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idle-up vs pwr-heat

karl2000

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Just wondering whats the difference between them?

Does pwr-heat have the viscous heater and idle-up just increases the idle revs via the ECU? Or,,,,?

Does anyone in the UK use them?
 
I used mine just last week waiting to pick Mrs up. Mine is marked power heat, so I was interested, when you mentioned idle up, what each did.
Looking in the handbook it would appear they both do the same function, and maybe marked dependant on what model we have. The book shows 2 pictures, each switch in exactly the same place, with exactly the same explanation on each, and obviously will only work if the engine temp. is up to normal .
Unfortunately no magic involved with pumping warm/hot air, if engine is cold. Bugger!
 
Just wondering whats the difference between them?

Does pwr-heat have the viscous heater and idle-up just increases the idle revs via the ECU? Or,,,,?

Does anyone in the UK use them?
My Amazon is labelled power heater and has the
Just wondering whats the difference between them?

Does pwr-heat have the viscous heater and idle-up just increases the idle revs via the ECU? Or,,,,?

Does anyone in the UK use them?

Mine has power heat and the viscous water heater, works well enough if I start it up first before using the de icer!
The 120 I had before the Amazon had exactly the same arrangement
 
Even more interesting there Geoff, if I'm reading you right.
Toyota state will not work in warm temperatures OR until reaching normal operating temperatures?
Which leads on to, if that's the case why have it when we might just as well use the fan?
There must be more to it than just upping the revs, as Karl first pointed out with the viscous arrangement.
 
My understanding with this is that the viscous heater has some magic which heats the coolant more quickly so that the engine warms up faster and we get heat quicker. Is that correct? The coolant goes through it - you can see the coolant pipes on it so I assume thats how it works.

The UK vehicles seem to have the viscous heater installed, so do all of those have PWR-HEAT rather than IDLE-UP?

Oz vehicles (for example) dont seem to have it - I wonder if those vehicles have IDLE-UP instead? I've looked on oz ebay but can't find a good enough picture!
 
Yep, I'll go with that Karl, - more info gained. The confusing bit to me though, is in the handbook, 2 pictures show the 2 differently marked switches in identical places, almost like options and there is no explanation as to why, just the exact same description of what they do
Mine works, so I won't worry. Prob. The Oz vehicles don't have it, is their higher ambient temp/climate?
 
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Yep, I'll go with that Karl, - more info gained. The confusing bit to me though, is in the handbook, 2 pictures show the 2 differently marked switches in identical places, almost like options

Exactly - so I'm wondering if IDLE-UP is no viscous heater option.

Both increasing revs and the heater would help warm things up over time, but with just revs and no heater it would take longer - the poor man's option!

and there is no explanation as to why, just the exact same description of what they do

Dont think it helps that PWR-HEAT increases the revs too when its cold/idle - presumably to compensate for the extra load of the viscous heater?

Mine works, so I won't worry. Prob. The Oz vehicles don't have it, is their higher ambient temp/climate?

Makes sense. We need to see if an OZ vehicle has IDLE-UP! Might be part of the cold climate package - they dont usually have two starting batteries either?

Those heaters are expensive too - around a grand - so they must be doing sommat useful!
 
Can't disagree or add anything useful to all that Karl. Yeh, that maybe the key if we find out what Oz models have, - or not.
 
Found lots of useful info 're the way it operates, on 'the other side'.
Hope fully I am repeating this correctly, and broadly speaking, its a belt driven pump that takes water from the top of the engine, and pushes it through the heater matrix.
It's a bit like a/c, the revs increase as the switch engages a clutch on the pump that then circulates water, in this case.
The clutch automatically disengages if you drive off, or you can switch off manually of course
Those models with idle up switch, apparently did not have the pump, it just increased the revs.
 
Are you sure it disengages when you drive off? yes it no longer raises the idle speed but as far as i'm aware the pwr heat is still working.

For sure using the pwrheat device does warm the coolant up much faster, invariably i'll switch it off for a moment whilst engaging gear (to give the torque converter an easier life by lower revs whilst engaging drive), but then turn it back on again, using it means there's some heat coming through the heater within half a mile or so, where it might be a couple of miles if you don't use the auxilliary heat device.

Don't think they are fitted for warmer climate markets, presumably they keep the fast idle switch operational so the airconditioning can work more efficiently, somewhere in 100' temps you'd want to start the engine and let the temp inside cool down a bit.

Just out of interest had the same pwrheat device on the noughties Hilux we had, on my early 90's build 70 series there was a manual hand throttle to control fast idle but no such mod cons as pwrheat or aircon.
 
Hi Jud, nice to hear from you mate.
As said, just repeating what was posted over there, and the driving off bit was definitely someone's post.
I've yet to try it. Maybe they meant what you said.
My 19992 78 has the hand throttle/ idle up and a/c but no power heat, they were not that posh then !!
 
Thanks for the info chaps.

Presumably if the engine is still warming up, the coolant is still cold; so it must do some magic inside the heater to actually help warm the coolant - ie a heater, not just a pump to direct it to the heater matrix?
 
As I understood it Karl, the water was being taken from the top of the engine, which gets warmest/hot first. As it's being pumped into heater matrix its 'stirred', so increasing the heating process, rather than going all round a stone cold lump of cast (engine) which by thermal transference, saps the heat until reaching temperature.
I don't think there is any magic, fairy dust or whatever involved. ha ha
 
The power heater works with viscous friction, generating about 1500 watts of heat, meaning it also takes about 2 HP from your engine. The engine ECU also increases the revs when the power heater clutch kicks in, and that probably helps more for heating than the heater itself. 1500 w is not much on a big engine. If engaged, it works as long as the engine is at a lower temp than working temperature, and is also disengaged if you ask for full power with the accelerator. The Power Heater switch can be left pushed in always, particularly in winter, as it disengages anyhow when the best operating temperature is reached, and the faster the better.
 
Good write up uHu, that explains a lot in easy speak, thanks.
Good find Karl, that added to uHu's explanation, just about completes the scenario. Silicone eh, who'd a thought it ?
 
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