vito 120 engine temp when towing

[sherco450]

l have been monitoring the coolant temperature when towing my caravan.

It seems to be reading 100 degrees (l.c.d) dash .. abating

I slow down accordingly and temp drops back to 85-90 degrees.

At what Temp is it getting dangerous ?

At what temperature do the thermo fan switch on ?

 

[BTB 500]

A rise of 10 deg or so when towing doesn't sound excessive IMO. I know I once got a high oil level warning just after a service when I was 'making good progress' with our 1500 kg caravan on the back. The oil level looked OK so I assumed it was just running a bit hotter than usual and went a little slower ... never had the problem again.

I guess it's a bit warmer in Aus though! And I get what you mean about the LCD display ... it doesn't have a 'red' segment like a normal gauge. FWIW that starts somewhere over 120C on my SL500.

 

[sherco450]

My van is 1500 kg bulky 8x18 foot and 8 tall.. It will make the vito work a little ..

Most high way limits are 110 kph and most travel at 120 kph ,so you need to push along with the traffic ..

The Vito pulls the caravan well but my eye is always on the temperature gauge.
l am curious to know when the thermo fan kicks in .. cant help being concerned that 100 degrees computes to boiling.

 

[Stratman]

........................

l am curious to know when the thermo fan kicks in .. cant help being concerned that 100 degrees computes to boiling.

It's 100 degrees at normal atmospheric pressure. The cooling system is (should be) pressurised, which will raise the boiling point according to the degree of pressurisation.

Ultimately the coolant filler cap is responsible for maintaining the pressure, so make sure it's in good condition.

 

[BTB 500]

My van is 1500 kg bulky 8x18 foot and 8 tall.. It will make the vito work a little ..

Most high way limits are 110 kph and most travel at 120 kph ,so you need to push along with the traffic ..

Ours is 8" narrower but a foot taller (weight and length are the same as yours), so pretty similar. The legal limit for towing here is 60mph (96.5 kph), but according to my mate Dave an outfit like ours would be quite comfortable at the sort of speeds you're talking about (120 kph is 75 mph).

I generally tow at about 65 mph on the speedo though ... this cuts down on the time taken to get past big trucks, which mostly have limiters set to 56 mph. I use cruise control a lot keep the speed down.

 

[optimusprime]

Could you fit another electric fan with a switch to turn it on Fitted on the inside of rad to pull air in .Thats if you have room. Or do they do an up rated fan blade or fan . Check with MB i may be a problem in hot climate like your in.

 

[sherco450]

l have researched a few hours now regarding the thermo fan temperature switch..
The only info l have found is for the w639 4 cylinder diesel . Switch on range for thermo activates at 110 degrees Celsius .. l recall my w638 activated at 90 degrees Celsius . So a lot different in range.

The 120 has never switched even with temps as high as 47 degrees ambient . The engine has always remained below 90 degrees.

l need to locate the switch to see if there is any stamped range scribed on it , and test the circuit.

 

[BTB 500]

I don't recall ever hearing the fan run on our Vito, hottest ambient I've driven it in was 'only' 40C though (not towing).

Of course the Vito is designed to haul a tonne of payload all day long so I assume the cooling system was designed to handle continuous high engine loads ... even in warm weather. It's certainly a fairly generous sized radiator.

 

[Benzowner]

I have towed for a number of years with a wide range of vehicles fitted with thermo electric fans and have yet to get even close to boiling.

You say the gauge reaches 100 centigrade, but what temperature is the red zone in, mine is about 115degrees. I always find that travelling downhill the temperature drops considerably and as said I have never boiled any car. If it's a real worry, you could always turn your heater on to assist cooling the engine

 

[BTB 500]

You say the gauge reaches 100 centigrade, but what temperature is the red zone in

That's the issue - the Vito doesn't have a temperature gauge. You can display a vertical 'bar graph' on the cluster, but there's nothing on that to show what temperature is considered too high.

 

[sherco450]

Another consideration , running the A/C while towing in the summer.

As l have not experience towing in 40 + degrees this may certainly raise the temperature bar considerably.

 

[sherco450]

l feel more comfortable now. Witnessed an ML 300 with an om642 v6 , has an analogue temperature gauge with 120 degrees (red zone )

 

[hotrodder]

Some numbers to go with this

It's 100 degrees at normal atmospheric pressure. The cooling system is (should be) pressurised, which will raise the boiling point according to the degree of pressurisation.

Ultimately the coolant filler cap is responsible for maintaining the pressure, so make sure it's in good condition.

https://durathermfluids.com/pdf/techpapers/pressure-boiling-point.pdf giving boiling points at various different pressures and water/coolant concentrations. Note that while 'antifreeze' also raises the boiling point it is nowhere near as good as water with regards to cooling i.e. never run more than 50% coolant because glycols have a lower heat capacity and lower thermal conductivity
Dunno about a Vito but MB rad caps are usually ~20psi at least which'd result in a boiling point of ~135°C for a 50/50 coolant mix

Also worth noting that a bigger fan, extra fans or lower cut in temps etc aren't gonna do much to lower temps when moving at 60 odd mph. They're about improving cooling in high ambient temps when stuck in heavy traffic i.e. less airflow through the rad and/or what air flow there is hotter than it would be on clear roads

 

[mushr00m]

Sorry for hijacking this thread. I too are having issues with the van. Long story short. Bought the van 4 yeas ago. Had major welding done on the front end. At this point the van was always running cold. max temp 40. This year, i decided to look into the problem. Disconnect bottom rad hose. I found some red plastic top in the pipe. Removed this. Reconnected hose filled up with fluids. Still ran at 40. Never lost any water.

Decided to remove thermostat. Pulled housing off, looked inside. The thermostat itself was not seated correctly. Removed thermo and reseated it. Repeated waters and bleeding. Max temp 60 if i block air flow to radiator.
Bought a new thermostat and housing. Fitted it. Filled once again waters and bleed system.
Now went to 85, driving locally max 10 miles from home. 2 weeks later, yesturday, travelled 30 miles and almost had a heart attack.
Max temp 100 and hoovering, NO load, no towing- running light. Is this normal or not.? Make things worse, I stop and idle. Tempreture drops so much the heating in the cab is vertually no existing UNTIL i start driving again. SO, I drive and cabin gets hot air, idle and no hot air - Temp on the clock drops to 80 or lower when idle but reaches 100 when driving. Did check thermo temp STAMP and stated 87.5.

Is this normal- 108cdi 2000 year.