Kevin.payne.15 Posted June 28, 2017 Report Share Posted June 28, 2017 I've just completed a head rebuild on the GT6 and ran it for the first time last week end For reasons that I'm not sure about it ran very very hot and we even had steam escaping from the top pipe into the radiator We have investigated and the thermostat appears to work Tonight my son has tried again and topped up the water whilst warming up. He then allowed to warm up further and stopped the car. After a few seconds we had a "rumbling" noise and then he loosened the rad cap which then Vesuvius erupted hot water all over the car, garage, floor ceiling ! Far too much water for the release of pressure. Is this normal ? Any clues what's happening? Thanks Kevin and Chris Link to comment Share on other sites More sharing options...
Colin Lindsay Posted June 28, 2017 Report Share Posted June 28, 2017 It's either an airlock, or a head gasket problem. Are you sure when you refilled it that there wasn't an airlock or blockage; refill it and let it run but don't over heat and keep monitoring pressure and refilling as required. In the past I've filled with a hose while the engine is running, and just keep the hose running water into the engine as it revs to clear any potential airlock that may be trapped. Otherwise it may be gas escaping through the head gasket which shouldn't be the case if you've just replaced it (as long as you used a good gasket and it's fitted correctly!). 1 Link to comment Share on other sites More sharing options...
Guest Posted June 28, 2017 Report Share Posted June 28, 2017 Colin's method is spot-on for getting rid of air locks. Also ensure you have opened the heater valve and placed the temp control to hot - this ensures the water circulates properly and reduces air-lock problems. Keep the rad cap off for as long as is necessary, it's not needed whilst expelling the system of air - infact it's a handicap if fitted. Normally a head gasket problem manifests itself very quickly..................with the rad & system full of water and cap off run the engine. As the engine warms look for tell-tale signs of constant bubbles coming up to the neck of the rad cap aperture and / or if the level of the water starts to rise in in pulses then it's fair to say that the head gasket is duff. A less likely outcome is the head has not been tightened down properly although I would expect to see other signs to suggest this. Regards. Richard. Link to comment Share on other sites More sharing options...
Guest Posted June 28, 2017 Report Share Posted June 28, 2017 I meant ask why the head rebuild ?? Was this down to a previous head gasket problem ?? If so has the head become distorted ?? Link to comment Share on other sites More sharing options...
Gully Posted June 28, 2017 Report Share Posted June 28, 2017 When filling from empty, how much fluid did the system take? Filled mine twice over the weekend (first time with water for a flush) and it took around 6.8 litres each time. I guess we all have slightly different radiators these days so capacities will vary, but usually upwards from the manual figures - if less, then you probably have air locks. Hope it's nothing more serious. Another thought - does your block drain tap run okay? If not, that may indicate some build-up of crud (technical term!) that could affect cooling. Gully Link to comment Share on other sites More sharing options...
dougbgt6 Posted June 28, 2017 Report Share Posted June 28, 2017 Guys, did you use the right head gasket? Reccessed or non reccessed? Wrong one would cause all these problems. 1 Link to comment Share on other sites More sharing options...
Pete Lewis Posted June 29, 2017 Report Share Posted June 29, 2017 Also thermost must have the air bleed jiggle pin fitted or a small hole drilled in the rim to let air locks out when filling get the front of the car up high can help make sure heater valve is open when filling always do a slow fill with the engine running and dont fill to the brim and leave cap off till youre happy . 1 Link to comment Share on other sites More sharing options...
Kevin.payne.15 Posted June 29, 2017 Author Report Share Posted June 29, 2017 Thanks all. I fear we have either a gasket or head problem. When running we thought we had lots of bubbles and then when we stopped the engine ( we hadn't fitted the rad cap by this stage ) we had a whole load of water suddenly erupt from the rad. We had the valves recently recut by DY engines who spotted a feared crack but pressure tested it hot and it was fine so not sure where to go now Pretty sure we have the right gasket. The block has recessed rings and the gasket has solid inserts to match. Suggestions? Take head off and check its flat? Reseal a gasket again ( I didn't use any sealant on it) pressure test head again? Give up and start drinking ? Regards Kevin Link to comment Share on other sites More sharing options...
dougbgt6 Posted June 30, 2017 Report Share Posted June 30, 2017 Don't like the sound of "feared crack" and I would have though DY engines would have checked for flatness, which makes me a bit suspicious of them. But you're right it's got to come off! Don't give up on the car, or the drink! Link to comment Share on other sites More sharing options...
Guest Posted June 30, 2017 Report Share Posted June 30, 2017 Hello Kevin. Be it head or gasket (unlikely the latter, I feel) the head must come off; so I would suggest that having the head fully checked over is the next step. If DY Engines feared a crack one must assume there was something tangible for them to say that and if so I thought it would have been good practice for them to repair that ???? You know the head, is it possible to repair this crack because that has to be done to eliminate this potential problem. If that can be done then I would have the head skimmed as a matter of course after completing that work - you know your head is "true" then prior to refitting. Needless to say you will need a new head gasket on refitting and to be honest you should not require any "gasket glue" if the head is torqued correctly. Are you happy with the engine block studs that the head is tightened on to as they can stretch causing uneven bolting down which of course will lead to its own problems. Regards. Richard. Link to comment Share on other sites More sharing options...
Clive Posted June 30, 2017 Report Share Posted June 30, 2017 Does the gasket have a tab sticking out at the rear of the head? recessed type ones do. When you say the water erupted once the engine stopped, was it shooting up out of the rad? Or just rose out and spilled over? A rise in water level on shut off is normal, just fill an engine and watch the level drop when revved, and rises as revs drop. Sounds like it could be localised overheating, but the head has presumably been cleaned out. How about the block, especially the drain plug area? Is the rad getting hot?? Link to comment Share on other sites More sharing options...
Kevin.payne.15 Posted June 30, 2017 Author Report Share Posted June 30, 2017 Thanks for the contributions. I had the head skilled a few months ago which was part of the journey that we've been on. So I believe it's flat. Very happy with DY service since they cut the valves in beautifully and also identified the crack which they pressure tested hot and found to be good So what happened exactly is that we kept topping up with water and saw continual pulses of th eleven going up and down. When we stopped then we had a large eruption of water so much so that we had to mop the floor. This isn't a dribble ! Head gasket has a tab on the back and says top so it's in the right place and orientation Question is if I take the head off again how do I tell if the gasket is leaking or not? I presume that if I re apply without gasket then I can check flatness at the periphery if nothing else I didn't use gasket sealing compounds - are they recommended? Kevin 1 Link to comment Share on other sites More sharing options...
Kevin.payne.15 Posted June 30, 2017 Author Report Share Posted June 30, 2017 Didn't check the rad - will check with son to see if he recollects but I think it must have because we had mist coming out of the neck of the road from the hot water Link to comment Share on other sites More sharing options...
dougbgt6 Posted June 30, 2017 Report Share Posted June 30, 2017 Yes, studs. I had to get my studs out to get my head off, which knackered the stud threads, so new studs. I was advised to put the new studs in finger tight! There is apparently no torque setting in the manuals for the studs. Uncle Pete said "nip them in", which is next up from finger tight. The trouble we had getting them out, I suspect it was a gorilla put them in previously, finger tight! Studs out is a good opportunity to clean up the block face but take care to pack the bores with cloth/newspaper to avoid crud dropping in. Link to comment Share on other sites More sharing options...
Guest Posted June 30, 2017 Report Share Posted June 30, 2017 Kevin. Head gasket glue is only necessary with certain types of head gasket, for example where the h/gasket is comprised of 2x different materials. It stops the the gasket "moving" due to differences of compound when hot. A number of Rootes vehicles use this type of gasket and quite often Stag WellSeal is used - I have never encountered such a sticky liquid from a tube ! Regards. Richard. Link to comment Share on other sites More sharing options...
DerekS Posted June 30, 2017 Report Share Posted June 30, 2017 Ah, Stag Red, that brings back memories. We used to use it from a tin; for it's time it was good stuff but it did harden with age. You couldn't help getting covered in ths stuff, either, it got everywhere... Link to comment Share on other sites More sharing options...
Guest Posted June 30, 2017 Report Share Posted June 30, 2017 Ah, Stag Red, that brings back memories. We used to use it from a tin; for it's time it was good stuff but it did harden with age. You couldn't help getting covered in ths stuff, either, it got everywhere... I will second that !! Kevin - this may be a long shot but could the water pump impeller be broken ?? I mention this because that is the only mechanical device that will circulate water around the system. If the water is not being circulated this might cause the air lock / block to occur. You said it erupted with some force, so that gives the impression that as the engine heats up the air lock expands until there is such a pressure that it clears itself in a somewhat spectacular form !! It's purely a suggestion and maybe way off the mark; perhaps cross-referencing with Clive's rad suggestion may confirm / disprove this. I know when I have had h/gasket problems the water tends to bubble first and then pulses up through and over the rad neck rather than an almighty explosion as you have described. It's an interesting puzzle. Regards. Richard. Link to comment Share on other sites More sharing options...
dougbgt6 Posted June 30, 2017 Report Share Posted June 30, 2017 You might have something there Richard. When I had the Great Head Gasket Disaster last year, I found the inlet to the pump blocked with rust crud. Presumably it would have a similar effect? Link to comment Share on other sites More sharing options...
Guest Posted June 30, 2017 Report Share Posted June 30, 2017 I reckon so Doug and perhaps it may well be the inlet - if it is this, that will be a great result compared to a defective head or gasket. Been refurbing the Vitesse leaf spring today, in the garage, so have had plenty of time to think about this problem Regards. Richard. Link to comment Share on other sites More sharing options...
Pete Lewis Posted June 30, 2017 Report Share Posted June 30, 2017 it has all the hallmarks of air locking , double check all the simples before you rip her apart youve had the head skimmed assume something simple is the culprit.......... apart from the what did do last rules there is no call for any sealant in the WSM , so its fit it dry !!! Link to comment Share on other sites More sharing options...
dave.vitesse Posted June 30, 2017 Report Share Posted June 30, 2017 I with Pete, check the simple things to start with. I would have thought if there was excessive pressure it would have blown past the rad cap? Start with an air lock to start with. Link to comment Share on other sites More sharing options...
Kevin.payne.15 Posted July 1, 2017 Author Report Share Posted July 1, 2017 Thanks for the advice. Will investigate. DY and going to recheck the leak for me and I'll check the block flatness as well as the head Will also check that I have sufficient thread on the studs because it could be that with the head skim in now not torquing the head down but am bottomoming out on the thread I also tried the spitfire grave yard for a replacement head but no joy. Does anyone else know of a source of heads? Thanks Kevin Link to comment Share on other sites More sharing options...
Pete Lewis Posted July 1, 2017 Report Share Posted July 1, 2017 has the car any history of boiling up ?? youve done all the work on the head , why look at replacing without due proof most heads have casting lines that look like cracks dont get carried away without good proof of the culprit pull the plugs is there any water in the bores ??? Pete Link to comment Share on other sites More sharing options...
Kevin.payne.15 Posted July 2, 2017 Author Report Share Posted July 2, 2017 I'll investigate tomorrow night and see if we have a swimming pool on top of a piston. Ok so DY believed there was a slight crack in the inlet valveseat of no 1 bore but they tested and believed acceptable but warned that they can quickly spread hence my worst fears Kevin Link to comment Share on other sites More sharing options...
dougbgt6 Posted July 2, 2017 Report Share Posted July 2, 2017 A slight crack? Much like being slightly pregnant? Link to comment Share on other sites More sharing options...
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