Any ideas??

[paulnb]

Driving in warm weather, I changed down a gear, put my pedal down exiting a corner and the engine seemed like she was missing.. it continued to run lumpy. I pulled over and the header tank was boiling, the fan was not running.. the car was ticking over but lumpy. White smoke from the exhaust.
I nurses her home maybe a mile.. let her cool down. The radiator was low as were the upper hoses. The header tank was over full and pulling any coolant up from the radiator. Tiny bit of "milk" on the oil filler cap. Dipstick clean. No oil present in the header or radiator.
The radiator switch connection was melted so answers why there was no fan.
So I have very basic skills where engines are concerned.. any ideas?

[AndyVAS]

If you're lucky it just got hot and you can refill the cooling system and she will run right. Fix the electrical issue to prevent the same problem.

Should it run poorly once cooled and refilled you can expect to find a blown head gasket. Maybe more damage but you won't know till you open it up.

Cross your fingers and sacrifice to the car gods. The first born is always a good choice.

[paulnb]

Sadly my first born is much bigger than me and I may end up being the sacrifice lol..
Head gasket is my thought.. I will fill her up when cold and give her a go.. fingers crossed

[jlw35]

Head gasket is not the death knell that most would assume, provided that there is no other damage done.
To replace the gasket itself is just time-consuming but certainly doable by most average mechanics. Just remember to take a lot of pictures, label everything and take your time.
Also is a time to replace other things that you may have been putting off, think hoses, belts etc.

Jeff

[JohnMc]

If it is the head gasket, suggest that you take the head down and see if it is warped. If so a machine shop will shave it to flatten it out.
if the head is warped than putting in a new head gasket will just lead to its failing again. Happened to me on my 1980 FI so had to take the head off again.
Also check your thermostat - something sounds kind of funny with it also.

[klweimer]

I'm voting head gasket as well. You could run a compression test on the engine and see what you see. Look at the spark plugs when you pull them for the compression test (keep track of which one was in which cylinder). Sometimes the plugs look really clean in a cylinder that is leaking, other times it looks wet, etc. Just a good reference point.

And I agree that head gaskets are not the end of the world. Well within the range of many home mechanics. Lots of help here on the forum.

Kirk

[paulnb]

Thanks guys.. bad news about the engine but good news I have another daughter today!!
I did rebuild the engine originally and the head was not warped.. however, I have a spare one just in case luckily.
I am not sure why it has blown..?? I did a 20 mile journey through the country doing up to maybe 60mph.. nothing unusual for me and she does love the twisty roads.. parked up for 15 minutes to grab some fish n chips (good old English dish lol) then set off home but the gasket failed within 2 miles.. I had to nurse the car home a further 2 miles where the engine ran fine at points and lumpy when having to slow down to give way.
The header was pushing out steam, the fan not working and white steam from exhaust. My guess was head gasket to. But how come the radiator coolant is pushed to the header which in turn pulls it from the top of the engine? Is it the failure of the radiator fan switch? Would the fact I stopped for food and the fan not cutting in have cause the problem? Not sure what else to check or change so the same thing doesn't happen again.
Any suggestions?

[RRoller123]

Had the cooling system recently been drained and refilled?

You can check the fan and the fan switch pretty easily by grounding them. The fan is always hot and the switch just gives it a path to ground when it closes. Short across the switch and the fan should come on. The leads are the 2 black wires at C4 in the upper left area of this schematic. Short them together anytime that the battery is connected and the fan should run.

Not having the fan on when you had your failure could indicate a large air bubble in the cooling system, (cooling system "burping" is required whenever coolant is replaced) which tends to keep the fan from coming on, or this could be a totally independent failure of the head gasket, with coolant being pumped out through the break by the water pump, hence the white smoke, etc.

[paulnb]

Aha.. the fan did work when taking the switch out of the circuit.. I may just replace the switch anyway.. but the connector looked melted. I need to check the wiring again. With the switch being low on the radiator should the fan still run even it the top end is void of coolant? The temp guage was just over the 190 mark which was higher than normal but only a little..

The engine has not needed any coolant and has never over heated in the last 5000 miles. She was properly burped as per manual manual and advice from the forum here.

I am thinking she boiled up when I pulled up outside the chippy, as I know I didn't hear the fan.. could that push coolant into the header tank from the radiator/engine causing the head to get too hot and blow the gasket?

Or as you say, it could be just a failure that pushed water through the engine..

[RRoller123]

Before you replace the switch, follow that ground lead from the switch over to the ground pod on the inside fender and make sure that there is a good ground connection there. The switch may be fine, and just the path to ground after it possibly gone bad. The "melted looking" switch connector is a sure sign that there is probably just a wiring problem.

An air bubble will stop the fan from running. The coolant down below never gets hot enough, and the engine will overheat. But if your system is full and burped, then it is very likely this is just a fan switch wiring problem. Good luck!