Radiator Temperatures

[Stagsongas]

Hi Steve, 1st paragraph how are you going to contain the hot coolant in the block from escaping while it's heating up via (thermal current) without a thermostat. Graham

Graham,

That's a good one and not so simple do without making it even more complex. Someone mentioned an electro-mech valve some way back but that's difficult to fit. Still, we might not have to prevent thermal current at all.

The thermal current is not huge in volume, and we mustn't forget that even with an entirely original system, the heater is taking and bypassing coolant to and from the same locations for the heater, it makes little difference to engine warm up at all. A heater and anti-hotspot pump would need to be restricted with a nozzle of equal size to the bypass hole in the standard thermostat.

Also, until quite recently, we have not been able to run with the pump offline, so we don't know the full effects. Perhaps having a pump offline is hardly any different to having the original pump being perturbed by a thermostat cutting off flow, albeit with a little hole in so it can pass some coolant.

If the volume of coolant circulated by thermal current and the little circulation pump (with the main pump offline and no thermostat fitted) is the same as goes through the standard thermostat bypass hole with the original pump fitted and running all of the time, warm up would not be any slower when modified.

Regards

Steve

[Staggard]

Graham,

That's a good one and not so simple do without making it even more complex. Someone mentioned an electro-mech valve some way back but that's difficult to fit. Still, we might not have to prevent thermal current at all.

The thermal current is not huge in volume, and we mustn't forget that even with an entirely original system, the heater is taking and bypassing coolant to and from the same locations for the heater, it makes little difference to engine warm up at all. A heater and anti-hotspot pump would need to be restricted with a nozzle of equal size to the bypass hole in the standard thermostat.

Also, until quite recently, we have not been able to run with the pump offline, so we don't know the full effects. Perhaps having a pump offline is hardly any different to having the original pump being perturbed by a thermostat cutting off flow, albeit with a little hole in so it can pass some coolant.

If the volume of coolant circulated by thermal current and the little circulation pump (with the main pump offline and no thermostat fitted) is the same as goes through the standard thermostat bypass hole with the original pump fitted and running all of the time, warm up would not be any slower when modified.

Regards

Steve

Hi Steve, you are in a great position now with your original pump removed. So if you connect hoses up as original without the lecci pump and the stat and run it up I would be really interested how much heat is circulated through the rad without pump assistance. Graham

[Stagsongas]

Hi Steve, you are in a great position now with your original pump removed. So if you connect hoses up as original without the lecci pump and the stat and run it up I would be really interested how much heat is circulated through the rad without pump assistance. Graham

Graham,

OK, got your PM which expands on this and I fully understand why you would want to know. I want to know as well. It isn't a PITA as I thrive on stuff like this.

So, your fans are wired so they can run with ign off. You shut the engine down, the fans run for a while, then cut off when the rad temp has dropped (sensor is in the rad). Then, after a little time, the fans come back on.

Why?

First of all I think your suspicion that thermal current continues after the engine has shut off is correct, the fans cool the rad and then it gets warmed up again. This is probably the most important factor. The second thing to consider is that you live in warmer conditions, and seperately that your engine is sitting and radiating heat soak (where underbonnet temps rise).

As you say, the rad must be warming up again after the fans initially stop because the temp sensor finds that, and then puts them back on. We have to trust the sensor as it works perfectly for all the time the engine is running, It is giving us a strong message. I think thermal current and radiated heat from both under the bonnet (and perhaps even outside in your case) warm the rad up again after the fans stop initially.

This does tend to prove good the idea that to have your fans wired independant of ign. is a good one, and helps to combat the heatsoak that caused my failing coil way back when I first joined up. It also gives us a clues as to how strong an effect both thermal current and heatsoak are.

As I get used to my EWP system I will do as you ask, disconnect the pump only (electrically) and see if I get the same effect both with engine running and not running - my fan going off and coming back on with no pump riunning will tell us a lot about thermal currents and radiator heat loss, although my temp sensor is close to the thermostat position, not in the rad.

Regards

Steve