Henry Boler Posted August 13, 2015 Author Report Share Posted August 13, 2015 Ooh, Lots to reply to!! So to confirm, the cooling system is as far as I'm aware extremely clean. I've had everything off apart from the core plugs and nothing bad ever comes out and I've not got any blockages, I've checked the flow in every direction, including the block and head plugs. I even went to the trouble of rebuilding the water pump housing, cleaned out all the faces threads and tidied up the hose tails, chamfering the rough edges and checking the bypass works fine etc., the heater matrix is fine and the tap works perfectly too. Really thorough check! The radiator looks immaculate where visible internally... My gut feeling is definitely head gasket at the moment, the whole reason I have always had a sight glass fitted is from when I had my Spitfire and it would let me know when it was time to buy a new head gasket each time with a good couple of weeks pre warning of total failure! Air in the glass means problem... She is still running very well at the moment by the way. No signs of failure yet from that point of view... So Like you say Pete, a compression test probably wouldn't reveal a lot. I could try though. Re the air blowing coolant out thing, how long should I be able to run the engine with the cap off without coolant coming out? Obviously it's going to expand at some point and pour out, then boil as it's under pressure... When I do that it runs for a good 5 mins without more than a tablespoons worth coming out. It jets out on the motorway, give away is the coolant on the inside of the bonnet and over the chassis. How full should the overflow bottle be cold? How much water should come out of the rad when hot? I think that answered everything from you both! Henry Link to comment Share on other sites More sharing options...
Henry Boler Posted August 13, 2015 Author Report Share Posted August 13, 2015 To add to that, I just drowned myself in the rain to have a quick look. The sight glass has filled back up with water from the overflow bottle. I took the rad cap off and managed to get a thimble full of water in, that includes pumping the bottom hose to help move water around in the system. The overflow bottle is full right up to the neck with coolant. Just a thought, what would happen if there wasn't enough antifreeze to water in the system? Also is there a right and wrong antifreeze to use? My system runs @ 13psi... Link to comment Share on other sites More sharing options...
Henry Boler Posted August 13, 2015 Author Report Share Posted August 13, 2015 This is the sightglass if you wondered. It's the shell of an old fuel filter... Link to comment Share on other sites More sharing options...
dougbgt6 Posted August 13, 2015 Report Share Posted August 13, 2015 Once again Henry, I'm impressed! Moderns have antifreeze in all year round but in the old days we only put it in for the winter. So no antifreeze at all at this time of year is fine. I have to have a sight glass! I need one. Link to comment Share on other sites More sharing options...
Henry Boler Posted August 13, 2015 Author Report Share Posted August 13, 2015 Haha, well ate least someone is!! That's good to know, rules out one other thought I had... It's been very useful to me in the past so I will always have one on every car I have! Link to comment Share on other sites More sharing options...
Pete Lewis Posted August 13, 2015 Report Share Posted August 13, 2015 Its not there i need to fit one !!!! our cars use a glyco based antifreeze, (Blue) never mix it with OAT (Pink/orange ) they react to a solid jelly the overflow bottle only needs enough in it to cover the bottom of the drop pipe, or it sucks air when sucking back in, running expansion would only be a cupfull or so, not litres too full and what expands comes out the breather hole. so it as little as possible , the cap should have a thin seal to the sprung washer seal just under its cap then this ensures what comes out gets sucked back in when it cools . if thats missing it sucks air and not the coolant the GT6 has the unforunate header and filler which is lower than the high point, all cars should run for months without a cap , the pressure just raises the boils point , unless its like the GT6 when the filler is below the head of the system then , i guess gravity lets it out just to say its raining here too Pete Link to comment Share on other sites More sharing options...
Henry Boler Posted August 13, 2015 Author Report Share Posted August 13, 2015 Where is it then??? I see, so is it a problem that I have pink stuff in mine? It was washed out very thoroughly before it went in. This stuff to be precise http://www.halfords.com/motoring-travel/engine-oils-fluids/antifreeze/halfords-oat-antifreeze-concentrate-2-litres... Okay, the overflow bottle does seem to fill itself up a lot, I keep siphoning water off it to keep the level down so it doesn't make such a mess every drive! The rad cap I bought this week from Rimmers had a very thin seal on the top so I changed it for a spare I had on another cap, that now seals fine. You can tell it works as every time the engine cools down as the sight glass fills with water. So if I could extend the radiator filler with a tube of some sort that is higher than everything else, I should be able to run the engine for ages with no air coming out? The rain has stopped here now!! Henry Link to comment Share on other sites More sharing options...
Henry Boler Posted August 13, 2015 Author Report Share Posted August 13, 2015 Just got home. Still got bubbles... New thing though, the rear most external head nut was bubbling from the thread!? Link to comment Share on other sites More sharing options...
John Bonnett Posted August 13, 2015 Report Share Posted August 13, 2015 Just got home. Still got bubbles... New thing though, the rear most external head nut was bubbling from the thread!? Henry, Every day, I've been living this problem with you. I guess now we can probably guess the answer to the bubbling. Although it is an odd coincidence that it should happen immediately after flushing the system. Link to comment Share on other sites More sharing options...
Henry Boler Posted August 13, 2015 Author Report Share Posted August 13, 2015 It's very annoying isn't it! Can't trust her on a long run now... Yeah, that is rather odd... Also I had a similar ish issue about 4 years ago with her which was solved by changing the water pump... Link to comment Share on other sites More sharing options...
dougbgt6 Posted August 13, 2015 Report Share Posted August 13, 2015 Hum, bubbling from the thread? Now what could that be? Sorry! It's an easy and satisfying job, but make sure you get the right gasket. Check for a tab, or lack of tab, on the back of your current one. This signifies recessed or non recessed bores. Shouldn't take more than an afternoon. And get new nuts and washers. Link to comment Share on other sites More sharing options...
Henry Boler Posted August 13, 2015 Author Report Share Posted August 13, 2015 It certainly looks like that's gonna have to happen. Mines a flat top block, no recessed bores. I never had any luck at all with my spitfires recessed bores and head gaskets! I just worry, I think I did about 20 head gaskets on my old spitfire... Never really worked! I reckon the GT6 could be done in a couple of hours no problem! I assume that was just a bad block... Had everything else done and fitted the head a different way everytime, 20 different ways!! Link to comment Share on other sites More sharing options...
dougbgt6 Posted August 13, 2015 Report Share Posted August 13, 2015 Not bragging but my GT6 has never blown a head gasket. Due to engine abuse by PO, a re-bore and re-grind. Due to ex-wife running it with no oil, another re-bore and a new crank. Means the original HG and 2 more in 42 years. The straight six is a very resilient unit! Do not despair! Link to comment Share on other sites More sharing options...
Pete Lewis Posted August 13, 2015 Report Share Posted August 13, 2015 I remember your trials and tribulations with you spitty on the long lost forum but with any head its good to clean it back to shiny, get all the black carbon deposits off with a hard block and some wet dry paper, even take the studs out , make sure the washers are flat not deformed pete Link to comment Share on other sites More sharing options...
dougbgt6 Posted August 13, 2015 Report Share Posted August 13, 2015 It's raining here too, just back from the Thames meeting, low turn out due to weather. My windscreen wipers are RUBBISH! Just passed an MOT too. Sorry thread drift. Link to comment Share on other sites More sharing options...
Henry Boler Posted August 14, 2015 Author Report Share Posted August 14, 2015 I've just ordered a new head gasket. I will however take the car to a garage tomorrow and have the coolant sniffed just to see what it is! Link to comment Share on other sites More sharing options...
Pete Lewis Posted August 14, 2015 Report Share Posted August 14, 2015 I really hope the orange coolant added has not jellied with the blue from a previous use oat + glyco mixed is said to be disaster anyone got more clues ???? google gives some mixed views http://mgaguru.com/mgtech/cooling/cool_121.htm http://www.the75andztclub.co.uk/forum/showthread.php?t=97926 Pete Link to comment Share on other sites More sharing options...
Henry Boler Posted August 14, 2015 Author Report Share Posted August 14, 2015 Yeah I hope not too! If it's any consolation I have seen no such jelly stuff anywhere at all... It's been running the red stuff for about 5 years now too... Update Today: So I made three journeys today, from my parners house to work, then work to home, then home back to her house. The last one was down the motorway for about 6 miles at high speed, I have not topped up the system today or opened the rad cap. Changes to note, after each journey there was air in the overflow pipe, however the water level in the overflow bottle appears to have stabilized, there are no ferrocious bubbles coming from the overflow and also the overflow pipe / metal parts of the sight glass were cold. They have been too hot to touch in the past. There was also not coolant all over the bodywork from the overflow. Just to put a spanner in the works! I love old cars, they're so mysterious! Henry 1 Link to comment Share on other sites More sharing options...
Henry Boler Posted August 14, 2015 Author Report Share Posted August 14, 2015 To confirm, the other day, I used the drain taps to drain all the coolant into a container, It came out so clean you could have sold it as new! I really don't think I have anything in my cooling system that shouldn't be there. Link to comment Share on other sites More sharing options...
Pete Lewis Posted August 14, 2015 Report Share Posted August 14, 2015 phew thats good maybe drive her more to get the confidence the squirting doesn't ............. re appear, you may have cleared an air lock , topping up on top of one wont remove it , they persist. but the persistent cursing and tea swigging may have beaten the problem time will tell happy motoring ...really Pete Link to comment Share on other sites More sharing options...
Henry Boler Posted August 15, 2015 Author Report Share Posted August 15, 2015 And another update of today. Today started very strangely, car wouldn't start properly, which has never happened before, immediate thoughts were oh finally the head gasket has gone and a cylinder is full of water! Would you believe it, an O-Ring on the plug in the front carb float chamber had shrunk overnight??? So there was a petrol flood down the driveway, how this happened and why at the same time as the water problems I'll never know. Anyway, two o-rings later and shes running beautifully again! Loads of driving done today about 4 individual journeys including motorway. Got out before switching the engine off and checked the sight glass, then switched off and continued keeping an eye on it. There has been no signs of air in the pipe at all today! It actually looks like it's working perfectly now! The heating has been working fine also. I guess this was just a really stubborn air lock in the system... I'll keep you all posted as time goes on. I'm going to drive her to Tadley, the other side of Basingstoke tomorrow, that's a good 50 min journey mostly on the motorway so should be a good proving run. Then hopefully the weekend after I'll drive to London, then the week after that Wales! Night All. Link to comment Share on other sites More sharing options...
Henry Boler Posted August 16, 2015 Author Report Share Posted August 16, 2015 Update... So I got to Tadley and back, but the engine was not happy. Struggled to start this morning and blew most the water out on the way... The engine sounded slightly rough at high load as well. So the cylinder head has just come off! Looks like there are blockages in the water ports where the head meets the block. More details when I have a proper look tomorrow! Got all but two of the studs out, they are very stubborn! Henry Link to comment Share on other sites More sharing options...
Pete Lewis Posted August 17, 2015 Report Share Posted August 17, 2015 note the studs have a cut in the threaded end that goes in the block this is to allow any oily stuff out or when you screw the stud in or you can blow the casting to bits with the hydraulic pressure created Pete Link to comment Share on other sites More sharing options...
Henry Boler Posted August 18, 2015 Author Report Share Posted August 18, 2015 Okay, all done. Back on the road all shiny and clean inside, with a Payen gasket instead of the old type in now. Running fine so far... Link to comment Share on other sites More sharing options...
dougbgt6 Posted August 18, 2015 Report Share Posted August 18, 2015 Well done Henry! I wish I could get myself down to work so quickly, there's always something else to distract! Link to comment Share on other sites More sharing options...
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