Jump to content


Photo

The Mystery Of The Vanishing Coolant


  • Please log in to reply
8 replies to this topic

#1 GoldPod

GoldPod

    16 LX Newbie

  • Members
  • Pip
  • 8 posts
  • Gender:Male
  • Location:West London

Posted 23 October 2018 - 03:13 PM

Hi There,

 

Sorry if this has been covered somewhere, I searched through the posts and cant find anything of any real use.

 

The car is a 2006 1.6 HDi 110. A few weeks ago after a couple of long journeys I noticed that there was some generalised steam in the engine bay, but no sign of any leak, the header tank was full, and it never happened again, so I assumed it was road water and rain splashed on to the hot engine.

 

However, I noticed since the recent colder weather that the heater wasn't very efficient. The rad top hose seemed "empty" so topped up the header tank (which was lowish) a few days ago, but aside from the hose feeling firmer there was no major difference to the heating.

 

Today there was less heat than ever. Checked and the header tank is still fully topped up but the radiator is very cool to touch, so I'm guessing I've lost most my coolant, but there is no sign of a leak anywhere (engine is still running fine).

 

As header tank is already still full and the water is not getting sucked into the cooling system, how do I get water into it so that I can try to search for the leak?

 

Any help is gratefully appreciated!


Jay


#2 stimulator

stimulator

    1.6 Cherry Red Metallic, wonder car

  • Members
  • PipPipPipPipPip
  • 9,532 posts
  • Gender:Male
  • Location:Waterlooville Hants
  • Interests:Model trains OO gauge. C3 Picasso, Grandchildren

Posted 23 October 2018 - 04:28 PM

Firstly hi.
By header tank I assume you mean the expansion tank that is mounted on the off side of the engine bay. This should be filled only to the line about half way up it. It's job is to accommodate the coolant that would otherwise overflow from the system once it gets hot.
The system consists of the water pump, radiator, thermostat, expansion tank fitted with the pressure cap and heater matrix.
When you first start the engine the water is cold so the thermostat is closed and water circulates round engine and through the heater matrix. Once the engine reaches operating temp the thermostat opens and the water can now flow through the radiator. It flows from top to bottom. . As the water is hot it will have expanded and some will be pushed into the expansion tank and the level will rise. The pressure cap causes the pressure in the system to rise, water boils at a higher temp at a higher pressure. If there is an overpressure the cap will release the excess and some of the coolant. As the pressure decreases as the engine coolant so the cap will allow air back in but the level will drop.
The heater matrix is fed with water all the time irrespective of whether the heater is off or on. A diverter flap just sends all the incoming sir around the matrix to give cold air, it's more efficient than turning the water on/off.
So what could be wrong with your car.
A) The HDi engine do run cool.
B) the pressure cap is not doing its job
C) there is air in the heater matrix, there are bleed screws on the hoses that go to the heater matrix, these are in the engine compartment by the bulkhead.
D) the thermostat is not working properly
E) there is air in the system there is a blue bleed valve on the thermostat housing.
F) the water pump is worn however you get serious overheating if that was the case.
G) radiator fan is running all the time. The rad fan should run only when triggered by the heat sensor. This will usually be when the car is stationary as during movement the airflow through the radiator is enough to keep temp in correct range. However it also runs every time the sir on is switched on. This is because the air con condenser is mounted in front of the car rad next to the rad fan. It runs at slow speed during air con use. If while stationary the water over temps then the fan runs at high speed.
So there you are. List of what you need to check. I'd start by ensuring the rad fan is off when the engine is cold and the sir con is off..
17 Reg C3 Saloon Flair 1.2 110BHP
Previous Xsara Picasso 20HDi, C3 SX 1.4HDi, C3 SX 1.6HDI, C4 Picasso 1.6HDi VTR+ EGS 62 Reg C3 Picasso VTR+ 1.6 HDi 92BHP

#3 GoldPod

GoldPod

    16 LX Newbie

  • Members
  • Pip
  • 8 posts
  • Gender:Male
  • Location:West London

Posted 23 October 2018 - 10:17 PM

Many thanks for such a comprehensive explanation, some of this I knew - most I'll have to check in day light, but meanwhile a couple of questions and some further info…
Where is the thermostat located? I couldn't see a blue valve but then on a dirty engine by torchlight maybe it's not too obvious.
Yes by header I mean expansion tank; "full" = up to the line..
The rad fan seems to hardly run at all, but will check more carefully next journey.
Had to go out tonight, journey was 9 miles;
- from about 5 miles on wards the temp gage showed 2 bars
- The heating started working from about 3 miles and got reasonably warm by 7 - 8 miles.
- After the journey the Rad was mostly still cold, just a slightly warm patch near the top. The top and bottom hoses are still easily squashed and feel empty.
- The expansion tank was warm (not hot) water coolant level unchanged (still up to the line).

Many thanks for your help, I'll let you know when I have more info or made progress!


Jay


#4 stimulator

stimulator

    1.6 Cherry Red Metallic, wonder car

  • Members
  • PipPipPipPipPip
  • 9,532 posts
  • Gender:Male
  • Location:Waterlooville Hants
  • Interests:Model trains OO gauge. C3 Picasso, Grandchildren

Posted 24 October 2018 - 08:43 AM

The thermostat is on top of the engine where the top hose returns to the engine. It's under the engine cover, that black felt looking item the blue valve is on the thermostat housing.
Its usual for thesexenginevto only just illuminate 2 or 3 divisions on the temp gauge. Early cars it was 2 later they changed the calibration to give 3.
My Picasso's xsara 2.0 and 1.6 C4 Picasso always ran cool, heating was not good, to big an area of ductwork. The same engine in C3 saloons and C3 Picasso give fantastic heating, small ductwork runs. Some Picasso's have electric water immersion water heaters to help overcome this problem.
17 Reg C3 Saloon Flair 1.2 110BHP
Previous Xsara Picasso 20HDi, C3 SX 1.4HDi, C3 SX 1.6HDI, C4 Picasso 1.6HDi VTR+ EGS 62 Reg C3 Picasso VTR+ 1.6 HDi 92BHP

#5 GoldPod

GoldPod

    16 LX Newbie

  • Members
  • Pip
  • 8 posts
  • Gender:Male
  • Location:West London

Posted 24 October 2018 - 10:02 PM

Hi and thanks again!

 

Firstly, I can confirm the radiator fan is off when engine is cold (or quite warm even) and the aircon is off.
I still can't find the thermostat, see picture of the engine with cover removed, I can't see anything that matches your description -
Attached File  photo_2018-10-24_22-59-21.jpg   166.91KB   0 downloads
Also the top hose goes down the side of the engine and not the top -
Attached File  photo_2018-10-24_22-59-38.jpg   188.84KB   0 downloads
I mentioned the temp gage as it implies there is still coolant in the system somewhere even though the unpressurised top and bottom hose imply the radiator is empty.
My most immediate concern is to get some coolant back into the system - is there any way of doing this other than via the expansion tank as clearly this way isn't working?
It is important that some coolant is in there as I don’t want to be running it/driving the car with this empty, but most importantly I need to try to trace where the leak is.
How would a garage refill the system if they had to, there must be someway other than via the expansion tank?

Thanks for any further help. 


Jay


#6 stimulator

stimulator

    1.6 Cherry Red Metallic, wonder car

  • Members
  • PipPipPipPipPip
  • 9,532 posts
  • Gender:Male
  • Location:Waterlooville Hants
  • Interests:Model trains OO gauge. C3 Picasso, Grandchildren

Posted 25 October 2018 - 01:49 PM

Oh sorry about this my brain is aging faster than I can think. You have a 1.6HDi and my answer about bleed screws was for 2L HFI.

Anyway there is a thermostat but it is in the actual top hose at the engine block end. I have copied pages from a well known book but for C3 but same ENGINE 1.6HDi which I hope will help. Problem this site will only allow me to post images that are small as there is a limit and I just about at that. 

 

I have sent you a personal message OK .

 


Edited by stimulator, 25 October 2018 - 01:56 PM.

17 Reg C3 Saloon Flair 1.2 110BHP
Previous Xsara Picasso 20HDi, C3 SX 1.4HDi, C3 SX 1.6HDI, C4 Picasso 1.6HDi VTR+ EGS 62 Reg C3 Picasso VTR+ 1.6 HDi 92BHP

#7 GoldPod

GoldPod

    16 LX Newbie

  • Members
  • Pip
  • 8 posts
  • Gender:Male
  • Location:West London

Posted 26 October 2018 - 09:34 AM

Hiya,

 

Thanks again for your help! I have replied to your PM.

 

 


Jay


#8 GoldPod

GoldPod

    16 LX Newbie

  • Members
  • Pip
  • 8 posts
  • Gender:Male
  • Location:West London

Posted 01 November 2018 - 01:44 PM

Hiya Stim
 
Many thanks for all the info and help. Would've replied sooner but not been able to get onto the site.
 
After reading through all the info I've decided that at my age I'm not really up to the kind of work it'd require to dig around doing this, and have booked it into my local garage.  
 
I did try their suggested way of filling with a bottle through the expansion tank, but it doesn't want to cooperate.
 
Other than that, I must say it seems a bit daft that there's no other way of filling the cooling system, but I guess that's modern cars, and I don't see any old car returning a regular 60 mpg!
 
Thanks again

Jay


#9 stimulator

stimulator

    1.6 Cherry Red Metallic, wonder car

  • Members
  • PipPipPipPipPip
  • 9,532 posts
  • Gender:Male
  • Location:Waterlooville Hants
  • Interests:Model trains OO gauge. C3 Picasso, Grandchildren

Posted 01 November 2018 - 11:20 PM

Ok mate, hope that the garage can help..
17 Reg C3 Saloon Flair 1.2 110BHP
Previous Xsara Picasso 20HDi, C3 SX 1.4HDi, C3 SX 1.6HDI, C4 Picasso 1.6HDi VTR+ EGS 62 Reg C3 Picasso VTR+ 1.6 HDi 92BHP