Flushing Xantia X1 Cooling System - Matrix still not ideal!

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Rhothgar
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Flushing Xantia X1 Cooling System - Matrix still not ideal!

Post by Rhothgar »

Morning all,

I spent the best part of yesterday, flushing, filling, flushing and filling and eventually just had to fill with coolant and deionised water.

When the engine temp gets to 90 deg which it never does on a normal drive, there is nice warmy toasty heat being developed in the cabin.

The flushing must have done something as I can now smell vinegar in the car!

Anyway, I tried to get the matrix hoses off at the block side so I could reverse flush through the matrix but no joy. Partly because I have shoulder which is freezing (ie not yet frozen) and space is limited.

Has anyone on here ever removed the (what I assume to be) plastic manifold on the rear of the engine that has 4 pipes connected to it (3 pipes and 1 cap I believe according to Service Citroen)?

The reason I ask is because there appears to be a pipe that connects opposite the heater matrix connection but then it doesn't show where it goes on the diagram. If I could find where that then goes to I could remove that and flush it assuming it's more accessible.

The radiator outlet hose flows to this manifold and into the engine. However, is this manifold blanked because otherwise you'd have cooler water heading straight into the heater matrix. So I assume this directs the water into the engine and then pipe 11 takes the heated water and this flows through into pipe 4 and into the matrix.

I can access the HM rubber pipe on the nearside of the engine block but currently don't have the strength to break its bond. I think also that the clip Citroen have fitted here at the factory on my car at least is incorrect because the rubber hose is flared slightly and the clip cannot be moved past this flare so I need to clamp the clip with one hand and try to rotate and waggle the hose with the other. Not ideal with reduced mobility.

If the nearside end is the return from the matrix, it is achieving a higher temperature which perhaps indicates the matrix may be suffering from a reduced bore or is simply blocked.

The other option would be to remove the connector from the matrix but I know from bitter experience that it is extremely challenging to refit even with full mobility so I don't really want to go down that route.
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white exec
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Re: Flushing Xantia X1 Cooling System - Matrix still not ideal!

Post by white exec »

Both hoses to/from the matrix should be operating at a similar temp.
If one is appreciably cooler, there is poor/no circulation through the matrix.

However, this "When the engine temp gets to 90 deg which it never does on a normal drive, there is nice warmy toasty heat being developed in the cabin" suggests that the matrix is not blocked, but points towards a thermostat not closing properly, or being an incorrect one.

Gauge inaccuracy is common, but if your drive the car hard (eg lengthy climb) the cabin heater should be HOT (if set to Hot, of course). If easing off the accelerator, or doing a long descent (i.e. burning very little fuel) causes both the gauge and the heater output to drop, then you definitely have a thermostat problem.
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Re: Flushing Xantia X1 Cooling System - Matrix still not ideal!

Post by Rhothgar »

Thanks Chris.

I did take the stat out and boiled it up. I thought it was fine. Starts to open at 83.

These days I’m like Driving Miss Daisy.

One thing I did notice with the thermostat was that I don’t think it closes 100% fully. By that, I mean I could make out a chink of light when closed. You’d need a feeler blade to measure it.

Would it be worth getting a higher temperature one. Citroen specs 83 deg
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Re: Flushing Xantia X1 Cooling System - Matrix still not ideal!

Post by xantia_v6 »

Rhothgar wrote:
06 Jan 2020, 20:13

One thing I did notice with the thermostat was that I don’t think it closes 100% fully. By that, I mean I could make out a chink of light when closed. You’d need a feeler blade to measure it.

Would it be worth getting a higher temperature one. Citroen specs 83 deg
A tiny gap in the thermostat will make a big difference, particularly on a diesel engine. I would suggest replacing it. I would not bother with changing to a different spec, you are just trying to restore original performance.
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white exec
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Re: Flushing Xantia X1 Cooling System - Matrix still not ideal!

Post by white exec »

Agree with that. The main 'stat on our XM had a tiny split in the rubber seal that the 'stat moving disc closes on. This tiny gap was enough to leak valuable heat away into the main radiator, and only permit decent gauge and heater temperatures when burning lots of fuel. When running downhill, gauge would drop from c.90°C to 60+, and cabin temp became decidedly chilly. A bit of welly got temps up again, only to fall on the next decline. All this happened Christmas of 2018, on way back from France, crossing the Pyrenees; outside temp was –1°C, something the car heater would normally scoff at.
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Re: Flushing Xantia X1 Cooling System - Matrix still not ideal!

Post by Rhothgar »

Great advice guys.

Just managed to get a genuine Vernet one on Ebay for £9.50 delivered. Excludes gasket.

I won't be paying Citroen £5+ for a new rubber gasket for perimeter. I'll use the existing one.

Great design of thermostat housing on the X1 Xantia. Previous owner always used Citroen main dealer I believe and they used something similar to Hylomar but cream coloured to seal the housing. Nothing is needed because the housing is in relief so seals by pressing on the gasket. I scraped off the 'Hylomar' and bolted it back up. It's tickety-boo.

It'll be nice to get some heat back in the car and for the economy to rise slightly. I do a mix of driving and achieve around 43.5mpg which is pretty good really. Be interesting to see if that increased marginally over the next 12 months.
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Re: Flushing Xantia X1 Cooling System - Matrix still not ideal!

Post by white exec »

Let us know how the running temp and heater goes...
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Re: Flushing Xantia X1 Cooling System - Matrix still not ideal!

Post by Rhothgar »

Just reading up on previous posts as I am about to reflush the engine and put fresh antifreeze in Chris after the cylinder head went.

It turned out and I suspect from reading this thread that the matrix was so badly blocked I am left wondering if this contributed to the head gasket going. I think using spirit vinegar to clean the internal galleries out of rust was a stupid ideal in hindsight. I think I left it in a week. An acid as strong as that in an engine could not have done it much good.

Anyway, since it was stripped down, I decided to do the matrix too and it's lovely and toasty and ready for the winter. Just need to do the antifreeze... :rofl2:
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Re: Flushing Xantia X1 Cooling System - Matrix still not ideal!

Post by myglaren »

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Re: Flushing Xantia X1 Cooling System - Matrix still not ideal!

Post by Rhothgar »

myglaren wrote:
19 Nov 2021, 15:42
Chuck some Forte Cooling System Stop Leak and Conditioner in too Roger.
You LOVE spending my money, Steve! :rofl2:
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Re: Flushing Xantia X1 Cooling System - Matrix still not ideal!

Post by myglaren »

Indeed!
Want to spend some more?
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Re: Flushing Xantia X1 Cooling System - Matrix still not ideal!

Post by Rhothgar »

myglaren wrote:
19 Nov 2021, 16:05
Indeed!
Want to spend some more?
No thanks but can you justify why I should put it in now I have a new matrix and cylinder head gasket. Is it really essential?
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Re: Flushing Xantia X1 Cooling System - Matrix still not ideal!

Post by Hell Razor5543 »

Valeo require you to use Forté Stop Leak when fitting one of their heater matrix in order for the warranty to be honoured.
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Re: Flushing Xantia X1 Cooling System - Matrix still not ideal!

Post by myglaren »

As James says it is required by Valeo for the warranty but it lubricates the pump, inhibits corrosion and will stop any leaks as they occur. It also won't clog any fine waterways in the system as other similar products have been shown to do.
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Re: Flushing Xantia X1 Cooling System - Matrix still not ideal!

Post by white exec »

Good to hear that the new matrix is doing its stuff so well.

Although the matrix is connected straight across the engine block (the circuit includes the water pump), it's in parallel with it, not series, so even if the matrix is completely blocked, it will not prevent coolant circulation round the block/head. By having this arrangement, both engine and cabin heater warm up quickly. Only when the 'stat starts to open does additional (radiator) cooling come in.

Likely that the earlier vinegar solution (which was run up to temp by driving?) finished off the heater matrix, as well as de-calc'ing it. Aluminium heater matrixes are delicate things, radiators somewhat tougher. A smell of coolant (or vinegar in your case) in the cabin is normally a sign that the heater matrix is weeping.