Ziggy Posted June 9, 2020 Report Share Posted June 9, 2020 Just rebuilt my engine and have all new coolant pipes/rad, the whole coolant system has been stripped and cleaned, but after refilling the temp is perfect but when the fan is on I get no hot air at all, is this an air lock? if so, how do I get rid of it? 1973 mk4 Spit 1300. Link to comment Share on other sites More sharing options...
dougbgt6 Posted June 9, 2020 Report Share Posted June 9, 2020 Sounds like it! Could be blockage in the heater, but did it work before? Disconnect heater hoses from block and fill heater externally, reconnect, try again. By trying to fill you will learn if more water was needed, or not. If not then thermostat or worse ☹️. Tell us what happens. Doug Link to comment Share on other sites More sharing options...
Pete Lewis Posted June 9, 2020 Report Share Posted June 9, 2020 release the top heater hose jubilee clip and partly pull the hose off the heater spout do this with engine running and up to temperature ,any air will escape but watch out for hot water did the the thermsat have a jiggle pin in its outer disk to bleed air when filling , if not drill a 3mm hole in the rim /disc Pete Link to comment Share on other sites More sharing options...
NonMember Posted June 9, 2020 Report Share Posted June 9, 2020 19 minutes ago, Pete Lewis said: release the top heater hose jubilee clip I think the MKIV Spitfire heater is the same as the Mk3, or similar, anyway, and doesn't actually have a "top" hose. The matrix goes up one side, there's a pipe across the top, then down the other side, so both hoses are at the bottom. Makes bleeding a pain. Link to comment Share on other sites More sharing options...
Pete Lewis Posted June 9, 2020 Report Share Posted June 9, 2020 in that case , well have you tried collapse the rad hose when the stats open forcing flow round the heater or put car up on ramps so front is much higher than the back or any other wierd ideas you can try Pete Link to comment Share on other sites More sharing options...
Ziggy Posted June 9, 2020 Author Report Share Posted June 9, 2020 6 hours ago, dougbgt6 said: Sounds like it! Could be blockage in the heater, but did it work before? Disconnect heater hoses from block and fill heater externally, reconnect, try again. By trying to fill you will learn if more water was needed, or not. If not then thermostat or worse ☹️. Tell us what happens. Doug I will try that. I will remove the heater out pipe as that is cold when engine running, but the inlet is hot, so must be an air lock. No idea if it worked before, but I have had it all out and flushed it so I know its not blocked, I have restored the car bottom up, so most stuff is all new. 1 Link to comment Share on other sites More sharing options...
Pete Lewis Posted June 9, 2020 Report Share Posted June 9, 2020 with the bleeding problems I would now drain as much as you can then fill the system with heater valve fully open and engine at a fast idle ??? so air is bled out as you fill ??? Pete Link to comment Share on other sites More sharing options...
Colin Posted November 29, 2020 Report Share Posted November 29, 2020 Have just developed the same prob with a couple of first tentative runs after much get-back-on-the-road runs:- have recently had heat from the vents whikst working on her and checking but on last test run I had no warmth from the vents (to remove the steaming up of window my body geat was causing). This won't risk the enginr seizing will it? But what's causing it? I have ordered a new 'stat and will replace unless I can find summat to test old one in :- but if it's an air block, what's causing it - and how to rid . . . ?🤔🤔 Link to comment Share on other sites More sharing options...
Pete Lewis Posted November 29, 2020 Report Share Posted November 29, 2020 we have one in dunstable being a pig to clear any air lock the guy is pulling teeth and nothing seems to solve it what happens if you charge fill with a garden hose on the heater hose after that its change heater, change valve ,change pump, change stat , change bypass , .............change Car has the stat got the jiggle pin or a bleed hole in the rim ?? sorry must have asked that before its a virus thing , Link to comment Share on other sites More sharing options...
Colin Posted November 29, 2020 Report Share Posted November 29, 2020 Have just developed the same prob with a couple of first tentative runs after much get-back-on-the-road runs:- have recently had heat from the vents whikst working on her and checking but on last test run I had no warmth from the vents (to remove the steaming up of window my body geat was causing). This won't risk the enginr seizing will it? But what's causing it? I have ordered a new 'stat and will replace unless I can find summat to test old one in :- but if it's an air block, what's causing it - and how to rid . . . ?🤔🤔 Link to comment Share on other sites More sharing options...
Colin Posted November 29, 2020 Report Share Posted November 29, 2020 Hi Pete. I'm amazed you followed my post. Just re-read it. What do you/does anyone think about running her up to temp with the rad cap of - just to the point where the stat opens (if it will) and begin to see the water circulating? Surely at that point it'll be clear that the stat os - or isn't opening. This thing about taking heater box pipes off anx trying to ram water in seems wierd to me and a goid way of introducing even more air into the system . . . 🤔😊 Link to comment Share on other sites More sharing options...
DanMi Posted November 29, 2020 Report Share Posted November 29, 2020 it could also be a blockage in the heater valve or in the pipe that runs under the manifolds, my mk2 has always filled without issue and the only time the heater failed it was a build up of gunge sorted by flushing with a garden hose. No problem running it with the radiator cap off to see if the thermostat works Link to comment Share on other sites More sharing options...
poppyman Posted November 29, 2020 Report Share Posted November 29, 2020 Hi Colin, are the pipes to the heater hot? Also if not run with rad cap off, any air will still be in the system. Tony. Link to comment Share on other sites More sharing options...
Pete Lewis Posted November 29, 2020 Report Share Posted November 29, 2020 well the smiths heater valve is prone to be clogged the stat must have a bleed hole or jiggle pin in the rim the by pass needs to be clear , often clogged up especially the adaptor union into the pump running with the cap off is fine , you should see the ebb and flow across the top tank as the stat opens and closes , should be able to drive for miles with the cap off , ( not when the header /filler is below engine heights like eg GT6 ) Pete Link to comment Share on other sites More sharing options...
Colin Posted November 29, 2020 Report Share Posted November 29, 2020 Hi Pete. I'm amazed you followed my post. Just re-read it. What do you/does anyone think about running her up to temp with the rad cap of - just to the point where the stat opens (if it will) and begin to see the water circulating? Surely at that point it'll be clear that the stat os - or isn't opening. This thing about taking heater box pipes off anx trying to ram water in seems wierd to me and a goid way of introducing even more air into the system . . . 🤔😊 Link to comment Share on other sites More sharing options...
Colin Posted November 29, 2020 Report Share Posted November 29, 2020 Hi chaps. I ran my Herald, rad cap off. All heater pipes came up hot before the rad water started to boil ! Just shut her down before everything got covered in boiling anti freeze! I guess, if the rad water boils visibly like that, that the stat is working (or hot water could not make its way to the rad, right?). So I'm guessing I'm safe from seizing the engine if rad cooling is available to me. Leaves me this conundrum:- windscreen vents put out virtually no warm air when the cabin vent is shut. Later, after a short run, I checked driver's side of the cabin vent and was horrified the air was not warm. Tried the passenger side which proved to be warm!! So how come that disparity for starters and, the fact that either way round, othing warm is coming through the window vents!!??!! Link to comment Share on other sites More sharing options...
NonMember Posted November 29, 2020 Report Share Posted November 29, 2020 1 hour ago, Colin said: So how come that disparity for starters and, the fact that either way round, othing warm is coming through the window vents!!??!! It's worth checking the air plumbing! It may be the heater itself is working fine but the hot air can't get to the screen vent because the hose has fallen off. 1 Link to comment Share on other sites More sharing options...
Pete Lewis Posted November 29, 2020 Report Share Posted November 29, 2020 I doubt it was actually boiling if you got a volcano of hot water out the filler there is an air lock , the air expands and pushes your coolant out then localised boiling occurs , a bit chicken then egg your herald should run quite happily with the cap off assuming the cable is operating the heater distribution ?? flap the flap is very crude and has wonders of nasty rubber and foam to make it effective deflecting to toes or screen Pete Link to comment Share on other sites More sharing options...
Iain T Posted November 29, 2020 Report Share Posted November 29, 2020 On 09/06/2020 at 10:23, Pete Lewis said: or put car up on ramps so front is much higher than the back I did this on my Vitesse and it worked! Not sure if it was by luck or design?!? Iain Link to comment Share on other sites More sharing options...
Pete Lewis Posted November 30, 2020 Report Share Posted November 30, 2020 errr yes ha ! ive always done refills with the engine on a light rev , problems seem always start if the thing is half full /not fully drained out Pete Link to comment Share on other sites More sharing options...
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