Technical coolant sensor 1992 1.9td

[rugchucker]

Hi this is my 1st post.
My 1992 Ducato 1.9td temperature gauge is reading hot, just on the edge of the red zone. I have changed the thermostat and it has made no difference. It is not using any water and other than the gauge is not giving any other indication of overheating.
The fan cuts in and out normally and when I stuck a probe in the header tank it was only showing 75 degrees at idle but the gauge was reading over 90.
So I suspect the temperature sensor!!! Next problem finding one!!!!!!!!
Can anyone help????

Des

 

[rugchucker]

Well I found a sensor at our local factors, I have fitted it and now I need to give it a run to find out whether that has fixed it

 

[rugchucker]

Well, I have changed the sensor & the thermostat, the top hose is hot, the bottom hose is cooler and the gauge is still reading hot, it seems to wander about a bit???

Any ideas??

 

[mikey72]

If it had been the mk2, I would have said new radiator. They are notorious for poor cooling as they get older, the flow through the radiator reduces, and the fins rot away as well, van is normally ok(ish) until you use more throttle, then the gauge rises well past the middle.

 

[rugchucker]

Thanks for that Mikey. I have ordered a radiator so will try that next. Only the pump left after that!!!!!

 

[mikey72]

I had a new pump on mine, (it was squealing), didn't make any difference. I changed the thermostat, as it looked like it may have been stuck half open, but again no difference. Eventually I wired a switch onto the fans, manually switching on greatly improved the cooling, so I reckon the flow was impeded by scale, so the water was cooling in the radiator enough to keep the fans off, but not flowing enough to get the heat out of the engine. The fins were rotting away as well, so the fans increased the air flow enough to over cool the water low enough to actually cool the engine. New rad sorted it out. (The heater matrix going was the decider, when I replaced that the radiator was easy by comparison)

 

[rugchucker]

When I open the bleed screw next to the expansion bottle, the coolant flows out, so hopefully that means the pump is working. It looks easy enough to change the radiator.
We are going to France in under 4 weeks so hopefully this will cure it.

 

[rugchucker]

Well that was a fun day!!!!:yuck: It p*ssed down all day. I removed the old rad, it was a bit shabby at the bottom, in fact the bottom framework disintegrated as I removed it. The new rad arrived at 1pm and only took just over an hour to fit.

Ran the engine up to temp on the gauge, the bottom hose is still cold I will give it a run on Saturday and see what happens:bang:

 

[hymercamp55]

Hi I know i could be stating the obvious but have you tried bleeding the water system I had a bit of trouble with my ducato 2.5td when i couldn't get a temp. switch and had to improvise to get the guage working
hope you get it sorted soon good luck

 

[rugchucker]

I have tried bleeding the system, the heater gets hot, the bottom hose doesnt, as if the thermostat isnt opening, I have checked the thermostat and it starts opening at 80 degrees and is fully open at 90 degrees.

I suspect the gauge. the warning light doesnt come on and other than the gauge reading high there is no other symptoms.

Strangely the thermostat controls flow to the bottom hose?????

 

[oscillator]

I have tried bleeding the system, the heater gets hot, the bottom hose doesnt, as if the thermostat isnt opening, I have checked the thermostat and it starts opening at 80 degrees and is fully open at 90 degrees.

I suspect the gauge. the warning light doesnt come on and other than the gauge reading high there is no other symptoms.

Strangely the thermostat controls flow to the bottom hose?????

Hi .Ive just joined the site and goin through these posts .
i two have a ducato 1993 1.9td and have been having the same problem as you are having and yesterday i got a new radiator and thermostat and installed them both. (took me a bit longer!)
the problem is still there! it runs up to temperature fine on idel. sits at 80 and after a bit the fan kiks in when it reaches 90! so all is good there. But if i take it out on a run an get upto 50-60mph! the temperature rises up to 100-110 say. and this has never happened before!
i had a head gasket done two years ago as my cambelt snapped and had the head redone
i did take it back to my local garage to check if the head gasket was leaking!( only by the test they do inserting a pump in the expansion tank to see if any gasses are in the water.) lucky it read ok the dye stayed the same. so i am pulling my hair out my self on this as i thought it was the radiator in the end ! NOPE!!! LOL
What can it be??
my conclusion left is--
the water pump not pumping the coolant enough when the engine is at high reve's
or there is a leak from the gasket and i need the garage to check it out properly .

last word the heater works then it doesnt and blows cold air when the engines upto temp!
can this be a problem conflicting with the overheat?
any ideas ?
thanx and good luck wiv yours.

 

[rugchucker]

Hi Oscillator,
Your description of the heater looks like an airlock or blockage and a reverse flush would be my next step.
I'm taking the van to work tomorrow and will give it a good flush through and a long bleed through.

Any chance you can do a diagram of the hoses attached to the thermostat housing showing the top & bottom hose connections

Des

 

[oscillator]

Hi Oscillator,
Your description of the heater looks like an airlock or blockage and a reverse flush would be my next step.
I'm taking the van to work tomorrow and will give it a good flush through and a long bleed through.

Any chance you can do a diagram of the hoses attached to the thermostat housing showing the top & bottom hose connections

Des

Hi des
thanx for the reply! ok wll try to show you . do you think then it could be a blockage? what procedure do you do ?
cheers j

 

[mikey72]

I have tried bleeding the system, the heater gets hot, the bottom hose doesnt, as if the thermostat isnt opening, I have checked the thermostat and it starts opening at 80 degrees and is fully open at 90 degrees.

I suspect the gauge. the warning light doesnt come on and other than the gauge reading high there is no other symptoms.

Strangely the thermostat controls flow to the bottom hose?????

I can't remeber how the hoses actually look on mine (in storage) but the water flows into the top of the rad, and is cooled, and flows from the bottom back to the engine. So if it runs low on water, it always pumps from the bottom up. Every other vehicle I own the thermostat controls the return, as the water heats the stat opens. And the bottom hose is always the coolest. I've never had any problem with airlocks, but on mine the expansion tank is the highest point in the system.
Any picures would be good.

 

[oscillator]

Hi des
thanx for the reply! ok wll try to show you . do you think then it could be a blockage? what procedure do you do ?
cheers j

Hi Des
Got the pic of the thermostat for ya but how do i upload it?? lol
sorry newbie !
i can send it to ya by email if you like?
TT

 

[rugchucker]

Thanks again for the pic. Today I have already tried more bleeding. The gauge gives a steady reading rising smoothly & slowly while warming up & at tick over remains steady at 90. Then when I pull away the needle moves rapidly and swings between just above normal and almost red. The bottom hose still feeling cool. The 1st fan occasionally cuts in.
I put a thermometer in the water coming out of the bleed hose and that was reading only 80 degrees.

What to do next?

 

[oscillator]

Thanks again for the pic. Today I have already tried more bleeding. The gauge gives a steady reading rising smoothly & slowly while warming up & at tick over remains steady at 90. Then when I pull away the needle moves rapidly and swings between just above normal and almost red. The bottom hose still feeling cool. The 1st fan occasionally cuts in.
I put a thermometer in the water coming out of the bleed hose and that was reading only 80 degrees.

What to do next?

Hi des hav ya thought of the senser? could be!

 

[rugchucker]

Hi, yup changed the sensor, no change

 

[mikey72]

Mine didn't get overly hot, as I used to switch the fan on when the gauge started to creep up, under load. I did stick another remote thermometer onto the thermostat housing, it read about 60 to 70 on the outside, but 90 to 100 on the gauge. You've replaced everything I did so far, what's the head gasket like?

 

[rugchucker]

Hi Mikey
So far the head gasket is holding good, but if I dont cure it soon I'm sure the gasket will let go.
Today I am going to bang some rad flush in, the radiator is new I'm just hoping that it wil clean any blockage in the engine or pipework,
Driving home from work yesterday it didnt overheat on the 5 mile trip home, the gauge stayed rock steady in the middle so maybe I'm getting there.
Des