Aux / condenser electric fan, always running?
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Winching
Joined: Dec 2009
Posts: 685
Likes: 41
The system sounds good on paper. It is designed to keep the engine temperature constant but in reality the whole bypass system heats up the motor at idle and cools it down as you start driving. It also decreases the efficiency of the radiator by constantly mixing hot coolant with cold. There is nothing wrong with your thermostat or your water pump. That is just how the stupid thing works. Search for a thread on discoweb titled "Fan Clutch", a couple of guys including myself switched to an in-line thermostat that keeps the engine temps lower and more stable.
That's crazy. You'd think alarm bells would have gone off when they first tested the car when they noticed the fan never shut off at idle?
Lame, so the bypass system is preventing everything from doing its job (aka all the fans are on, water pump is flowing, radiator is working.. it's just not going to the right places?)
That sucks. So what's actually happening? The way it's supposed to work is that the bypass only works when it's cold enough that the main valve closes, allowing water through the bypass (if there's enough pressure?) but if it's hot and that main valve is open, I don't understand how it's getting through the bypass. I mean I believe you when you say the tstat is working, but I'm still trying to figure out how it works in the first place (while looking at that drawing of the coolant flow.. ) ahh it's all good I guess.
At least we have heat really fast in the winter, right?
I'll go search that thread.
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Winching
Joined: Dec 2009
Posts: 685
Likes: 41
Okay I'm convinced that the inline tstat is the way to go, however I don't understand how flow is maintained if the tstat closes? In a normal car it's on the block, and will just flow back through the engine if the tstat is closed.. in this system wouldn't it just stop the flow if it closes? Again I'm just having a hard time visualizing the way the disco works.
EDIT:
Okay it looks like I've partially answered my own question; it seems like you all are using the heater core loop to act as a bypass since it's an inline tstat with no return since it is located before the tstat location. This would seem to make sense, except that the heater core loop isn't designed to cope with water pressures higher than idle. In the factory configuration, higher pressures open the bypass valve - in your configuration it seems like (in the closed state) the tstat will force 100% (well, except for the bypass hole.. ) of the coolant through that heater loop. This kinda scares me, but maybe I missed something.
From RAVE: "...at idle the coolant pump does not produce sufficient flow and pressure to open the
valve. In this condition the valve prevents coolant circulating through the by-pass circuit and forces the coolant through
the heater matrix only. This provides a higher flow of coolant through the heater matrix to improve passenger comfort
in cold conditions.
When the engine speed increases above idle the coolant pump produces a greater flow and pressure than the heater
circuit can take. The pressure acts on the flow valve and overcomes the valve spring pressure, opening the valve and
limiting the pressure in the heater circuit."
EDIT:
Okay it looks like I've partially answered my own question; it seems like you all are using the heater core loop to act as a bypass since it's an inline tstat with no return since it is located before the tstat location. This would seem to make sense, except that the heater core loop isn't designed to cope with water pressures higher than idle. In the factory configuration, higher pressures open the bypass valve - in your configuration it seems like (in the closed state) the tstat will force 100% (well, except for the bypass hole.. ) of the coolant through that heater loop. This kinda scares me, but maybe I missed something.
From RAVE: "...at idle the coolant pump does not produce sufficient flow and pressure to open the
valve. In this condition the valve prevents coolant circulating through the by-pass circuit and forces the coolant through
the heater matrix only. This provides a higher flow of coolant through the heater matrix to improve passenger comfort
in cold conditions.
When the engine speed increases above idle the coolant pump produces a greater flow and pressure than the heater
circuit can take. The pressure acts on the flow valve and overcomes the valve spring pressure, opening the valve and
limiting the pressure in the heater circuit."
Last edited by EstorilM; Jun 7, 2010 at 12:26 PM.
1st Gear
Joined: Oct 2019
Posts: 1
Likes: 0
Hi,
I have the same issue and I have taken my car to the dealership twice and they had no idea about this issue. I got them to hook it up to the system called T4 which apparently is LRs genuine diagnostic system for the TD5. However, I tried going through the menus but couldn't find any option to turn the fans off.
If anyone here is familiar with this system, can you please guide me going through what menus will lead me to an option to turn this forced assist off.
You help is much needed and would be really appreciated!!
I am from Pakistan and the TD5 Defender was never launched here but the dealer has some experience with TD5 Discos.
I have the same issue and I have taken my car to the dealership twice and they had no idea about this issue. I got them to hook it up to the system called T4 which apparently is LRs genuine diagnostic system for the TD5. However, I tried going through the menus but couldn't find any option to turn the fans off.
If anyone here is familiar with this system, can you please guide me going through what menus will lead me to an option to turn this forced assist off.
You help is much needed and would be really appreciated!!
I am from Pakistan and the TD5 Defender was never launched here but the dealer has some experience with TD5 Discos.
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