What is the "technical" name for the coolant heater?

KD6ICZ · **Posted:** Fri Nov 16, 2012 7:57 pm

Not the block heater but the belt driven clutch activated device? I want to eliminate it but to do searches I need to know what it's proper name is.

truckbouy2 · **Posted:** Fri Nov 16, 2012 8:31 pm

55037539AA Heater, Engine Automatic (Parts Description)
Here, Viscous Heater

papaindigo · **Posted:** Fri Nov 16, 2012 9:14 pm

I'm not sure you can completely remove it from the system although if you could find a shorter serp belt of the proper length then looking at the serp belt routing it might??? be possible to bypass the viscous heater by routing that shorter belt from the alternator across the top of the top center idler pulley and then directly to the power steering pump pulley and on up over the serp belt tensioner. That would preserve the existing routing EXCEPT for the idler pulley so then the question becomes would reversing the rotation of the idler pulley tend to unscrew it from the engine? I have not clue.

Simpler approaches are:
1. get a GDE tune which lowers the cutoff temperature for the viscous heater so it runs less or
2. disable the viscous heater so its clutch never engages by pulling relay R-36 in the power distribution system.
I have a GDE tune and I've also pulled that relay. The only downside of pulling the relay is a small delay in receiving cabin heat in winter but given my location that's not an issue. How much of an issue it would be in colder areas I cannot say although in those areas if you use the block heater IMHO the viscous does nothing useful.

FYI if the viscous heater clutch burns out as far as I know it cannot be replaced except by replacing the whole viscous heater which is a bit pricey. However, the clutch can be pulled and just the bearing replaced in which case pull the relay and let the viscous run completely disengaged.

If the viscous relay is pulled I don't know what would happen if you bypassed coolant flow to the viscous and I'm not sure I'd want to find out by trying. I suppose you could gut the unit so it could be bypassed but I've not looked into how.

Dennis MacGyver · **Posted:** Fri Nov 16, 2012 11:52 pm

On the '06 if you pull the relay to the viscous heater you get a CEL.

KD6ICZ · **Posted:** Sat Nov 17, 2012 12:48 am

Viscous heater! Thank you. I don't so much mind it's existence except it appears the baring in the pulley has dried up on mine and is making this annoying little squeak. I replaced the tensioner today because I couldn't completely identify which part the squeak was coming from. But that made no change. So since that thing has little or no value to me I would be fine with just eliminating it altogether if possible. In the three weeks I've had the vehicle I don't believe it has ever been engaged. It just seems like one of those emission parts that does nothing except cause problems.

ChooChooman74 · **Posted:** Sat Nov 17, 2012 1:04 am

Nothing to do with emissions. All about "creature comfort". Suppose to provide heat to the cabin quicker.

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papaindigo · **Posted:** Sat Nov 17, 2012 9:25 am

Several comments re. diagnosis
1. the squeak is more likely coming from the alternator pulley which is a not uncommon failure point. Diagnosis is usually to crank the CRD up; open the hood; while standing by the front left (driver side) tire have a second person bring the RPMs up to say 1500 and hold it; look down the serp belt from the alternator pulley to the tensioner; if the tensioner is bouncing (i.e. not essentially rock steady) you almost certainly have a bad alternator pulley. Fix 1) simplest is get a new life time warranty alternator from like AutoZone and install; 2) replace pulley-IdParts has them but removal is a bit tricky (there is a Miller tool and some have reported success with an impact driver and an appropriate sized allen head bit); 3) get new OEM alternator-a bit pricey. FYI a bad alternator pulley will eventually destroy the serp belt tensioner.
2. a dried up bearing is a bearing that will fail soon. A squeak implies a bearing that is low on grease or otherwise rubbing on something. Inspect the front of all the bearing for signs of leaking grease and replace as needed.
3. if no luck invest in a modestly priced infrared temperature gun from like Amazon. Drive for a while and then check to see if any serp belt driven bearing is hotter than any other.

As I mention earlier the bearing on the viscous is replaceable see viewtopic.php?f=5&t=60567&start=20

Joe Romas · **Posted:** Sat Nov 17, 2012 9:46 am

Or since your in sunny California where it does not get cool enough for it to come on is it possible the metal plates on the clutch have rusted and are your noise. I would think it it's the clutch or clutch bearing watching it with the engine running you would see it "twitch" every now and then.

But X2 on the alternator over run clutch going bad. My alternator was replaced by the dealer under my extended warranty at only 54k miles :JEEPIN:

KD6ICZ · **Posted:** Sat Nov 17, 2012 11:48 am

OK. Let me get caught up here. I do try to acknowledge every post because I do appreciate the helpful knowledge from everyone.

So the first thing I did was stand in front with the engine on and idling. By the way you only hear the squeak at idle. Any speed above idle it's quiet as can be.

With that the "rust" theory is a good one! My poor CRD has been around the world (belonged to a ranking general in the service) and has rust underneath which I am trying to get under control before it does damage. Like I said in previous post I believe I have narrowed the noise down to the passenger side of the engine. But I am going to double check it again to make sure it's not the alternator. The mechanic yesterday did spin everything and he said everything seemed to spin freely and not have any noise. But of course under pressure he did mention it can change the characteristics of the pulleys.

I have some free time this morning so I will get a long screw driver and see what each device sounds like.

truckbouy2 · **Posted:** Sat Nov 17, 2012 12:03 pm

"My poor CRD has been around the world (belonged to a ranking general in the service)"
Better check under the seats for underwear that's not your's or your wife's. Could be trouble trying to explain.

KD6ICZ · **Posted:** Sat Nov 17, 2012 1:10 pm

truckbouy2 wrote:

"My poor CRD has been around the world (belonged to a ranking general in the service)"
Better check under the seats for underwear that's not your's or your wife's. Could be trouble trying to explain.

Hahaha! Good idea! It did spend 6 months in Guam according to CarFax!

What is the "technical" name for the coolant heater?

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