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Omega Help Area => Omega General Help => Topic started by: bored bigyin54 on 24 December 2011, 22:22:29

Title: head gasget
Post by: bored bigyin54 on 24 December 2011, 22:22:29
 ;D hi guys how can you tell a head gasget is gone on a 2.o no muck on oil filler cap no oil in water ??? just water pipes going solid when warm?????
Title: Re: head gasget
Post by: RobG on 24 December 2011, 22:39:55
Sounds like it`s overpressurising. Under normal running the coolant system is under constant pressure, but, if the system has a small leak it will allow coolant to be forced out under pressure, ie. engine under load.
However, when that pressure is reduced, ie. when the load is reduced then a vacuum is formed at the leak which will then suck in air.
Due to the fact that air expands when heated, get enough in the system (and it doesn't require much) and the system becomes overpressurised causing overheating problems.
Dead giveaways are rock hard coolant pipes pipes and a "hissing" from the coolant cap as it tries to vent off the excess pressure.

Title: Re: head gasget
Post by: RobG on 24 December 2011, 22:43:12
Sounds like it`s overpressurising or there`s a blockage. Under normal running the coolant system is under constant pressure, but, if the system has a small leak it will allow coolant to be forced out under pressure, ie. engine under load.
However, when that pressure is reduced, ie. when the load is reduced then a vacuum is formed at the leak which will then suck in air.
Due to the fact that air expands when heated, get enough in the system (and it doesn't require much) and the system becomes overpressurised causing overheating problems.
Dead giveaways are rock hard coolant pipes pipes and a "hissing" from the coolant cap as it tries to vent off the excess pressure.
Title: Re: head gasget
Post by: bored bigyin54 on 24 December 2011, 22:44:03
 ;D so do you think the head gasket is gone or not :y ???
Title: Re: head gasget
Post by: bored bigyin54 on 24 December 2011, 22:46:26
 ??? i forgot to say its the RAC who said the head gasket was gone :y
Title: Re: head gasget
Post by: adey2 on 24 December 2011, 22:48:03
i used to work for a sub contractor of the aa, did the rac guy do a sniff test on it to confirm
Title: Re: head gasget
Post by: RobG on 24 December 2011, 22:48:51
i used to work for a sub contractor of the aa, did the rac guy do a sniff test on it to confirm
Inconclusive
Title: Re: head gasget
Post by: RobG on 24 December 2011, 22:49:20
;D so do you think the head gasket is gone or not :y ???
What`s the bottom hose doing Ralf?
Title: Re: head gasget
Post by: adey2 on 24 December 2011, 22:53:17
are all pipes getting hot, id be more thinking along lines of thermostat or possible water pump if none getting warm
Title: Re: head gasget
Post by: RobG on 24 December 2011, 22:57:50
are all pipes getting hot, id be more thinking along lines of thermostat or possible water pump if none getting warm
OP says hose/s get warm, if a differential in temp between top & bottom hoses could possibly be rad core partial blockage
Title: Re: head gasget
Post by: bored bigyin54 on 24 December 2011, 22:58:25
 ;D as far as i know they are the same have to ask him in morning :y
Title: Re: head gasget
Post by: adey2 on 24 December 2011, 22:59:48
yeah i was just thinking that it may be getting slightly warm off heat off engine rob
Title: Re: head gasget
Post by: RobG on 24 December 2011, 23:03:16
Need to run engine with expansion cap off (to prevent pressurising), get it up to temp and check warmth of top & bottom hoses, if coolant is circulating as it should, both hoses should be roughly the same temp, if not, blockage, which would give hard hoses
Title: Re: head gasget
Post by: Darth Loo-knee on 24 December 2011, 23:05:36
I have to agree with Rob sounds like over pressurising which can be a sign of a head gaskets failing.

I would not take everything the RAC/AA men tell you. Alot (not all so no disrespect to anyone that is one) have no clue. Have seen to many diagnose head gaskets etc which turnout nothing of the sort. Sniffer Tests do not always work either..

I must add this is in my opinion  :)
Title: Re: head gasget
Post by: adey2 on 24 December 2011, 23:06:08
or make sure heater is blowing hot, shoould elliminate the water pump being problem
Title: Re: head gasget
Post by: adey2 on 24 December 2011, 23:08:23
oh trust me ive made aa and rac look idiots on more than one occasion so will agree with you there
Title: Re: head gasget
Post by: Andy H on 24 December 2011, 23:15:14
are all pipes getting hot, id be more thinking along lines of thermostat or possible water pump if none getting warm
OP says hose/s get warm, if a differential in temp between top & bottom hoses could possibly be rad core partial blockage
Sorry, that is complete 'dangle berries'. The only reason for having the radiator is to create a temperature differential to cool the engine. Hot water in at the top, cooler water out of the bottom.
Title: Re: head gasget
Post by: adey2 on 24 December 2011, 23:24:27
if moving down the road through cooler air yes, but sitting on a driveway ticking over its not
Title: Re: head gasget
Post by: bored bigyin54 on 27 December 2011, 16:54:17
;D so do you think the head gasket is gone or not :y ???
What`s the bottom hose doing Ralf?
he said the bottom hose go hard as well
Title: Re: head gasget
Post by: bored bigyin54 on 27 December 2011, 16:57:57
oh trust me ive made aa and rac look idiots on more than one occasion so will agree with you there
who cant make them look idiots i have done it with my car and a astra they said the head gasket and it was the rad
Title: Re: head gasget
Post by: Neil (Cardiff) on 29 December 2011, 01:08:59
It doesn't sound like a head gasket to me...

However I'm no expert. Is there any mayo on the dipstick or filler cap? Is the coolant a rusty colour? Lastly what is the engine temperature like? And is it loosing any water??

No disrespect to the RAC man but I wouldn't say squeezing a radiator hose was any way to confirm HG failure.

To be sure you could compression test each cylinder - very quick, easy and conclusive test

Are you still driving the car? If so, you'll soon find out for sure  :P
Title: Re: head gasget
Post by: Michael2.6 on 29 December 2011, 08:56:28
when car is running is there any bubbles in the expansion bottle