 | Home > Puma (Tdci) > Coolant, rad & thermostat change…Now runs even hotter! |
 
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| andy63 Member Since: 30 Jun 2023 Location: north east Posts: 542  
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I'm not sure if it's been mentioned but there is a small hose of the top of the radiator into the expansion tank.. If the system is full and the pump working should there not be a flow of water through that pipe.. Its a way of ensuring that air is allowed to leave the system while engine is running..
The bleed on the heater return has been mentioned so assume that has been used.. There isn't much to go wrong with the pump in terms of its ability to pump water, so I wouldn't be rushing to change that.. Again only my two penneth but I'd be inclined to try it with no thermostat before I did anything and see what temp you got then and how quickly you got there.. |
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21st Aug 2023 1:44pm |
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| Yesjus Member Since: 19 Sep 2022 Location: Surrey Posts: 78 
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Picked up a new pump but had no gaskets so can’t do for now.
Decided to burp again…maybe it is air! I have spells of hot coming through now but goes cold again, it definitely comes through hot when I open the bleed screw near the heat valve it comes hot in the cabin. Also when I squeeze the top rad hose air bubbles are still coming out of coolant overfill cone, don’t know if I should carry on squeezing it or not but surely that’s air escaping when I squeeze it? |
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21st Aug 2023 6:27pm |
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| MK Member Since: 28 Aug 2008 Location: Santiago Posts: 2429  
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The theory is that the pump is not working so the hot coolant stays on the top of the circuit. Puma 110" SW
............................................................. Earth first. Other planets later |
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21st Aug 2023 11:01pm |
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| andy63 Member Since: 30 Jun 2023 Location: north east Posts: 542
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Pretty much what would happen if the thermostat didn't open.. No flow through radiator and top hose hot.. Or could be a blockage but thermostat can be ruled out by removing it..
And if there is a flow of water from the small hose off the top of the radiator to expansion tank then there is a flow... All easily checked before resorting to changing pumps, which at the end of the day are more likely to leak than just stop working... |
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22nd Aug 2023 5:58am |
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| Yesjus Member Since: 19 Sep 2022 Location: Surrey Posts: 78
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I feel like the thermostat isn’t the issue.
It’s a brand new OEM one that is a 82degree one. I have an ultraguage that monitors real time temps. When it’s up to temp and I start reving it goes past 82 and keeps rising but at idle it does return back to 82 in a good time, so surely this means it’s opening? If I was to remove what’s the problem with this and would you just remove the thermostat from inside the casing and then use the casing as the as an empty fitting? |
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22nd Aug 2023 7:28am |
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| andy63 Member Since: 30 Jun 2023 Location: north east Posts: 542
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Hi.. Yep have to agree.. It sounds unlikely if it a new thermostat.. It was just my thoughts from reading the thread..
I'm just sceptical about the pump failing because you changed the coolant.. And flow can be checked.. The small hose I've mentioned.. Or a messy disconnect the top hose and give it a bit head.. Keep theheader tank full and if the throttle is blipped then it should push the water out the hose.. |
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22nd Aug 2023 7:38am |
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| andy63 Member Since: 30 Jun 2023 Location: north east Posts: 542
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Sorry I missed the last bit of your post.. If you did decide to try removing the Stat it's just as you say.. Remove it and run with an empty housing.. It won't do the engine any harm..
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22nd Aug 2023 7:57am |
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| Yesjus Member Since: 19 Sep 2022 Location: Surrey Posts: 78
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So it’s not the waterpump 😩
Changed it tonight and it’s still the same! Any one with any other suggestions?? A bit more info, when I was heating it up the temp was saying 65 degrees. I bled from the bleed screw to encourage the air and the coolant was cold! After a while of bleeding it came through hot? Cabin is still cold? Could this be something to indicate a problem? |
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22nd Aug 2023 7:27pm |
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| MK Member Since: 28 Aug 2008 Location: Santiago Posts: 2429
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J!
IIRC the 2 hoses from the heater are easy to spot. I would use the garden hose to rule out some obstruction. Same for the rest of the circuit if possible with such miriad of hoses. Puma 110" SW ............................................................. Earth first. Other planets later |
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22nd Aug 2023 7:36pm |
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| Yesjus Member Since: 19 Sep 2022 Location: Surrey Posts: 78
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So the white heat diverter valve, it has two going in front, one off to side and one connected on the back?
Which should I set a hose up too? Also just been for 30 min drive, sits at 100degrees on motorway in 5th, if I put in 6th it spikes to 115 and goes into limp mode (won’t be trying that again) As soon as I get off motorway it drops down again to around 93/94, if I let idle it then returns to normal (mid 80s). Is it safe to drive with these temps or should I avoid till sorted? |
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22nd Aug 2023 8:30pm |
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| Yesjus Member Since: 19 Sep 2022 Location: Surrey Posts: 78
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Sorry for all the posts but want to give as much info to the people that know more than me!!
So after this drive I’m sat in it watching the temp at idle, it’s sitting at 99 for about 3 mins, then all of a sudden it shoots down to 86 degrees in about 15 seconds?? Now I’m thinking could it be a dodgy thermostat or air or something more sinister? |
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22nd Aug 2023 8:42pm |
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| Clemmo Member Since: 03 Aug 2012 Location: Mile Oak Posts: 1219  
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I wouldn’t allow it to run over temp..could end up very costly.
I experienced similar problem on a BM I changed the Coolant on a BMW Z4 only to find it was then overheating. Like you I chased thermostat and pump only to eventually find several cores in the rad had become blocked. Found out when I removed rad and took it to be tested. I was told it happens frequently when coolant systems are “disturbed” In the end a new aftermarket rad was cheapest option and problem solved. Clemmo  Make today a little better than yesterday but not so good as tomorrow....
Defender 90 HT............Pangea Green BMW X3 Msport............Carbon Black Mini Electric................Grey. (wow!) MGB Roadster……..........Vermillion 17k miles Honda Benly CD200....Maroon --------McLouis Fusio........7.4m of fun |
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22nd Aug 2023 9:30pm |
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| MK Member Since: 28 Aug 2008 Location: Santiago Posts: 2429
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Have a look here https://www.defender2.net/forum/post160984.html
I would not drive it neither. If the head temp sensor is playing you, then you would not have a hot top and cold bottom. Such sensor is located behind the head. https://www.defender2.net/forum/post144576.html Have you actually tested the thermostat? Puma 110" SW ............................................................. Earth first. Other planets later |
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22nd Aug 2023 9:46pm |
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| Yesjus Member Since: 19 Sep 2022 Location: Surrey Posts: 78
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So I’m back to thinking maybe air!
Flushed the heat matrix to make sure it’s not blocked and whilst I had my torch out I noticed when I connected it all back up the inlet of the heat divert vale was full of coolant and the outlet (one with bleed screw) was completely empty. So I setup my coolant over fill kit and observed what was happening. With the coolant overfilled and the bleed screw slightly unscrewed the coolant then flowed through both inlet and outlet but with the torch shined up against the white plastic I could see lots of air moving through it. I assume it’s supposed to be a steady flow of pink coolant as it shouldn’t have air if I’m not mistaken? I haven’t got any coolant left but I’m thinking set it up again tomorrow, open the bleed screw slightly, over fill the coolant and run engine until the flow through that diverter is a steady stream no air pockets? |
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22nd Aug 2023 10:42pm |
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