The 60 million dollar question AKA the overheating bugbear

Here are the only pics that I have that show anything.

Thank you Rich, it was carburettor connections I wanted.

I can show you some carb connections as well but still don't think they will help much.

Overheating topic revival...

I've just stripped down my 1300 engine that came in Ernie the pickup.

It had over heating problems, air locking, unable to make it stay full of water etc. Fan wouldn't kick in.

The head gasket HAD NOT failed anywhere!

I think the leaking earlier circled nipple and the non fitting radiator pressure cap under the passenger seat were to blame.

But I shall find out slowly.

Right, I went to Daihatsu, spoke to them, they said I had the wrong radiator caps fitted, so ordered some more, I was away with work so the missus went to pick them up, they gave her the same ones we've already got fitted!!!

Can anyone picture what radiator caps are fitted exactly and have part numbers please?

Steviel81 wrote:Can anyone picture what radiator caps are fitted exactly and have part numbers please?

Can't give piccys, but on the 1.0l the cap on the radiator should just be a flat cap, no spring. The cap under the passenger seat is a short-neck, narrow, 0.9 bar sprung cap. FRC74 is the one I get from my local factors, yours should be able to cross-reference from that.

PFM wrote:

Steviel81 wrote:Can anyone picture what radiator caps are fitted exactly and have part numbers please?

Can't give piccys, but on the 1.0l the cap on the radiator should just be a flat cap, no spring. The cap under the passenger seat is a short-neck, narrow, 0.9 bar sprung cap. FRC74 is the one I get from my local factors, yours should be able to cross-reference from that.

We've got two of them sprung ones (well four before I take the two Daihatsu sold my missus back to them), I'll have a phone about in the morning, thing is I've got to go back to work tomorrow night and we were going to go away in the camper this weekend, but I don't trust it if it's going to over heat with the wrong caps on it!

Right,

Fitted new, correct caps. Bled it all. Ran fine, went on a 30 min drive, perfect, drove another 30 mins over some Welsh hill side, up and down some big hills, walked the dog, drove 30 mins back, up the big hill to get home, got to the bottom of the missus street, over heated! It filled the expansion tank to the max! Checked the cap seat, seems ok, going to take it off and clean it up with the dremel though to be sure.

Strange thing is, heaters work on hot when aimed to the screen, but cold when on middle and down are cold all the time? So I'm thinking there's a blockage in the heater matrix causing the over heating?

Drove it back to my work, stopped twice to let it cool down, empty the expansion tank and re-filled the system, missed the f*ckin football too!!!

Guess guess guess... hope you have time and patience for the wild goose chase

Make yourself something like this, old tyre valve and a bit pipe:-



Then hook it onto the nipple under the drivers seat like this:-



Then get your foot pump, 12v fag lighter pump or bike pump out and charge it up.

Don't worry about over pressuring it, the rad cap will protect it.

First do it with all the water in the system, see if you can spot the leak. Also get a tyre pressure gauge and see if it loses pressure.

Then drain all the water out and see if you can hear the hiss and watch the pressure drop.

I'm pretty certain its just a blockage as it's not leaking any water out, it's all going into the expansion tank. I'm going to order a new thermostat and do another system flush out and go from there.

Water kept within a container does not boil at 100 degrees. The fixed boiling point of water is a myth. You can have liquid water at 130 degree no problem, but if you open the container it will become steam instantly.

Water starts to bubble when heater at about 85 degrees if not kept in an enclosed environment. Even lower at low pressure e.g. up a mountain

A slight leak on one of the rubber pipes on top of the engine under the manifold will allow the water pressure to drop a little, thus allowing the boil to occur, thus resulting in an air pocket which expands quickly, thus the over heating.

You would never see this water leaking as it will evaporate instantly because it will be bloody hot. This is why the water gets pushed out into your header tank - because your making steam somewhere thus the pressure goes higher than the rad cap can retain - for good reasons too, you don't want it to explode.

P.s if you thermostat was stuck closed it would over heat in 5 to 10 mins from start up easy.

If it was stuck open you would never get half way up the temp gauge