Goce's 06 twin turbo diesel peugeot

I've only just seen this and would like to thrown 2 cents in. From the 1st post
" the first 50km was fine but then temp gauge started to drop and engine oil temp went up "
Most engines have the temperature gauge in the wrong place which is at the top of the engine. What happens if you have a leak is that the coolant level drops and leave the temp. sender dry. It will still work though as the remaining coolant boils off as pressurised superheated steam maintaining a reading which will read low then drop completely,(usually shortly before seizure).
The oil temperature rise,(if you have a gauge ),is a dead giveaway as the oil is absorbing extra heat that the coolant would normally remove.
If you have a leak in the cooling system and it is internal and you have to run the vehicle that is the only time I would advocate running without a pressure cap and you have to watch that temp. gauge and top up frequently.

Whenever I build up a water cooled engine I relocate the temperature gauge to the bottom radiator tank and fit a level sensor connected to a buzzer where the original temp. sensor used to be.
There are operators, drivers and steerers in the commercial sector. That we should ever be so blessed as to have a fleet worked by operators.
 
NortonDommi said:
I've only just seen this and would like to thrown 2 cents in. From the 1st post
" the first 50km was fine but then temp gauge started to drop and engine oil temp went up "
Most engines have the temperature gauge in the wrong place which is at the top of the engine. What happens if you have a leak is that the coolant level drops and leave the temp. sender dry. It will still work though as the remaining coolant boils off as pressurised superheated steam maintaining a reading which will read low then drop completely,(usually shortly before seizure).
The oil temperature rise,(if you have a gauge ),is a dead giveaway as the oil is absorbing extra heat that the coolant would normally remove.
If you have a leak in the cooling system and it is internal and you have to run the vehicle that is the only time I would advocate running without a pressure cap and you have to watch that temp. gauge and top up frequently.

Whenever I build up a water cooled engine I relocate the temperature gauge to the bottom radiator tank and fit a level sensor connected to a buzzer where the original temp. sensor used to be.
There are operators, drivers and steerers in the commercial sector. That we should ever be so blessed as to have a fleet worked by operators.
Click to expand...

I've dealt with a lot of cars, they all behave the same when overheating but this one is very different, despite being fully computer controlled it shows no indication that is overheating, no power loss, no noise, smooth, quiet, very different than any other engine. Vehicles of its age first thing they will show is a warning and go into limp home mode, not this one it still had all its power. You can see where they located the temp sensor on the side and top of the engine on a rubber hose, stupid design. I thought of relocating it but i don't want the ECU to freak out. You can see the only temp sensor circled in red.
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French engineers in general do weird stuff with engines like backwards numbering but I have to admit those Peugeot Diesels are rock solid powerhouses. The point I was trying to make was that a temp. sensor up high in the system is a recipe for disaster if there is a coolant leak. Relocating the sensor to a place it can do its job means nothing to the ECU as all the ECU wants is a clean signal and the temperature gradient across the radiator is not huge. If some real thought was put into the cooling system then low temperature coolant would be put into the head and then made to flow through the block. In a pressurised system the radiator doesn't care which way the coolant flows, up, down, sideways it doesn't matter.
That is an awesome job you are doing. I have a friend who had a similar Peugeot sedan and what a lovely long distance cruiser. Very relaxing to drive in cruise mode but had a flip side if you decided to drive aggressively. Posh sleeper is an good description.
 
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On the older engines relocating sensor was easy there are threaded plugs, places to drill and thread on the block and the cylinder head, but on this engine there is nothing, the block is double wall so there's no easy way to place it in a coolant passage.
 
The coolant temperature sensor has only one function and that is to measure the temperature of the coolant. It can only do so if immersed in the coolant. The easiest way is to Braze a fitting onto the bottom tank of the radiator or if it is a cross flow one into the lowest point of the cold side. As long as the sensor is at a low point it will be immersed even if there is leak and will give a true reading.
If the sensor is up high and the coolant level drops the sensor drops out of contact with the coolant and reads low, it will rise again slightly due to steam right before damage occurs.
What you observed with the temp. gauge reading low and the oil temp. high is the classic example.

We are engineers and our job is to make things right - right?
 
NortonDommi said:
The coolant temperature sensor has only one function and that is to measure the temperature of the coolant. It can only do so if immersed in the coolant. The easiest way is to Braze a fitting onto the bottom tank of the radiator or if it is a cross flow one into the lowest point of the cold side. As long as the sensor is at a low point it will be immersed even if there is leak and will give a true reading.
If the sensor is up high and the coolant level drops the sensor drops out of contact with the coolant and reads low, it will rise again slightly due to steam right before damage occurs.
What you observed with the temp. gauge reading low and the oil temp. high is the classic example.

We are engineers and our job is to make things right - right?
Click to expand...

An old car I had some years ago would irregularly lose coolant and the temp gauge would stay normal. I fitted a second sensor on the bottom tank and whenever the lower gauge reading was higher than the top one, I knew I had a problem.
 
Today i started my work in the big garage very early in the morning and started with bolting on couple of seat belts on the engine so i can attach my engine hoist. Then came the 6 hours struggle to install it in the car, there's a lot of hoses and cables that need to be attach mid way in the installation. Who ever thought installing a V6 in a front wheel drive car is a good idea was wrong, there is absolutely no space to spare. By the time i was finishing for the day i've seen some water at the door but i did not hear any rain looked out and there is alot of snow. All winter we did not have any snow and now snow in april.
IMG_20200401_175407.jpgIMG_20200401_175415.jpgIMG_20200401_210158.jpgIMG_20200401_210209.jpgIMG_20200401_210239.jpgIMG_20200401_210530_1.jpgIMG_20200401_210703.jpg
 
Wow, that's a big job.

You sure have to hope you didn't miss one connection part way, it looks like there is no room to work around that engine!

Thanks for posting!
-brino
 
Downunder Bob said:
An old car I had some years ago would irregularly lose coolant and the temp gauge would stay normal. I fitted a second sensor on the bottom tank and whenever the lower gauge reading was higher than the top one, I knew I had a problem.
Click to expand...

There is one thing you are forgetting, this is a modern car, it is computer controlled and its ECU wants the engine at 90 degrees celsius to run correctly, the thermostat only opens when the temperature is more than 90 degrees, often when moving the radiator is stone cold, i've had check engine lights on other vehicles because engine temp too low.
 
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