What 2.7 viscous heater

[Bob 2.7]

Hi I’m from the uk so I actually need the viscous heater! I can’t find anyone who knows anything about it apart from a few threads on here, so long shot but I thought I’d ask.
My viscous heater doesn’t switch on at all fuse and relay are fine and if I power the heater directly via the relay socket it works fine but the car won’t switch it on if that makes sense. Any ideas?

[JeanLuke]

Hi Bob and welcome.

The viscous heater only comes on when the temperatures are below (around) ten degrees. Even then, it only comes on in bursts of around 30 seconds or so. If you want to test it, set yourself up with the WJ Diag Pro software and it has a function to manually turn it on for testing.

It is effectively a pot of high-viscosity oil with a water cooling pipe running through it. When the clutch engages, a set of vanes stir up the oil which heats it. The water cooling of the oil transfers the heat into the cooling system. The purpose is to allow the engine (and cabin heater) to get up to operating temperature quicker.

It was developed by Toyota/Denso and is found on Landcruisers - making it easier to buy from wreckers. See https://www.toyota-industries.com/pr...miscellaneous/

[JeanLuke]

See also: https://patents.google.com/patent/US6089222A/en

[Bob 2.7]

Thanks for the help so far it’s well below 10 degrees here and it used to work on my old wj so know what to expect.
I will try the wj diag pro didn’t know it could do that.
Any links to a decent elm device?
Don’t think it’s related but I notice the fuses for glow plug 1 and 2 have gone as well

[JeanLuke]

I use https://elm-327.eu/

For recommendations see https://jeepswj.com/software/

Sent from my moto g( plus using Tapatalk

[bodgie]

The clutch may have an issue too if you've got a multi-meter you can check the could resistance you can also measure the voltage to see if it's being told to engage.