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Essex head gasket failed?

Posted: Mon Aug 12, 2019 6:27 pm
by Stornoway Grey
I've been losing small quantities of coolant on every journey for a few years now and replaced the entire cooling system one bit at a time, then had it tested (pressure/ gas emissions) for head gasket failure but the garage said all was fine.
Yesterday I did a 120 mile round trip and at the end I observed gas bubbling through the header tank for 7-8 seconds after I turned off the engine.
I think I know the answer to this already but... Could this be anything other than a head gasket failure?
Its a 1978 SE6a with standard cooling setup.
Cheers, Adam

Essex head gasket failed?

Posted: Mon Aug 12, 2019 6:36 pm
by Roger Pennington
Are there any other supporting symptoms?

Essex head gasket failed?

Posted: Mon Aug 12, 2019 6:44 pm
by Terry H
If the garage did a "sniff test" and the liquid in the tester did not turn green then the head gasket is more than likely OK. Not wishing to teach granny how to suck eggs but it could be that your system is not being topped up correctly. You should make sure that the heater control is set to hot when you fill up the system to avoid getting an air lock in the system. Apologies if you already knew that.
Regards Terry H

Essex head gasket failed?

Posted: Mon Aug 12, 2019 6:55 pm
by AJL Electronics
Stornoway Grey wrote:
Mon Aug 12, 2019 6:27 pm
I've been losing small quantities of coolant on every journey for a few years now and replaced the entire cooling system one bit at a time, then had it tested (pressure/ gas emissions) for head gasket failure but the garage said all was fine.
Yesterday I did a 120 mile round trip and at the end I observed gas bubbling through the header tank for 7-8 seconds after I turned off the engine.
I think I know the answer to this already but... Could this be anything other than a head gasket failure?
Its a 1978 SE6a with standard cooling setup.
Cheers, Adam
By 'header tank' do you mean the 6b system?

Essex head gasket failed?

Posted: Mon Aug 12, 2019 7:03 pm
by peter freeman
I have had head gaskets fail and the sniff test not showing the failure so I don't think it is always a good guide. How is the thermostat cap - often the problem with the 6A water loss.

Essex head gasket failed?

Posted: Mon Aug 12, 2019 7:18 pm
by Stornoway Grey
Thanks all, I've been through every part of the cooling system over the past 5+ years, I am confident the thermostat cap is good Peter (replaced more than once with dealer supplied replacements until got a good seal and working well). By header tank I am referring to the plastic overflow bottle on the standard 6a system (apologies for the confusion). I must admit terry that I did not know to set the heater control to hot when filling the system. However, since the last empty and re-fill I must have topped up using about 4 litres of coolant over 2-3 years. After every journey the level falls by 1-2cms in the overflow bottle. When it gets so low that hardly any coolant appears in the bottle once the engine is up to temperature, I then top up. The oil is not emulsified (although I must admit it seemed a little 'thin', almost watery last time I checked the level... although I cant be sure if I was imagining that due to paranoia). I have no visible drips or leaks anywhere. Engine temperature and pressure are always good (temp sender was replaced at QRG 8 or 9 years ago). For peace of mind I might take it to a different garage and get it re-checked...

Essex head gasket failed?

Posted: Mon Aug 12, 2019 7:22 pm
by scimjim
Heater control position is irrelevant on the 6 series as there's no valve.

I would have said pressure cap if it's passed a sniff test - but I wonder if you're just getting a bit of localised boiling somewhere?

Essex head gasket failed?

Posted: Mon Aug 12, 2019 7:40 pm
by gtcse8
As Jim points out the SE6 system does NOT have a valve for the heater, so is irrelevant. :idea:

Do you keep the overflow bottle half full when topping up at the Rad Cap?. :?:

Hot/Warm water that is pushed into the overflow bottle WILL evaporate and then not enough will be sucked back into the engine, unless the overflow AND radiator are kept topped up. :o

In the 30 plus years I have had/worked upon these cars there are some that ALWAYS lose water, and others that NEVER seem to lose it.
Just as a thought, have you ever put radseal in the water??. :wink:

It will stop any of those tiny leaks that you may not have noticed.
Mark

Essex head gasket failed?

Posted: Mon Aug 12, 2019 8:12 pm
by Stornoway Grey
Thanks Jim, Mark. I only ever top up at the overflow bottle (since first replacing all coolant in the rad up to level), could this be my problem? I decided it was best to leave the rad cap once I got one that sealed properly as it took a few attempts to get it working properly.
I guess I too had reached the conclusion last year that it would always loose some coolant and not worry too much about it. But this is the first time I have seen bubbling in the overflow bottle like this.

Essex head gasket failed?

Posted: Mon Aug 12, 2019 8:19 pm
by peter freeman
The best thing I did was fit a outlet top/rear drivers side of the rad - fit a sealing cap to the thermostat housing and it a 5 type of expansion tank with the pressure cap on it. Of course the extra rad pipe goes to the "new" tank. End of problems - even worked very well when I got rid of the Essex and fitted a Rover V8

Essex head gasket failed?

Posted: Mon Aug 12, 2019 10:17 pm
by AJL Electronics
The bubbling is normal, it is the coolant expanding. This is why the cap has a return valve, as the engine cools it creates a vacuum to draw it back in again. As it is open to atmosphere there will always be some evaporative losses.

Essex head gasket failed?

Posted: Tue Aug 13, 2019 12:10 am
by Roger Pennington
Stornoway Grey wrote:
Mon Aug 12, 2019 8:12 pm
Thanks Jim, Mark. I only ever top up at the overflow bottle (since first replacing all coolant in the rad up to level), could this be my problem? I decided it was best to leave the rad cap once I got one that sealed properly as it took a few attempts to get it working properly.
I guess I too had reached the conclusion last year that it would always loose some coolant and not worry too much about it. But this is the first time I have seen bubbling in the overflow bottle like this.
I only ever top up at the overflow bottle, and that's how I've done it for the last 36 years (when I first fill the system, I fill it to the brim at the thermostat cap, of course).

Have you done a compression test?

Essex head gasket failed?

Posted: Tue Aug 13, 2019 10:41 am
by Stornoway Grey
Roger Pennington wrote:
Tue Aug 13, 2019 12:10 am
Stornoway Grey wrote:
Mon Aug 12, 2019 8:12 pm
Thanks Jim, Mark. I only ever top up at the overflow bottle (since first replacing all coolant in the rad up to level), could this be my problem? I decided it was best to leave the rad cap once I got one that sealed properly as it took a few attempts to get it working properly.
I guess I too had reached the conclusion last year that it would always loose some coolant and not worry too much about it. But this is the first time I have seen bubbling in the overflow bottle like this.
I only ever top up at the overflow bottle, and that's how I've done it for the last 36 years (when I first fill the system, I fill it to the brim at the thermostat cap, of course).

Have you done a compression test?
No I haven't Roger - can you explain it to me please? Not sure what it is or why it will be useful?
Regards, Adam

Essex head gasket failed?

Posted: Tue Aug 13, 2019 10:52 am
by JoeySully
Stornoway Grey wrote:
Tue Aug 13, 2019 10:41 am
Regards, Adam
this may help




you will need one of these

https://www.ebay.co.uk/itm/Petrol-Engin ... SwasZdUndP

Essex head gasket failed?

Posted: Tue Aug 13, 2019 4:27 pm
by gtcse8
Roger Pennington wrote:
Tue Aug 13, 2019 12:10 am
Have you done a compression test?
I think Roger is referring to a Cooling System pressure test, otherwise known as a Rad Leak tester.
I have one and it`s a Sykes Pickavant kit with various clamps to replace the Rad Cap on different cars.
You can either let the engine run and watch the guage, or pump it up to test for leaks or drop in pressure.
If you run a car with gasket or head failure the system will pressurise and keep doing so till something gives. :w