Viscous cabin heater and it's clutch

Jeep WJ 2004, I6, 4WD.

OK.......

I'll bite......

The 'viscous' part of the fan is normally the part that causes the 'radiator' fan to freewheel when the engine is cold and to stiffen up almost solid when the engine heats up so it sucks cold air to cool down the radiator.

This is a 'gas saving' device apparently saving the gas needed to spin the fan when the engine is not running hot. The fan does take several HP to spin up under load.

Your 'heater' gets it's fluid from the waterpump bypassing the thermostat so the inside heater core sees warm fluid before the radiator sees warm fluid.

If you want instant heat, you need to add a circulating block heater that uses a 'lot' of 120 volt power via an extension cord plugged into your house to preheat your engine so it doesn't freeze solid and is easier to start in sub zero weather. 2-3 hours at -20C is usually good enough for instant heat.

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT's - Gone to the rust pile... Canadian Off Road Trips Photos: Non members can still view! Jan/06 (More Off Road album links at bottom of the view page)

This post is incoherent to the point of surrealism.

Unless you use a 120 volt overnight block heater, there is no such thing as "instant" heat, and there is no "viscous heater".

Saludos cordiales,

Earle

Seems the viscous heater is esoteric enough that googling "viscous heater clutch" returns no entries! More information on the viscous heater clutch; here are three relevant pages from the factory service manual:

I can see that you really do not know how these work either. It works on the theory of a silicone fluid between discs that transfer power via fluid between them due to shearing forces. The fluid is constantly pumped out of the "disc" area into a reservior so that is can free wheel, it starts to engage so to speak when the bi metal coil allows fluid to return to clutch area and when it is returned at a rate that exceeds the rate at wheich is it removed at it reaches it sate of least slippage. It is never a solid or even should be described as one. The fluid used has been choosen because of its shearing properties (as rate of shear increases, the power to shear it increases dramatically unlike motor oil) and for very high resistance to the tempatures generated by this shearing. It is a old and proven concept. The amount of torque this design can transfer it limited by the diameter and amount of clutches and the cooling for them because the shearing can generate a lot of heat. BTW, when fan engages it also improves A/C efficency and output (if you have one) as it cools the refrigerant more before it is expanded again which makes it cooler when it is expanded. When clutch fans first made their appearance in the 60's, they were mostly on cars with A/C on them and later were used on basically all cars by early to mid 70's or so A/C or not

Yes it was designed as a gas saving device of sorts and also a way to allow for increased cooling capacity during times of need and reduce fan noise when it is is not needed. The only weakness of the design is too fold, first detriot tends to be conservative with the bi metal coil setting on some applications lets vehcile get pretty warm some times and the second is as the mi metal coil ages by nature it will increase engagement temp and make you think that your clutch fan is worn out when it may only need a adjustment. As long as the clutch does not wobble on shaft and fluid has not leaked out it is likely still good and may at most need a little tweaking to restore its operation. I have been tweaking them for many many years and if you want to know how you can find instructions in link below.

----------------- TheSnoMan.com

The text is unreadable, but it looks like an air conditioning refrigerant compressor.

Saludos cordiales,

Earle

Once again you have absolutely no clue what you are talking about and are too stunned to realize it.

Stalking me only proves you are a total idiot!

You have proven beyond any doubt to be a lying Idiot stalker that gives out advice on a regular basis that will 'kill' people.

Stalking me will 'only' cause you grief and harassment foole.

Once again, Screw off eh.

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT's - Gone to the rust pile... Canadian Off Road Trips Photos: Non members can still view! Jan/06 (More Off Road album links at bottom of the view page)

Neat, that's a totally new toy to break down.

I can't say as I really would want one, but it is neat to have an actual fluid heater for the coolant. I wonder how many HP it eats up with it's friction drive?

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT's - Gone to the rust pile... Canadian Off Road Trips Photos: Non members can still view! Jan/06 (More Off Road album links at bottom of the view page)

Naw, I could read it. It is a new toy. A 'friction' heater for the coolant to help the inside have warm air faster than if not plugged in in the winter.

Just something expensive to wear out in my opinion.

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail > The text is unreadable, but it looks like an air conditioning refrigerant > compressor.

Earle, try clicking on the image thumbnails of the OP's link, it should bring the images up to readable size. I've never heard of a viscous heater, but the page does describe it. Kind of a neat idea, it creates heat by causing friction in silicone fluid inside the V.H. pump. The coolant is piped through the pump and then into the heater core, which provides quicker heat to the cabin than would be from getting the engine to operating temperature.

I would guess the viscous heater clutch is similar to an A/C compressor clutch.

Denso produces the viscous heater used on the VM Diesel that Chrysler installs in KJ's. The operating principle is the same as a viscous fan drive but instead of dumping slip heat to the airstream via the fins on the outside of the fan drive, it transfers this heat to the engine coolant. A clutch much like used on an AC compressor is used to switch the heater on and off.

The power consumption is in the range of a few horsepower (3-5 ?) depending on engine RPM. They use these on high efficiency diesel engines (CRD) which don't warm up very fast in cold weather. These efficient engines will also fail to maintain coolant temperature in low speed driving and while idling - leading to complaints that the heater isn't working correctly. So they switch the viscous heater on in these conditions too.

This is a less expensive solution than using a PTC (positive temperature coefficient) electric heater in the HVAC. PTC heaters are in the 1kW to 1.5kW range so at 12 - 14 VDC they're pulling a hell of a lot of amperes and the alternators, batteries and of course the wiring are all upgraded.

PTC heaters warm the air immediately because they are directly in the air stream in the HVAC. Viscous heaters are slower because a portion of the heat is lost in the block and head. Even so they are a big improvement over no supplemental heating.

In Europe they also use fuel fired heaters (Webasto is a well known name) but these are real expensive and add a lot of complexity.

reboot

As usual, the "troll" is insecure and attacks what he does not understand in a attempt to make him feel better about his own lack of knowledge and understanding.

I do not come to NG's to stalk anyone and if it seems I am stalking you it is because you are basically one of the biggest BS'ers out there and post a lot of tripe too leaving yourself wide open when you post things that are not correct. Some people (not trolls like your self) come to NG's for info while you come for ego. Maybe if you controled your ego and posted less BS you would find that less of what you posted would be challanged.

BTW, if I really wanted to stalk you, it would take far more time than I care to spent in NG's because you seem to post a lot of tripe and I would not waste my time trying to read and respond to it all.

----------------- TheSnoMan.com

At aadt we refer to him as the "Idiot"

Thus your most recent post.

Well Idiot, you have described yourself and your actions.

Hopefully those looking for info will not look to most of the BS you post.

That is what folks at numerous groups and forums have been trying to get you to do, STFU

Hell, why don't YOU respond to the wrong and at time's dangerous stuff you have posted in various groups over the past year or so?

Let me adjust that sig again for ya.

What's even more interesting is why the OP is so interested in every nook and cranny of his Jeep's anatomy. I recommend putting the factory service manual on the shelf for a while and driving it to get some real world experience.

We used to use fuel fired cab heaters in the old air cooled Volkswagens, especially the vans. I believe that tractor trailers use something similar. The main problem is that they are dangerous and finicky if not maintained properly. That usually consists of cleaning and adjusting a spark gap.

Saludos cordiales,

Earle

Once again you have absolutely no clue what you are talking about because you are too busy stalking my posts and are too stunned to realize it or even to read the thread.

Enough said....

Mike

The best place for these types is the killfile. I have seen enough of SnoMan's wisdom to last me a long, long time.

Saludos cordiales,

Earle

Why am I interested in supposedly useless information?

(1) I find the engine innards fascinating. I am amazed at how human innovativeness has created such a beautiful, intricate and harmonious machine which just about all of us take for granted. The automatic transmission is about the most complex and ingenious machine I know.

(2) I plan to overhaul my engine in due course. I must know every insignificant object under the hood, know exactly why it is required and how it works. I plan to absorb everything in the service manual - all the thousands of pages. Don't laugh - eventually I plan to overhaul the automatic transmission.

(3) I have already done some service myself - I plan to do most, if not all of it. I need all the information I can get.

I hope in the process others also gain appreciation and insight into their vehicles.