Max D4 SDV6 safe transmission and coolant temperatures while towing
Hi guys, owner of a beautiful 2015 D4 SDV6 coming from a 200 series Sahara and have learned so much from this forum.
I have a question regarding maximum safe transmission and coolant temperatures while towing.
My SDV6 has 85k kms on the clock, had transmission serviced with life guard, towed from Sydney to Vic HC and back. On the way back on the Hume HWY in 40-45 degree heat towing about 3.2 tonnes I notice coolant temp needle reached just under the hot mark on a slight incline. I connected the Gap Iid tool to monitor the transmission and coolant temps.
Transmission was between 106-110 degrees celcius and Coolant was between 110-112, I was barely touching accelerator to keep it at those levels, any increase in load and it would climb to 115, i noticed the needle reached just under hot mark when at 115 so would slow to keep it around the 110-112 mark.
Speed was between 90-100kms.
I then received a low coolant level warning and pulled over to the nearest service station after a minute. (luckily)
Found out the top radiator hose had been slit from rubbing on the engine cover. Apparently a common problem. Rang LR dealerships who advised no dealership in Australia has one! Luckily managed to source one from an independent in Burwood and got an Uber driver to deliver it. Yes, long story, but Uber was able to deliver my part 2 hours into country from Melbourne.
Anyways, after installing it needed about 3 litres combined coolant and water poured while engine running and heater on max.
Temps remained generally the same as above after driving. Towing in D or S made generally no difference.
When the weather temp dropped to 30 degrees I was averaging 105 on both tranny and coolant temps.
Question is a: what is the max safe temps to run,
b: what is everyone else getting while towing in similar heat and
c: is this considered normal levels or should I be getting something checked out? The reaching just under hot mark has got me worried to do any outback touring.
In mid to high 30s ambient I get coolant just over 100 and oil ~102 on the flat, and up to 115 screaming up a big hill going as hard as it'll go. I've never seen the temperature gauge budge from 50%. My van weighs less than the car though, although it has the aerodynamics of a small block of flats (not unlike the car).
At the coolant cap pressure of 16psi, water boils at ~122C, so regardless of glycol content I'd want to be keeping it fairly well under that.
The coolant gauge on the dash will never move under normal use, including towing even in hot climates. It’s designed to maintain the same position under normal operating temps which includes towing. The fact it moved for you was a clear indicator of a problem which became apparent not too much later. Honestly, you don’t need to worry, just drive it and take note of the errors. The gearbox temp is aligned to the coolant as it uses the engine coolant as a cooler - so it will be similar temps.
Appreciate the quick responses gents. The thing is it reached just under high again when temps hit 115-116 degrees AFTER I did the repair. And that was up a long slight incline but only just pressing on the accelerator, maybe 20% accelerator. What I'm afraid of is if I were to climb Mt Ousley near Wollongong for those familiar with that road and Ill need to give it 75% to 100% accelerator it will definitely over heat as it's a punishing long incline over a few kms.
Will definitely be doing a full radiator flush. When I removed the top radiator hose the water appeared brownish green and not pink as per the coolant colour. Not sure if that means anything to those more mechanically minded than myself.
When I removed the top radiator hose the water appeared brownish green and not pink as per the coolant colour. Not sure if that means anything to those more mechanically minded than myself.
I had a pinhole leak in one of the EGR cooler hoses and the coolant coming out of that looked for all intents and purposes a dirty brown/green, yet the freshly flushed and filled coolant in the bottle was the as-supplied orange colour. I dunno what is in that coolant, but I had to collect a bit in a test tube from the leak to convince myself it was actually the same stuff I put in. It only looked the right colour in sufficient quantity, in the right light and with transmitted light rather than reflected. Odd stuff.
Appreciate the quick responses gents. The thing is it reached just under high again when temps hit 115-116 degrees AFTER I did the repair. And that was up a long slight incline but only just pressing on the accelerator, maybe 20% accelerator. What I'm afraid of is if I were to climb Mt Ousley near Wollongong for those familiar with that road and Ill need to give it 75% to 100% accelerator it will definitely over heat as it's a punishing long incline over a few kms.
Will definitely be doing a full radiator flush. When I removed the top radiator hose the water appeared brownish green and not pink as per the coolant colour. Not sure if that means anything to those more mechanically minded than myself.
If you didn’t have the IID tool you’d be none the wiser. Turn off the tool and just drive it. Presumably after fixing it the temp gauge was stable? You’re fixating on numbers you have no idea on to be frank. If you see the temp gauge move then you have a problem to be concerned about. If that’s the case I’d presume it’s not repaired correctly eg has a leak still or has an air pocket etc. trust the temp gauge. The factory knew what temps it can handle before indicating a problem.
If you didn’t have the IID tool you’d be none the wiser. Turn off the tool and just drive it. Presumably after fixing it the temp gauge was stable? You’re fixating on numbers you have no idea on to be frank. If you see the temp gauge move then you have a problem to be concerned about. If that’s the case I’d presume it’s not repaired correctly eg has a leak still or has an air pocket etc. trust the temp gauge. The factory knew what temps it can handle before indicating a problem.
The hopefully attached extracts from the Ashcroft site may help with part b of your questions. Visit their site for fuller information.
I know that the TD5 can operate up to 120C, but can't help with the V6 versions I'm afraid.
I too like to keep an eye on these things, especially when heavy towing, and don't subscribe to the "she'll be right mate" approach recommended by some.
Happy travelling
D4 MY16 TDV6 - Cambo towing magic, Traxide Batteries, X Lifter, GAP ID Tool, Snorkel, Mitch Hitch, Clearview Mirrors, F&R Dashcams, CB
RRC MY95 LSE Vogue Softdash "Bessie" with MY99 TD5 and 4HP24 transplants
SADLY SOLD MY04 D2a TD5 auto and MY10 D4 2.7 both with lots of goodies
The vehicle will tell you when the transmission is operating beyond it’s designed temperature with a warning on the screen, something akin to “transmission overheated/over temp”.
Appreciate the quick responses gents. The thing is it reached just under high again when temps hit 115-116 degrees AFTER I did the repair. And that was up a long slight incline but only just pressing on the accelerator, maybe 20% accelerator. What I'm afraid of is if I were to climb Mt Ousley near Wollongong for those familiar with that road and Ill need to give it 75% to 100% accelerator it will definitely over heat as it's a punishing long incline over a few kms.
Will definitely be doing a full radiator flush. When I removed the top radiator hose the water appeared brownish green and not pink as per the coolant colour. Not sure if that means anything to those more mechanically minded than myself.
As per DiscoJeffster, the gauge will only move if you have a temperature issue, and the engine management system told you low coolant and you did the correct thing.
Well done on getting the top hose replaced, hope you’ve modified the engine cover to give it extra room, otherwise the same will happen again.
High temp after your roadside repair would indicate either trapped air or incorrect coolant concentration, but the engine should still be in the “safe zone”, otherwise the low coolant or other over temperature messages would have appeared.
I would also do a complete flush with the correct coolant concentrate mix and ensure all trapped air is removed via both air bleed valves, one at the engine end, coming off the coolant outlet, the other at the coolant overflow bottle.
Coolant should be bright red / pink, any other colour indicates overheated coolant, so it’s done it’s job.
I’d also disconnect the hoses from the transmission cooler and drain, then reconnect and flush the entire system with demineralised water, then refill and bleed all air from the system.
I’ve towed our van through 38-40 deg temps at 100-110 kms with no coolant issues in the 5 years of ownership, my temp gauge has never moved past halfway in 100,000kms.
I too like to keep an eye on these things, especially when heavy towing, and don't subscribe to the "she'll be right mate" approach recommended by some.
It is a not a "she'll be right mate approach" as the driver does not need to keep tabs on what is happening - the ECU does that and if the engine gets too hot, in addition to the visual indication on the gauge the ECU will flash up a message, the red engine light will and most likely the ECU will shut the engine down to protect it. Same with the gearbox.
So in these vehicles doing all this individual monitoring is pointless - as mentioned you would be never have know there was a problem because there wasnt - if there was the car would let you know as it did when there was low coolant.
REMLR 243
2007 Range Rover Sport TDV6
1977 FC 101
1976 Jaguar XJ12C
1973 Haflinger AP700
1971 Jaguar V12 E-Type Series 3 Roadster
1957 Series 1 88"
1957 Series 1 88" Station Wagon
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Originally Posted by shadzta
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