AgentC Posted October 16, 2021 Share Posted October 16, 2021 Hi all. Been a long time since I posted with an issue but now own a 2014 Transit Connect with a mysterious coolant loss that has so far stumped 3 different garages. 2 have vaguely but not very confidently suggested the thermostat and the other one did an extensive pressure test that maybe showed a tiny leak when slightly over-pressurised (25psi vs 21psi). None have even mentioned head gasket. Other than the below behaviour of the expansion tank there are no other symptoms. Van drives and runs great. Gets up to and maintains temp just below 90c and the fan blows toasty Clean oil cap and dipstick I've changed the expansion tank as it was cheap and "easy" to do and it seemed to have a few cracks (spoiler: rear clip was well stuck!!). It was pretty manky too. Made no notable difference. I have a GIF to show how low and pressurised the coolant is after a 30-40 mile run and then left overnight. The level started off at the minimum line when cold with cap off and the gif shows the day after that 30-40 mile run cold as I undo the cap again. Level comes up with the pressure release but is still notably lower than the minimum line. Any suggestions greatly appreciated. Quote Link to comment Share on other sites More sharing options...
unofix Posted October 16, 2021 Share Posted October 16, 2021 Have you fitted a brand new Ford filler cap to the expansion tank ? They do fail from time to time and the built in pressure releif allows the coolant to escape via the overflow pipe when the engine gets hot. 1 Quote Link to comment Share on other sites More sharing options...
AgentC Posted October 16, 2021 Author Share Posted October 16, 2021 6 minutes ago, unofix said: Have you fitted a brand new Ford filler cap to the expansion tank ? They do fail from time to time and the built in pressure releif allows the coolant to escape via the overflow pipe when the engine gets hot. I haven't but I have temp swapped mine for my dads identical cap from his CMAX with no difference on either vehicle. Then I changed the tank which didn't come with a cap. If only a garage would confidently diagnose the issue I would pay for it to get done but none seem to want to do it! Quote Link to comment Share on other sites More sharing options...
Crusader Posted October 16, 2021 Share Posted October 16, 2021 IDP Film YouTube channel. Video on focus coolant leak part 2 posted September 2021 shows similar problem. Pressure test of coolant system showed heater matrix leak 1 Quote Link to comment Share on other sites More sharing options...
AgentC Posted October 16, 2021 Author Share Posted October 16, 2021 17 minutes ago, Crusader said: IDP Film YouTube channel. Video on focus coolant leak part 2 posted September 2021 shows similar problem. Pressure test of coolant system showed heater matrix leak Interesting. I'll have a good look tomorrow but I have checked the cabin filter a few weeks ago on the passenger side and there were definitely no leaks there but will also check the drivers side. I hope it isn't this as it looks a nightmare job to fix yourself or very expensive... I would've thought I'd be having cab heating issues of some sort if was this though? Quote Link to comment Share on other sites More sharing options...
AgentC Posted October 17, 2021 Author Share Posted October 17, 2021 I've had a good look under both footwells again today and see no signs of a leak and all the insulation etc looks clean and dry. So after checking the heater matrix I started to browse through the pages here and came across Lexibo's thread from a couple of years ago with almost exactly the same symptoms I have and it looks like the thermostat could be the cause? I think I'm going to bite the bullet and grab a genuine thermostat housing and find a good garage to fit it. I will contact the three garages that have looked at the van for prices but what would a rough estimate be to get a thermostat replaced? Quote Link to comment Share on other sites More sharing options...
unofix Posted October 17, 2021 Share Posted October 17, 2021 Hi Chris, a faulty thermostat can causes issues with over heating which leads to excess pressure in the system. Those engines that Plastic thermostat housings also sometimes suffer from leaks when the plastic gets hot. I don't know if your engine has the plastic or the aluminium alloy thermostat housing but it's something to take a look at. If you want to check to see if the coolant is being expelled from the coolant tank, place the overflow pipe in a plastic bag and fasten with an elastic band. If the coolant is being blown out of the expansion tank due to excess presure you will be able to see it collected in the plastic bag. 1 Quote Link to comment Share on other sites More sharing options...
AgentC Posted October 17, 2021 Author Share Posted October 17, 2021 29 minutes ago, unofix said: Hi Chris, a faulty thermostat can causes issues with over heating which leads to excess pressure in the system. Those engines that Plastic thermostat housings also sometimes suffer from leaks when the plastic gets hot. I don't know if your engine has the plastic or the aluminium alloy thermostat housing but it's something to take a look at. If you want to check to see if the coolant is being expelled from the coolant tank, place the overflow pipe in a plastic bag and fasten with an elastic band. If the coolant is being blown out of the expansion tank due to excess presure you will be able to see it collected in the plastic bag. Hi unofix, The thermostat housing is indeed plastic and rather big with multiple pipe connectors and a temp sensor on it too. I assume with the pressure test showing no evidence of it leaking (the thermostat housing is easily seen under the bonnet) if it is faulty then it could well be an issue like Lexibo had with a very partially open fault which can't be confirmed until/unless it is removed? The plastic bag trick.... which pipe is that? In my Gif above I assume it is the front return pipe below the 'min' level line? The only other pipe is the ~1" rubber hose at the rear of the tank. Quote Link to comment Share on other sites More sharing options...
unofix Posted October 17, 2021 Share Posted October 17, 2021 Hi Chris, I know this is not your model but just as an example: https://www.transitcenter.uk/coolant-reservoir-hose-overflow-ford-transit-connect-2002-thermostat-housing-p-4121.html I've just looked at your picture and you don't seem to have the pipe next to the filler cap 😟 for an overflow. I guess on your model it just blows the excess out of the filler cap, if that is the case then I think you would be able to see quite a mess 1 Quote Link to comment Share on other sites More sharing options...
AgentC Posted October 17, 2021 Author Share Posted October 17, 2021 Looks like that is the MK1 Connect, unofix. Ford must have changed things with the MK2. 1 Quote Link to comment Share on other sites More sharing options...
AgentC Posted October 22, 2021 Author Share Posted October 22, 2021 Quick update. Van should be going to the garage on Mon/Tue hopefully to definitively diagnose the problem. Compression test (if passes), then check oil cooler/thermostat. In the meantime I took a picture of the inside of the ~3 week old coolant bottle to show the black soot/dust. 1 Quote Link to comment Share on other sites More sharing options...
Daveewers Posted September 4, 2022 Share Posted September 4, 2022 Did you get this problem sorted pal as i have same issue Quote Link to comment Share on other sites More sharing options...
Daveewers Posted September 7, 2022 Share Posted September 7, 2022 Hi did this problem get fixed as i have same issue but no forums ever say if they get things sorted Quote Link to comment Share on other sites More sharing options...
unofix Posted September 7, 2022 Share Posted September 7, 2022 11 minutes ago, Daveewers said: but no forums ever say if they get things sorted Sadly that is normally the case. We very rarely get to have anyone come back and report when something is eventually fixed. @AgentC last visited this forum 30th January 2022. Quote Link to comment Share on other sites More sharing options...
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