urgent car boiling

14th January 2013, 21:31

hi i fitted a new h/g to my car new waterpump timing belt ect but the car never had a thermostat so i got one and fitted it today i bled the system and when i drove it home it boiled.

when you first start the car the red light for it boiling comes on but the needle doesnt go over half way so the fan doesnt cut in as it thinks its not hot enough to cut in i have tried 2 temp sensors from vtr's at the scrappy and both made no difference any ideas what it could be as i need to drive to work tomorrow

14th January 2013, 21:33

also it has been bled water flowing out of the rad then loosened the allen key side of the head good flow out of it. and the valve on the pipe at the back

14th January 2013, 21:47

Did you use a header tank when bleeding so the water level was higher than the engine?

Sounds like you have a air lock in the system Also did you get the head skimmed when replacing the hg?

14th January 2013, 22:32

head was skimmed yeah

no just poured it in the rad like normal but had water flowing out of all the points

am i right in thinking there is 2 coolant sensors as i only changed the one next to the rocker cover gonna get the other one tomorrow that is on the side of the head below the stat housing

14th January 2013, 22:37

Needle doesn't go over half way? but the light comes on, doesn't that indicate oil temp? someone please correct me if I'm wrong

14th January 2013, 22:39

how do you know it boiled over then. Try the header tank method too to bleed it

the thermostat sensor is for the ECU not the gauge, although mk2s use this for the fan

14th January 2013, 22:59

i knew it boiled because when i opened the bonnet i could feel the water bubbling in the top hose

so what is the sensor for at the side of the head i have replaced the one pointing up the way but not the one on the side its a navy blue colour and had one wire

the needle goes up to half way no higher but the red light is on as soon as i start the car as if it is boiling but it isnt obv as the car is just started

15th January 2013, 00:06

Quote:

Originally Posted by turbomad

i knew it boiled because when i opened the bonnet i could feel the water bubbling in the top hose

so what is the sensor for at the side of the head i have replaced the one pointing up the way but not the one on the side its a navy blue colour and had one wire

the needle goes up to half way no higher but the red light is on as soon as i start the car as if it is boiling but it isnt obv as the car is just started

That's prob's just air in the system I reckon you just not bled it correctly.

15th January 2013, 00:20

I wouldn't rely on the sensors to be honest

15th January 2013, 03:24

Check to see of the water pump is turning as could be the system not flowing due to a faulty pump or could even have a blocked water way from all the shit from H/G going

15th January 2013, 10:41

if the water pump wasn't turning then it'd most likely wreck the cambelt. When the engine is cold open the header tank and rev the engine a bit, if the level drops slightly chances are the pump is OK

16th January 2013, 10:21

@gandi1699

Your right there but 40% of the time people have cheap patterned parts fitted and the water pump pull can still spin but the the pump its self has sized ya be surprised what I have seen working in Citroen and I have seen som Crazy shit!

16th January 2013, 10:25

Yeah I know what you mean, come off the spindle inside the pump. I've seen that happen on K-series engines and the impellor was just laying at an angle not attached to anything in the coolant channel.

16th January 2013, 10:27

Might be a stupid question, but you did fill it with coolant and not just water? because just water will boil and create air pockets if you don't have enough coolant in your mix.

16th January 2013, 21:28

bit of a update on this

it doesn't boil i ran it to work the other day (40 mile trip and in traffic) as i bled it again and worked ok but fan still doesnt come on i keep the heaters on all the time as its freezing

when i start the car the needle stays at cold then after 10 secs the little red light comes on. then after a while the temp needle will rise to half way and stay there the problem is when i start the car after being hot it floods itself and is a nightmare to start as the needle goes to cold which would make you think a sensor is buggered and not telling the ecu it is hot so it puts the choke on and horses the fuel in idle is also at 2k

so i replaced the sensor on the side of the head 1 wire green plug navy sensor made no difference.

if i have the needle up half way and unplug both sensors it doesnt affect the gauge or the red light nothing changes

any idea's all i can think is maybe a broken wire?

16th January 2013, 23:30

so it doesnt boil over now? Fan probably wont come on easily as its very cold outside at the mo and the cooling system can keep everything cool with just ambient air temp around it. You've change the CTS then and its made no difference?
also is this a mk2 ?

22nd January 2013, 12:18

Yeah its a mk2. yeah changed both sensors no difference and its flooding now when starting when the car has been ran a while

22nd January 2013, 12:31

sounds like air lock.
Mine did this once just randomly half way home from Uni. Temp sensor was half way, red light on, same symptoms.
I filled my radiator up, drove up the road and it was to hot, then opened the rad cap and it was still cold.
bleed points -
There is a tire valve looking cap at the back left of the engine, the temp sensor on the right hand side of the engine and a bleed screw on the side of the radiator.

Undo the rad cap and with anything really that works (i used half a coke bottle turned nose down into the rad filled with water) undo each bleed point and see if the water level falls in the bottle.
If not that, check thermostat, then water pump.

22nd January 2013, 12:52

That doesn't explain the car flooding though?

22nd January 2013, 12:58

have you had it on a fault reader?
I'd be inclined to try another ECU on (unlocked obviously)

22nd January 2013, 13:42

Yeah had a diagnostic on it before I did h/g as it was misfiring could try another ecu but it is a lot of cash if it makes no difference

22nd January 2013, 17:24

ahh sorry i missed you say it was flooding.

22nd January 2013, 17:30

Bloody thing I had a £150 rusty civic with 172k and never had no trouble paxo has been one thing after another

22nd January 2013, 20:56

could always sell the ECU again if it doesnt make much difference, VTR unlocked ecu wont be very much money.
Are you 100% sure the head and gasket are good?

22nd January 2013, 21:46

Yeah head was skimmed and triple layer gasket