Over Heating Issues 1996 3.9 V8 D1

**Landover** · 7th February 2010, 08:30 PM

Hi all. Of late I have been having some over heating problem amongst other things

. I have just had the radiator rodded and cleaned, flushed the engine and pipe work, replaced the thermostat and put new coolant in.

I took it out to Wombat state forest today to give it a real test and most of the day it worked fine with the temp not moving past half way. After a long steep rocky climb, low range with the engine playing some nice tunes for about 10 minutes I hit the top and my car tuned into a steam engine. Let it cool for about 15 minute and headed off on some easy going tracks. After about 10 minutes temp rose again so I stopped and let it cool right down and refilled with water. From here it was highway driving home for about 30 minutes. The temp was fine on the highway and ever put the Air conditioning on to test and was no problem. It wasn't until I went slow through town before I got home that the temp went up again.

When the engine was hot I did note that I did not hear any loud fan noise. Even the Thermo fans only came on occasionally. I suspect the Viscos Fan may be faulty and what set the Thermo Fans off or is that only for the AC.
How do I test the engine fan to see if it's working or is there something else that could be causing it.
The Day was 31 deg by the way.

Cheers, David.

**justinc** · 7th February 2010, 08:34 PM

David,

To test the viscous fan, when cold in the morning rotate it quickly by hand for about 10 to 15 seconds, if it becomes very easy to turn IE spinning uselessly without any resistance, its time for a new one.

These hubs when working correctly fairly roar when rad is hot, there are plenty out there that are failing/ have failed after 12 to 15 years.

JC

**trobbo** · 8th February 2010, 07:57 AM

further to what JC said (which is right of course) you will also hear the fan roar and continue on for some time when you first start the car. I'm trying to think how long mine goes for - it is probably somewhere between 30 sec to a minute before it starts to quiten down

**big guy** · 8th February 2010, 02:02 PM

The thermo fans will cut in as soon as you turn the air-con on.
Regardless of engine temperature.

Have you checked the thermostat?

Could be sticking or faulty.
Mine sure was.
I swapped mine over as a precaution and the new one was the faulty unit.

Slipped liner, hope not though.

**roverv8** · 8th February 2010, 02:25 PM

The aircon thermo fans will cut in also when the engine is to hot,
It's triggered by the sensor in the thermostat housing, they usually continue to run even after the car has been switched off. (when too hot)

**dirtdawg** · 8th February 2010, 06:41 PM

i did all that and still had probs, turned out to be a dodgy fill bottle, never gets over half anymore

**cucinadio** · 8th February 2010, 08:07 PM

Originally Posted by roverv8

It's triggered by the sensor in the thermostat housing, they usually continue to run even after the car has been switched off. (when too hot)

....

cheers

**Landover** · 8th February 2010, 08:11 PM

Ok, thanks for the info guys. Just cooled down outside so went and checked a few things.

If I spin it by hand from cold as Justin suggested there is initially some very slight resistance but after about 10 to 20 sec it probably free spins a two or three turns with one push, hardly any resistance.

When I start it up, after about 10 second the fan starts to roar at idle. After about 1 minute I gave it a rev and the fan noise stopped.

I dont Know what problem you had with you bottle Dirtdawg but mine seems to hold pressure, only the cap let off steam when hot. I heard the earlier one split.

So I think from this it look like I need a new Viscous Fan.

Options I have found:

- After market one on Ebay $120 plus $20 postage
- From a Land rover parts supplier - Original Boxed about $400, Original unboxed $250 inc or reproduction $187 inc. He tells me the Reproduction one aren't as reliable and don't work as good as the original.

Has any one had any experience with after marked ones or recommend a place to buy one from. For an extra $100 on top of the Ebay one may be the best option I think.

Cheers, David.

**big guy** · 8th February 2010, 08:17 PM

Originally Posted by roverv8

The aircon thermo fans will cut in also when the engine is to hot,
It's triggered by the sensor in the thermostat housing, they usually continue to run even after the car has been switched off. (when too hot)

Yep, that kind of goes without saying really.
Thanks for pointing out though.

**roverv8** · 8th February 2010, 08:35 PM

After market one on Ebay $120 plus $20 postage

I bought one of these,
It's only been on a couple of weeks, cuts in & out as it should.
Time will tell how long it lasts!!

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