Has My Head Gasket Gone?

[Peetypug 5]

was checking my 306 meridian (1.8 16v) over as i'm going to bristol on a stag weekend on friday

i noticed that it didnt have much water in the rad

so i filled it up and started it as i thought i would have to bleed the system

i went to get a drink while it was running

 

when i came out it was pissing water out past the filler cap

 

any ideas what could be putting pressure in the system?

 

forgot to add

 

there's no oil in the water and no water in the oil

Edited July 1, 2008 by sorrentopete

[steve@cornwall 100]

was checking my 306 meridian (1.8 16v) over as i'm going to bristol on a stag weekend on friday

i noticed that it didnt have much water in the rad

so i filled it up and started it as i thought i would have to bleed the system

i went to get a drink while it was running

 

when i came out it was pissing water out past the filler cap

 

any ideas what could be putting pressure in the system?

 

forgot to add

 

there's no oil in the water and no water in the oil

 

As you said, it prob needs a bleed - got an airlock somewhere

[Peetypug 5]

just had a look at the rubber on the rad cap

it doesnt fit right, its slightly to big

so i'm wondering if that could be the reason

[Henry Yorke 269 3 Cars]

Get a new rad cap as they often go over time as the spring goes weak. Water should escape out of the over flow at the back, not the actual cap itself

[Peetypug 5]

will get another cap first. I've got one at the farm. I hope its just that.

But would that explain the build up of pressure?

[richard 0]

What you describe is exactly what started to happen to my engine when its head gasket had started to break down.

 

Hopefully it will be just an air block, which can be sorted by putting in coolant, leave the cap off, run the engine up to temperature with the heaters on and top up as required. You'll be able to feel if there is extra pressure in the cooling system by feeling the pipes when the engine is running.

 

This way works for me. Just dont use freezing cold water when its stopped.

 

School of thought is that it will distort the aluminuim head due to rapid temperature shift. However, i dont know how feasible it is in reality.

 

Oh and if your not convinced, get it to a garage for a sniffer test. sticking the gas analyser into the header tank will provide all the proof you need.

[welshpug 1,657]

to aid with the bleeding process on a 306+405 I wedge a large pop bottle (2 litres) upended into the expansion tank with the base cut off, basically adding a header tank.

 

fill up and open each bleed point in turn then wait for the thermostat to open, this should get most of the air out.

 

no need to do anything at all with the heaters, the flow of coolant through them is unaffected by the controls.

[richard 0]

no need to do anything at all with the heaters, the flow of coolant through them is unaffected by the controls.

 

I do not agree, its a good way to make sure you dont have an airlock around that area. Personally.

[James_R 3]

Noo Rich, he means regardless of it being on hot or cold the collant still flows through the matrix, the conrtol just diverts the air over the matrix or not to make it hot, unlike other cars which actually control the flow of coolant through the matrix to make it hot or cold, make sense?

 

Got me for a while too

[richard 0]

I see James,

 

my point was, that if your heater isnt getting hot then you could have an airlock or blockage elsewhere in the system, causing boiling of the coolant

 

going slightly off topic, i flushed my coolant and replaced without using the bleed screws. Maybe im lucky.

[James_R 3]

right get you.

 

Yeah I've not had issues not bleeding th system just filling it and going, maybe it's the rev's it sorts itself out

[Peetypug 5]

well

i got up at 2:30 today so i could bleed the system

driving home this morning (23 miles) i only lost around 200ml

so i've put a rad weld in just in case its a slight hole in the system pulling air in (dont know wether this can happen but its one thing to do)

bled the system let it get up to temp and fans kick in

anyway as soon as i start the car i could see the water rising slowly and its still doing it

 

i've also noticed a slight film of oil on the top of the water

 

so i'm defo thinking head gasket, i had a cam belt service about 6 weeks ago where they replaced the water pump.

i'm wodering if something has gone wrong with that and its lost fluid which has then caused the gasket to go

 

i'm just clutching at straws really as i dont know what causes them to go

[richard 0]

get the expansion tank sniffed, that will tell you.

 

Before mine was replaced, it would be fine driving a normal speeds (ie crawling along) as soon as you want a bit awol on the throttle, and came to a stop, water would litterally flood out of the expansion tank due to the pressure.

 

im lucky in that i got mine done before it went, which was a bit of a miracle with the condition of it

[Peetypug 5]

i called into my mates garage tonight before work.

He checked the oil, said it was fine

He checked the water, said it was fine.

Then had a good look at the rad cap, he says its knackered, it should have 2 rubber seals but it only has one.

So he's ordered me one for tomorrow and said it should be fine!

The spring on the cap should work off pressure but the rubber seal has come off thus not stopping the pressure from building up, so the bit of pressure there is, is getting forced past the cap where the rubber seal should be.

Well i'm baffled, but i suppose its another thing to tick off the list

[Peetypug 5]

cheers for the input gents

 

got it sorted with the new cap

 

it shouldn't have 2 rubber seals, just the one

 

the seal on the old cap had come completely off stopping it from sealing, so when a hose is squeazed i could hear the air getting

 

past the cap no there's nothing

 

the new one is on and its not leaking water now

 

to think i nearly booked it in for a head gasket as well!