V70: Engine Normal engine running temperature

[Richy Clark]

I have been having similiar thoughts but have rationalised as follows:

The engine has to heat up from a low temperature to I guess 80 to 90 degrees centigrade. This should be normal operation.

The engine temperature therefore has to pass through this 40 degrees to 60 degrees range. This is normal.

I am guessing that the onboard computer is not programmed to trigger a fault within these temperature ranges or the length of time it is at these temperatures as everything is variable, ambient temperature, driving style etc.

The thermostat is a mechanical device and I am not sure whether there are any sensors to pick up the fact that it is open at low temperatures (does anyone know).

As there are no faults recorded or applicable sensors then the garage is stumped, "the computer says no", and they are not inclined to get the stat out and put it on the hob to check it like we all used to do.

The only thing therefore that can pick up that there is something wrong is you and me? All made easier with my OBD2 reader of course.

[krzemien]

Your rationale seems correct.

My friends heartily advised me just to wear warmer jumper

In the view of that, lack of any warning messages etc. from the ECU and finally bearing in mind previously quoted proverb ("If it ain't broke don't fix it") I tend to agree with him

I will probably wait until the first heat wave, re-check this again and move it from there. So watch this space.

[Richy Clark]

Car has been booked in for service on Thursday 7th March.

[tt82]

Originally Posted by krzemien

But! This still puzzles me though, because:

* no indication whatsoever that there's something wrong - now I wish I had not bought this OBD reader the first palce (ignorance is bliss)!
* how come no one had spotted this during three car services at three different VOLVO dealers?
* how come car has gone well through emission tests during its first MOT?
* more importantly: I have read that in the case of DPF filters & low engine temperature regeneration might not start at all. I had no seen any issues with DPF filter - how's that possible?
* most importantly: if car seems fine after 30 months in the current setup, how is it going to react when its working operation condition will suddenly change?

• I'm struggling to think of how the car could realise that the coolant temp not getting warm would be an issue. There are so many facors that could effect it that it would be hard to come up with a fool proof warning system.
• I doubt that mechanics would notice this unless they took it for a test drive with VIDA/DICE plugged into it. They do a quick test drive but not far enough to get the engine fully upto tempature. Were they to do this they would have constant complaints about the added mileage and fuel usage.
• It's probably passed the emissions test as most cars will probably be tested with the engines not at operating tempature. Even for motoring enthusiast that take the car for an Italian tune up before the MOT, it would probably cool down whilst waiting or if the tester did other things and didn't do the emissions test first.
• Based on my understandings of the DPF, which may be wrong, my opinion is this - the DPF catches soot and when the exhaust is upto temperature, it burns the soot off. Even if your engine is not operating at the correct tempature, this should not greatly affect the heat of the gases coming out of the exhaust, only cooling them a slight bit so in theory, your exhaust should reach temperature enough for the DPF to work.
• I fail to see how the car should have any issues once it's working correctly, any changes are likely to be poitive in any effect, ie warm cabin, possibly better fuel consumption, cleaner emmisions.

[v2brett]

hi sorry for the delay in replying, i managed to log the engine temp on a 4 mile run to work this mornin (approx 10 mins driving) in that time it got up to 82c, no idea why intake hit 32c though?

[tt82]

Managed to get an app similar to torque on mine today and while going round the block the engine temp was between 87 and 90 degrees.

[GrantA]

Originally Posted by v2brett

hi sorry for the delay in replying, i managed to log the engine temp on a 4 mile run to work this mornin (approx 10 mins driving) in that time it got up to 82c, no idea why intake hit 32c though?

I've been following this thread for some time and yes the engine coolant temp of a diesel should be between 80C and 90C. If you think about it some engines, Mercedes for example, fit a heater to bring the engine temperature up quickly as the block (in most Mercedes) is made of cast iron and takes a long time to heat up. In Sweden Volvo and other vehicle manufacturers used to fit sump heaters for use in the winter so the engines could be (almost) at working temperature before you got into the car to go to work. Not sure if they still do that. I can't remember the details of the efficiency graphs I learnt as a young Marine Engineer but a diesel engine runs at its most efficient between 80C and 90C.

Oh and to answer your question v2brett the turbo, driven by exhaust gases, heats the air up that is why it is/was at 32C, I'm not sure if that temp was after the intercooler or before it. If you were stationary when you took the screen shot I suspect it was after the intercooler. Look at it again when moving and I suspect it will only be a couple of degrees above the outside temp.

[v2brett]

Cheers GrantA everyday is a learning day and i like to learn more things about cars all the time.
the readings in my shot are all max readings from the journey i did,
it would be good to start a thread which records readings so anyone monitoring there car can tell if everything is performing in the ball park were it should be

Also i think the maf figure can be used in a sum to roughly work out hp, not sure how this would work with Volvos though as im new to them

[GrantA]

Originally Posted by v2brett

Cheers GrantA everyday is a learning day and i like to learn more things about cars all the time.
the readings in my shot are all max readings from the journey i did,
it would be good to start a thread which records readings so anyone monitoring there car can tell if everything is performing in the ball park were it should be

Also i think the maf figure can be used in a sum to roughly work out hp, not sure how this would work with Volvos though as im new to them

Not sure how to work out the HP from the MAF but if you were stopped in traffic, even for a brief minute or two, with no air going across the intercooler the inlet temp will rise and 32C is not excessive.

I agree it would be a good idea to start a "Thread of Recorded Readings" but you must be careful, whereas your car might be running a "good" set of readings another car, not driven the same way as you drive, might give slightly lower or higher readings. If you were to use the readings purely as a guide it would be okay but outside air temp, height above sea level, air pressure, mileage, and a number of other factors can affect the engine's readings.

[Richy Clark]

Wow, such a lot of posts in such a short time. Thank you to you all.

My V70 is now in the garage for a service and also for them to look at this problem; they've had to keep it overnight 'cause they need more spares? I'm glad it's under warranty.

They've lent me a new V40 with a D2 engine and guess what? I plugged in my OBD2 reader and in less than 10 minutes it was up to 80 degrees. I'm going to log my journey to work in the V40 this morning to compare the traces.

Should have my car back later today?