I just recently got my Ford ka which is my first car so I am relatively new to this stuff. 

My coolent had been leaking under the hood creating a lot of steam. I went to a garage to get it fixed and they changed the valve but this problem has happened a few times after so in total I've been to the mechanics 3 times to get the same problem fixed. 

My friend did a diagnostic check in my car and it said there is a coolent pressure surge which probably caused the valve to break and coolent to leak.

I've been told by my mechanics that if it happens again they may have to look at the head gasket but I am fairly certain it is not. No steam or coolent coming out of the exhaust and no milky deposit on the oil cap. However my temperature light does come on now and again.

Can anyone give me any guidance on what to do or how it can be fixed, would really appreciate it. Thank you

Is the steam coming out of the cap on the expansion tank. The cap is rated at around 15psi to let steam out. If it is not coming out of the cap then change it. Do not remove the cap when the engine is hot as the expansion tank is pressurized.

58 minutes ago, Kevin#95 said:

Is the steam coming out of the cap on the expansion tank. The cap is rated at around 15psi to let steam out. If it is not coming out of the cap then change it. Do not remove the cap when the engine is hot as the expansion tank is pressurized.

The steam is coming from coolent leaking from the back under the hood and hitting the pipes and evaporating it. No steam coming out of the coolent unless I open it when its warm.

The system is pressurized when hot. It might be a hose is split and leaking under pressure.

1 hour ago, Kevin#95 said:

The system is pressurized when hot. It might be a hose is split and leaking under pressure.

If I show you where it was leaking from would it help?

Yes. Also run the engine with the expansion cap off. If you see bubbles in the expansion tank it could be the head gasket on the exhaust side is split and blowing exhaust air into the water.

2 hours ago, Kevin#95 said:

Yes. Also run the engine with the expansion cap off. If you see bubbles in the expansion tank it could be the head gasket on the exhaust side is split and blowing exhaust air into the water.

It would leak from behind there. The screw on the left would break off leaving a hole where coolent would leak.

I'll check the expansion cap now.

14 hours ago, Kevin#95 said:

Yes. Also run the engine with the expansion cap off. If you see bubbles in the expansion tank it could be the head gasket on the exhaust side is split and blowing exhaust air into the water.

Once I turn the engine on there are a few bubbles forming but it mainly goes after a minute.

The engine needs to run until it heats up and the thermostat opens. Then the bubbles will appear, but don't get to close to the cap as hot water will bubble over.

After leaving the engine on say 10 minutes am I looking for a lot of bubbles appearing?

Also a side note my car has 46k miles, not sure if it's been clocked back but the service history and mot history add up.

Yes you should see the hot water foaming with lots of small bubbles.

21 hours ago, Kevin#95 said:

Yes you should see the hot water foaming with lots of small bubbles.

After 10 minutes the coolant resovior looks like that.

My car was completely cold to start and left to idle for 10 minutes. Bubbles initially showed up but all went after the first 2 minutes.

Thats what the cap looks like.

I did about 50 miles yesterday doing deliveries and my temperature light only came on once just as I went to turn my car off as I parked. I opened the bonnet and heard a lot of bubbling coming from the coolant tank. A few deliveries later I went to go check the coolant (temperature light was not showing) and the coolant was more or less stable, a slight noise coming from it.

This may be a stupid question but as I can't see it mentioned in your previous posts , have you tried replacing the coolant reservoir cap, as a faulty one will cause a lot of the problems you are experiencing.

 

Agree. Change the cap.

Also, if you have air conditioning, turn it on full and check the fan on the radiator comes on.

I've just ordered a new cap but its gonna take a while to come because of the current situation. But from the pictures could you be able to tell if the caps bad or not.

My radiator fans come on pretty early when I'm normally driving. 

You won't normally see anything wrong with cap as its rhe pressure relief valve that's opening too early usually. It's worth a try for what they cost and not an uncommon problem. Surprised a garage didn't try that?

Yh that really confused me. But they always thought it was a head gasket every time I went. They would say "your head gasket might have gone" or "it could be your head gasket" but wouldn't really do anything about it or check it.

Of course it could be the head gasket but normally if one cannot conclusively determine what the problem is with the cooling system eg hose radiator or even head gasket. etc then its always worth eliminating the pressure cap first as its a relatively cheap item and they do fail/deteriorate over time.