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Author Topic: A better 2.2 cooling system  (Read 2479 times)
roy4matra
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« on: June 26, 2016, 09:23:57 am »

I have owned a 2.2-litre Murena from new and know that the cooling system, as originally designed and fitted, works perfectly in all conditions including heavy traffic in really hot weather.  I have an 88/89 degree thermostat fitted which is in fact higher than the original 82/83 degree one the factory fitted, and it can still cope with slow moving or stationary heavy traffic for long periods in London with the ambient temp. around 35 degrees, so in normal conditions it is totally fine as with any other manufacturers car.  (I changed to an 88 degree thermostat because in the UK the weather is often colder and the heating will perform better with the engine that little bit hotter)

However, I also know from experience with these cars over the last 35 years that if the system is not kept in top condition, they can suffer, and since the engine fills its mid-location much more than the 1.6-litre power unit, leaving much less air around it, it can quickly get very hot or overheat if the system is not in the best condition.  So the first thing with any 2.2-litre is to make sure you keep the system healthy.  This means changing the anti-freeze every six years maximum and I would suggest you renew the thermostat, and radiator fan switch at the same time, maybe the temperature gauge sender if the gauge has not been reading consistently, and maybe the vee-belt too but certainly check it carefully and the water pump at the same time.  Most of these things cost very little, especially if compared to the problems and cost of overheating an engine!  You should also check all the coolant hoses and pipes.  Check hoses for anywhere they may have been rubbing against something that could eventually cause the hose to split or puncture and leak.  Or hoses that have gone soft owing to age and could fail.  Check hose clips for security or breakage owing to corrosion.  And finally check the metal pipes for signs of corrosion or leakage.  All this applies equally to the 1.6 or any car really.

One item which is known to be prone to failure is the radiator fan switch, and these were fitted to many other cars not just our Matra, and they failed on those cars too.  One reason they may fail more often is that they were wired directly to the fan motor so were switching the whole current, and they may have been more reliable if the system had included a relay, taking the load off the radiator switch contacts.  Anyone can still alter the system and rewire it so the switch only controls a relay, and the relay controls the fan, and I would advise this is done in conjunction with a manual over-ride switch, so if the radiator switch does fail during a journey, you can at least switch the fan on from the driver's seat.  However, if you do have the fan fail to activate, you must stop as soon as possible to check and make sure the coolant level is still correct.  If the level has dropped substantially, the radiator switch may have no coolant against it, so it cannot detect the coolant temperature and it may not have failed but simply be in a pocket of air.

This brings me to the next point.  These cooling systems are a sealed system like most modern cars.  A sealed system means that it should *never* ever need topping up... at all!  If you ever have to top it up, no matter how little, then it has lost some coolant and you need to find out why and the sooner the better.  It may be an external leak or it could be internal but you need to know and rectify it quickly.  The worrying thing is if the leak starts during a long journey.  The sooner you know the quicker you can take action to avoid costly damage, but if you wait for a temperature rise to indicate a problem or the fan to fail to cut-in, it may be too late already.  So a float level sensor is really required to indicate a drop in level almost as soon as it starts.  This is something that can be done and quite easily since the Murena has a level sensor system (for the brake fluid level) that can be coupled into, using the same wiring and warning light.  Once this is done, you will have much more peace of mind as you will get a level drop warning when there is still plenty of coolant remaining, and therefore long before it would cause any damage.

OK so hopefully we have a well maintained system now with a relay and manual over-ride for the cooling fan, and a coolant level sensor, but can we make any other improvements?  Yes.  Most hoses on the Murena 2.2 last very well and many of the cars may still have original hoses fitted even after 35 years, which is pretty amazing.  I put this down mainly to the engine being so remote from the radiator.  On a front mounted engine, the vibration and movement of the engine stretches and works the hoses that provide the flexibility between the engine and radiator.  With the Murena engine being so far from the radiator most hoses are never flexed that much if at all, and so they have lasted much longer.  But there is one hose/fitting that was not so well designed and often causes a problem.  This is the small recirculation hose that is attached on the right hand end of the thermostat housing and is often difficult enough to get the hose clip tight to seal it in the first place.  It has to turn through 180 degrees in a very small distance and therefore often cracks on that tight bend.  This should be eliminated and we have the option to do this as we have a spare port on the thermostat housing.

The thermostat housing has two large ports on the left (looking forward), the top one feeds the heater matrix, and the one below it is for the inlet manifold heating.  On the right of these at the top is the temperature gauge sender, and below it is a blanking plug.  Then on the right hand end is the small recirculation hose connection, but this has in fact a large port and therefore needs a great reducer to get down to the small size required for the hose.  What you need to do is remove the blanking plug and replace it with a small connector for the recirculation hose, which can now be shortened and will only have a gentle 80 degree curve instead of that tight 180 degree bend.  You could leave it at that and simply put a blanking plug in the end port where you have removed the recirculation hose connection, and that would be fine.  However, this does leave you with one more possible improvement...

Modern engines no longer use a radiator fan switch, but use a temperature switch on the engine that the injection computer uses to operate the relay that switches the cooling fan on and off.  The Murena does not have a computer but we can still have an engine fan switch, which will switch the cooling fan more accurately than the remote radiator switch.  Owing to its remote position in the radiator, the normal fan switch is not switching at engine temperature, because the coolant temperature drops slightly by the time it reaches the front.  This figure is variable owing to different outside air temperatures and the speed of the car and therefore the airflow under the car.  So by the time the radiator switch reaches its cut-in point, the engine will usually be a few degrees higher still.  It would be more consistent if the engine triggered the radiator fan.  We can do this.

Now we have moved the recirculation hose from the right hand end of the thermostat housing, that port is not only free but it is exactly the size we need for an engine fan switch!  It is an M14 x 1.5 thread.  FAE and others do a variety of switches that will fit this port.  If we fit a switch in here and couple this to the cooling fan relay we have now fitted, you will have fan activation from the engine temperature directly.

So what switches do we use?  The original radiator fan switch was a 95/86 degree switch. i.e. it cuts-in when the switch reaches 95 degrees and cuts-out when it drops to 86 degrees.  I suggest you change this to a 92/87 switch and then use a 95/90 engine switch.  Both of these settings are 3 degrees different which is about right for the difference between front and rear temperatures in normal use.  So the fan will get triggered when the *engine* reaches 95 degrees and not the radiator, so the fan will operate a little sooner than before (not a bad thing) and more accurately regarding the engine temperature as the temperature at the front tends to vary slightly.  The fan will cut-out when the engine drops to 90 degrees or the radiator switch drops to 87 which might be a little later.  You will now have an automatic backup because if one switch fails you have a second one, and if both should fail (much more unlikely) you still have the manual over-ride switch.

Roy
P.S.  In view of my latest findings with possibly faulty 2.2 water pumps, please also read my other thread concerning 2.2 pumps with alloy impellers.
« Last Edit: June 26, 2016, 11:10:17 am by roy4matra » Logged

Oetker
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« Reply #1 on: June 28, 2016, 10:48:20 pm »

Good ideas.
My fanswitch broke down for the 3rd time last month because of switching the high currents.
I avoid the Chinese copy's (bad quality) and stick to old stock switches but that doesn't prevent it.
The relais wil help to keep the switch alive for longer period.
Also a second switch in the thermostath housing is something I think of.
Good work Roy.
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I feel like Jonah, only my fish looks different.
Murena 2.2 Red 1982. Murena 1.6 black on places.
Colin
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« Reply #2 on: June 30, 2016, 05:29:32 pm »

Do you know the capacity of the whole cooling system? As when we get to reassembling my car I would be very tempted to go for Evans water less coolant, as it helps to prevent any corrosion, and never needs changing, unlike antifreeze/water mix... 
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GP
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« Reply #3 on: June 30, 2016, 06:04:27 pm »

Do you know the capacity of the whole cooling system? As when we get to reassembling my car I would be very tempted to go for Evans water less coolant, as it helps to prevent any corrosion, and never needs changing, unlike antifreeze/water mix...  

11.5 Litres

http://www.automobile-catalog.com/oil_coolant_capacity/1982/1458620/talbot_matra_murena_2_2-litre.html
« Last Edit: June 30, 2016, 06:08:24 pm by GP » Logged
Jon Weywadt
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« Reply #4 on: July 01, 2016, 12:02:52 pm »

Do you know the capacity of the whole cooling system? As when we get to reassembling my car I would be very tempted to go for Evans water less coolant, as it helps to prevent any corrosion, and never needs changing, unlike antifreeze/water mix...  
Before you fill the system with Evans waterless coolant you should check that the system is water tight first.

I have plans for Evans also and last year re-assembled the engine after a head repair. Since Evans is rather expensive, my friend Jan said I should make sure the system was tight first. So I filled it with water and antifreeze and drove for some time. After about two months the water pump bearing and seal failed. Probably because it had been sitting without water and allowed the shaft to rust.
All the coolant leaked out and I had to have thee car hauled home on a transport. So a new pump got installed and the system tested again. Now after a few months the hose off the top of the water pump failed and the water leaked out again.
Fortunately I still haven't used the 12 liters of Evans and 10 liters of Evans prep fluid, about £200 worth.

So my recommendation is to first of all get all new hoses. Change the coolant/heater pipes to stainless if you haven't already (engine compartment too). Then try the system for some time with water/antifreeze to make sure it is tight. Then drain and clear water from the system with Evans prep fluid, before filling with Evans.

Just advice, based on my own experience. Shocked
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Matranaut par excellence Cool
GP
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« Reply #5 on: July 01, 2016, 05:51:39 pm »

Oh yes... Jon forgot to mention changing out the brittle plastic coolant expansion tank for a modern aluminium replica!  Roll Eyes

http://www.ebay.co.uk/itm/Matra-Murena-2-2-Reproduction-Aluminium-Coolant-Expansion-Tank-/191907915315?

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Colin
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« Reply #6 on: July 01, 2016, 06:12:57 pm »

Thanks, one hopes all will be well, the engine is currently with Roy, awaiting the cam shaft. I think running it on water/antifreeze first is a good plan....
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Jon Weywadt
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« Reply #7 on: July 02, 2016, 12:54:38 pm »

Oh yes... Jon forgot to mention changing out the brittle plastic coolant expansion tank for a modern aluminium replica!  Roll Eyes

http://www.ebay.co.uk/itm/Matra-Murena-2-2-Reproduction-Aluminium-Coolant-Expansion-Tank-/191907915315?


Sorry.
Yes I have indeed already replaced the expansion tank with an aluminium version that was offered on this forum some years back.
You should too.  Wink
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Matranaut par excellence Cool
GP
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« Reply #8 on: February 02, 2017, 08:51:42 pm »

Before I fit my lovely new shiny Radiator from Simon I have just been confirming with my brain if we should use new Organic Acid Technology (O.A.T.) Anti-Freeze.... No booo very bad and usually pink in the U.K. or Inorganic Acid Technology (I.A.T) Anti-Freeze......Yes very good and usually blue in the U.K. I then came across this product as an alternative to the nasty "pussy killing" Ethelyene Glycol used in I.A.T. Anti-Freeze:

Propylene Glycol pre-mixed coolant, 5 litres. NON TOXIC, LONG LIFE, ENVIRONMENTALLY FRIENDLY

https://citroenclassics.wordpress.com/2012/03/17/what-is-the-right-coolant-to-use-in-our-older-cars/

http://shop.citroenclassics.co.uk/propylene-glycol--pre-mixed-coolant-5-litres-non-toxic-long-life-environmentally-friendly-928-p.asp

I have no wish to go waterless with a product like Evans personally, although this isn't cheap as 3 x 5 litre containers would be required. Anyone used this stuff or have any comments to make about it?

Either way an interesting article to read and could save your engine if you inadvertently put the wrong Anti-Freeze in.
« Last Edit: February 02, 2017, 10:31:09 pm by GP » Logged
roy4matra
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« Reply #9 on: February 02, 2017, 10:37:56 pm »

Before I fit my lovely new shiny Radiator from Simon I have just been confirming with my brain if we should use new Organic Acid Technology (O.A.T.) Anti-Freeze.... No booo very bad and usually pink in the U.K. or Inorganic Acid Technology (I.A.T) Anti-Freeze......Yes very good and usually blue in the U.K. I then came across this product as an alternative to the nasty "pussy killing" Ethelyene Glycol used in I.A.T. Anti-Freeze:

Propylene Glycol pre-mixed coolant, 5 litres. NON TOXIC, LONG LIFE, ENVIRONMENTALLY FRIENDLY

https://citroenclassics.wordpress.com/2012/03/17/what-is-the-right-coolant-to-use-in-our-older-cars/

http://shop.citroenclassics.co.uk/propylene-glycol--pre-mixed-coolant-5-litres-non-toxic-long-life-environmentally-friendly-928-p.asp

I have no wish to go waterless with a product like Evans personally, although this isn't cheap as 3 x 5 litre containers would be required. Anyone used this stuff or have any comments to make about it? Either way an interesting article to read and could save your engine if you inadvertently put the wrong Anti-Freeze in.

Hello Graham,

After reading the information in those references the first question that springs to my mind is 'what about water pump lubricant?'  There is no mention of it anywhere.  Normal anti-freeze contains corrosion inhibitors and water pump lubricant and one of the reasons for regular six yearly replacement of anti-freeze is to replenish those as much as to change the anti-freeze.  I should add here that our 'relatively modern' water pumps have sealed bearings but older classics do not, and this is supposed to be for all classic cars.  So my question about water pump lubricant is more to do with older cars (pre-war) that I also work with.  Changing the coolant every six years also gives you the opportunity to replace the thermostat, temperature sensor and radiator switch as these don't last forever.  So whilst they say this coolant can stay in much longer, to me that is not a great selling point.

The features I do like are - it is supposed to have a higher temperature transfer efficiency, and better cavitation corrosion protection.

Regarding your own engine, with the new cam now finished, and bearing in mind the price of this pre-mixed coolant being roughly three times normal blue anti-freeze, is it really time to change it just yet, since you will be presumably stripping the engine to change the cam very soon. Smiley

Thanks for bringing our attention to this product.

Roy
« Last Edit: February 02, 2017, 10:53:40 pm by roy4matra » Logged

GP
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« Reply #10 on: February 03, 2017, 11:15:55 am »

Hi Roy,

Yes I agree with your comments and will change out the other items mentioned.

I will stick with the blue I.A.T. Anti-freeze especially with the jobs planned ahead.

Thanks,

Graham
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GP
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« Reply #11 on: February 05, 2017, 01:02:28 pm »

Hi Roy,

Update from my previous post. I just removed the lower front radiator hose and out came red coolant/antifreeze!  Shocked
I was sure I had used O.A.T. so I checked my spare bottle on the shelf (which is made by Bluecol) and to my relief it is red O.A.T. This clearly makes the colour as an identifying feature in the U.K. not much use anymore.

Something to add to your F.A.Q. page perhaps?

Graham
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roy4matra
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« Reply #12 on: February 05, 2017, 06:34:49 pm »

Hi Roy,

Update from my previous post. I just removed the lower front radiator hose and out came red coolant/antifreeze!  Shocked
I was sure I had used O.A.T. so I checked my spare bottle on the shelf (which is made by Bluecol) and to my relief it is red O.A.T. This clearly makes the colour as an identifying feature in the U.K. not much use anymore.

Something to add to your F.A.Q. page perhaps?

Graham

Er Graham - O.A.T. is supposed to be red.  The Murena should be using I.A.T. which is supposed to be blue.  Bluecol obviously make both I.A.T. and O.A.T. so you need to make sure the description says I.A.T.

Since you have had the wrong type anti-freeze in your system I would make sure you flush the old out and check all the other pipes and hoses.

Roy
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GP
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« Reply #13 on: February 05, 2017, 07:56:15 pm »

Hi Roy,

Jeez my brain is not working very well these days. Shocked I'd covered that earlier. I'd better get flushing and checking as you say!

Graham
« Last Edit: February 05, 2017, 07:58:28 pm by GP » Logged
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