Bleeding the cooling system

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Talat

Newbie

Joined: 22-July-2004
Location: United Kingdom
Status: Offline
Points: 20

Topic: Bleeding the cooling system
Posted: 08-August-2004 at 00:07

Hello all,

I've tried bleeding my cooling system over the last couple of days with limited success. I've done a few seaches and seem to only find variations on how to bleed the cooling system. At the moment I do the following:

- Remove cap, fill expansion tank to the top with coolant and then replace cap.

- Turn heater to full hot

- Start car and wait till the temp guage is in the middle.

- Turn the bleed screw and let the air/water with bubbles escape.

Are the above steps correct ? At one stage I had just pure coolant coming out of the bleed screw and so I thought that I had solved my airlock/overheating problem. To my dismay the car started to overheat later in the afternoon when I took it out for a spin - when I got home I released the bleed screw again and bubbles started flowing out of it again. Plus the heater is still blowing out cold air although sometimes it feels luke warm.

Local garage suggested that I may have a cracked cylinder head but he hasn't even seen the car so was making a blanket assumption. I think I've made some progress as now it takes slightly longer to overheat, all the coolant pipes now get hot and all of the radiator gets hot (whereas before only one side would). I'm hoping to get rid of the airlock myself rather than waste the time of a specialist.

Any advice would be much appreciated.

Cheers,

Talat.

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b8alk

Banned User

Andy K

Joined: 15-May-2004
Location: United Kingdom
Status: Offline
Points: 874

Posted: 08-August-2004 at 11:25

hi talat i belive what your doing is right, but you do have to repeat these steps a few times once pure coolant is flowing from your bleed screw retighten wait a short while so if any more air is in your system it will find its way to that point then release again do thie a few times a you should be ok, it took me about half an hour of opening and closing that bleed screw before i got all the air out,just when you think you,ve done it a little more finds it way to the highest point ie that b/screw.remember air can be flowing at diffrent places so just because you have removed one lot there may be more making its way around,thats why i say wait a while then release again, hope this is of some help..

Talat

Newbie

Joined: 22-July-2004
Location: United Kingdom
Status: Offline
Points: 20

Posted: 08-August-2004 at 15:10

Thanks for that b8alk.

One other quick question - am I supposed to set the heaters to the highest level (i.e. 5) whilst bleeding ? As there's a lot of difference between how much air comes out as I initially bled the car with the heater set to 1.

Cheers,

Talat.

Newbie

Joined: 08-April-2004
Location: Ireland
Status: Offline
Points: 18

Posted: 08-August-2004 at 15:14

Talat, have you had the cooling system 'open' recently e.g. for a thermostat change? This would explain trapped air in the system.
If not 'open' this would be more worrying viz-a-viz the cylinder head,
and I wouldn't hesitate to get it to a specialist for a pressure test.

b8alk

Banned User

Andy K

Joined: 15-May-2004
Location: United Kingdom
Status: Offline
Points: 874

Posted: 08-August-2004 at 16:49

yes you should have the heaters set to full open. Also what karl has posted is a very good idea as air will only get in to the system if it has been opened,if you are getting air in the water system and it has not been opened you may well have a problem.

have you replaced the coolant lately is that why you are bleeding it though?

or did your temp gauge start to move up past half way ie start over heating.

As for your local garage i think they have plumetted for the worse case sinario

Edited by b8alk

Talat

Newbie

Joined: 22-July-2004
Location: United Kingdom
Status: Offline
Points: 20

Posted: 08-August-2004 at 17:39

Thanks for the responses.

Not sure what has been done to the car. I bought the car a couple of weeks ago and drove it home around 40 miles without any problems. Then I was driving in traffic one day and the temp started to creep up. Coolant was leaking heavily out of the expansion tank - I replaced the cap and it no longer leaks from the cap when it overheats.

The bleeding has had some effect as it seems to take longer to overheat now - there are no sudden movements in the temp gauge, it just slowly but surely overheats. I'm going to book it in with a specialist but since most of them have a lead time of around 2 weeks, I'm going to try and bleed it over the next couple of days in the interim.

Cheers,

Talat.

Talat

Newbie

Joined: 22-July-2004
Location: United Kingdom
Status: Offline
Points: 20

Posted: 14-August-2004 at 17:55

Well I've given up on bleeding the system - seemed to be going around in circles and not making any progress Anyhoo time to let the pro's have a look - dropped the car off at Bexleys this morning and I'm hoping it's nothing expensive - will find out next week.

Cheers,

Talat.

b8alk

Banned User

Andy K

Joined: 15-May-2004
Location: United Kingdom
Status: Offline
Points: 874

Posted: 14-August-2004 at 18:06

Sorry we could not help hope you have some good luck

Edited by b8alk

520ian

Newbie

Joined: 06-August-2004
Location: United Kingdom
Status: Offline
Points: 36

Posted: 15-August-2004 at 00:37

Easiest way to tell if there is a problem with c/h is to get engine up to working temp then try to squeeze top hose, if it is solid or really hard to squeeze then likelyhood is gasket gone letting gas into water jacket. bottom hose will be equally hot and hard to squeeze, if not then probability is air in system due to not being bled through properly.

Ian

thaskitz

Newbie

Joined: 13-August-2004
Status: Offline
Points: 9

Posted: 15-August-2004 at 12:58

had a customers 535 in and the only way we could bleed the system successfully was to jack the front end of the car right up in the air still took nearly an hour though!!!!

hope this helps

Talat

Newbie

Joined: 22-July-2004
Location: United Kingdom
Status: Offline
Points: 20

Posted: 15-August-2004 at 18:42

Cheers folks.

This site has been good for advice/tips etc but I think I was getting out of my depth due to my limited mechanical knowledge. Interestingly enough, whilst driving down the A2 to drop the car off, the gauge stayed in the middle (for around 15 mins) and it only started moving towards the redline once I got stuck in a bit of traffic in the town centre.

I'll have to wait and see what the diagnosis is - will keep you folks posted.

Cheers,

Talat.

Talat

Newbie

Joined: 22-July-2004
Location: United Kingdom
Status: Offline
Points: 20

Posted: 23-August-2004 at 19:50

An update for anyone that's interested:)

It turned out to be the fan clutch in the end - but it will still overheat if the aircon is on and the car is stationary. Apparently it's been fitted with an aftermarket aircon system and the fan isn't up to the task. This isn't a major issue for me and so I'm happy that it wasn't anything expensive

Cheers,

Talat.

520ian

Newbie

Joined: 06-August-2004
Location: United Kingdom
Status: Offline
Points: 36

Posted: 23-August-2004 at 20:18

Thankfully it wasnt anything expensive.

Ian.

Author	Message Topic Search Topic Options Post Reply Create New Topic Printable Version Translate Topic
Talat Members Profile Send Private Message Find Members Posts Add to Buddy List Newbie Joined: 22-July-2004 Location: United Kingdom Status: Offline Points: 20	Topic: Bleeding the cooling system Posted: 08-August-2004 at 00:07
	Hello all, I've tried bleeding my cooling system over the last couple of days with limited success. I've done a few seaches and seem to only find variations on how to bleed the cooling system. At the moment I do the following: - Remove cap, fill expansion tank to the top with coolant and then replace cap. - Turn heater to full hot - Start car and wait till the temp guage is in the middle. - Turn the bleed screw and let the air/water with bubbles escape. Are the above steps correct ? At one stage I had just pure coolant coming out of the bleed screw and so I thought that I had solved my airlock/overheating problem. To my dismay the car started to overheat later in the afternoon when I took it out for a spin - when I got home I released the bleed screw again and bubbles started flowing out of it again. Plus the heater is still blowing out cold air although sometimes it feels luke warm. Local garage suggested that I may have a cracked cylinder head but he hasn't even seen the car so was making a blanket assumption. I think I've made some progress as now it takes slightly longer to overheat, all the coolant pipes now get hot and all of the radiator gets hot (whereas before only one side would). I'm hoping to get rid of the airlock myself rather than waste the time of a specialist. Any advice would be much appreciated. Cheers, Talat.

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b8alk Members Profile Send Private Message Find Members Posts Add to Buddy List Banned User Andy K Joined: 15-May-2004 Location: United Kingdom Status: Offline Points: 874	Posted: 08-August-2004 at 11:25
	hi talat i belive what your doing is right, but you do have to repeat these steps a few times once pure coolant is flowing from your bleed screw retighten wait a short while so if any more air is in your system it will find its way to that point then release again do thie a few times a you should be ok, it took me about half an hour of opening and closing that bleed screw before i got all the air out,just when you think you,ve done it a little more finds it way to the highest point ie that b/screw.remember air can be flowing at diffrent places so just because you have removed one lot there may be more making its way around,thats why i say wait a while then release again, hope this is of some help..

Talat Members Profile Send Private Message Find Members Posts Add to Buddy List Newbie Joined: 22-July-2004 Location: United Kingdom Status: Offline Points: 20	Posted: 08-August-2004 at 15:10
	Thanks for that b8alk. One other quick question - am I supposed to set the heaters to the highest level (i.e. 5) whilst bleeding ? As there's a lot of difference between how much air comes out as I initially bled the car with the heater set to 1. Cheers, Talat.

KP Members Profile Send Private Message Find Members Posts Add to Buddy List Newbie Joined: 08-April-2004 Location: Ireland Status: Offline Points: 18	Posted: 08-August-2004 at 15:14
	Talat, have you had the cooling system 'open' recently e.g. for a thermostat change? This would explain trapped air in the system. If not 'open' this would be more worrying viz-a-viz the cylinder head, and I wouldn't hesitate to get it to a specialist for a pressure test.

b8alk Members Profile Send Private Message Find Members Posts Add to Buddy List Banned User Andy K Joined: 15-May-2004 Location: United Kingdom Status: Offline Points: 874	Posted: 08-August-2004 at 16:49
	yes you should have the heaters set to full open. Also what karl has posted is a very good idea as air will only get in to the system if it has been opened,if you are getting air in the water system and it has not been opened you may well have a problem. have you replaced the coolant lately is that why you are bleeding it though? or did your temp gauge start to move up past half way ie start over heating. As for your local garage i think they have plumetted for the worse case sinario Edited by b8alk

Talat Members Profile Send Private Message Find Members Posts Add to Buddy List Newbie Joined: 22-July-2004 Location: United Kingdom Status: Offline Points: 20	Posted: 08-August-2004 at 17:39
	Thanks for the responses. Not sure what has been done to the car. I bought the car a couple of weeks ago and drove it home around 40 miles without any problems. Then I was driving in traffic one day and the temp started to creep up. Coolant was leaking heavily out of the expansion tank - I replaced the cap and it no longer leaks from the cap when it overheats. The bleeding has had some effect as it seems to take longer to overheat now - there are no sudden movements in the temp gauge, it just slowly but surely overheats. I'm going to book it in with a specialist but since most of them have a lead time of around 2 weeks, I'm going to try and bleed it over the next couple of days in the interim. Cheers, Talat.

Talat Members Profile Send Private Message Find Members Posts Add to Buddy List Newbie Joined: 22-July-2004 Location: United Kingdom Status: Offline Points: 20	Posted: 14-August-2004 at 17:55
	Well I've given up on bleeding the system - seemed to be going around in circles and not making any progress Anyhoo time to let the pro's have a look - dropped the car off at Bexleys this morning and I'm hoping it's nothing expensive - will find out next week. Cheers, Talat.

b8alk Members Profile Send Private Message Find Members Posts Add to Buddy List Banned User Andy K Joined: 15-May-2004 Location: United Kingdom Status: Offline Points: 874	Posted: 14-August-2004 at 18:06
	Sorry we could not help hope you have some good luck Edited by b8alk

520ian Members Profile Send Private Message Find Members Posts Add to Buddy List Newbie Joined: 06-August-2004 Location: United Kingdom Status: Offline Points: 36	Posted: 15-August-2004 at 00:37
	Easiest way to tell if there is a problem with c/h is to get engine up to working temp then try to squeeze top hose, if it is solid or really hard to squeeze then likelyhood is gasket gone letting gas into water jacket. bottom hose will be equally hot and hard to squeeze, if not then probability is air in system due to not being bled through properly. Ian

thaskitz Members Profile Send Private Message Find Members Posts Add to Buddy List Newbie Joined: 13-August-2004 Status: Offline Points: 9	Posted: 15-August-2004 at 12:58
	had a customers 535 in and the only way we could bleed the system successfully was to jack the front end of the car right up in the air still took nearly an hour though!!!! hope this helps

Talat Members Profile Send Private Message Find Members Posts Add to Buddy List Newbie Joined: 22-July-2004 Location: United Kingdom Status: Offline Points: 20	Posted: 15-August-2004 at 18:42
	Cheers folks. This site has been good for advice/tips etc but I think I was getting out of my depth due to my limited mechanical knowledge. Interestingly enough, whilst driving down the A2 to drop the car off, the gauge stayed in the middle (for around 15 mins) and it only started moving towards the redline once I got stuck in a bit of traffic in the town centre. I'll have to wait and see what the diagnosis is - will keep you folks posted. Cheers, Talat.

Talat Members Profile Send Private Message Find Members Posts Add to Buddy List Newbie Joined: 22-July-2004 Location: United Kingdom Status: Offline Points: 20	Posted: 23-August-2004 at 19:50
	An update for anyone that's interested:) It turned out to be the fan clutch in the end - but it will still overheat if the aircon is on and the car is stationary. Apparently it's been fitted with an aftermarket aircon system and the fan isn't up to the task. This isn't a major issue for me and so I'm happy that it wasn't anything expensive Cheers, Talat.

520ian Members Profile Send Private Message Find Members Posts Add to Buddy List Newbie Joined: 06-August-2004 Location: United Kingdom Status: Offline Points: 36	Posted: 23-August-2004 at 20:18
	Thankfully it wasnt anything expensive. Ian.