Xantia 1.9TD temp gauge.

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Blackdog
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Xantia 1.9TD temp gauge.

Post by Blackdog »

I have got myself another Xantia 1.9td estate recently the heater was blowing only cold air..so I replaced the thermostat..and flushed the whole system before adding new coolant with header tank and bled it best I could can only find one bleed screw. I now have heat[minimal) but the temp gauge rockets up high!! as soon as I switch heater off it drops down 2 more or less normal should be the other way round shouldnt it.. hoped changing coolant and thermostat would have sorted this out seems to me that its not telling me the right temp otherwise how could it drop down so quickly? also twin fans dont come on which suggests to me that the engine really isnt that hot..anyone got any ideas?? thanks
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1.9TD Green xantia estate sx 99.
deian
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Post by deian »

Did u replace the coolant with the heater settings on hot so it emptied the matrix too? Your airlock may be in this area if not.

I think there is a bleed screw near the bulk head if you stand at the driver side and look inside, it will be a schraeder valve cap on it. Is this the one you found?

the best way to fill the system is by using a header tank on the coolant reservoir, seal it against the header tank opening so it doesn't leak, so you can over fill the system: with the heat settings on hot so the water fills the matrix too.
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Xaccers
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Post by Xaccers »

The heater matrix doesn't get isolated when the heat switch is set to cold (wish it did, would make life easier for when the matrix fails!). It always has coolant flowing through it (bar blockages/airlocks), it's a flap under the dash that controls whether the air goes via the matrix to be heated or bypasses it to remain cold.

When I'm filling with coolant, I open the top bleed screw (with the three pipes going to it by the back of the fuel pump on the TD), fill the expansion tank with coolant, squeezing the rubber pipe that runs along the front of the engine to help expell air.
Once coolant comes out the top bleed hole, I do the cap up.
There is another bleed screw by the heater matrix pipes but the air intake pipes along the back of the engine make access difficult and I've never had to use it.
Start the engine, let it get up to temperature so that the fans kick in and the thermostat opens.
Top up the coolant.
The engines are good at bleeding themselves.
Last edited by Xaccers on 07 Jan 2010, 21:13, edited 1 time in total.
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Blackdog
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Post by Blackdog »

Hi thanks for reply yes heater setting was on hot when refilling and I sealed a header tank to the resevoir inlet..will have a look for that other bleed screw you mentioned..does that mean you think it is an air lock?? strange about the temp gauge though innit! I should be getting more heat than i do also the coolant was a real rusty brown (old stuff) and I could only get about 6 litres of fresh coolant in which has now taken on a rustic colour probably mixed in with some of the old stuff that was left....
I.9TD Green xantia estate sx 96.
1.9TD Green xantia estate sx 99.
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Xaccers
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Post by Xaccers »

Could be that some of the channels are blocked with rust then :(

Probably worth flushing your cooling system lots.
What state is your rad in? Rusty and about to fall apart, brand new so recently replaced, or somewhere in between?
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deian
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Post by deian »

yea the temp gauge measures the water temp in the engine/thermostat housing, so maybe there is an airlock/blockage in the matrix area... finding that other bleed valve near the bulk head for the matrix may help a lot.

Also a good idea to find the inlet and outlets to the engine, rad, and matrix and shove a hose pipe on the inlet first to look for blockages/restritctions, if anything dodgy happens, put a hose pipe the other way might loosen some dirt up and wash it out.
Last edited by deian on 07 Jan 2010, 21:19, edited 1 time in total.
Blackdog
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Post by Blackdog »

hello xac thanks for reply...I am wondering about the fans on this xantia I have now...they do come on as I have heard them but today when temp was high I noticed they hadnt kicked in..I think there might be 2 settings for them and maybe they are not coming on in the lower setting..I need to check this out...did pinch the pipes as you mentioned but am now thinking I really need to make sure the system isnt airlocked.
I.9TD Green xantia estate sx 96.
1.9TD Green xantia estate sx 99.
Blackdog
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Post by Blackdog »

Radiator condition is ok.. will check for other bleed screw 2morrow...and drain system again..and make sure coolant flows airless from both screws.Still think the fans should have come on...but it does sound like there could be a block somewhere with all the build up(guess coolant hasnt been changed for a while) both pipes are warm and hot coming from engine to heater though.will let you know how I get on many thanks for your replies. Blackdog.
I.9TD Green xantia estate sx 96.
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Xaccers
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Post by Xaccers »

If you turn the A/C on (assuming you have enough gas in it to kick in) then the fans should come on in slow mode.
Someone correct me please if I've misremembered that.

When the thermostat opens and the fans kick in fast, the large rubber pipe should be hard and hot (ooo-er).


As Deian says, I'd get a hose pipe on the engine and flush the heck out of it.
Once you get heat, smell the hot air for cat pee/curry scent. If you detect it, then it's time to replace the heater matrix (check under the passenger carpet now, if it's wet, then it's already time to change the matrix) which is a fun job to keep you occupied over a weekend.

The 3 pipe bleed screw near the fuel pump is the highest point, but you need the thermostat open to bleed fully.
1.9TD+ SX Xantia Estate (Cassy) running on 100% veg
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Blackdog
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Post by Blackdog »

A/c needs gassed up I checked it through the little window when I bought the car and it was streaming with bubbbles.....
I.9TD Green xantia estate sx 96.
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deian
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Post by deian »

how is the head gasket?
Blackdog
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Post by Blackdog »

I did think about the head gasket as am having starting problems only when cold and boy has it been cold up here...anyway I put it down to the glow plugs needing replaced as once she has started...then no problems for the rest of the day...excuse my ignorance but how can i check if the head gasket is ok or not??
I.9TD Green xantia estate sx 96.
1.9TD Green xantia estate sx 99.
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Xaccers
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Post by Xaccers »

Blackdog wrote:A/c needs gassed up I checked it through the little window when I bought the car and it was streaming with bubbbles.....
That means gas is low but not below the minimum level for the A/C to kick in :)
So when it's running and you can see the bubbles, the fans should be running.

One of the important reasons to re-gas is actually to replace the lube so the bearings are looked after.
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deian
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Post by deian »

Blackdog wrote:I did think about the head gasket as am having starting problems only when cold and boy has it been cold up here...anyway I put it down to the glow plugs needing replaced as once she has started...then no problems for the rest of the day...excuse my ignorance but how can i check if the head gasket is ok or not??
Simple answer is compression test...

I'm not educated enough on doing compression tests on diesel engines (just petrols) glow plugs out maybe, but how to stop it firing?

Someone else will know... xac?
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Post by Chlorate »

Blackdog wrote:I did think about the head gasket as am having starting problems only when cold and boy has it been cold up here...anyway I put it down to the glow plugs needing replaced as once she has started...then no problems for the rest of the day...excuse my ignorance but how can i check if the head gasket is ok or not??
Typical Head Gasket Symptoms:
-Loss of coolant
-Pressurising of the coolant system (i.e. the pipes feel very firm and the rad cap can't be taken off without coolant going everywhere after the engine has been running)
-Overheating, this may not be obvious from the temperature gauge. But your fans may start doing odd things i.e. come on full blast whilst driving.
-Coolant in the oil and vice versa (you'll find what looks like mayonnaise under filler caps and or what looks like chicken soup on the dipstick) N.B this isn't so common on the TD engines, and if you find it. Panic.
-Irregular temperature across the radiator
-No heat from heater
-Loss of power
-Grumpy starts
-Thick blue smoke from exhaust

Head gasket failure can cause: all, some or none of the above.
If you find any it is suggested to check it AS SOON AS POSSIBLE.

XUD engines are notorious for this, to avoid head gasket failure. Coolant needs to be changed every 2 years at least.
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