Ok i have been trying to bleed my car for a couple of weeks and i have had no luck i hae changed thermostat twice but nothing. My problem is when i start from cold evertything is good heater is on and temp gauge is reading normal then after about 10 mins temp rises and hot air in car goes cold. So the fix i have to do when this happens is re-bleed system and then its fine intill car is left not running for about 3/4hours and then same problem. I i have recently banged a universal air filter which i fitted direct on to the carb and im wondering if this is what is causeing air to get in to the water system. cause when i do the blled i get pure water while everything is running i have even left 1 bleed screw half open with light revs to get air out but nothing just get water. Also on original air filter there are 2 small air pipes 1 is brown and 1 is black i do not have a haynes manual but i would like to know where they attatch to on air fiter as there are 2 holes for them bu ti dont no which way round they go e.g if brown 1 which comes from carb goes to the smaller hole on the air filter. Someone please help me

Also the only pipe which let out air when my car over heats is the pipe near matrix it goes from engine to carb the other pipe with bleed screw 1 near thermostat side does not let out air just pure water when cars over heating..

the airfilter wont have anything to do with it. the 2 pipes are breather hose's, they're nothing to worry about.

here are the main clues

-if you bleed the system everything is fine as long as the engine is kept running (the heaters work and the engine temp remains constant)

-if you leave it switched off for some time and then restart the engine everything is fine for 10 mins then you overheat and find air in the system

the only possible explanation i can think of is your radiator is leaking slowly, meaning it has air inside once the car is left for a few hours, and then when you start it the thermostat opens after 10 mins which allows the air to enter the rest of the cooling system and rise to the heater matrix pipes, causing a loss of hot air from the vents and overheating.

the only other possibility is a head gasket failure allowing air to enter the system, however if this was the problem you could not bleed the air out successfully for more than a few minutes because more would be added, and you said if you bleed it there is are problems as long as the car is run, which suggests a slow leak from somewhere in the cooling system that is on the radiator side of the thermostat.

do a test, fill the coolant ot the max and bleed the system, then leave it parked over a dry surface for a few hours. when you return look for a damp patch on the floor. check the coolant level is still the same. now start the car and wait till it overheats, bleed it, then check the coolant level. if it looks like you've lost coolant it must be going somewhere, and if there isnt a damp patch on the floor it must be a head gasket failure.

I have checked for leaks and there are none i have made sure of that, and its only 1 of the matrix pipes which releases air the other 1 which is on a kink lets water out constanty when open meaning if there is. But about the head gasket like i said 1nce it over heats and i re bleed everything is fine intill car is left for a while. ITs wierd. Any more suggestions???

And about the 2 breather hoses i still need to know which 1 goes where on the little pink switch?

dont know about the breather hoses. what engine is it? i'll check my manuals

donovan2123 said:

its only 1 of the matrix pipes which releases air the other 1 which is on a kink lets water out constanty when open meaning if there is.

Click to expand...

only 1 bleed screw releases air when it overheats. that would be expected because the air travels up to where the highest bleed screw is, and unless there is a lot of air any lower bleed screws will still bleed water. so this tells us that there is not enough air to reach the second bleed screw.

donovan2123 said:

But about the head gasket like i said 1nce it over heats and i re bleed everything is fine intill car is left for a while. ITs wierd. Any more suggestions???

Click to expand...

you say the car is fine once bled, have you tried driving it for an hour or more and then bleeding it again? if there is still no air after an hour of driving, but there is if you leave it switched off for a while, i'd call the ghost busters because its very strange.

so you think its just an air block??? so what then drive car for hour after 2nd bleed then rebleed again??? I just can get my head around this i just want it to be done. lol

Whats the best way to get air out of my system??????

Could it be a blockage???? but then again surely if it was it wouldnt be fine after overheating and rebleeding?

Engine is 1.4 1996

i dont think its as simple as a bit of trapped air. i dont really know what to make of it. the problem only occurs after the car is switched off for a while, that doesnt make sense unless it has a leak, which it doesnt, so i suggested a long drive and then try bleeding it so we can see if it makes any difference if the engine remains on, if it does then we have another clue, if it doesnt then we know leaving it switched off for a few hours isnt having any effect and the build up of air occurs the same no matter if the engine is switched on or off. another test is to bleed it then switch it straight off and see if there is any air in a few hours. with more information you can start to rule out a few more possiblities.

hopefully the attached pics will show you where your 2 pipes should go.

I have drove the car for like an hour or 2 and it was fine. And even when i wake up in the morning i check coolant and it seems fine.

Also Do you mean for me to bleed it while the engine is running????

Pictures do not show which cable goes on which hole on the thermostatic valve.

Donovan-

Have just quickly read over this problem I don't see you mentioning that you have eliminated Jugs suggestion that it may be head gasket failure. Clues that this may be your problem include oil or smell of oil out of the coolant expansion bottle by the radiator, or a creamy mayonaise like substance under the oil filler cap.

Also if there is a leak in the cooling system this might only be obvious when the system is at full working temperature as that is when it is fully pressurised. Professional mechanics have a tool for this job - there is one part way down this page on the left.

http://www.carmechanicsmag.co.uk/cgi-bin/show.cgi?d=ae-news-archive

The final thought of mine is that the heater matrix may be leaking. Are your footwell carpets dry?

Oops, that link isn't for a standard pressure tester, thats something even fancier!

This is a normal one:

http://www.shop-com.co.uk/op/~Seale..._Cap_Test-prod-23051724-31031489?sourceid=309

With one of these the system is pressurised and then you can see if there is even a minute leak, because it will be obvious as the pressure dial moves as it leaks.

I'm not suggesting you rush out and buy one by the way, just pointing out sometimes tools like this are needed to sort the type of problem you have.

Oh, and Jug is 100% right, forget about your airfilter and any other breathing tubes outwith the cooling system.

HAve checked the oil to see if its milky and it isnt as for the radiator everything looks ok there.All foowell carpets are dry. its wierd just cant get my head around it i have bleeded it many of times and change thermostat twice. So could it be down to air somewhere traped in system??? I just dont know!! all help is helpfull bt need more suggestions.

You have a suggestion you haven't tried, get the cooling system pressure tested. Beg or borrow the tool, or spend more time looking for a leak, or take it too a garage.

If you're desperate redrain and refill the cooling system more slowly than a very slow thing. Pre-measure your coolant so you have the exact 6 litres at hand. Then if the car hasn't taken it all you know there is air in there.

Remember the obvious things like having the heater dial turned to hot when refilling, and replace the bleed screws in sequence as coolant emerges from them on refill. If you can't get the last drop of coolant in run the engine briefly with the expansion bottle top only loosely fitted. You may find the system 'burps' and the level in the expansion bottle drops allowing you to get that last bit in..

Measuring before filling is the crucial thing......I have nothing more to say

My car doesnt take the whole 6 litres i can tell you that now it takes about 3/4 litres and that with it over max line after i have done all bleed screws. also when i bleed the first 2 water gushes out of them but the final bleed screw(drivers side on matrix hose) water does not gush out it just comes out slowly????

also should i bleed with engine running???

Just checked, the car should swallow 6 litres or very close. If you can't get it to do this you're refilling incorrectly, probably too quickly. Make sure the heater control is turned to full heat so coolant can flow into the heater matrix.

Pour a little in at a time and give the radiator hoses a vigorous repetitive squeeze in between fills to purge air. A tea cup a go if that makes sense. Running the engine is a final resort to clear the airlocks for the last wee bit (with the expansion bottle top loose). Replace each bleed screw as coolant without bubbles emerges from the bleed point.

If the car has swallowed much less coolant than 6 litres on previous attempts that is the source of your problems. Drain and start again.