so I have searched and I'm sure what's wrong i just want to double check a couple of the symptoms i'm experiencing in case there is anything else i need to be thinking about before i consider attempting the work.

So the bleed cap blew off my radiator and blew coolant out all over the M4, being honest the temp didnt go into the red whilst i was driving for at least another 20 miles so i just hoped i'd make it home and had a go, needless to say it hit the red eventually and i stopped straight away popped the hood then did something stupid and pored cold water in which made a mountain of steam!! stopped quickly as i instantly remembered what happens to rapidly cooled metal. anyway AA sorted me out, to home at least.

It has been a couple of weeks since then getting a part and around to jump starting it and filing with some plain water.

So it starts straight off no probs getting a little white smoke from the exhaust to be expected after its down time and after 5 mins the temp hadn't really risen so i held it at 4K for a bit to try and get some warm air through the heaters. Nothing, i let the revs drop back down then the temp soared, cut it off just as it hit the red, went around to the engine bay everything was cold except for the block and head but when i opened the rad cap it fired a fountain of semi warm water out at me, such pressure!! and the start of baileys cream development under the oil filler cap

So i think i know that this is a head gasket failure, and roughly what i have to do with regards to that, just wondering if there are side issues with my cooling system?

And if anyone can offer any advice before i start working on an engine for my first time :s got to start somewhere right??

I know will need to get a pug gasket, head skimmed etc i had a cambelt kit done only last year, should i be replacing this too or would it be ok to keep?

Thanks for reading, this probably regurgitated thread.

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This site is my mechanical bible, Thank-you everyone!!

I only used the top nearside bleed cap and a header tank made from a milk 4 pinter.

Looks like the oil contaminating started today, was looking at a £30 compression testing kit would be handy to have if its a good one at that price

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This site is my mechanical bible, Thank-you everyone!!

I had the head on my rally car 306 skimmed with the valves all left in place, there is just enough to allow for a skim but not much.

Martin

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- Maxi rear axle hub spacers +53mm per side
- Maxi front steering rack extensions +40mm per side

Hat the head skimmed on mine the other week, valves left in place, just popped the cams out

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My 306 Rallye Project Thread

Few recent Youtube track videos, more on my channel
Pair of Rallye's doing a few laps of Anglesey


Lap of Anglesey Coastal

3 sisters circuit

Few laps at Blyton

erm you can get mayo under the oil cap in this weather from short journeys. Best option is water bottle lid off top it up then leaving the lid off start it up at idle and keep topping it up. Undo each bleedscrew in turn and bleed all the air. Its too soon to just take the head off unless you have already compression tested it

They do have a habbit of getting bad airlocks in the thermostat housing if not filled and bled correctly, it sounds like you do have more pressure than you would blame on an airlock but you never know.

As I said in my first reply I wouldnt be at all surprised if it is the head gasket but you really should eliminate other things first.

I wouldnt take the head of before having a compression test done, it's to much work and money to find that it isnt the problem. Any garage should be able to do a test for you and you will then know for sure.

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Ryan

Cheers for all the advice guys

unfortunately its brown stuff and fan times for me at the moment. Haven't got much money or insurance so whatever does happen to my six is going to be taking place in my carport unfortunately it is facing downhill at the moment, but not too steep.

Gonna get out there in a min and give it another go, see what happens......

as for compression tests I've seen a few cheap kits anyone had any experience?

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This site is my mechanical bible, Thank-you everyone!!

Sweet will pick one up soon then!

just an update, might of been a massive airlock in the system. Only using fresh water as i didn't want to waste coolant while problem solving, but i managed to get nearly a whole bucket of water in it. Thing is i was impatient waiting for the thermostat to stop bubbling and start flowing so i undid the screw a little more by hand and in the process burnt myself and the screw has F**ked off somewhere now

looked like an M4/5 with matching copper washer before i threw it away anyone know for sure which it is?

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This site is my mechanical bible, Thank-you everyone!!

yeah picking one up today hopefully get this sorted over the weekend and confirm its not the HG

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This site is my mechanical bible, Thank-you everyone!!

sorry to go off topic but on one of the posts about bleeding the system and burning yourself, i blled my cooling system and by the time i get to the matrix pipe the waters scoulding and burn my hands trying to screw it back in, is there a way around the burning?

and ps, my oil filler cap does the going creamy thing untill the engine gets warm, when i first noticed it i also worried alot untill i had a compression test and the engine was fine, the mechanic said this is normal in the temperature we have in autum, winter and early spring,

pugjim: i hear what your saying and hopefully i'd be able to give this a go, i've never taken the head off an engine before but i cant afford to take it to a garage so best just give it a go.

Oh and rubber gloves did work on the burning front! although after many attempts to fully bleed the system i now know its defiantly the HG

For others future reference the system was fully bled with the header tank still on everything was working fine and as it should so i felt really hopeful.

Took the header tank off replaced the filler cap and went to sit in the car to watch the gauge. No sooner had i sat down white smoke/steam started to poor out of the exhaust so i turned it off.

Back off with the filler cap loads of pressure again fired out steam and boiling water so i didn't avoid the burning after all ha ha ha

So in summery i must have a small HG failure which when the coolant system isnt closed and pressure can release it doesn't show, as soon as the coolant system was closed water must have been forced into one of the cylinders fingers crossed I've caught this soon enough to not be a total pain in the ass and I still get a chance to mess up an engine after all :p

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This site is my mechanical bible, Thank-you everyone!!