Thermostat for the 2.2

[Jon Weywadt]

I am having yet another problem with my 2.2.
I was driving it every week, or so, until 3 weeks ago when it refused to start. Ignition was working and the electric fuel pump was working, but no way it would start. Then when a friend came by we tried again and noticed a bubbling sound from the expansion tank when cranking. Investigating it there was plenty of coolant in the tank.
After many attempts the engine finally started and ran at idle without any further bubbling from the expansion tank. After a while at idle I happened to touch the cooling pipe where the original fuel pump is located and the pipe was cold. So was the thermostat housing.
So I shut the engine off and removed the air vent screw on the cooling hose by the termostat housing. No water came out.
I then removed the cover on the housing and discovered that there was no coolant in the top even though there was coolant in and around the thermostat.
I assembled everything and using my homemade bleed bottle I sucked the air out of the hose from the thermostat housing until water came out. Also from the hose from the radiator until water came out. Once more with the engine at idle the pipe and housing did not get warm.
Conclusion, the water is not circulating to the radiator. Can that be a stuck thermostat?
I have not had it out since I do not have a new gasket, but can it block the flow so the pipes stay cool? The fan belt is ok and the pump is turning.
I want to get a new thermostat to try, but apart from the expensive option from Simons, which car/model use the same thermostat as the Murena?

[MatraIan]

Could be a stuck thermostat. Might be a problem with water pump??
have you read Roys FAQ page 5 http://www.matraclub.org.uk/faq5.html#top
also from roys parts page http://www.matraclub.org.uk/Murena.html

i think the original was a QTH 165 or 165K (with seal )
also see this
http://www.matrasport.dk/forum/index.php/topic,3095.msg23121.html#msg23121

[Jon Weywadt]

Digging through my stash of spares I found an assembled thermostat housing, alas without thermostat. Then deeper in the pile yet another housing and this time in luck, with thermostat. After cleanup and removal from the housing i immersed it in water and added a dip boiler and a thermometer. It say 83 degrees on the thermostat and wouldn't you know at 83 degrees it began to open and opened fully at about 90.
Next, I pulled out som gasket material and hammered out a new gasket using the housing as template.
This weekend I plan to replace the thermostat and then check what is wrong with the current one. Wish me luck. 

[roy4matra]

I am having yet another problem with my 2.2.

... After a while at idle I happened to touch the cooling pipe where the original fuel pump is located and the pipe was cold. So was the thermostat housing.
So I shut the engine off and removed the air vent screw on the cooling hose by the termostat housing. No water came out.
I then removed the cover on the housing and discovered that there was no coolant in the top even though there was coolant in and around the thermostat.
I assembled everything and using my homemade bleed bottle I sucked the air out of the hose from the thermostat housing until water came out. Also from the hose from the radiator until water came out. Once more with the engine at idle the pipe and housing did not get warm.
Conclusion, the water is not circulating to the radiator.

Sounds like it Jon.

Can that be a stuck thermostat?

Possibly, but it could also be one of the faulty water pumps.  If you leave the thermostat out altogether does it then circulate?

I have not had it out since I do not have a new gasket, but can it block the flow so the pipes stay cool? The fan belt is ok and the pump is turning.

Forget the thermostat for the moment Jon.  You need to check the water pump impeller and that you haven't got one of those faulty pumps!  Check out my posting here on water pumps with alloy impellers and also check out my FAQ's on just this as Ian has pointed out but go to the last item or click this link: http://www.matraclub.org.uk/faq5.html#one.  If you have one of those curved vane impellers it will not circulate the coolant until over 1500 rpm.  You should change any pump that has a curved vane impeller or at least replace the impeller with the correct straight blade one.

I would also advise all 2.2 owners to read and seriously consider my improvements to the Murena cooling system also posted here under the title 'A better 2.2 cooling system'.

Roy

[Jon Weywadt]

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I would also advise all 2.2 owners to read and seriously consider my improvements to the Murena cooling system also posted here under the title 'A better 2.2 cooling system'.

Roy

I have printed that out and will consider my options.
A year ago Jesper and I replaced the water pump with a rebuilt, using shaft and seals from a Dolz T116. The impeller was the original cast iron type and is pressed onto the shaft. Jesper does not think it can have come loose. The fan belt is intact and the pump wheel is spinning.
So the thermostat is coming out and i will test it. But also fill it up and run the engine without thermostat to see if it circulates.

[Oetker]

I replaced the thermostat in my 1.6 with this one.


This is opening at 81 C and has automatic air venting to let trapped air out.
It made my coolsystem better.
As far as I know the 2.2 uses the same thermostat according to the manual.

Herman

[Jon Weywadt]

----
So the thermostat is coming out and i will test it. But also fill it up and run the engine without thermostat to see if it circulates.

The weather was finally good yesterday, so the thermostat came out. After refilling the coolant until it came out of the vent screw on the hose by the thermostat housing, I started the engine.
In the expansion tank I now could see coolant coming out of the top inlet which vents the thermostat housing. What a relief. 
That means that the pump is circulating the coolant and the impeller has not come loose. This was checked without thermostat installed, as suggested by Roy.
Next the replacement thermostat goes in and we try again.

[Jon Weywadt]

Next the replacement thermostat goes in and we try again.

Success. The replacement thermostat is working and water is circulating as it should.
A short test drive to warm it up and clean the brakes, then back in the carport.
All is well again.