Thread: Coolant Loss - Engine Overheating

Originally Posted by Sol

Yep, seems like a common issue but of course I didn’t know that until it happened and read the numerous posts. Preventative seems to be the way to go if you’re on a long trip, especially towing.

MR Auto are sending one today and hopefully fitted and fixed in a day or two.

Praying there’s no further issues or over-cooked motor.

You'll be ok.
My son's 2008 2.7 D3 split his housing bigtime down on the Tasman Peninsula (Tassy) going up a steep hill towing his c/van and he drove around 6 klms before realising it.
Engine didn't seize but got pretty hot.
Had the local Indie fix it and the engine suffered no ill effects at all.
Still didn't use a drop of oil between 10k services and no horrible new noises @ 164,000 klms.
Mind you, we run (swear by) Wynns oil additives in our compartments and I am convinced that helped reduce potential seizure or pistons picking up.

Some engines, by design I guess, seem to get away with massive overheats more than others.
For example, I've seen V12 Jaguar (all alloy) engines get sooo hot due to one of the many hoses failing, yet they don't seem to suffer with any ill effects. Preferably get the water in slowly (as its cold and could cause metal cracking) but soon as possible, so as to allow the block and head/s to cool uniformly, particularly if they are different metals.
Some of the Jap stuff will blow a head gasket as soon as looking at it!!

Originally Posted by BobD

You can watch the temp on a GAP11D if you really want to be sure. The fan doesn't even start to partially lock until 107 and the gauge only moves at 117 on the D4, at which point it jumps to just below the top. The fan is fully locked at about 115. Low coolant is a completely different kettle of fish to over heating, as Tombie said. Easy to reduce load and increase engine speed by dropping down a gear or two if it gets hot but loss of coolant destroys the engine very quickly, which is why you need to the low coolant alarm, which the D4 has.

Unfortunately at the moment my low coolant warning works too well and is intermittently activating with full coolant level. I will have to try to find out what is wrong I guess, so that if it does lose coolant I will know about it.

Re the plastic housing, I replaced mine with an alloy version when they did the two manifolds. I think it should be replaced at least with the timing belts, if not at lower mileage and 7 years of age perhaps.

MR Automotive changed my plastic housing at 100k as a precaution. I carry the old one as a spare now.

On GAP you can watch 'Viscous Fan Pulse Width Modulation Pulse' which is the bottom right parameter in the screenshot below. The fan starts to be controlled when the temperature hits 100 deg. Depending on the gear, torque, angle, outside temperature etc the Modulation Pulse acts accordingly. This is shown on the two pics below where a drop in torque required causes the PWM of the fan to ease off a bit. There is obviously some pretty smart control happening to keep these vehicles cool. I have never seen 100% but at 50% the sound of the fan is unmistakable.

Screenshot_20181222-130336_IIDControl.jpg Screenshot_20181222-130400_IIDControl.jpg

Originally Posted by Milton477

MR Automotive changed my plastic housing at 100k as a precaution. I carry the old one as a spare now.

On GAP you can watch 'Viscous Fan Pulse Width Modulation Pulse' which is the bottom right parameter in the screenshot below. The fan starts to be controlled when the temperature hits 100 deg. Depending on the gear, torque, angle, outside temperature etc the Modulation Pulse acts accordingly. This is shown on the two pics below where a drop in torque required causes the PWM of the fan to ease off a bit. There is obviously some pretty smart control happening to keep these vehicles cool. I have never seen 100% but at 50% the sound of the fan is unmistakable.

Screenshot_20181222-130336_IIDControl.jpg Screenshot_20181222-130400_IIDControl.jpg

They are interesting numbers and prompt me to ask where in the engine/trans "circuits" are the temps taken?

I have a Scanguage 11 and amongst other features , can monitor the engine coolant and trans temps.

Generally speaking, the trans oil is always around 15 to 20 deg less than the engine (common is 75-80 v 90 Celcius) and they both fluctuate remarkably (in my opinion).
For example, today I went to my shack and returned on the Tasman Peninsula, Tassy.
Ambient temp 4 deg and trying to snow.
Going uphill the engine would go to 88 deg and trans to around 70, but downhill with trailing throttle, I could watch the engine drop to 82 and trans to very early 60's.

Earlier this year on a warmish day (from memory middle 20's ambient temp) whilst towing my 3.0 T c/van I'd see up to 102 deg engine and early/middle 90's with trans.

Do others experience similar temps and fluctuations?

Originally Posted by BobD

Unfortunately at the moment my low coolant warning works too well and is intermittently activating with full coolant level. I will have to try to find out what is wrong I guess, so that if it does lose coolant I will know about it.

Re the plastic housing, I replaced mine with an alloy version when they did the two manifolds. I think it should be replaced at least with the timing belts, if not at lower mileage and 7 years of age perhaps.

Hi Bob. Is your float suspect?

Re alloy housing, which I think Tombie also has, I would logically think that was a once only purchase/fit, but seem to recall some even had troubles with the metal replacement/s?

Originally Posted by gavinwibrow

Hi Bob. Is your float suspect?

Re alloy housing, which I think Tombie also has, I would logically think that was a once only purchase/fit, but seem to recall some even had troubles with the metal replacement/s?

Said Tombie did post once that a couple of the early units did split. I have an alloy unit as the engine compartment in my vehicle rarely cools down due to the higher ambient temperatures up here. A 10km round trip to Woolies keeps it warm for hours. I therefore decided I wasn't going to be changing the plastic unit every couple of years as a precaution.

Originally Posted by Narangga

Said Tombie did post once that a couple of the early units did split. I have an alloy unit as the engine compartment in my vehicle rarely cools down due to the higher ambient temperatures up here. A 10km round trip to Woolies keeps it warm for hours. I therefore decided I wasn't going to be changing the plastic unit every couple of years as a precaution.

Thanks for that. Without having to look anything up, anyone have an idea what is the ballpark cost for the alloy version and from where?

Originally Posted by gavinwibrow

Thanks for that. Without having to look anything up, anyone have an idea what is the ballpark cost for the alloy version and from where?

Only made by TRS.

You can replace 4 standard units for the price.

But it is such nice billet.