Citroen Berlingo 1.9D 54 plate - 'Unsolvable' over-heating problem! - mss1tw

I promise this one will tax your grey matter more than radio code questions and bumping down kerb and pothole worries...;-)

I did get some suggestions in another thread but will keep the two seperate as that was a braking problem that is now solved.

The problem is that the temperature quickly rises on the motor way at or over 70mph. Around town is fine.

This morning I changed the radiator hoses and thoroughly bled the system.

I just took it for a run up and down the M3 and thought it was solved, but no, the temp eventually started creeping towards 100. Once it gets there, it takes quite a while to come back down even coasting and blipping the throttle to maintain coolant flow.

I managed to stabilise it at 65mph, bang on 90C.

What I have tried so far:

  • Numerous thermostats and coolant changes.
  • Upper and lower radiator hoses
  • New radiator fitted in January (It is a Nissens part - anyone in the trade care to comment if these are OEM quality?)
  • New water pump fitted last month. (Symptoms matched loose impellor exactly, but the old one was fine)

My next move is to measure the oil temperature on the motorway as I wonder if the cooler has failed/blocked up inside.

The only other things I can think of are

  • that the radiator is no good, but it gets very hot all over it's surface and must therefore by definition be 'radiating' heat.
  • The coolant temperature sensor is faulty - although it accurately reflects warm up temps and it is possible to 'see' when the thermostat opens.

Is there any way of measuring cooling system flow rate?

The oil is 5w40 and changed every 5000 miles. No mayo or obvious signs of HG failure.

Such a frustrating problem considering the basic design of this engine.

Edited by mss1tw on 25/09/2014 at 13:26

Citroen Berlingo 1.9D 54 plate - 'Unsolvable' over-heating problem! - Railroad.
The only thing I can think of is that coolant may not be circulating at higher engine speeds. You've already changed the water pump and the thermostat, but I would ask is the replacement thermostat a double stage type? These are recognisable by the circular disc at the bottom. This disc opens a bypass port when the thermostat is closed, and closes the bypass port when the thermostat opens. Its purpose is to allow for even cooling and eliminate engine hotspots. If the bypass port were to be open when the thermostat is open coolant would take the easy option and would not flow through the radiator. If this was happening it would explain your problem. I would remove the thermostat, cut a short length of 15mm copper pipe, and then cut that piece lengthways to give you a piece of copper. Hold the thermostat open in a vice and wrap the piece of copper around the spindle so that the thermostat is held fully open. Then refit the thermostat making sure as you do the disc is closing the bypass port. Coolant will now have nowhere to go other than through the radiator. Refill the cooling system and go for a test drive to see if the problem is cured. If it is then you know where to concentrate your efforts.
Citroen Berlingo 1.9D 54 plate - 'Unsolvable' over-heating problem! - mss1tw
The only thing I can think of is that coolant may not be circulating at higher engine speeds. You've already changed the water pump and the thermostat, but I would ask is the replacement thermostat a double stage type? These are recognisable by the circular disc at the bottom. This disc opens a bypass port when the thermostat is closed, and closes the bypass port when the thermostat opens. Its purpose is to allow for even cooling and eliminate engine hotspots. If the bypass port were to be open when the thermostat is open coolant would take the easy option and would not flow through the radiator. If this was happening it would explain your problem. I would remove the thermostat, cut a short length of 15mm copper pipe, and then cut that piece lengthways to give you a piece of copper. Hold the thermostat open in a vice and wrap the piece of copper around the spindle so that the thermostat is held fully open. Then refit the thermostat making sure as you do the disc is closing the bypass port. Coolant will now have nowhere to go other than through the radiator. Refill the cooling system and go for a test drive to see if the problem is cured. If it is then you know where to concentrate your efforts.

Thinking along similar lines, a while ago I did try cutting several slots in the surround of the thermostat with a Dremel, and re-installing it. This did keep the temperature more under control for a bit, but it still crept over 90 eventually!

Citroen Berlingo 1.9D 54 plate - 'Unsolvable' over-heating problem! - Railroad.
Cutting slots in the thermostat will achieve nothing, just as neither will removing the thermostat altogether. As I said before, it is imperative that the bypass port is closed off when the thermostat is opened, otherwise the coolant will take the easier option of returning to the block via the bypass instead of through the radiator, resulting in overheating because engine heat will not be dissipated.
Citroen Berlingo 1.9D 54 plate - 'Unsolvable' over-heating problem! - mss1tw
Cutting slots in the thermostat will achieve nothing, just as neither will removing the thermostat altogether. As I said before, it is imperative that the bypass port is closed off when the thermostat is opened, otherwise the coolant will take the easier option of returning to the block via the bypass instead of through the radiator, resulting in overheating because engine heat will not be dissipated.

Thanks railroad - this is something I had not considered as the radiator does get very hot so assumed the flow was OK, but what you say makes sense

Citroen Berlingo 1.9D 54 plate - 'Unsolvable' over-heating problem! - Cyd

Sounds like a blockage in the flow somewhere.

Have you had any problems with corrosion in the coolant at all?

Have you tried flushing out the coolant circuit with a hose?
Do each component seperately - the heater matrix is often a culprit because the coolant entry and exit are at the top and so any deposits settle into the bottom of the matrix.

After a thorough flushing use a double dose of proprietry cleaner in water only.

When you refill, use deionised water to prevent any possible scale deposits forming.

Citroen Berlingo 1.9D 54 plate - 'Unsolvable' over-heating problem! - mss1tw

Sounds like a blockage in the flow somewhere.

Have you had any problems with corrosion in the coolant at all?

Have you tried flushing out the coolant circuit with a hose?
Do each component seperately - the heater matrix is often a culprit because the coolant entry and exit are at the top and so any deposits settle into the bottom of the matrix.

After a thorough flushing use a double dose of proprietry cleaner in water only.

When you refill, use deionised water to prevent any possible scale deposits forming.

I've only owned it for just under 3 years, although in that time it has had numerous (4 or 5 now, I think) coolant changes! I always use de-ionised water myself, and requested that when the garage did the most recent waterpump/TB change, they used it. Said no-one normally asked for it, but they had some they were happy to use!

The heater does provide a steady flow of hot air, if that was blocked I'd expect that not to be the case?

A clean and flush is the next thing on the list, then - any recommended products?

Citroen Berlingo 1.9D 54 plate - 'Unsolvable' over-heating problem! - Cyd

yes, this
http://www.ebay.co.uk/itm/325ML-WYNNS-COOLING-SYSTEM-FLUSH-GOOD-FOR-OIL-RESIDUE-HEAD-FLUSH-WY45944-/321060956976?pt=UK_Vehicle_Oils_Lubricants_Fluids&hash=item4ac0b96b30

It does sound like it probably isn't a blockage, but you don't know how the vehicle was treated before you got it, so you can eliminate this as a cause by a thorough flush and clean. It's easy and cheap enough to do on a diy basis. You just never know, there might be a slug of corrosion product in a small waterway in th head that simply isn't moving in normal use. It'll also ensure there is no scale layer hitting the heat transfer from metal to water.

I'd use a double dose and run it for a week. I kept it in my Dispatch HDi for a fortnight and it made a very good job of cleaning it up.

Of course, there could be a casting flaw causing a restriction - it might have been like this from new??

the other suggestion of checking the bypass system sounds good too.

Citroen Berlingo 1.9D 54 plate - 'Unsolvable' over-heating problem! - mss1tw

Cheers Cyd

Citroen Berlingo 1.9D 54 plate - 'Unsolvable' over-heating problem! - mss1tw

Is there any way the fueling/igntion side of things can affect temperature? I know diesels can't run lean, but thought it worth asking.

Citroen Berlingo 1.9D 54 plate - 'Unsolvable' over-heating problem! - Wackyracer

I once had a similar problem after changing a radiator and thermostat, The new thermostat was faulty. I eventually went to Toyota and bought a genuine thermostat and that cured the problem.

Citroen Berlingo 1.9D 54 plate - 'Unsolvable' over-heating problem! - mss1tw

Apologies for the bump - I've just had a thorough look over a Citroen parts CD I got hold of looking at every part of the cooling and air flow system, and saw this little thing:

Part code 1308 V4 air grille

i583.photobucket.com/albums/ss275/chronyx/a_zpsd2f...g

It's missing from mine - is it a long shot that this could cause the problem? :-/

It's a pointless looking thing but as it's not a styling exercise (Hidden behind the bumper etc) they must have put it there for a reason.

Cheers all

Edit: Copied the exact screenshot and posted

Edited by mss1tw on 27/09/2014 at 20:06

Citroen Berlingo 1.9D 54 plate - 'Unsolvable' over-heating problem! - elekie&a/c doctor

Nissen rads are fine.Does the car have a/con?

Citroen Berlingo 1.9D 54 plate - 'Unsolvable' over-heating problem! - mss1tw

Nissen rads are fine.Does the car have a/con?

No A/C on this one, Doc. Just a 2 speed fan.

Please see my post above as I'd welcome your input re: this seemingly insignificant part!

Citroen Berlingo 1.9D 54 plate - 'Unsolvable' over-heating problem! - elekie&a/c doctor

I doubt if this vent will make any difference. Overheat under load or at speed tends to suggest lack of heat disipation.Does the new rad have the correct depth "core"?Also may be an idea to get a combustion test done on cooling system,just incase the system is being pressurised /heated by combustion process.Just a few ideas.

Citroen Berlingo 1.9D 54 plate - 'Unsolvable' over-heating problem! - mss1tw

I doubt if this vent will make any difference. Overheat under load or at speed tends to suggest lack of heat disipation.Does the new rad have the correct depth "core"?Also may be an idea to get a combustion test done on cooling system,just incase the system is being pressurised /heated by combustion process.Just a few ideas.

Yes the dimensions are correct as far as I can tell. I did wonder if an uprated rad from a more powerful one might fit!

A headgasket check is next on the list (after doing a few suggestions from here!)

Edited by mss1tw on 27/09/2014 at 22:37

Citroen Berlingo 1.9D 54 plate - 'Unsolvable' over-heating problem! - mss1tw

Happy Christmas all,

I posted this a while ago, and now the colder weather has arrived, the gauge now indicates only 80 celcius while driving around town even with the heater off. (Please bare in mind this is not a superbly economical modern diesel, and did not do this when I first bought it several years ago)

So the bizarre thing is that it now seems to be under-reading at colder temperatures, but still wants to get hot on the motorway, although as the ambient temp is now so much lower, it does not get up to 100+ like in the summer.

Bascially, the temp gauge seems to want to sit anywhere apart from the usual just under 90 it used to.

Does anyone think this could be a faulty temp sensor, or a bubble of air around the sensor itself causing such exagerrated readings, whether high or low?

Citroen Berlingo 1.9D 54 plate - 'Unsolvable' over-heating problem! - Peter.N.

Is it possible to remove the thermostat and try it? if it still runs hot without it the problem has got to be either restricted circulation or a faulty radiator. Without the thermostat it should run almost cold, if it does your new thermostat must be faulty.

Citroen Berlingo 1.9D 54 plate - 'Unsolvable' over-heating problem! - madf

Water pump broken impellers/corroded.

Citroen Berlingo 1.9D 54 plate - 'Unsolvable' over-heating problem! - mss1tw

Water pump broken impellers/corroded.

I wish - I had that replaced in the summer! :)

Citroen Berlingo 1.9D 54 plate - 'Unsolvable' over-heating problem! - mss1tw

Is it possible to remove the thermostat and try it? if it still runs hot without it the problem has got to be either restricted circulation or a faulty radiator. Without the thermostat it should run almost cold, if it does your new thermostat must be faulty.

Quite a while back I cut slots in the stat surround and re-installed, it still ran hot but took longer, so I put in a new one. Back to the same 'fault'.

I think I'm going to have to bite the bullet and buy a genuine Citroen rad. It's got a Nissen replacement in that's only a year old, but everything apart from the temp. sensor, small link hoses, the expansion tank, the oil cooler, and the heater matrix has been changed - often several times.

The radiator seems to get hot evenly all over, with no pressure in the hoses at 'normal' temps and it uses no coolant.

I was just pondering everything and wondered if a trapped air bubble could confuse the temp sensor.

Edit: Temp sensor has always and still does accurately reflect warmup interval and isn't one of the new 'sits at 90 regardless unless it's overheating' designs.

Edited by mss1tw on 27/12/2014 at 19:51

Citroen Berlingo 1.9D 54 plate - 'Unsolvable' over-heating problem! - focussed

Have you checked that the temperature sender is telling the truth?

Remove it, extend the wiring, dunk the business end it in 90 C water, turn the ignition on and check that it's reading correctly.

Citroen Berlingo 1.9D 54 plate - 'Unsolvable' over-heating problem! - mss1tw

Have you checked that the temperature sender is telling the truth?

Remove it, extend the wiring, dunk the business end it in 90 C water, turn the ignition on and check that it's reading correctly.

Good idea focussed, hadn't thought of that. Thank you

 

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