No heater ,air in system 1.2 petrol kangoo

[garrymossley]

Hi everyone

My car heater is cold, there is air in the system , ive slackened off the bleed screw and it got rid of the air in the system and the heater worked , but one day later its back to no heater again with air in system , what is the cause for this , its had a head gasket about 12 months ago, please help!!!!!


Thanks
Garry

 

[malcolm]

Sounds like water loss definately. I have three ideas (not often I have this many).

It could be blowing out through a poor hose connection (loose clip maybe) as the system does pressurise itself when it gets hot. First fill and bleed the system and check if there are any leaks when the system is hot. Helps to park the car in a garage so you can see the water leaks on the floor in the morning.

Could be the system isn't bleeding correctly and is getting too hot. Squeze the radiator hoses by hand when filling the system to get the sir bubbles out. If they feel like they have air in the system open a bleed, sueeze the hose, close the bleed, release the hose and keep doing that until there is no more air in the system.

Final one is head gasket failure (more common after replacement than before as it's not always done right, or warping of the head might not have been fixed). Fill and bleed the system when cold. Run the car for at least 20 miles. Leave it overnight so it gets properly cold again. Undo the water filler. If there is a hiss it means gas from the cylinders is forcing water out of the system and the head gasket is at fault.

 

[garrymossley]

HI malc

Thanks for that malc, it looks like from what you said its the head gasket, ive bled the system this morning and ive been about 20 miles and ive just checked it now and there is a hiss when untightening the filler bottle

Thanks ill have it sorted

Cheers
Regards
Garry

 

[malcolm]

Well worth getting the head checked while it's off - could need skimming if it's overheated badly in the past and warped.

 

[GREAT UNCLE]

Whenever I do a head gasket job on an aluminium head (like the Kangoo) I always have the head skimmed every time now. Some customers ask if it really needs doing as it's another 35 quid on their bill, but in my experience it's well worth doing!
Also remeber to clean out the bolt holes well, if there is any oil or water sitting in the bottom of them it will stop you tth head bolts torquing down properly.

 

[renault4mad]

Ive just done a scenic with poor heaters (usual on them) but i found the impellers on the water pump and broken off which would result in no circulation and over heating...

Did the water pump get replaced with the timing belt when headgasket done last time..?

 

[GREAT UNCLE]

That is a good point. The rover k series engine are a similar problem to this, the impellers look fine but as the engine warms up the impeller spins on the shaft so the water isn't pumped around the engine causing it to overheat very quickly.
I've not seen it yet on a Renault, but I have had a peugeot were the impeller blades were corroded away.:eek:

 

[garrymossley]

kangoo drawing air

I called to see the machanic he is not 100% sure it is the head gasket, he mentioned the water pump fins as mentioned on one of the posts on this subject being broken , but he also mentioned the cap on the filler bottle that may be faulty , hes done a pressure check and there is no leaks,now im really confused

any suggestions would be greatfull ,what do you think about the cap on the filler bottle?? do they fail??

Thanks

 

[GREAT UNCLE]

You can get problems with the filler cap, this is because the cooling system should run under pressure.

If the cap is faulty you will be losing pressure and coolant while you are driving along. Most garages should e able to check this for you on 'pressur test' kit. On a Kangoo the pressure should reach about 1 bar / 15psi before it leaks off. If in doubt just put a new one on as they aren't that expensive.

What i feel should be done as well as the pressure test that has been one is a block test. This is usually a blue fluid that is put in a special container and sits on top of the header bottle. With the engine fully warmed up (so that the rad fan has been running), some air is drawn from the bottle and bubbles up through the fluid. If there are any hydrocarbons in the air travelling through the fluid it will change to yellow.

Pretty much all garages will have a block test bottle and fluid, and is a simple, straight forward and reliable test if done properly.

p.s. Make sure the cooling sytem is bled of air properly first though

let us know how you get on

 

[garrymossley]

HI
The Head gasket was the fault, its now fine

Thankyou everyone
Garry