Td5 Temperature variations

**Xtreme** · 13th April 2018, 05:51 PM

2003 Td5 110 with 210000kms
Travelling south today (ambient temp 》35deg C) on Hume Hwy with Nanocom in instrument mode.
Temp sitting at around 90 untll Catherine Hill when temp climed fairly rapidly and triggered a 102.5deg High Temp alarm on Nanocom. Engine still running smoothly and didn't miss a beat - unlike me!
No engine faults logged on Nanocom.
Reset Nanocom and temps back to normal. Coolant level checked and OK although there was slight evidence of spillage/onerflow from filler reservoir.
Kept an eye on Nanocom for rest of run to Wagga Wagga and every time an incline was encountered temp rose 5 to 7 degrees but returned to normal just as fast as it rose once incline was crested.
Once I arrived at Wagga I kept engine idling, temp was steady at around 91deg and viscous fan was spinning.

I find these rapid variations in temp difficult to believe and am wondering if it is simply a sensor or electrical fault.
It's a little worrying though as I'm heading for a week or so of slow, steep driving through the Victorian High Country.

I'd be interested in reading thoughts from the AULRO guru's regarding these temp variations

**rangieman** · 13th April 2018, 06:29 PM

Viscous fan would be my first port of call

**strangy** · 13th April 2018, 07:22 PM

Im going to say head gasket...

**djam1** · 13th April 2018, 07:27 PM

The TD5 ECU maintains normal operation until 120 degrees C then reduces fuelling.
You are not overheating but if behaviours have changed you should look into it
What EGTs are you running on the hills?

How old is the radiator? They should be replaced every few years in my experience as they gradually block up

If it’s loosing coolant after a hill it’s likely a head gasket probably won’t fail most TD5s drive in for a change
Wouldn’t push your luck though the heads walk and the valves can hit the bores

**Xtreme** · 13th April 2018, 08:17 PM

I'm unaware of EGT's as there is no sensor for Nanocom to read.
Motor is standard and only extra 'gauge' I have is the Nanocom.
AFAIK radiator is original - 15 yrs old. I'll take your advice re replacement.

The temps are rising and falling over a fairly short time and I wonder if this is really possible with such a large mass. Hence my thoughts that I may have a faulty temp sensor or bad electrical connection (earth!) somewhers.
Maybe this is wishful thinking so that I can continue my trip without trouble.

**djam1** · 14th April 2018, 06:44 AM

I use a Nanocom as a guage as well and the temperature readings are pretty random at times but only for a couple of polling intervals which I think is about a second per interval.

Originally Posted by Xtreme

I'm unaware of EGT's as there is no sensor for Nanocom to read.
Motor is standard and only extra 'gauge' I have is the Nanocom.
AFAIK radiator is original - 15 yrs old. I'll take your advice re replacement.

The temps are rising and falling over a fairly short time and I wonder if this is really possible with such a large mass. Hence my thoughts that I may have a faulty temp sensor or bad electrical connection (earth!) somewhers.
Maybe this is wishful thinking so that I can continue my trip without trouble.

**rangieman** · 14th April 2018, 07:58 AM

I run my Nanacom in dash mode , When towing the camper over the range from Tumut to Cooma i spiked at 98 degrees and all up 4280 Kg loaded car and camper

.
My alarm was set at 95 degreee`s and gave me the ****s on that climb since changed it to 105

My temp unloaded normaly sits on 88 degrees and does go up and down a few degrees at times

**rangieman** · 14th April 2018, 08:46 AM

Something worth noticing is at those temps you state the viscous fan should have been howling it`s head off , Could you hear it over the defender drum

Have you checked the fan with the old new`s paper trick

Or a welding glove

How to: Diagnose Viscous fan clutch failure - YouTube

**AK83** · 14th April 2018, 09:11 AM

I used to do it with a padded glove too(a woollen padded freezer glove), but if you do it that way, make sure to slow the blades down from the side that doesn't cut into the glove!
Not like the chap in the video that rangieman posted!
If the clutch is fine and doesn't stop, you don't want the leading edge of the fan blade cutting into the glove, you want to slow it via the trailing edge .. ie. the video guy should have slowed the fan from the inside edge, not the front edge.

Engine has to be at operating temp too. If cold, the fan should slow/stop, even if it's working fine.

**PhilipA** · 14th April 2018, 09:31 AM

The VC really only provides cooling under about 60KMH.
Above that the force of air through the grille overcomes it.

I think that you have a problem, maybe a blocked radiator or leaking head gasket.
Do you have stuff like driving light across the grille?

Over 28C if you have the air on, the electric fan will kick in. Does it kick in?

I find mine runs cooler at 28 c than it does at 26C. That was at only say 40-60kmh because of the bends.

As an example climbing the Alpine Way from Tom Groggin to Thredbo towing my 1000Kg camper over 20Kms on a 24C day, mine only touched 100C once by Nanocom and engine head temp sensor. It the dropped to about 95C when I lessened throttle and turned the aircon off.
No coolant was used.
How much coolant do you normally use? Mine has dropped by about 3MM in 7000km over one year.( I haven't been on any long trips recently)
Regards Philip A

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