If it turns over still its not seized The car will run with a head gasket issue but will run poorly and probably wont idle. Do a compression test and give us the results.
Of course what matt says will 99.99%correct

Sorry, it was just a follow-up thought to the previous question I asked, more out of curiosity as to what would cause the stalling/not starting as a result of the blown head gasket, I guess I was thinking it would let air in, and lean it out a lot causing the stall - just my rambling thoughts at 5am is all

Anyhoo, I did as doc suggested and put the thermostat in a pot of water, and it did open up, but at what temperature I'm not sure. I don't have a thermometer that goes that high. Matt is probably still correct. It could well have been that I accidentally freed it up whilst pulling it out - it was quite gunky in there around the edges. Only other thing I can think of is that the water pump has had it.




It turns over! I don't have a compression gauge, I will have to see if someone at work has one I can borrow as I'm short on cash at the moment. I'll report back when I can get a hold of one. Thanks all, I'm feeling more positive about the whole thing now.

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'77 Leyland Mini Van

Try removing the plugs and turn motor over and see if any of the pots squirt any water out of the spark plug hole. If this happens it's head gasket or cracked head, remove the head before corrosion starts in the bores.

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DID I MENTION THAT I AM THE BEST SUPPLIER FOR MINI ELECTRICAL PARTS AND REPAIRS?
"Let us remove your "SHORTS"

Thanks Tony!

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'77 Leyland Mini Van

Similar to what Tony suggested, when you have the plugs out, get a piece of white paper. Hold the paper close to the spark plug holes while someone else uses the starter motor to crank it over for a few turns.

With the pistons moving fast from the starter you get a fine mist spray out of the plug holes, which ends up on the paper. So you can then analyse the paper as to wether there is nothing, petrol or water (maybe even oil, but that would be really bad!)

Just one of the many ways to diagnose a problem.

I did the paper trick, and 2, 3 and 4 don't look suspicious, but #1 has a fair bit of clear/very light brown (or perhaps green, can't be sure) splashes coming out that don't look too misty.

So I guess my next step is to remove the head. This is daunting, I've never done this before :/ I'm assuming the hard part is putting it back together again. Anything in particular I need to worry about before I start removing bits and pieces? Should I bother getting a compression tester first, or just take it off anyway?

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'77 Leyland Mini Van

Head should be off in 1hr or less, go find a workshop manual if you've not done it before.
But it's pretty easy.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

This is actually the most sensible thing suggested during the "is it seized" conversation.

Don't forget to drain the radiator before you start loosening the head.

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1969 Cooper "S"
1967 Mini Deluxe
1973 Clubman Van (the fleet spare)
1978 ex 1275 LS ("Wizard" Eaton Supercharged)
2015 HSV GenF GTS(occasional drive & tow car)
2019 MINI F55 Cooper S