head gasket or airlock??

[roverman]

have a problem that i urgently need to sought out
its a bit convoluted but here goes
after use i seem to have a problem that occurs occasionally. if i leave vehicle and restart it after its cooled down (appox 1 hour) after a couple of minutes the temp gauge goes up to hot.
when i get out there is a horrible smell and you can hear a lot of hissing i leave it until its cool enough to undo pressure cap
which leads to a lt of air bubbles coming through system and escaping, once the air has gone the coolent level drops dramatically i sometimes need upto 5litres to refill.
the annoying thing is it only does occaisinally ,not on a regular basis
any suggestions /offers of help greatly received as i am thinking of getting rid of it because iam fed up with having to deal with it!!!

[helen&tony]

Hi
I hate to be the harbinger of doom, but it sounds "head gaskety" to me....hopefully some more opinions later
Cheers
Helen

[Aethelric]

have a problem that i urgently need to sought out
its a bit convoluted but here goes
after use i seem to have a problem that occurs occasionally. if i leave vehicle and restart it after its cooled down (appox 1 hour) after a couple of minutes the temp gauge goes up to hot.
when i get out there is a horrible smell and you can hear a lot of hissing i leave it until its cool enough to undo pressure cap
which leads to a lt of air bubbles coming through system and escaping, once the air has gone the coolent level drops dramatically i sometimes need upto 5litres to refill.
the annoying thing is it only does occaisinally ,not on a regular basis
any suggestions /offers of help greatly received as i am thinking of getting rid of it because iam fed up with having to deal with it!!!

You are putting in a lot of water, have you seen it coming out anywhere?

[Dolly1]

Hi,you say after use.wot happens before use,no hissing or smell ???

[GICarey]

Hmm, 5 litres is a lot of liquid to loose "Now n again"!

Do you have a coolant alarm, would indicate if you're losing fluid over time, but only noticing due to the hissing noise, etc, once it gets particularly low? Are you able to keep a good eye on your levels to see if they are dropping over time?

Any plumes of white smoke to indicate head-gasket failure? or do you have one of those kits to test for exhaust gasses mingling with your coolant?

Suspect others here of a more mechanical/sound mind will have better feedback.

[roverman]

right just some other facts
i don't have cooling warning system (i think)
there is no "mayonesse" type deposits anywhere ,as usual for hgf
i can't find a water leak either with or without engine running
my thought was i had a small split in a hose but surely i should find water escaping somewhere.

[westonwarrior]

do you get white smoke when you start the car after such an incident?

[Harry]

Have you or have you had the water system bled properly.

If you have an airlock the water could be boiling and causing back pressure through steam, pushing water out of the overflow on the header tank?

Just an idea?

H

[roverman]

haven't see any white smoke .
i have to say it hasn't done it for a while now but i need to get it sorted as it will do it without any warning.
any one know how much for a new headgasket to be fitted.??

[Aethelric]

haven't see any white smoke .
i have to say it hasn't done it for a while now but i need to get it sorted as it will do it without any warning.
any one know how much for a new headgasket to be fitted.??

It sounds to me like you have a leak in your water system. It must be losing water somewhere. When it gets too low to provide cooling the engine gets hot and you boil over. Although you add water, you will now probably have air in the system. If you do not have a Haydn alarm, check your water every day before setting out. You should see the water going down.

[roverman]

this is odd!!!
haven't used or started the bongo for about 10 days
in that time it appears to have lost about 1 and a half litres of coolant since i last checked it!!!

[mikeonb4c]

this is odd!!!
haven't used or started the bongo for about 10 days
in that time it appears to have lost about 1 and a half litres of coolant since i last checked it!!!

Unless its gone into the cylinder pots (v unlikely from all you've said and you'd soon know as you'd have a hydaulic lock that wrecked the engine) it is either leakage (again unlikely 'cos you ought to see some liquid underneath the car if so), or it has settled in the system.

As Harry asked, have you ever had the system properly bled since it first happened? If not you could possibly be just caught in a vicious cycle of topping up an airlocked system which subsequently complains and spews it out again (tthough from where I don't know unless there is some kind of overflow pipe somewherewhich seems unlikely on a pressurised system).

I'd say:

1) Bleed and refill system properly with 50/50 antifreeze mix (maybe while you are at it drain it and fit a new thermostat just in case - not expensive and most likjely a bit old anyway so worth changing)

2) Fit Haydns coolant alarm (essential insurance anyway plus will alert you the moment coolant level drops)

3) Look out for causes if it happens again (symptoms of blown head gasket, pinhole leak in water hose etc.)

Good luck - keep us posted

Mike

[Dolly1]

Hi,check your hoses,your cooling system is like a pressure cooker when hot.coolant can be forced out and evaporate upon contact with colder air.Listen and locate the hissing.Easier than it sounds