Technical Overheating Update

[Hess]

Hello again. I ran a few checks today as advised by a few of ye good people out there and came up with some sort of results but I'm still not sure about some things.
First off I looked at the oil cap and didn't find any white sludgey stuff, also had a look into the coolant bottle and didn't see any sign of oil so hopefully this is a good start. No head gasket needed.
I then started up the engine and had a look under the dashboard and there was a drop of cooling fluid (blue) hanging from the plastic casing - ok, something wrong with the heater matrix.
Next I went round the water pipes in the engine and found that the two pipes comming from the rad were hot but only one of the pipes going from the back of the engine to the matrix was hot. The one on the right was cold.
I then opened up the small plastic bung on the rad and got soom steam coming out. Done the same on the pipe at the back and got more steam and then some coolant so I closed it up. Not sure if I was doing this right, anyway the rad fan was kicking in every now and again and kept the temp needle between 1/2 an 3/4's on the temp gauge. After a while there was no sign of any fluid coming out of the rad so I closed up the bung, let the engine cool down and then topped up the coolant bottle (it was below the min).
This is where it gets a bit funny, I started it up again and went round the block to get it warmed up. Then checked the pipes and found that only the top pipe coming from the rad was hot, then noticed that the rad fan wasn't kicking in and the temp needle was heading towards red. I tried bleeding the rad again but got lots of steam and no coolant. So hear I am scratching my head. Have I got two-three problems here?
1) a dodgy thermostat that only works when the car is not moving.
2) a blocked heater matrix with a small leak.
3) an air locked radiator.
Sorry about the small book I've just written, any comments would be appreciated otherwise I'm left with a hot engine and cold feet...

 

[Evil-Punto]

It certainly sounds like your matrix is blocked.
The rad fan should regulate the temperature at halfway and shouldn't go any higher.
Never run the engine with the rad cap off unless its cold.
It sounds like the coolant that you put in has created an airlock somewhere. Wait until the engine is cold and remove the bleed screw from the top of the coolant pipe, fill the rad and massage the water through the pipes.
You could also pull both pipes off the matrix (2 pipes going into the bulkhead), join them together with a pipe connector and 2 jubilee clips. Once the matrix is unpluged you could try using a spare bit of pipe and blowing into one matrix pipe to see if you can blow out the other side.
Your thermostat may be faulty but not totally knackered (try starting the engine, hold the top radiator hose and see how long it takes to get hot. If the thermostic switch is working it should suddenly get hot as it redirects the coolant to the radiator, if it very slowly warms up it could be half open.
The key is to squeeze the pipes as you fill the rad, sounds silly but if you heat the distilled water before you put it in the rad you will be able to feel where the water is inside the pipe.


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Evil-Punto AKA Evilution.