Replacing Thermostat Housing

Technical Area Engine, Transmission, Exhaust etc
2

Hi All,

I replaced the rad on Saturday. Easy job, all went well. As I had bought a new 'stat too, I thought I’d just replace it as “preventive maintenance”. Of course, the thermostat cover bolts were seized and sheared. I’ve tried plus-gas, heat, mole grips and broken a stud removal kit trying to get them out. My drill and most of my tools are at the other end of the country, so I don’t really want to go and buy another decent drill and reversible bits to get them out.

I’ve got two options - the first being to get it towed to a garage and get them to sort it (it needs a cambelt soon anyway so they can do that at the same time), or too replace the whole housing.

 My question is how do I remove the thermostat housing? The only guides I can find that mention it are the waterpump replacement guides which say the rocker cover and all the timing belt covers have to come off to get at it? Is this really the case or is there a quicker way?

Mk1 1.6 by the way

thanks for help!

Mike P

3

 If it’s like the 1.8, then the timing belt covers have to come off, but probably not the belt itself, which means the cam cover needn’t come off.  The housing just fastens onto the block with 2 bolts.

4

Brilliant, I’ll have a look first thing in the morning. I’m hoping it’s pretty straightforward…

 thanks

 Mike P

5

 It’s not as simple as that I’m afraid. In order to swap out the thermostat housing you will need to remove the backing plate behind the camshaft pullies, which entails removing both the timing belt and the camshaft pullies.Once you’ve got to this point it’s an easy 2 bolt swap (+ a new ‘O’ ring).
You can get the info you need here:-
http://www.miata.net/garage/water_pump.html
you can see what has to come off here:-
http://www.miata.net/garage/images/campulley.jpg
Though you don’t need to take the water pump off.
 
Good Luck