AW11 cooling system problem

[Vertigo]

i took a drive to see the olds today, about a 70km trip. just as i got there, i noticed i was overheating. once it had gone cool, i spent some time with mr old diagnosing/fixing the issue.. it had lost some coolant, so he would fill at the cap while i muddled around at the front end, squeezing the radiator cool end pipe, which felt rather empty. every time i let go, it sounded like coolant was being sucked into the radiator at the hot end.

i took off home again when we were sure it was full, and everything was fine again until i stopped at the takeaway place. started her up again and she started overheating almost instantly - could only get 100m before i had to turn it off. took 30 mins to go 2km, stopping and starting :/

the final time i stopped, the radiator was stone cold, while the pipes on either end were quite hot

so, radiator $&#$%? guess ill be looking for a new one..

[touge_ae101]

yep my guess would be blocked radiator or collasped hose. not familiar with aw11's but i can imagine there being a lot of hose from rear-front which could be causing the problem

[Vertigo]

hmmm... now that im thinking about it, theres a few other issues im having that may be related, and possibly pointing to a BHG..

ive been hearing a strange asthma weezing like sound above 3.5k, but noone else, including mechanics, can hear it, oddly enough. and also, at times coolant can be forced through my cracked overflow bottle cap, through the vents, and onto the engine cover.

i really do hope its not a BHG... as well as a blocked radiator..

[Quint]

take out your rad and flush it out. disconnect the lines connecting to the motor and flush them out too. When you're refilling the lines make sure the bleed screw on your rad is undone and keep filling it until water comes out your bleed screw.

[Dell'Orto]

Get the rad properly cleaned, it's probably well blocked. The one on my S/C one was 1/4 completely blocked and 1/4 partially blocked
Also hows the radiator cap? If thats stuffed then it can blow coolant back into the overflow

[Vertigo]

checked this morning, and im seeing white foam at the rad cap.. not good

[Dell'Orto]

TK check it first before you pull it to bits.

[MAGN1T]

Tk checks dont work all the time.
The bubble check works 100%.
Yes do the TK check.Then you 'll see how useless it is.Then wonder why anyone would bother.

Steve

[Dell'Orto]

Well shit, it must have a BHG then, Steve said so

[Truenotch]

Sometimes AW11's get foam under the rad cap from having such a large volume of water.


Have you been filling it with all bleeders open?

AW11's are very sensitive to being filled the correct way... If you get it wrong, you will get an air lock and the water won't flow. It may look like it's "full" at the cap, but you need the radiator bleeders open to start with.


A good technique is to pull the top pipe off the radiator and force feed water into it with a hose. Do the same with the heater core then open up the bleeders. (make sure the heater is turned to hot).

You'll need 3 decent lenghts of clear plastic hose of ~6-8mm ID - connect this to the radiator bleeder, the heater core bleeder and the Thermostat bleeder and open the taps.

Run the car and keep the radiator topped up.

Keep an eye on the temp gauge and check that all pipes are warming up.

It will blow bubbles out all bleeders for a long time... Be persistent and do it until there are no signs of bubbles - it will take at least an hour to do it properly.


The main issue is WHY has it lost water in the first place? It could have had a stuffed water pump or dead thermostat. Thermostat's are often the cause of these issues in AW11's.

[Vertigo]

the mechanic ive taken it to reckons its the thermostat, thinks the head gasket is fine. well find out tomorrow.

[MAGN1T]

What do you mean by "water", If you use water instead of antifreeze you end up with a leaking headgasket.

Steve

[Truenotch]

Water = coolant. Coolant/water ratio should normally be about 50/50, but 4L in an AW11 is fine (even though they carry 13L of water).



Make sure your mechanic takes the time to bleed it right.

[MAGN1T]

Ahhhhh, so that's why it's "normal" for them all to bubble.

Steve

[Truenotch]

Yes, you've got it... not because they have 13 litres capacity and have a lot of trouble with airlocks .

[levinguy]

Ahhhhh, so that's why it's "normal" for them all to bubble.

Steve

love this guy

[no_8wire]

Ive found that jacking the back of the car up while refilling the coolant system helps to minimise the risk of any airlocks (plus having the bleed valves open with plastic tubing etc)

[GDII]

I know this is an AW11 but when I replaced the coolant in my SW20 it worked perfectly the first time. I measured the door sill height from the ground, front and back, before I lifted it up to do some other work. Then I measured the same points when it was jacked up to check it was level. I just kept filling it up till it came up the clear hoses I had attached to the radiator and heater and then checked it was level with the filler in the engine bay. This was the first time I had ever tried doing this in an MR car. I don't see why everyone says it is hard to get it to fill properly. It was abit foamy in the filler cap for a week as I kept checking it. Only had to add 200ml.

[rollaholic]

bubbles do not automatically equal BHG. you know this MAGN1T. TK check works very well as long as you dont expect it to do things its not designed for. you know this also.

[Vertigo]

thermostat it was! well ill be. running fine again now! thanks for your suggestions people