2.0 BlueHDI OBD water temperature readings, do we all read the same?

[Saragon]

Hi everyone,

first off I want to say this is not a Water Pump failure post.

Me and another owner (both with SpaceTourer manual gearbox) have noticed that the OBD Water Temperature reading is generally around 100ish degrees, while sometimes it drops to 82-83 degrees, and it doesn't seem to be related with the drive style or roads.

Water pump and Thermostats changed, no differences.

I've been suggested there could be air in the Water system, any idea? Does any of you perform OBD readings and what does it say?

Thank you in advance!

[GiveMeABreak]

I'd ignore it - that may be normal until you get a warning. These can run at quite high temperatures and on some engines the temperature threshold for the STOP warning illumination isn't until 118 °C and 115°C for it to go off.....

The low speed fan will be on anyway if you have the climate control on Auto as this operates with the A/C on, generally at 97 °C. High speed fan will kick in at 103 - 105°C.

This isn't specifically for your Spacetourer, but just as an example.

[Dormouse]

OBD "live" readings should be exactly what the onboard ECUs are seeing - you are normally only piggybacking the signals if you are using a standard OBD reading device.
If you have done the thermostat and the water pump then air in the system could be an issue. Put "bleeding radiator" or "bleeding heater" in the Search section in black at the bottom of the blue banner bit at the top of the page. You might need to refine the sections devoted to your make and model.

Bear in mind that the instrument panel temperature gauge is slow reading while the obd signals are live and quick reading.

[Saragon]

Thank you, I'll pick up both suggestions!
Strange that the fan doens't kick in, could it pick up temperature from its own sensor? Cause the temperature sits between 97° and 101° but fan never turns on (unless I have A/C on).
About the reading speed, the OBD temperature is quite stable, and the instrument panel also stands flat at 90°, and it's supposed to be so under certains limits, not-to-worry the driver, as long as I know. The strange thing is that the other owner using OBD like me, says it's been sitting at 82° for the first 50k miles, then started the dance, and mine seems to be following the same path. I'm just afraid it could be a common hidden issue of these engines. Hope somebody else has performed OBD on this engine, to have more data and match them...

[Mihael_M]

I had a 2.0 Hdi engine and I measured it with an OBD device. The temperature was always around 83 C. This is normal since the thermostat for that engine is of that value. The gasoline engine has a thermostat of 89 C. Did you put the appropriate thermostat. The temperature should not go that high. You should check if there is CO gas in the antifreeze. This is easily done in the garage with some device .And if there is, then it means that gases from the engine enter the antifreeze and it needs repair.It is possible that the head gasket was damaged .

[Saragon]

Thank you Mihael,

Ok I'm going to perform this at the garage and see what happens. Anyways today I've found something new... If I start driving faster it drops down around 85°, while slowing down it goes back up. Could this be a normal behavior? Mine is a Euro6 model and I know they have to be hot in order to keep emissions low. My thermostat is electronically controlled by the way

[kantica]

I think on that BlueHDI engine thermostat opens at around 98°C. On older engines like mine 2.0 HDi 165 (RHH) thermostat opens at around 83°C. I did this OBD measurement two months ago (while changing cooling fluid) and it was hard to bring the engine above 83°C while driving. At rest it would need 5 min reving up to 3000 RPM to bring it to 95°C (with environment temperature around 35°C). So I would think that your engine should run around 100°C ...

[Mihael_M]

Sorry, my 2.0 Hdi had that thermostat of 83 C. And Spacetourer one with 98 C. The thermostat is good and suitable, but then the temperature should goes around 98 C. You should still check the CO gas value. It's a simple test.
https://www.autodoc.co.uk/quinton-hazell/23141296

[Saragon]

All right, so there's a difference between HDI and BlueHDI as the second has a different thermostat. Got this. I'm going to bring it at the garage this friday for a temperature and CO gas value check, and see what they say. It's an official Citroen dealer so they should know what to do, but the mechanic seemed to have no idea about the temperature of my van, said it changes depending on engine. May make sense seen what you say.

[Mihael_M]

Your engine has a thermostat with 98 C. If the temperature is around that, then it's fine. I think 110 C is a lot. If they do a CO test in the garage and establish that there is no CO in the antifreeze, then the engine is fine , and you don't have to worry .

[Saragon]

Thank you Mihael, never had 110, usually it stops at 105 when forcing the engine, as if the thermostat opens fully at that temperature. In normal usage goes 97 to 101, so definitely around 98. I'll keep you updated on what the garage says

[Saragon]

Hi everyone, I want to give you an update, hoping this can help somebody else.
Today I brought the van to the garage and discovered a few things:

- no Co in liquid (thank you Mihael)
- the head over there had no idea what the temperature should be but performed a temperature test and said the water was between 94° and 97°. When it reached 97, the fan kicked in (as GiveMeABreak said) and brought it back to 94°. Quite different than my OBD measurements, but sounds familiar.
- He performed the same test on another engine like mine (not a SpaceTourer but another 2.0 BlueHDI Citroen) and got the same results. Good to hear.
- I read in another thread of this forum (here the link: viewtopic.php?t=66155 ) saying that Euro5 engines have a "special Thermostat" that use to keep temperature high to get low fuel consumption and low emissions, until the engine is heavy stressed, and in that case it drops the temperature down to 82°. So, coming back home, i stressed the engine (I went on highway with hot engine and gave full gas for around a mile at least) and the magic happened: temperature dropped down to 82°. Unless i stopped pushing, and immediately went up again. In the Euro5 models, this thermostat is "hybrid", mechanically moved, while in Euro6 like mine there are 2 thermostats, a mechanical one that opens at 82° and an electronic one that opens at 98°, but the second one fully opens in case of engine stress, leaving the mechanical thermostat alone, getting the job done.

Now I don't know why their measurements are different than mine (94-97° garage vs 97-101° mine), I suppose we're all reading a Ohm signal instead than a number, and each OBD/diagnosis translate in a slightly different reading, if anybody has an idea, it could be good to know, but the main purpose of understanding that high temperature is at least (for me) satisfying.

Thank you everybody for your help!
Iuri