Symptoms of an airlock?

[james_16v]

Hi
Yesterday I changed my oil cooler and coolant and I dont think I fully bled the system afterwards. Drove to work today (20 miles) and pulled up to put some petrol in and noticed a dripping from under the car. I popped the bonnet and the water was being forced through the pipes on the oil cooler past the hose clip. The clips are on tight, seem to be seated correctly with no obvious splits or holes but water is still escaping from them. Would an airlock cause this or maybe the hose clips worn and not able to maintain enough tension? Also water & oil temps are normal.
Im still learning as I go so any suggestions would be greatly appreciated.
Cheers

[DarnPB]

Yes an airlock could cause this, or just not enough water in the system.
The water system is a pressurised system, the pressure being caused by the air at the top of the system in the expansion tank getting hot with water temp. If there is too much volume of air at this pressure wanting to expand, this will cause overpressurisation in the system.

[james_16v]

Thanks for the suggestion.
Ive just been out to try and bleed the system but when the water temp got to around halfway the coolant started gushing out the expansion tank and lost most of the water. I think im out of my depth now! ill book it into a garage for them to take a look at.

[Conker]

Thanks for the suggestion.
Ive just been out to try and bleed the system but when the water temp got to around halfway the coolant started gushing out the expansion tank and lost most of the water. I think im out of my depth now! ill book it into a garage for them to take a look at.

Nah! You'll be fine. Some tips for bleeding, but have a search as well as this is a common issue...

- Massage the big fat radiator pipes A LOT and at the same time.
- While filling, try overfilling the exapansion tank past the max mark as the extra gravity can help push the water into the system. Don't leave it too full after filling though!
- Keep a check of how much coolant you put in, I think it takes about 4-5 litres to fill it, so you can tell if you've got an airlock i.e. if you only put two litres in but it says "Full" (although this only works from an empty system).
- Rev the engine occasionally, you should see a "squirt" of fluid into the expansion tank from the water pump.
- Leave the cap off for a while to allow it to "burp".

[Khare]

stuff jay said really. and do it when the engine is cold, cos when warm water will expand and you will get less in. leave expansion tank cap off and run the engine for 10 mins or so and give it a few revs here and there to get the water pump pumping.

[Conker]

...and do it when the engine is cold, cos when warm water will expand and you will get less in...

Hmmm. I don't think that matters as the system has got to get hot enough for the thermostat to open anyway (otherwise you won't fill the rad properly IIRC).

[Khare]

...and do it when the engine is cold, cos when warm water will expand and you will get less in...

Hmmm. I don't think that matters as the system has got to get hot enough for the thermostat to open anyway (otherwise you won't fill the rad properly IIRC).

also very true. forgot about that way i did it is fill it from cold, then wait till its full, then turn it on and keep topping up until no more.

[james_16v]

I did more or less exactly as you've written conker (squeezing rad pipes, occasional rev etc) but after about 10 minutes it suddenly boiled over. Ill top it back up to max before I leave for work in the morning and see how I go.
Could my symptoms point to any other possible causes (dare I say it the head gasket!) 

[Khare]

stuff jay said really.

sorry lol. meant conker. 

[Conker]

It could be lots of things, e.g. thermostat, water pump, blocked rad etc. etc.  But [just to make you feel better] I bet you've just got an ordinary fault e.g. the oil cooler pipes are worn and split allowing the system to depressurise, or something like that.

Diagnosis required using rubjonnys guide!!!