Td5 Temperature variations

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Originally Posted by PhilipA

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

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yes and no!

Dunno about the TD5 (yet), but on my 300 Tdi, it does make a difference at highway speeds.

I took my fan off the D1 in early summer, and ran around town. Ambients around mid to high 20's, (note I have a digital coolant temp readout).
Tdi normally ran at about 80-83°C. In some instances with the fan now off, so no forced cooling through the rad, coming to rest at a set of lights, I noticed the coolant temp dropped down to 79, before it rose back to the low 80's again after a couple of mins!

So the next test had to be on the freeway out west, up a set of hills.
On the freeway run about 40-50ks, Tdi sat on the standard 80-83C, but then on the long climb up the hills(about 5mins or so) where my D1 struggles to hold about 90k/h, now with the engine loaded and no aircon, it did rise up to 88-90C, where I'm sure it maintained 83-ish.
So back down the hill run, fan back on and drive up again.
This time with the fan on tho, it did hold it's normal 80-83C again.

That was with the D1 front grille on tho, and that's the major factor in how hot/cold my D1 runs.
I'm currently running without the front grille fitted(but will soon refit). I've been trying to get to a store In know of that sells some nice looking mesh that I'm trying to convert my grille from the std D1 horizontal flats to a mesh type(ie. Saudi type grille).

I reckon my rad isn't flowing the best it can too tho. Doesn't overheat as such, but does run hot(can reach close to 120C) only with A/C on on a hot day when the engine is loaded up(ie. up a hill).
The removal of the front grille has sorted that, so I know that it doesn't.

So I thought temp variations in the coolant die to varying loads on the motor is a normal thing .. and I'd expect that it should too .. probably more so on a diesel.

One thing to keep ,in mind before you go spending money - the reason the temp gauge on Rovers (and other cars, too) doesn't read accurately, is because the company don't want their dealers to be inundated with punters complaining about the wild fluctuations of their temp gauges. I have a digital readout on my 300Tdi, and it varies between 84 and 97 degrees just cruising on the highway. Get behind a truck or a caravan, and it climbs, uphill or with a cross wind, it climbs, put the camper trailer on the back, and it will climb quicker, but still to around the same levels. I generally drive by the EGT reading - anything over 620-650, i start easing back on the throttle. Often you don't actually drop much (if any) speed, but the EGT's (and consequently the coolant temps) drop back. During all of this, of course, the factory temp gauge doesn't move at all.

I'm going to start looking at alternative grille options, to try to improve airflow, particularly in cross winds, or when running in the disturbed air behind large vehicles.

Did a few checks on viscous fan this morning -
1. There is a fair amount of resistance when turning fan with engine off, more than I thought there would be.
2. With engine idling and temp at 35deg I couldn't stop the fan spining when using a magazine.
3. A short test run at 60 to 70 kph had temp rising to 88 in normal time and then varying between 88 & 92 when roundabouts and a few small inclines were encountered.
4. Cold coolant level is OK

Ambient temps today are about half of what they were yesterday so that may have been the main reason for my high coolant temps yesterday. So, with cool weather predicted for the next week plus the checks I have done, i feel more confident to proceed with my trip the high country.

Thanks to everyone for the advice and suggestions given - they are much appreciated and points me to have a closer investigation of a few items, especially the radiator and the viscous fan, when I return home.

yes and no!

Dunno about the TD5 (yet), but on my 300 Tdi, it does make a difference at highway speeds
It is a old furphy re fans over 60k`s not having much impact [wink11]and on a Td5 it is no different they do help over 6o k`s [thumbsupbig]

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Originally Posted by rangieman

yes and no!

Dunno about the TD5 (yet), but on my 300 Tdi, it does make a difference at highway speeds
It is a old furphy re fans over 60k`s not having much impact [wink11]and on a Td5 it is no different they do help over 6o k`s [thumbsupbig]

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Chris, I know that replacing my dud Viscous fan in the TD5 certainly dropped temps on hill climbs -over 60 + KPH, I did a standard test up Mt Dandenong before & after, to see for myself, as I wasn't sure it caused my overheating issue.

Not wanting to detract from Rogers initial question ( & it seems his Viscous fan is OK) I found this excellent video.

How Does a Viscous Fan Clutch Work? - YouTube

Roger,
I hope your high plains trip goes OK, but I think Vic will turn on some dirty weather in the next couple of weeks. If you get stuck, give us a holler, any excuse to get out of Melb.
David

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Originally Posted by DeeJay

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Roger,
I hope your high plains trip goes OK, but I think Vic will turn on some dirty weather in the next couple of weeks. If you get stuck, give us a holler, any excuse to get out of Melb.
David

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Thanks David, hopefully the weather won't be too bad - usually quite good at this time of year but has turned quite cool and a little damp here at Wagga. Heading for the Howqua Hills tomorrow to set up base camp with son and family of five with day trips in the local area. He wants to visit some of the huts so we'll probably find ourselves bouncing from one hut to another. Hopefully the tracks won't be too greasy.
We'll probably be based at Fry's flat if you want to duck up for a night or two.

Agree re that video (also linked by Chris in an earlier post) giving an excellent understanding of how a VFC works.

You hit Catherine hill in 35c ambient and you are surprised your engine temps increased!
A Turbo charged 2.5L tractor engine that is already stressed pulling 2200kgs is going to make more heat, its got too to get up the hill some how, and its going to create a hell of a lot more heat to do it, dont buy an exhaust gas gauge or you will be having conniptions continuously.
You say you hit 102c and it fell back just as rapidly as it rose, I would say cooling system is doing its job.
You report less than a 10% increase in temp on other hilly roads and an expected reduction on the flats, and thats what you got.
Thermostat takes a little time to react.
You also report no abnormal operation or feel from the engine

Nanocom does engine load? if it does I would be looking at these figures and correlating it with temps.

Set your high temp alarm around 107c--------if you have the correct mix it should be good for 120C+

Too much gauge watching enjoy the drive. Chill out.

Check out the cooling system with a decent flush as it should see this every 3-4 years anyhow.
A radiator is not so expensive.