Nightmare-ish XM ES9J4 coolant bleeding

[Raatokalle]

Hello everyone. First of all, sorry for my rusty english. I'll try to explain this situation as simply as i can. Im just having such a time with this car and i just don't know what to do anymore.

So i have this XM with ES9 V6 which needed new coolant radiator. Old was leaking a bit, and i got tired of topping it up every weekend. And because car has 380 000KM's in it, i decided to also change new thermostat as well as new temperature sensor(brown one). As i had no idea, when thermostat was replaced last time.
At this point, i want to also say before changing these parts, car was running fine. Maybe bit slowly warming in winter, but it got warm after a while. And in summertime i had no problems at all. Car would cool no problem at all both cooling fans spinning. Sometimes, totally randomly i got overheating warning althought running temperature was only at around 80-90C. Pretty certain it was only a false alarm, thats why i decided to change sensor as well.

Now that i have replaced radiator, thermostat and sensor, it was time for coolant system bleeding. If i understood correctly its pretty simple overall. Just put revs between 1500-2000RPM, open all four bleeding points and keep around 1 extra litre of coolant in expansion chamber while engine is running. Process is done after all air is out, BOTH of fans have spinned and warm air is coming in.

So i did that all and everything was going fine, air was coming out from system, and car was blowing warm air in to cabin. Temperature was precisely at 90 C when first fan started to blow. Around same time thermostat opened, system sucked almost all that extra coolant and no more air was coming out from the system. Nice, all i had to wait was the second fan to spin and i was DONE. Except it didn't. Engine didn't just get around 100-110C to get second fan running.

And at this point i started to have trouble. After waiting for some time, still only slower fan has blown few times, everytime at 90C. So i thought if i rev engine bit more than 2000RPM, maybe it will heat just enough and im sure both fans will start run.
Instead of that what happened, was coolant level started to RISE slowly in expansion chamber and all the sudden it simply blew everything up around engine bay.

At that point i had no idea what happened. According to temperature gauge, car didn't overheat. Temperature didn't really go much over 90C.
One thing that came to my mind was blown head gasket, but im not sure about that. System isn't closed so therefore it can't have too much pressure in it? And before changing parts i had no problems at all.

I bled system all over again few more times, first time it did same thing as said above but second time i didn't bother to rev it. After all air came out, i just let it idle and no problems at all. Except second fan didn't spin and that faulty overheating warning occured once, so i didn't even change right sensor.


Any ideas or thoughts what would be the problem?

[GiveMeABreak]

Hi and welcome.

I've checked the bleeding procedures and they are the same as for the later C4 and C5 X7; here is my post on the official procedures, which are the same for the XM V6:

viewtopic.php?f=3&t=61971&hilit=bleeding#p601625

[white exec]

That sudden rise of coolant level, and expulsion of coolant, would be explained by there still being trapped air in the system (an air pocket) causing localised boiling. With the system not being pressurised (pressure cap off), boiling would occur easily.

High-speed fan cut-in in some XMs does not occur until 100degC+, with slow-speed only operating at such temperatures.

Recommended thorough bleeding procedure involves the use of a temporary "header bottle" inserted into the neck of the expansion tank, in order to provide an additional head of liquid to expel trapped air from the bleed screws.

Mike here (xantia_v6) will be able to add extra detail, based on his V6 XM.

[xantia_v6]

The fan motors always spin together, so if one is spinning and the other stationary, there must be a fault, which could be a blown fuse, or a faulty motor, or a faulty relay or a wiring fault.

I have been running cars with ES9 engines since 2001, and have never had any trouble bleeding the cooling system, and have never needed to bleed with the engine running.

The ES9 is however a wet-liner engine, so is susceptible to head gasket failure if run with a significant quantity of air in the engine block.

If you have head gasket failure, it should be fairly obvious, and if not, you should concentrate on getting the fans running correctly.

[GiveMeABreak]

Info on Cooling System for Ref:

So the fans run together but at 2 speeds - low at 96° and the higher speed at 101° if I'm reading this right.

(1) Bubble trap. (2) bleed screw(s) . (3) Oil / water heat exchanger. (4) bleed screw(s) . (5) bleed screw(s) . (6) heater matrix. (7) bleed screw(s) . (8) temperature switch. (9) Water inlet housing. (10) Coolant outlet housing . (11) Temperature sensor . (12) Temperature sensor . (13) Header tank. (14) drain plug. (15) drain plug.

Click Table to Zoom

(*) Degassing chamber plug with violet marking (inscriptions on top).
N.B. : The 2 fans are controlled by the coolant temperature housing.

Reference	8	11	12
sensor	Temperature switch	Temperature sensor	Temperature sensor
Information	Coolant temperature : Gauge	Coolant temperature : Warning	Coolant temperature : injection
Connector colour	Blue	Brown	Green
Tightening torque (daNm)	1,7	1,7	1,7

[Raatokalle]

Huge thank to everyone of you! Always something new to learn.

Of course, i totally forgot that infamous fusebox in enginebay. Yes, F2 fuse(if i remember it correctly) was melted. Unfortunately i don't have enough time to test, if it was that what caused the problem.
If its not the problem, next im going to change fan motor. Can i borrow one from 2.5TD? According to citroen service, part number isn't exactly same tho(1253-52 V6 and 1253-29 TD).

About that sudden rise of coolant in header bottle. Before that happened, for few minutes there was no air bubbles coming out at all. Thats why i was really suprised how coolant just came all over the place at once. Thats why i was worried about possible gasket failure, but there isn't any other signs except that.

[white exec]

The famously overloaded XM engine bay F2 is for AC and cabin blower, where running current can be up to 25A.

The two radiator fans are each fused at the large maxi fuses (40A) in front on the engine bay fusebox.
If your fans are both working, then these will be ok, although a clean-up of the fuse contacts won't go amiss.
The low-speed/high-speed switching (fans in series and then parallel for the two speeds) is controlled by the bank of three 'cube' relays under the slam panel. Worth cleaning the base contacts on these too.

As your fans are obviously working, I don't see the need to replace them - just check the items above.

If you pull the connector on the Brown temperature sensor, the fans should first come on at slow speed, and then jump to high speed*. This shows that both speeds (i.e. relay action) are working. If you re-connect, fans will continue to run; simply turn on the IGN to reset everything back to normal. *A fail-safe arrangement, in case of sensor/control failure.

Temporary header bottle on 2.5 XM

A short length of old radiator hose can fit snugly into the neck of the header tank, and seal off the drain-hole at the same time.
Keep the bottle at least one-third full throughout the bleeding, and leave it in place as the engine cools.
Possible also to squeeze one of the large radiator hoses now and again to help expel air.
Air has only been fully removed when bubbles stop appearing in the header bottle. This may take some time, and workshop manual suggests allowing cooling fans to come on automatically at least twice before finishing the session.
Periodically upping the engine revs (c.2500-3000) will also encourage air out.

[Raatokalle]

Ok. First of all, big thanks for advices.

Now that im back in a garage i took another round with bleeding. Some success and some problems.

Lets start with good news.

1. Other fan not working was caused by faulty relay. Done. Now both work fine. And in both speeds.

Problems
1. Unlike earlier, now i don't even hit 90C before fans start to blow. Fans start now at 80C and in 2h of idling only once temperatures went to 90C.
Car is still blowing very warm air into cabin tho.

2. Im kinda worried about blown head gasket. Only symptom related is to it, is bubbles coming out when i rev.
But the thing is, it doesn 't do that all the time. For a long time i thought all air had come out, but all The sudden when i quickly rev'd to around 3000-5000rpm, some bubbles came.

And If i put it around, lets say example 2000rpm and let it sit there, no bubbles coming out.

Coolant doesn't smell like exhaust fumes either and exhaust fumes don't have that "sweet smell" either.

Gosh, im getting paranoid. Should just stick with BX's

[white exec]

Sounds like there could still be some trapped air in there.
If a leaking HG, I would expect the bubbles not to stop, but be being produced continually.
HG blow also usually shows up as
- coolant overheating
- coolant being thrown out, and level dropping, and continuing to drop
- coolant smelling of exhaust
and you don't seem to have any of those.

I know it's a different engine, but whenever I've had to bleed our 2.5TD (same procedure), revving the engine to 2000+ produces bubbles, which then reduce in number. Letting the hot engine idle again (fans cutting in and out periodically) only produces a tiny stream of bubbles, but upping the revs to 2000+ again produces more large bubbles. After 30mins or more of this, there are no further large bubbles, even at fast revving, and the job looks done. All the bleed screws (four on my engine) opened several times each; make sure you haven't missed any.

The whole bleeding procedure, from cold, can take at least an hour on the diesel 2.5.

Engine then allowed to go cold, header bottle still in place. Excess coolant drained out (lift the bottle slightly to expose the drain hole), and level set to normal.

Well done in getting both fans working. If they are cutting in at as low as 80C, then either the gauge is not showing accurately (not unknown - check with a thermometer on the water output housing on the engine), or the temperature sensor is faulty (cheap enough to replace).

Possible, too, that the coolant thermostat is faulty. Clue would be the cabin heater never getting really hot. Even if the cooling fans are coming on prematurely (and over-cooling the radiator), if the thermostat is working as it should, cabin heater (and engine block) should still get decently hot, but only if the 'stat is working properly. Again, hopefully cheap enough to replace.

Mike will be able to add some more to this.

[Raatokalle]

So with leaking HG, there would be bubbles coming out even when idling?
I do have to try again tomorrow, If i have better results. Not compeletely happy with it and especially confident.

Otherwise what you just told, sounds exactly same. Streams of tiny bubbles coming out when i rev really high, but when idling, everything is fine.

[xantia_v6]

I don't have much to add, except to warn you that the temperature gauge is not an accurate indicator of engine temperature on these engines, because the sensor is located in a position that gets a mix of hot water from the engine block and cooler water returning from the radiator, so when driving the car (especially in winter), the gauge shows a lower temperature than the actual engine temperature, maybe there is up to 10 degrees error, depending on driving conditions. If you have a Lexia, you can see the actual engine temperature in the engine ECU parameters (it has a separate sensor in a different location).

[white exec]

So with leaking HG, there would be bubbles coming out even when idling?

That is what usually happens: bubbles (maybe small) are pretty much non-stop, even when idling.

Thanks, Mike, for that. I'd forgotten the odd positioning of the gauge sensor on that engine.

[Raatokalle]

Hello, again.

Apogolies for lack of communication, ive been busy enough with work and other things. Haven't had time to take a look at my car for a while.

SO back to where i left. After a few weeks of not doing anything at all, i had some time to work on it again and decided it would be much easier to take a short video about "micro bubbles" i meant earlier rather than me trying to explain this all.

Don't mind about engine, it doesn't rattle like that in reality. But yeah, there is no air coming out at all in idle or around 3000 RPM, but when i rev higher, 4000RPM and above, these small bubbles start to appear. And i did this for a few hours today. But i didn't keep reving 4000 all the time, just from time to time. Bubbles just kept coming and coming. Some time more frequently, sometimes not.

Coolant was at the same level where i left it last time in header tank. And i didn't notice coolant level dropping at all when i was bleeding, so i assume car doesn't leak it anywhere. Otherwise everything runs great. Fans work nice, especially when i got new relays for them.

[Mandrake]

Late to this thread, so will try to catch up.

I replaced the radiator in my Xantia V6 a couple of years ago and didn't have any difficulties bleeding the system. And then at a later time replaced the thermostat and bled the system again. I think your procedure isn't right and your expectations of what should happen are a little bit out...

So i have this XM with ES9 V6 which needed new coolant radiator. Old was leaking a bit, and i got tired of topping it up every weekend. And because car has 380 000KM's in it, i decided to also change new thermostat as well as new temperature sensor(brown one). As i had no idea, when thermostat was replaced last time.
At this point, i want to also say before changing these parts, car was running fine. Maybe bit slowly warming in winter, but it got warm after a while. And in summertime i had no problems at all. Car would cool no problem at all both cooling fans spinning. Sometimes, totally randomly i got overheating warning althought running temperature was only at around 80-90C. Pretty certain it was only a false alarm, thats why i decided to change sensor as well.

There are three different coolant temperature sensors for the ES9J4 - one is for the dashboard temperature gauge, this is the one around the rear of the block on the left hand side of the car. From memory it's blue. The second is to control the cooling fans - this one is on the side of the block on the left hand side of the car, from memory this one is brown.

Finally the green sensor is near the front corner of the engine on the thermostat housing - this is the one that goes to the engine ECU.

While the blue sensor controls the gauge reading on the dashboard, it's actually the brown sensor that controls the fans which lights the red over temperature warning light within the temperature gauge. So if you get a faulty connection (open circuit/high resistance) on the brown sensor on the side of the block it will cause the fans to instantly go to high speed and the red over temperature warning light come on.

If the temperature gauge reading is normal at this time then it's almost certainly a fault with the brown sensor wiring. Using contact cleaner on the sensor plug might be worth trying. It can also be caused by a bad connection on the "bitron" control module which is the control unit for the fans. On a Xantia this is mounted under the left headlight with a long plug with a slide release - not sure where it is on an XM!

Now that i have replaced radiator, thermostat and sensor, it was time for coolant system bleeding. If i understood correctly its pretty simple overall. Just put revs between 1500-2000RPM, open all four bleeding points and keep around 1 extra litre of coolant in expansion chamber while engine is running. Process is done after all air is out, BOTH of fans have spinned and warm air is coming in.

This is not the way I would do it. There's no need to have all the bleed screws open while running the engine with an ES9J4, and it may actually result in air being sucked in. There's also no need to rev up the engine and this may also contribute to sucking in air through the bleed caps.

The way I did mine is to open all 4 bleed screws and leave the expansion chamber cap off, then start to slowly pour coolant into the expansion chamber. One by one from the lowest to the highest each bleed point will start to flow coolant - as soon as it flows coolant close that bleed screw then continue pouring, when the next one starts flowing, close that one and continue, keep repeating this until all 4 bleed screws/caps have flowed and been closed, then finish filling the coolant level until it's about half way up the expansion chamber. Don't overfill the expansion chamber.

Only at that point would I start the engine. Just let it idle do NOT rev it up - there's no need. It will take a good 5-10 minutes for it to warm up sufficiently for the thermostat to open, you can tell when this happens by monitoring the temperature of the upper radiator hose with your hand - it will stay completely cold for 5-10 minutes then all of a sudden within a few seconds it will start to get hot, this is the thermostat opening.

At this point it will probably gurgle through the open expansion chamber filling hole as new pathways are now flowing in the block and the coolant level may go down a bit. At this point you should top up the level again, but no higher than half way. Once it's idled for a few minutes with the thermostat open and flowing you should put the cap on before it gets any hotter.

So i did that all and everything was going fine, air was coming out from system, and car was blowing warm air in to cabin. Temperature was precisely at 90 C when first fan started to blow. Around same time thermostat opened, system sucked almost all that extra coolant and no more air was coming out from the system. Nice, all i had to wait was the second fan to spin and i was DONE. Except it didn't. Engine didn't just get around 100-110C to get second fan running.

And at this point i started to have trouble. After waiting for some time, still only slower fan has blown few times, everytime at 90C. So i thought if i rev engine bit more than 2000RPM, maybe it will heat just enough and im sure both fans will start run.

As others have pointed out later in the thread, both fans always run together - either slowly or fast. If only a single fan runs then there is a fault. It sounds like your low fan speed was not working and you have now fixed that.

I think your expectation that you should be able to reach the high fan speed is mistaken - under no load at idle or even holding 2000rpm it should only heat to the low fan speed, then cool down enough for the fans to go off again. Going to the high fan speed with no load would actually indicate a fault.

Instead of that what happened, was coolant level started to RISE slowly in expansion chamber and all the sudden it simply blew everything up around engine bay.

At that point i had no idea what happened. According to temperature gauge, car didn't overheat. Temperature didn't really go much over 90C.
One thing that came to my mind was blown head gasket, but im not sure about that. System isn't closed so therefore it can't have too much pressure in it? And before changing parts i had no problems at all.

The dashboard temperature gauge runs from the blue sensor on the back of the block - this measures the return temperature from the radiator, not the flow temperature from the thermostat. So it always reads 10-20C lower than the true temperature at the thermostat.

So when the dashboard gauge says 90C the coolant in some parts of the engine can easily be over 100C. Because you have the cap off the system is not pressurised so will boil just above 100C. So by leaving the cap off you caused some point in the cooling system to boil, this will spray water and steam all over the place through the filler neck. I've actually done this myself once by accident by forgetting to put the cap on immediately after finishing topping up after bleeding.

To see the true engine temperature at the thermostat, use a Lexia and look at the temperature reported by the engine ECU.

[Mandrake]

Problems
1. Unlike earlier, now i don't even hit 90C before fans start to blow. Fans start now at 80C and in 2h of idling only once temperatures went to 90C.
Car is still blowing very warm air into cabin tho.

If you're going by the dashboard gauge this is to be expected - as in my previous post it reads 10-20C lower than the true temperature. I would only go by the Lexia reported temperature, where it will go on to low speed at about 94C and high speed about 104C.

2. Im kinda worried about blown head gasket. Only symptom related is to it, is bubbles coming out when i rev.
But the thing is, it doesn 't do that all the time. For a long time i thought all air had come out, but all The sudden when i quickly rev'd to around 3000-5000rpm, some bubbles came.

By revving the hot engine up with no system pressurisation you're causing "kettling" on hot spots in the coolant channels that is generating small steam bubbles - by leaving the cap off you're causing the exact problem you're looking for! Normal operating pressure is about 1.4 bars and this will raise the boiling point of the coolant a lot. The steam bubbles are only forming because you left the cap off.

It's not enough to put the cap back on when the engine is already hot because that won't pressurise the system as the water has already expanded. You'd have to put the cap on and let the engine fully cool down, allowing air to be drawn in through the one way valve in the pressure cap, then next time the system heats up it will pressurise and everything should be fine.

Gosh, im getting paranoid. Should just stick with BX's

Yes you are getting paranoid.

One other thing to consider at least on the Xantia is that the split welded coolant expansion chambers are notorious for developing a leak around the seam. This can prevent the system from pressurising correctly. They typically only last about 20-30k miles before needing replacing! I had to replace the expansion chamber on my first Xantia V6 when I bought it, and on my second Xantia V6 as well.

My second Xantia V6 had only done 65k miles when I bought it and the service history showed that the expansion chamber had already been replaced twice before and then I had to replace it again! Average time between replacements was only 25k miles.

Not sure if the XM uses the same unreliable expansion chamber, but if so I would be looking very closely at it for any signs of leaking around the seams! It's critical that the coolant system remains properly pressurised when operating under a high load.