That's that done then. Only took three days.

[BackinaBX]

Hurrah! Three days of getting the right parts, home-made gaskets, the breaking of three sets of cirlip pliers and lots of swearing and mutterings of 'this never happened on the Mondeo... perhaps I should buy another one' and other impure thoughts, I've finally got the thermostat out, and replaced.

This is what the old one looked like. I think this could have been part of the trouble, that and the fact that the coolant that came out was... well, black, with a bit of green in it.







That rubber shim on the back was wedged down the rad top hose. Little wonder I kept getting over heating warnings... I bet it was restricting flow to the rad - which is now so clean I would eat my dinner of it.

Now the real test will be if I overheat again now I've done all this...

Now, a question. Does the fan have two stages, or it just an on/off job. I know the Xantia has a two stage system.

[jeremy]

BX Turbo-diesels should have a 2 stage fan. The fast one will only come on under extreme provocation - I've only heard mine twice I think - and its very powerful. The circuitry is that they are wired in series for the slow speed and parallel for the fast - so if one motor goes open circuit and ceases to work the fans will remain off until the temeprature rises to the cut in point of the second speed - then one motor will receive full power. Not entirely daft.

The old large type thermostat is fun to get out - I recall putting the housing in a vice and tapping the circlip all round with a punch, catching something thin in the circlip hole and tapping and levering until I could get a thin screwdriver in behind it and working it round - took some time abd as far as I can see doesn't work any better than the later conventional type fitted from about 91 onwards.

[BackinaBX]

Well, I took Bertha (for that is her name) out for a fairly long journey today, seeking out hills and long inclines.

Everything is perfect. No over heating, no warning lamps.

Hopefully, touch wood, this problem is now resolved.


Thanks for all your help chaps.... until the next time...

[tim leech]

Good News!

[roscoe]

Hi Backinabx - how did you clean your rad out? Although my coolant is nice and clean in my TZD and I change it every year (is cheap here), I think my rad is probably restricting the coolant flow as the car tends to run a bit over the 90C mark when working or on hot days. I took the thermostat out completely to see if it was causing it, but other than taking longer to get up to temp, didn't make a lot of difference. Water pump is new, some of the hoses are new, heater blows loads of hot air, so figure it must be the rad.
Will one of those rad flush treatments work or is it a rad out- off to the rad shop for a professional flush job?

[BackinaBX]

I was lucky with my rad insomuch that it's relatively new. I just flushed it and reverse flushed it with water until it came out clean. Looking down the tubes with a torch I could see that although it was a little silted up, it wasn't anything serious so I chucked it back in.

Lots of people on the forum suggest that if your rad it the original (they're date stamped) then you should really think about replacing it. I have no idea about the availability of parts in your part of the world, but here a new rad for a non-turbo diesel is about £50 inc VAT and delivery... so it's not a great expense for some peace of mind.

You could try a two part system flush & anti-corrosion mixture that you put in the cooling system and run for a few miles and then change for regular coolant.

One thing you should never do though is mix the anti-freeze. I leaned this the hard way a few years back with my Saab. I topped up with some modern glycol based stuff and it turned my coolant into this sort of gungie soup. Not good. Buggered everything from the rad to the coolant pump!

[Oscar]

Roscoe

I've successfully used a weak solution of Hydrochloric acid to unblock a blocked rad, getting the bottom fifth of the rad back in operation. I've heard of people using vinegar too.

Oscar

[BackinaBX]

I've heard that one too... 25% mix of vinegar (not balsamic...) to water and run it through the engine for a couple of days. Clean enough to eat off...

[AndersDK]

I believe I started out suggesting a 50/50 vinegar solution years ago on the old andyforum

Pro's :
1) cheap & readily available
2) weak acid - controllable over time
3) you know from your kitchen it works on coffee machines and boilers
4) smells like heck - you know when its not yet flushed out
5) environment friendly

Con's :
1) your car smells like a french kitchen
2) unknown longterm effects if you're too lazy to shift it out
3) needs several flushings to get rid of the smell

[roscoe]

Thanks folks. Rads for a TZD are non-existent over here - I probably have the only one or one of a couple in Australia so getting a new one means ordering from GSF or similar and freight would be a killer. I'll try the vinegar trick and run a 50/50 mix for a week and see how it goes - will let you know.

[Brian]

Hi,

I would not exceed a 25% mix of vinegar, even this mix will presurise the system, especiaslly if it is well gunged up, and may blow at the weakest point.

So keep an eagle eye on the area and run it static for a while, feel the pressure on one of the larger rubber pipes, to gauge if pressure seems excessive...

Good luck

[ed4ferrets]

Okay, I have a car which is more than twice the age of some of you young whippersnappers out there It has an original steel vertical thingy type radiator which I can therefore visually see the clumps of rust etc from above.
I have used a bottle of proprietary type rad flush (10minutes) which did loosen and flush out some gunge but I can still see loads. Would running it on a vinegar mix help with a rusty steel rad without damage ?

[AndersDK]

Hi,

I would not exceed a 25% mix of vinegar, even this mix will presurise the system, especiaslly if it is well gunged up, and may blow at the weakest point.

So keep an eagle eye on the area and run it static for a while, feel the pressure on one of the larger rubber pipes, to gauge if pressure seems excessive...

Good luck

How on earth would the system pressurise to the blow point? The cap valve will always open at max 1.5bar.

[Brian]

Hi Anders,

Easy, it will leak at the weakest point, most likely the rad core, as the crud is being dissolved......

Don't ask me how I know...

Cheers

[ed4ferrets]

Okay, I have a car which is more than twice the age of some of you young whippersnappers out there It has an original steel vertical core type radiator which I can therefore visually see the clumps of rust etc from above.
I have used a bottle of proprietary type rad flush (10minutes) which did loosen and flush out some gunge but I can still see loads. Would running it on a vinegar mix help with a rusty steel rad without damage ?

Surely there are at least 3 wise men who can advise