If top and bottom radiator hoses are the same temp and the two heater pipes going into car at bulkhead are similar then hopefully OK.
Technical Ducato 2.8 idTD Temp Gauge and Fan issues.
- Thread starter GaryGavlaar
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Technical Ducato 2.8 idTD Temp Gauge and Fan issues.
GaryGavlaar
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The old one wasn't working though either.
GaryGavlaar
Member
Whats involved in changing the temp sensor again, now it's full of fluid? Will i lose a lot?
Can anyone recommend a decent make of temp sensor to go in the thermostat housing for these things?
Can anyone recommend a decent make of temp sensor to go in the thermostat housing for these things?
GaryGavlaar
Member
If no obvious bleed screw, two things to try.
One with cold engine and coolant cap released so no pressure, remove the temp sensor, if above where the thermostat is positioned and let any air come out then replace the temp sensor, so you are letting gravity push water out from the coolant tank and must top up again. Be ready to refit the temp sensor quickly as soon as all air is out, so probably best not to drop the sensor.
Reason being the highest part of the engine is usually where any air collects and also where most damage can be done due to head gasket failure if overheating.
The other bleeding is done carefully with warm engine so pressure in system. This is, release slightly the highest heater hose clip and wriggle the hose enough so that any air is allowed out and then hot water will start to come out, be ready to tighten hose as if it blows off you will get a facefull of hot water!!!
I have bled heaters at this point many times but am fully aware of the risk and my hands were fairly thick skinned then.
If you have access to a garage coolant pressure tester then this job can be done easily without a hot engine, but where is the fun in that?
GaryGavlaar
Member
Is there a way to actually verify the temp that the sensor should be feeding back to the guage? This will at least tell me if it is in fact overheating, which I'm still not 100% convinced it is, I'm leaning more towards some issue between the sensor and the guage itself.
In the old days we used to have a Smiths Instrument tester for fuel and temp gauges, but these days most is done with diagnostics.
I know on some Vauxhalls they don't use a gauge which annoys me as I think it important , but when hooked up to a diagnostic tool it shows engine temp.
Other than that some form of Laser temp reader that you point at engine, as I mentioned before I believe, I test thermostats in a pan of water on stove using a suitable thermometer. I did try a normal houshold one and blew it off the scale in the past.
As a very rough guide if engine temp normal 90 degrees Centigrade and I grab a top hose to the radiator I can only hold for about 30 seconds before unbearable.
GaryGavlaar
Member
Ahh i do have an infrared temp gauge somewhere for my pizza oven thing. So if i point that at the brass body of that sensor, it should basically give me a similar temp to what's on the gauge if its working correct.In the old days we used to have a Smiths Instrument tester for fuel and temp gauges, but these days most is done with diagnostics.
I know on some Vauxhalls they don't use a gauge which annoys me as I think it important , but when hooked up to a diagnostic tool it shows engine temp.
Other than that some form of Laser temp reader that you point at engine, as I mentioned before I believe, I test thermostats in a pan of water on stove using a suitable thermometer. I did try a normal houshold one and blew it off the scale in the past.
As a very rough guide if engine temp normal 90 degrees Centigrade and I grab a top hose to the radiator I can only hold for about 30 seconds before unbearable.
You could point near sensor but also above where the engine thermostat is fitted towards top of engine on metal part at highest point that water goes through/around, also where top hose joins the radiator.Ahh i do have an infrared temp gauge somewhere for my pizza oven thing. So if i point that at the brass body of that sensor, it should basically give me a similar temp to what's on the gauge if its working correct.
This will only be a rough guide.
Generally speaking if you are not losing coolant and there is no signs of knocking like dodgy central heating that needs bleeding, either of which will need urgent attention.
The main thing is having a good quality coolant pressure cap screwed on correctly.
Reason being the hot water doesn't damage the engine until it boils then turns to a gas/steam at which point temp rapidly increases in localised spots causing head damage etc.
In simple terms a 10 lb radiator cap working correctly prevents water from boiling until it reaches 115 Degrees Centigrade, so no problem until some idiot undoes the cap!!!
GaryGavlaar
Member
ok found it.
So even though the temp gauge gets here and sits here solid........
The infrared temp reader is actually only showing temps of around 70C to 80C Which I'm sure isn't exactly completely accurate but should give me a round about idea shouldn't it?
So even though the temp gauge gets here and sits here solid........
The infrared temp reader is actually only showing temps of around 70C to 80C Which I'm sure isn't exactly completely accurate but should give me a round about idea shouldn't it?
Communicator
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The 2.8idTD only needs one temperature sensor for the gauge. A high temperature thermostatic switch for the warning light is incorporated in the same unit which screws into the thermostat housing. (I note that @airwave did mention finding two sensors on his 2.8idTD.) The engine temperature is normally controlled by the thermostat itself which is typically a wax capsulr device. These usually fail in an open position making the engine run cool.
That would appear to suggest a normal operating temperature, so why change the gauge temperature sensor? Fans do not usually operate in normal driving.
The new sensor may be reading high, but a high resistance connection coud give a similat effect. Nice to know that fans are working.
Yes fans seem to be working, but gauge may be reading high. If OK before then possibly faulty sensor, but a high resistance connection to the sensor is apossibility. Also I have a niggling thought that some earlier Ducatos used a voltage regulator module for the fuel and temperature gauges, or was that only for the fuel gauge?
I agree.
GaryGavlaar
Member
I don't think it was ok before, it was sitting really low. 90C is straight up on the guage which is where I'm used to every other car/van I've owned sitting under normal circumstances once warmed up, but it sat very much below that level. Initially i thought this was the issue with my fans never kicking in, but after a bit of back and forth on this thread i found out about the rad switch.
I purchased both the rad switch and the temp sensor, and while my water pump was being done i got the garage to fit them for me, hoping to get a nice steady normal reading on my gauge. However i am now where i am. Maybe i should try a new more expensive sensor. I have noticed that the one ive bought doesn't actually list a switching temp, where as a lot of others do, at 107C.
Communicator
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Access. On my 2.8jtd it is difficult to see the sensor unless yor remove air filter or intercooler hoses.
I was planning on filling the coolant reservoir to the brim, and replacing cap. I was hoping that fluid would pull apartial vacuum and only come out slowly provided that I dis a quick change. In the event I discoered that my gauge going immediately to normal ws due to a high resistance connection at the sensor. I gave it a squirt of contact cleaner and put everything back again without removing the sensor.
GaryGavlaar
Member
Ahh ok, i can see the sensor fine, so i think it would be pretty straight forward to get out. Its more the logistics of the job i was thinking about. Like loss of coolant, or how to avoid that if possible. Obviously during this conversation I've found the sensor isnt linked to my fans, so its not that important, but it would be nice to get the right reading, something i can rely on
GaryGavlaar
Member
Before you bought that did you contact the seller(autodoc by another name) with vin number to confirm part correct?
Hint parts listed by reg number are not guaranteed to be correct-essential to confirm with that seller via vin of vehicle.
NRF been great for rads and ac condenser for me
FACET good brand of old type temp sensor-provided the correct part
Or coastal motor homes via vin number- coastal are very good
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Communicator
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I usually use Ebay, where I can view a selection of makes/suppliers/prices.
If you buy a different spare sensors you could compare resistance with a multimeter. Note that sensor element is connected between one terminal and sensor body. Other terminal should be open circuit under normal conditions.
Alternatively, I earthed sensor body with a large terminal clip (like jump lead) and moved connector between two sensors. You shoud see minimal readind at ambient temperature.
The resistance of the gauge sender reduces as the temperature increases.
If you ground the gauge wire at the sender end you should see full(hot) deflection of the gauge needle.
You have focused on 90 degrees c reading at one point, what is the correct thermostat opening temperature ?
Have you fitted a new thermostat?
If yes was it checked for correct opening temp before fitting?
If you ground the gauge wire at the sender end you should see full(hot) deflection of the gauge needle.
You have focused on 90 degrees c reading at one point, what is the correct thermostat opening temperature ?
Have you fitted a new thermostat?
If yes was it checked for correct opening temp before fitting?
GaryGavlaar
Member
I looked up my OG part number in eper, and searched based on that.
I think you will find on those Sofim engines the thermstat is meant to open at 80 degrees Centigrade.
