the torque values like that, it's not usual for an A series and not needed. Maybe two stages if you must but generally you get them all finger tight, then hit them once to full torque. It might be that it's not sealing because of this. Probably not, but it's unusual so it might be that.

Have you found where the water is going? If you lost 2 litres into the engine in 2 minutes, it would be locked up hydraulically or destroyed by now. I wouldn't do a compression test, I wouldn't turn the engine again now until you have found the water.

Am I right in remembering this is the engine you asked about last week? I have to say that I didn't think hand surfacing the block with emery cloth and then sandpaper was a good idea, but it seemed you had already done it so I left it. It could be that it can't seal because of surface damage, it could be the head is cracked as Roy says but it sounds more and more like there is a physical problem with this engine. It would be very unusual for the block to have failed though.

[minimissionary]

Ok.
Seems like I should straighten a few things out.

When I first changed the head gasket, the methods used were all wrong (due to poor advice from a family member). Tyre levers were used to prise the head off, and emery cloth was used to clean off the old gasket. The worst damage I can imagine this doing is bruising to the head, and possibly scoring the block slightly. I'd have to be some kind of superman to sand a cast iron block with just a cursory scrub.

The second (and last) time I changed the gasket, I used 260 sand paper with a flat block of wood, gently smoothing things over. The head was professionally skimmed and hot washed, and therefore went back onto the car dry as a bone.

I torqued the head nuts in a gradual fashion, and in the Haynes specified order, because I was being overly cautious about getting the head to settle level. If the head is to be torqued in 2 stages as it says in the Haynes manual, I think doing it in 4 or 5 stages is probably of little or no benefit, but certainly not detrimental to the stability of the gasket seal.

When I refilled the coolant system, I used regular blue coolant with a corrosion inhibitor suitable for cast iron engines. After losing a litre or two of it, I switched to water to save unnecessary wastage. The heater valve was open.

I drove it again today. Went about 1/2 a mile to the garage up the road (long time Mini specialist, has a Mk1 Cooper S among others...apparently) and left it running for the 5 minute conversation I had with him. He mentioned the fact that flushing such an old radiator could have loosened a lot of crap, causing a blockage, especially after having the head hot washed. I then drove the 1/2 mile back without and problems of overheating.

I am going to do a compression test when I get home from Uni, and will also change the radiator.

Conclusion: Agh!

Edited by minimissionary, 27 February 2012 - 07:50 PM.