xantia cooling efficiency uphill

[John Plum]

Hello Citroen drivers;
I need to look into a cooling efficiency problem. , and want to list the potential - and most likely areas for examination. I'd be grateful for your input on this.

Symptoms
--------------
At high atmospheric temp, say the recent 25 degrees C, when going up a motorway hill at 70 mph the tempreature rises to above 90 and wants to keep rising; I had to ease off a lot to get to Scotland, onn all those hills. At about 16 C, it seems much better, holding a steady 85 C on hills, more or less.

I also noticed last December, towing a 800kg trailer (caravan), the temperature rose in much the same way.

The two fans come on OK. The water pump turns OK (examined at cambelt change). The cabin heater runs hot OK - No apparent airlocks.

History
------------
I replaced the radiator, unfortunately with a non-genuine citroen - three years ago, and have kept it filled with distilled water and about 50% of best red antifreeze. I have yet to rinse out the radiator.

Possibilities
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- At the moment I can only suspect the radiator - thinking that this patterned version is not quite up to the job: have you had such experience?
- Perhaps there is another bit of ancilliary technology I need to look at, like the thermostat, or something more arcane?

Cheers guys,
Plum.

[addo]

Do you lose any coolant?

[VertVega]

At high atmospheric temp, say the recent 25 degrees C, when going up a motorway hill at 70 mph the tempreature rises to above 90 and wants to keep rising; ...

I think this is not normal in Xantia, at least not in petrol Xantia.

In mine 2.0 16V Estate it used to be between 70-90 degrees while driving motorway speeds during summer. Even during very hot temperatures 38-40 deg (In Greece) and motorway speed 130 km/h (80 miles/h) didn't move the temperature gauge above 90 degrees.

- Thermostat wrong one?
- Aircondition cooler (in front of radiator) does not let enough air flow?

[VertVega]

One more thing, When both fans are running, do they switch to faster speed or spin in slow mode?

[Stempy]

When you added the red anti freeze did you make sure all the blue stuff was flushed out first?

[Xantidote]

Temperature gauges aren't always accurate. What indicated temperature do the fans cut in at?

I see you're driving an automatic - is the transmission oil level OK? It might run hotter if the level's on the low side

[oscar]

Hi also how good is the auto box? as if theres alot of work with for it to do with worn bands etc it can run hotter as it's a friction plus if you need to drop down a gear use the lever not kick down as that puts a lot of strain on internals.
got told that by an auto box specialist that built custom valve chests and boxes.plus another saver is if running around at lower speeds like in town 30's leave in 3 as many just stick and leave in drive but what happens it will change up when pedals light but then has to change down when re applying throttle and all this has to be cooled found out when i had an auto car found many ways to save on fuel.

Have a look also at box fluid see what colour it is and if burnt smell as it does get "hot" when working but see if it's that that's not getting cooled enough of getting or if worn will be running hotter so will send to rad which will make rad hotter.
Aircon esp when towing will make temps climb as shifting heat in front of water rad not a massive rise but some.

Also have a peek in header tank for the ole air bubbles when gaskets going as mine creeps up on hills as it has a slight weep inside somewhere but if keep sensible don't worry me it pressures it a bit if bit heavy with R foot.
what you can do to check is brim header tank right to lip with it running then see if any there as could be only slight leak but under load with hiher resistance from hill/load will send into water way as gets easier then more the gasket fails.

One other thing that many do is replace water pumps with after market ones and vauxhalls esp suffer with that as seen many that have steel impellers that sit away from housing the OE's are an alloy impeller which is shaped flush bit like a screw what the A/Market one does it cause water to cavitate at high rpm's whipping up the water and not circulating the water round and over pressurising the cooling circuit.

[Dommo]

My XUD does this too, upon going up a fairly long and very steep hill near my house at a fair rate (not full throttle though) my coolant temp reached 105 degrees and oil temp was 130 degrees, needless to say I put the heating on full hot and flicked the AC switch so the fans come on (but the AC doesn't work so the AC rad didn't add any heat to the system). It soon dropped down but it does seem very well affected by heat.

I do have an undertray too, do you? I don't know if that helps or hinders, it's supposed to help but I'm not convinced.

[Mandrake]

The fans should come on in low speed mode at around 97 degrees, if you're at 105 degrees and you're having to turn the A/C on to make the fans come on something is wrong with the fan control system! Are you sure the fans are working in low speed mode ? The A/C only puts the fans on in low speed mode (unless the pressure in the A/C system is too high from over heating, which rarely happens) and they should already be in low speed mode at 97 from the coolant temperature alone.

[isisalar]

Nice to hear of a XUD auto on the road, similar to my old n/a one. I would not be particularly worried if it heats up on hills as long as the fans come on and cool it down ok. Sat in traffic it would also heat up, similar situation on long hills, engine working hard, lower airflow, engine heats up, fans cut in and cool it down, all how it should be.
The gearbox will certainly need its fluid changing at the very least if it hasn't been done recently. At that milage a dose of Lube gard wouldn't be a bad idea either. These boxes can last very well but not if you ignore them.
Cheers
Paul
Edit
I've just noticed your towing as well, this makes the above re fluid etc even more important. If your towing a caravan an additional oil cooler is almost essential to keep the oil cool enough to work properly. It's not that much of a job to fit one IIRC.

[andy5]

Are you certain the radiator fans are working?

This sounds exactly like my car, and mine aren't.

I have had to open the windows and turn the cabin heat and fan fully up to high a couple of times when towing uphill or stationary for a while. This will keep it manageable, about 95 when stationary, 100 on longer hills. And even before that I think it will run a bit cooler with the air conditioning off.

In the past, the thermal switch to change fan speed has been replaced or cleaned, and I assumed it was the same again, but I'm told this time it's the fans themselves

[oscar]

Hi with engine running? try pulling one of the plugs on top of thermostat housing and fans should come on full watch how they spin up as one could be lame as if hesitating it needs changing they do seize up one thing i do is once in a while pull plug off and let them spin for a while so grease in them gets moved around so less inclined to seize as heat from rad etc dries it up.
I think you can pull blades/spinner off so can blob a bit of grease back in motor shaft there a brushless motor.
Behind grill there the black box that has fan relays in for half speed etc sometimes get corroded from being stuck out in the weather/muck

[John Plum]

This is all good advice. I'm going to observe closely, before I write back.
Meanwhile, I. Can report:

Fans come on at low and high speed; whilst standing still, engine running, the temp rises to about 95 and fans kicks in;

• - Revving hard it goes onto full speed; I have heard this whilst driving too.
  - Suggests thermostat is Ok too
  - I have topped up coolant and bled carefully; shall observe for loss.
  - It had been losing earlier on, but suspect due to removal of bottom hose - seems better since care to clean up that joint.
  - I didn't clean out blue antifreeze b4 adding red, because I filled with red the radiator when brand new.

I think an extra oil cooler may be useful.

ATF: My service notes indicate it is about time for replacement; when last done there was no sign of burnt oil.

• - Yes, ATF may well be on low side .

Head Gasket detoriation and Air in water galleries:

• - I may have seen some small amount tiny bubbles in the coolant header tank -
  - Difficult to be sure due to vibration and, a little scale frothing there.
  - There is no mayonnaise.
  - I imagine a compression test is not so simple.
  - Shall keep observing, maybe get a well experienced XUD eye on it.

The symptom of heating up on motorway hills which I reported occurred with Aircon both on and off.

I did ease off when temp guage hit 95 C, (recalling when towing trailer last winte)r.

• - Should I have just drove on and maybe seen the temperature eventually come down after going above 95c
  - What temp is it safe to run at

Water pump is original manufacturers.

Thanks, John

[oscar]

Hi sorry to be one of bad sounding tidings! but that does sound like the start of head gasket going(you don't really get mayonnaise unless really bad nore in oil) but when like that you get pin bubbles in header tank whats the pressure like on hoses/tank?
Mines been like this for few years now as long as sensible it can last for years i used some K-seal which has i guess held it off.

you could try the high water tank job like they use for bleeding system something like a 2liter bottle with the bottom cut off so that becomes the highest point then you will see clearly if bubbles at all just need something to fit tank hole so sealed.
One easy one is find an old cap then modded it like drill through it then slide a tube through it glue it in so nothing escapes round sides or out of cap make sure what ever you stick through cap is flush to inside of cap so not below level or bubbles will build up below but above pipe/outlet.
find something say like a bottle or bag type say something like what they connect you to when on a drip in hospital type or leg/night bag or whatever you find then glue a piece of tube/hose maybe piece of brass tube that the outside hose can fit over then fill h/tank right up then use modded cap then with bag half filled hang up on bonnet or willing helper then then fluid in the bag/bottle or whatever will fill to tank then any bubbles/air will rise to bag so purge system or see if making them.

might have a look round myself see what i can find to make one?

[John Plum]

try the high water tank .... something like a 2liter bottle .... to fit tank hole so sealed.....One easy one is find an old cap....then slide a tube through it glue it in....flush to inside of cap...then glue a piece of tube/hose maybe piece of brass tube that the outside hose can fit over...

Thanks for that idea Oscar... I'll keep a look out to gather those things.