I am going to mention it again! Coolant Level Sensor

lindenengineering

Well-known member
Check your coolant level sensor at every oil change--just takes a few minutes--or else $$$$$.
Had one in on the hook plus U haul trailer all loaded on the way to yes the West Coast--BUT climbing the wall on 1/70 out of Denver the radiator blew a hole in the seam and it was "Poly put the kettle on we will all have tea"--while a tow truck comes and hooks it to my place--engine seized!

Guess what?--The level sensor wan't working so no warning there was a loss of coolant!
No time for retard on this 'un! Its an exchange engine from Jasper for a quick in and out!
$7250 exchange plus$ plus$ plus$!
A $25 sensor might have saved the wallet flush!
Beware guys
Dennis
Mechanic
 

ECU

2006 T1n 118 Sprinter
Re: I am going to mention it again!

...and how do you check the sensor?
 

Cheyenne

UK 2004 T1N 313CDi
Re: I am going to mention it again!

Hi Dennis,

So let's see if you can help me out...

UK Spec 313CDi with the OM611 engine. My Low coolant light comes on momentarily on start up as a bulb check, all good so far.

But if I either unplug the switch in the header tank and/or short the wires together nothing :idunno:

So where do I go from here? I must admit I haven't had time to investigate further but do you have any suggestions for me to start with please.

Cheers from across the pond.
Keith.
 

lindenengineering

Well-known member
Re: I am going to mention it again!

Keith
Seemingly the bulb check is working.
When doing an oil change simply withdraw the sensor from the radiator keep it plugged in, let it dangle in the wind like fairy! (and maybe the rain in your case!)

At some stage leave the ignition on and the bulb warning should light up after a few seconds.
If it doesn't light up disconnect the socket shove a split pin of suitable size into the socket to bridge the contacts ,now check is the light is on.
If it still no workee consider a new sensor, as soon as possible.

The you won't run the risk of an engine exit during the Brexit vote!:laughing:'
Cheers Dennis
PS English English for a cotter pin is a split pin--make sense?
 

Cheyenne

UK 2004 T1N 313CDi
Re: I am going to mention it again!

OK Cheers Dennis. Never thought to wait for a delay between turning ignition on and light coming on. Doh! :bash:

And as for Wind and Rain, no way! We've had SNOW in the last 24 hours!!!

Cotter pins, split pins, Yep all the same thing :cheers:

Keith.
 

Graphite Dave

Dave Orton
Re: I am going to mention it again!

Another suggestion is to buy a Scan Gage and have one of the four choices of data be the water temperature.

My sold 08 Sprinter's water temperature varied depending on engine load and outside ambient temperature. I could tell when the electric fans turned on and also when to use the optional diesel heater to bring the engine up to the correct operating temperature on cold days. The design of the Sprinter cooling system depends on the proper operation of the electric cooling fans. Mine had two fans and some fans only had one. Apparently there is not much extra radiator capacity so proper operation of the fans is a requirement.
 

MillionMileSprinter

Millionmilesprinter.com
Re: I am going to mention it again!

What happened to the old fashioned way to check fluids?
That's what Dennis is saying: don't rely on the idiot lights, check it the old fashioned way. Pull off the cap and look.
...and also make sure the idiot light is working...
You know if the reservoir wasn't integrated into the radiator, someone could make a clear/translucent reservoir like most other cars have so a visual check is easy.
 

Cheyenne

UK 2004 T1N 313CDi
Re: I am going to mention it again!

Another suggestion is to buy a Scan Gage and have one of the four choices of data be the water temperature.

My sold 08 Sprinter's water temperature varied depending on engine load and outside ambient temperature. I could tell when the electric fans turned on and also when to use the optional diesel heater to bring the engine up to the correct operating temperature on cold days. The design of the Sprinter cooling system depends on the proper operation of the electric cooling fans. Mine had two fans and some fans only had one. Apparently there is not much extra radiator capacity so proper operation of the fans is a requirement.
All very well for you Dave but my UK Spec 2004 does not have any electric cooling fans, only the engine driven viscous fan. The reason being it does not have aircon!

I'll have to check my warning light operation later in the week but I do have a SG2 and Coolant Temp is one of my displays.

Keith.
 

220629

Well-known member
Re: I am going to mention it again!

All very well for you Dave but my UK Spec 2004 does not have any electric cooling fans, only the engine driven viscous fan. The reason being it does not have aircon!

...

Keith.
I wouldn't sweat it. Get it? (I'm a poet.)

My 2004 has A/C with one aux electric cooling fan. The only times I've noticed that fan cycle on was in hot summer temperatures while towing my sailboat up long(er) grades. Other times the thermostat and viscous fan seem to keep temperatures under control just fine.

What happened to the old fashioned way to check fluids?
I was thinking that. That is fine for maintenance, but not for on road monitoring.

If there is a fairly large leak then the level sensor can warn you before the cooling system is negatively affected. The old days of reacting to a rise in the temperature gauge in time are mostly gone. Today's engines are built with a minimum of material (metal) to keep weight down. That makes them very susceptible to damage from overheating. Often by the time the engine temperature gauge shows a rise in temperature the damage is already done.



vic
 
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lindenengineering

Well-known member
Re: I am going to mention it again!

A couple of comments
The UK is a temperate climate so far as vehicles go so extra cooling capacity isn't required.
Other territories DO require extra cooling so you have tropical packages installed during production for a designated territory. The USA is one of them due to the sheer size of the territory and climate variation..

Now every quality build installation of an engine in a frame must have a coolant draw down test conducted and certified by "Engineering". MB will have done this on a pre production unit!
The test usually goes like this:-
A glass tube is inserted in the top hose of an engine & run up to normal operating temperature and put into a stabilized condition. The test operative then starts to bleed off coolant into a graduated catchment vessel. The draw down continues until trace air bubbles start to form in the top pipe.
This is your maximum loss allowance before possible engine damage may occur. The norm is about 3 litres on a light duty application and around three gallons (12 litres) on a big rig or a bus.
To finalize the test the air bubble MUST diminish and clear withing ONE minute of filling back to max level with the pressure cap on.

If you do self conduct a test on your Sprinter you will see that the unit will lose about 3 litres before you hit the danger point! The light will come on at two litres lost!

Like I often state it is a very well designed van is the T1N unit--but it isn't idiot proof nor neglect resistant. MB certainly from my observations doesn't have time for neglectful behavioral repair tolerance nor idiotic repair procedures.

Now the Scan Gauge relies on info from sensors and the coolant temp sensor in particular is located in the thermostat housing.
It relies on HOT liquid passing over it to relay the temperature but NOT hot steam or gases.
Once you get a loss of coolant past the draw down test maximum only gases are passing over the sensor and this is why so many operators of vehicles not equipped with a coolant level warning light get caught out with a heat distressed engine.

The factory warning lamp on the Sprinter gives you enough time to stop & shut down before you do any damage .That is why it is vitally important you maintain it together with the rest of the cooling pack.

Daily I never cease to be impressed with this van as the cobble ups I often see by DIY'rs and questionable repairs it still keeps going!:thumbup:
Just a bit of simple TLC on the cooling system and it WILL do 1,000,000 miles.
Again a great design.
Dennis
Mechanic
 

312d

Member
Re: I am going to mention it again!

tFor who might be interested, the coolant sensor is magnetic operated, the reservoir/radiator has a floater magnetic ring inside the expansion tank that surrounds internally the coolant sensor probe, so as you might think , the white probe does not ever touch the coolant. I am no expert on Hall effect sensors.
 

lindenengineering

Well-known member
Re: I am going to mention it again!

Eduardo
Hi:thumbup:
Please don't confuse the ambiguous English term of the engine temperature sensor in the THERMOSTAT housing as the hall effect coolant LEVEL sensor we have both mentioned located in the pocket location of the expansion tank.
Both have two separate job to do.
Cheers Dennis
 

312d

Member
Re: I am going to mention it again!

Yes Dennis, i am talking about the coolant level sensor, thanks
 

Cheyenne

UK 2004 T1N 313CDi
Re: I am going to mention it again!

tFor who might be interested, the coolant sensor is magnetic operated, the reservoir/radiator has a floater magnetic ring inside the expansion tank that surrounds internally the coolant sensor probe, so as you might think , the white probe does not ever touch the coolant. I am no expert on Hall effect sensors.
Hi Eduardo,

The Coolant Level Sensor is nowhere near as fancy as a Hall effect sensor. It is a straightforward magnetically operated reed switch! Just like the door contacts for your house alarm!

You can test the switch by removing it from the tank, then while testing for continuity with a DVM move a magnet along the shaft of the switch. And in answer to my earlier posting Yes my switch is functional on this test.

Keith.
 

srmpf

New member
Thank you for the warning! went outside and checked the coolant level sensor and it's dead. Whoever designed this circuit wasn't really thinking about making it fail safe. It's a joke that you can unplug the sensor and the warning light stays off.
 

lindenengineering

Well-known member
First
With the socket separated from the sensor insert a straightened out paper clip into the female socket pin, insulate it and turn on the ignition --the bulb should light up on the dashboard.

If the bulb is OK & working then plug the sensor back in and turn on again.
The light should come on after a few seconds if the sensor is working
Dennis
Mechanic
 

srmpf

New member
First
With the socket separated from the sensor insert a straightened out paper clip into the female socket pin, insulate it and turn on the ignition --the bulb should light up on the dashboard.

If the bulb is OK & working then plug the sensor back in and turn on again.
The light should come on after a few seconds if the sensor is working
Dennis
Mechanic
now i'm confused. should the warning light come on when the circuit at the connector is closed or opened?
 

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