You can make an easy check. Fill the cooling system. Don’t place the cap. Start the engine and check the water through the filler neck. When you see the water clear and constant bubbled in the radiator than you have a head gasket problem.
You'll need to get the radiator fixed before checking for a failed headgasket 'bubbles' in the water. However you need to get the rad fixed regardless, so to check for bubbles coming into the rad when it is all assembled will hopefully answer that one as 'no' (not 100% guaranteed though)
The radiator could have failed like that due to an age related or quality related problem without anything else being to blame.
On the flip side there could be a few things going on that added to the problem.
It would not hurt to renew the rad cap anyway. The minor is meant to be fairly low pressure, but if someone had used a different cap it could be at much higher pressure.
Whilst it is 'in bits' it is an ideal opportunity to flush out the entire cooling system. (basicaly just run a hose pipe into the engine until it runs out clear, then reverse the direction until clear again, then do it a few more times... And then the same by holding the hse pipe on the endo of the heater hose, and then the other heater hose). The cooling system and heater will work a lot better if they are cleaned out! If the car has been run without a good antifreeze the block will corrode (good antifreeze has corrosion-inhibitors) and the rust swims around in the water until it causes sludge/deposits/blockages.
If the thermostat had stuck, the engine could get very hot causing violent boiling - was there any 'glugging' and 'spitting/fizzing' when it failed? Checking the thermostat is easy (watch it open and close when you heat a pan of water to boiling and cool down afterwards) but removing and refitting the thermostat housing can be a pig of a job. The simpler way to check is to run the car from cold - the top hose should not get hot to start with and after the engine is hot the thermostat should open and the top hose will get hot fairly quickly. It is much harder to spot if the thermostat is struggling to open but when it is hot you should be able to see a nice steady flow from the engine into the radiator (looking through the filler cap) - and when you rev the car up you should see a nice increase in flow into the rad.
Ray. MMOC#47368. Forum moderator.
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