Jimbob jenkins

New Member
Hi Guys,
I'm new to the forum and I drive a 2004 Defender 90 G4 Edition TD5
I've just got my beloved out of the garage last week for the winter and sent her for a fresh MOT no worries !!!
I've been using her for the last couple of days and I've noticed that the heater is blowing Hot & Cold
goes cold especially on very low speed or tick over ?
I've checked the coolant and all seams well but obviously it isn't
Any suggestions would be appreciated ???
 
It sounds like you need to bleed your coolant system so I would check that if I was you, and don’t be driving silly until you do
 
Hi Guys,
I'm new to the forum and I drive a 2004 Defender 90 G4 Edition TD5
I've just got my beloved out of the garage last week for the winter and sent her for a fresh MOT no worries !!!
I've been using her for the last couple of days and I've noticed that the heater is blowing Hot & Cold
goes cold especially on very low speed or tick over ?
I've checked the coolant and all seams well but obviously it isn't
Any suggestions would be appreciated ???
My suggestion would be thermostat stuck open so it's over cooling on tick over. Exacerbated by the cold weather.
 
My suggestion would be thermostat stuck open so it's over cooling on tick over. Exacerbated by the cold weather.
Thanks for your message and I think you might be right I've bleed the system and got a little bit of air out but nothing untoward, it's still blowing Hot & Cold so I've ordered a new thermostat and fingers crossed that should do the trick
 
Is it just blowing cold when your not moving and stuck in traffic?
Mine has always done that and is a defender thing. On the motorway, fast A roads or even in town as long as the motor is under load it stays hot. Sit in a traffic jam and it slowly cools down.
It's just the engine doesn't seem to give out enough heat to keep the matrix warm. Even with the rad covered on mine or the viscous fan removed it still does it
 
Is it just blowing cold when your not moving and stuck in traffic?
Mine has always done that and is a defender thing. On the motorway, fast A roads or even in town as long as the motor is under load it stays hot. Sit in a traffic jam and it slowly cools down.
It's just the engine doesn't seem to give out enough heat to keep the matrix warm. Even with the rad covered on mine or the viscous fan removed it still does it
Have you ever checked your thermostat?
 
Yes mate. I have a bilge blower in the inlet of my fan and get such a good flow that it cools the whole lot down in really cold weather. You dont see it on the guage but the heat dies off
 
That's your problem then! Op, check/ replace the stat but in fairness an open stat would do the opposite of what you describe, allow it to idle and feel the rad, is it hot?
 
care to enlighten me, not sure what that means.
Aye, should have said more, but I'm trying to multi-task. :rolleyes:
If the stat is stuck open then the engine can warm up if it's under load. If the load drops and there's not so much fuel being used, to release the heat energy, then it all cools down. The stat would close, if it wasn't stuck, to limit the flow of water and so reduce cooling. That way the temp stays within it's target range, otherwise it'll over cool.
 
Aye, should have said more, but I'm trying to multi-task. :rolleyes:
If the stat is stuck open then the engine can warm up if it's under load. If the load drops and there's not so much fuel being used, to release the heat energy, then it all cools down. The stat would close, if it wasn't stuck, to limit the flow of water and so reduce cooling. That way the temp stays within it's target range, otherwise it'll over cool.

Had a 207 roll into the workshop last week, ECL was on, plugged it into the brain which said it had a full DPF, tried a forced regen but as you know an engine won't regen unless it reached the proper op temp, so took it for a good drive, still stone cold, motorway, still stone cold, changed the stat (nightmare on a 207) and all was well, regen worked perfectly, managed to clear the codes and off it went to fight another day.
 
my point being, a stat isn't simply open or closed, if it's stuck open no matter how hard you drive it it will still be stone cold, more so when the vehicle is moving in this cold weather and the rad is doing its job, at idle it should get slightly warmer but not by much, the stat is a good place to start, but ot the answer to everything.
 
my point being, a stat isn't simply open or closed, if it's stuck open no matter how hard you drive it it will still be stone cold, more so when the vehicle is moving in this cold weather and the rad is doing its job, at idle it should get slightly warmer but not by much, the stat is a good place to start, but ot the answer to everything.
Aye, you're right. Forgot mine was made better by the rad being full of mud and mummified flies. When I changed it, it got cooler as the new rad was more efficient.
 
Never do a 207 stat again! It was like digging a grave with a spoon trying to get to it.
 

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