Thread: Max D4 SDV6 safe transmission and coolant temperatures while towing

Good question & one to which I have often wondered what the answer is.
These are the kind of temperatures I occasionally see & I always back off the power when they occur. I always watch the Viscous Fan to see when the system is running out of cooling option.
My vehicle is a MY15 TDV6 & has done 81K with a gearbox service at 60K.
My van weighs close to 3 tons & I tow in Sport mode with Cruise Control 90% of the time.
To better maintain speed, I use the gearbox paddles to help select the correct gear before my speed slows.

Screenshot_20181222-130336_IIDControl.jpg

Appreciate all the responses gents and I accept some people like to know specific temps and others are more than happy to wait until a warning appears. Each to their own.

Note I didnt connect the Gap tool until I noticed the temp guage reach just under hot.

The benefit of monitoring is that I knew that at exactly 115 degrees is when the needle would move to just under hot. If I wasn't monitoring I would have no idea and would not have been able to adjust my throttle accordingly to keep it in the safe zone. Id much rather that and be able to drive 8 hrs home than wait for an overheating message and possibly do irreversible damage.

So there you have it. 115 degrees is when the ecu picks up the start of overheating range.

After blowing my turbo while towing full pedal up a hill in my 200series I like to keep an eye on things these days. At least until Ive reflushed this system and retest.

Originally Posted by shadzta

Note I didnt connect the Gap tool until I noticed the temp guage reach just under hot.

Just to fully understand I assume the red light did not come on when the needle went up?

This would indicate that the needle could raise another step with the red light to indicate a catastrophic temp rise?

Originally Posted by shadzta

Note I didnt connect the Gap tool until I noticed the temp guage reach just under hot.

While I certainly stand by my post above - it is important to know your car and respond to indications presented to you - and I agree with you if I saw the temp gauge rising, even though there are no other indications, I would be wondering why and starting to check - I know that in an car with a basically good cooling system the gauge will sit around normal through the acceptable operating heat range and will only rise if something is up even if the temps are still within acceptable sensor temps. I would go looking why - in my experience it is normally a slow leak as with a catastrophic failure the gauge will stay on normal as there is not hot coolant around the gauge sensor.

You used you Gap tool and got temps - I dont have a Gap tool but have some experience in this and know that the coolant on hot parts has a particular smell - so for me it would have been up with the bonnet and off with the engine cover and started "sniffing" and looking. This would probably detected your cut hose. You Gap tool gave you temps but to me 115 is a little highg but given the outside temp and what you were doing didn't help - it was not until coolant had dropped enough to trip to coolant level sensor that highlighted the actual issue.

Now if you had not used the Gap tool and I did not lift the bonnet we both would have continued on suspicious that something was up based on the temp gauge - the first indication would be the low coolant message, if we ignored that all the other systems would have kicked in.

You did the right thing and checked and you still have a good engine, how many times do we read on this and other forums that the dash board lit up with overheat information but I continued on to the next service center - and a dead engine.

I have a low coolant/hot engine alarm on my 101, the equivalent for my air cooled Haflinger and I am seriously considering a Engine Watchdog for my RRS because irrespective of what we have discussed here, none of the car's systems are likely to protect you if you have a catastrophic loss of coolant at freeway speeds - the first you will know is when the dash lights up with an associated death rattle from the engine with the temp gauge still sitting on normal - with no coolant in the engine the systems will pick it all up too late.

Garry

Originally Posted by PerthDisco

Just to fully understand I assume the red light did not come on when the needle went up?

This would indicate that the needle could raise another step with the red light to indicate a catastrophic temp rise?

No the red light did not come on so yes may have a few more degrees until overheat but didnt want to push it to that. The gap tool allowed me to ensure i didnt push it to 115 with accuracy.

Not a D4 I know my mates BT 50 Mazda 2016 model has just had auto replaced under warranty at 60000km it failed he fitted a scan gauge as he tow’s he found his gearbox temps were rising very quickly on any hill Mazda don’t recommend separate tranny cooler but the advice from independent shops is to fit one as soon as it’s out of warranty the Ford gearbox apparently has issues. Whereas in all the threads on this forum not once has anyone needed to fit a separate tranny cooler so assuming cooling system is not faulty looks like LR/ZF got this right

I thought my D3 trans was getting some level of cooling through the radiator, and seems to have survived quite well thus far (and my D3 runs much cooler than most as have had EGR's removed), but figure a separate cooler might help trans run even cooler.
Always happy to make it easier on the trans, as I work and drive in central Australia.
Has anybody fitted a separate trans cooler to a D3-4, and any suggestions on what brand/type if fitted?

Originally Posted by vbrab

I thought my D3 trans was getting some level of cooling through the radiator, and seems to have survived quite well thus far (and my D3 runs much cooler than most as have had EGR's removed), but figure a separate cooler might help trans run even cooler.
Always happy to make it easier on the trans, as I work and drive in central Australia.
Has anybody fitted a separate trans cooler to a D3-4, and any suggestions on what brand/type if fitted?

When I was waiting to pick up my vehicle, another D3 owner who towed a large caravan was talking to one of the mechanics about fitting a second transmission cooler.

While over at Moreton Island along the western beach, I was surprised that the transmission temp got to 98C. Sand was damp and a bit soft, maybe sinking in 4cm and doing 50 km/hr. Highway driving in summer not towing, it gets to about 80C.