late bx 1.9 diesel cooling

tomsheppard · Unread post by **tomsheppard** » 02 Jan 2003, 17:27

Having become frustrated I left the car alone and at home for Christmas. New stat, coolant switch and rad cap. Heater always warm, all but the bottom of rad stone cold. coolant warning on except when stopped. Xantia 1.9 non turbo motor in late '92 BX TGD. Bleed from pipe on stat housing seems to be returning air/steam to left hand side of rad, causing sufficient pressure to inhibit rad circulation. car seems to run ok but coolant level is (to my eyes)usually low.I suspect that it loses a certain amount of water to start with and then stops losing it. Can somebody tell me hand on heart that this variant runs with the rad half empty and stone cold after a 10 mile motorway run? Am I worrying about nothing or does anybody out there have a handle on this? I am still not entirely sure about bleeding it as the car seems to be a bit of a mongrel or hybrid.

Unread post by **Jon** » 02 Jan 2003, 17:58

From what you are saying, it sounds like the bottom of the rad may be silted up. The whole of the rad should get hot due to the fact that hot water would enter from the thermostat end at the top, and exit through the bottom hose to the water pump at the bottom.
It may be an idea to remove the rad, and try and flush it through with a hosepipe and a good shake in an effort to remove this silt, otherwise a replacement rad may be on the cards.
There may also be an airlock somewhere. I assume that you have bled out water at the thermostat housing, but there must be another system bleed somewhere. As your BX differs from what is "normal", it may be worth checking to see if another bleed point exists.
It could be, that on the top RH as you stand looking at the car with the bonnet open, there is a bleed bung in the top of the radiator. I would also imagine there may be another bleed somewhere past the thermostat towards the matrix.
I'd suggest a "cold bleed" first, heater turned on to full, and engine off. Remove the bleed bung in the top of the rad, and pour in coolant, until it flows here, then replace bung. Next remove the bleed at the thermostat hosuing, fill coolant until it runs through, then replace. Finally check if there is another bleed somewhere else, then repeat. Then start the car,and bleed agin at the thermostat housing. I hope that this will help. Otherwise, as I say, the radiator is looking suspect.
Jon Wood
[email protected]

tomsheppard · Unread post by **tomsheppard** » 02 Jan 2003, 18:17

Been there done that, I'm afraid. backflushed rad ok.Running with no stat whole rad got warm. It appears that there is an air lock in the block or head. The stat housing has a pipe coming off which returns to a point near the coolant level sensor on the left of the rad.(On a ZX I am told, there is a header tank in this circuit) Air here could be giving me a bubble around the sensor and also one behind the stat.Both bleeds run free normally but there seems to be considerable difficulty in bleeding this (stat bypass?)pipe, spurts of hot water coming out at intervals of a few seconds, then air. If I could confirm that the rad was at fault, I would fit one today but I am still sceptical about it.

Unread post by **Jon** » 02 Jan 2003, 18:36

hmmm, OK.
Well it sounds just like the ZX setup (BTW ZX diesels don't have a header tank). The ZX has a bleed at the thermostat housing, and another at the bulkhead behind the master cylinder (RHD). The one at the bulkhead is hard to find, its a pipe that ends with a black screw on cap, which is in fact a tyre valve dust cap!! Have you got anything similar? Unless water flows from this bleed point, then all sorts of troubles can occur.
My neighbours Berlingo 19D was very like the above, but it lacked a bleed at the thermostat housing. As a result of this, we could not get water to flow from the bleed point (the tyre dust cap one) at the bulkhead. We resorted to literally blowing down the header tank until some water was forced through!!!!!
With the engine running, and (importantly) rad cap off so that any air could rise up through the system and escape, heater on, we then pulled off the pipe from the rad to the thermostat housing a few times and replaced it until water ran as normal.
If the car seems ok with the 'stat removed, maybe there is a bleeding problem in this area. You certainly have me stumped here, anyone got an better ideas??
Jon Wood
[email protected]

tomsheppard · Unread post by **tomsheppard** » 02 Jan 2003, 18:55

Sorry, no apparent screw on cap. I have two pipes going through the bulkhead on the driver's side, one above the other. One of these returns to a metal pipe then to the incoming side of the stat via a short rubber pipe. Releasing this pipe from a warm engine and hosing water into the filler cap causes cold water to flow from the heater and hot from the stat housing. I am grateful for your help here and I'm not surprised you're stumped. I thought that I was quite good at cars but I am hanged if I'll let this one beat me. I have seen reference to home made header tanks being used for filling the system. What's your view on this?

Unread post by **Jon** » 02 Jan 2003, 19:08

well, these home made header tanks.
I know that people swear by 'em, and they have been constructed using 2L Cola bottles forced into the rad filler neck and the like. The "proper" version used at Cit dealers and the like is an open topped plastic bottle which joins to a rad cap.
Just to raise controversy, I've never used one. And I've bled out loads of Citroens.<img src=icon_smile_wink.gif border=0 align=middle>
I personally feel, that if water flows from the bleed points with the heater matrix tap open, with the engine both stopped or running, then the thing is bled OK. Leaving the engine ticling over with the rad cap off until the fans kick in is the best test/bleed of all.<img src=icon_smile_shock.gif border=0 align=middle>
I now await comments. (ouch).
Jon Wood
[email protected]

tomsheppard · Unread post by **tomsheppard** » 02 Jan 2003, 19:17

If I were to leave the engine running filling constantly from a hose all would be well until the final bleed was closed. Then the level in the filler neck would rise inexorably. The hot heater rules out a duff pump doesn't it? But for the facts that there are no cross contaminations, starting problems, steam in exhaust or power losses, I would think it could be head gasket woes but I am reluctant to pull it apart for lack of evidence.

Unread post by **Jon** » 02 Jan 2003, 19:31

Get a pressure test done on it before you pull it apart. The pressure tester fits on the rad/header tank, and air is pumped in the system at a certain pressure. If the pressure drops, it means that either there is a leak somewhere (which you will be able to spot as water will start leaking as the system is under pressure, e.g. from a hose, the rad etc); or, if there is no extrenal leak, then theres an internal leak, that is the head gasket or the head itself.
If the pressure does not drop dramatically during say 10 mins there should not be too much wrong.
Let us know when you solve this one!!!!!!!!
Jon Wood
[email protected]

tomsheppard · Unread post by **tomsheppard** » 02 Jan 2003, 20:11

Yes, I reckon that you are right to advise a pressure test. Just to baffle us all further, the residual air pressure in the system is maintained for many hours. Pulling the cap off after an overnight wait gives a pressure release. hissing noise etc. water level 3-4 cm down neck. squeeze top hose, bubbles and level drops. release stat bleed and water drops until almost not visible in rad.Were there even a minor leak, I would expect to find system at atmospheric pressure on the following morning- curiouser and curiouser!

Dave Burns · Unread post by **Dave Burns** » 03 Jan 2003, 03:41

"I would expect to find system at atmospheric pressure on the following morning- curiouser and curiouser"!

Not necessarily, gas will pass through a tiny gap alot easier than water, and especially with a couple of thousand psi behind it.
Water might only pass back through the gap very slowly because of its low pressure, and maybe hardly at all, with the minute crap that floats around a cooling system any gap could be further restricted.

Engine stone cold, fill the rad, then start engine, after fifteen seconds remove rad cap, if you get a surge of water out the rad, or pressure is heard escaping when the cap is removed, say goodbye to your head gasket, any pressure present this soon after starting a cold engine can only come from combustion gasses.
If the rad or expansion tank where coolant is put in isn't the highest point in the system, then idealy you should use a header tank to fill it.
Dave

tomsheppard · Unread post by **tomsheppard** » 03 Jan 2003, 17:47

Yep, that's it. Bother.
Thanks for the diagnosis Dave.

huwhop · Unread post by **huwhop** » 07 Jan 2003, 03:52

I have more or less the exact same symptoms as Tom with a K reg 1.9 bx diesel with 106k on the clock. I'm pretty sure my head gasket is shot but I am going to take it to a garage for the pressure test described above by Jon.
>>Dave B.....when you say "Engine stone cold, fill the rad"..should i do this wwith the rad top bleed screw loose ..to ensure the rad's full? ..or doesn't it matter.

tomsheppard · Unread post by **tomsheppard** » 07 Jan 2003, 13:45

I reckon that it doesn't matter too much whether the system is entirely full or not, the air in the system woulddn't be pressurised to any huge extent by the temperature rise over 30 seconds. Referring to the Haynes book of Archery, reference is made to a level checking tube, fitted to the filler neck (but not there on my car) which is not referred to in my owner's handbook. Is it important, and if so, what are the dimensions?

vanny · Unread post by **vanny** » 08 Jan 2003, 01:46

Following this with high hopes for useful information, but still only watching!! Fingers crossed i havent had this sort of problem yet, but i guarantee its only time!!
As for the 'mystery neck extension' for the radiator, im quite sure it DOES NOT EXIST. Its become one of those habbits now, everytime im int he scrap yard first thing i do is pop the bonnet and have a look to see its there. I keep seing a black GTi LHD from some where in Europe, next time i see it ill collar the bloke and ask if he has one!! Im onto about car 30 with one, inclusive of 16v, GTi (Mk1 1+2), 1.4, tzd, 1.7td, 19rd - still looking!!
Best of luck though!!
Vanny
Merseyside, UK
[email protected]
http://www.bxproject.co.uk

mbunting · Unread post by **mbunting** » 08 Jan 2003, 01:52

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Please mister, I've got one in my Xantia, or does that not count ?
It's a creamy coloured ( probably originally white <img src=icon_smile.gif border=0 align=middle> ) hollow sleeve which sits in the expansion tank neck, and has a few marks on the side ( visible in-situ ).