Coolent System Thermostat

[rita]

Right, I'm at the end of my tether.....thermostat changed...bottom of the radiator is still cold....I have read back and whilst I wouldn't expect the bottom hoses to be as warm I would expect a little more even temperature in the rad.
So am I facing the almost inevitable conclusion that head #2 has gone, in which case I am afraid she's down the road!!?
All Ideas gratefully considered.

What other symptoms are you getting to give you concern, the thermostat (owing to its location)is up and down like a Fiddlers elbow ( open shut).Is the system over pressurising?

You could try draining the coolant , removing the temperature gauge sender ( top /front driver side of cylinder head) refill the system until the coolant flows ,refit sender, to bleed the system.

Good Luck.

[Simon Jones]

My advice would be to test old and new 'stat in a pan of boiling water so you can see what works or doesn't. If you have bought a new Mazda one then it WILL work correctly. When you test them both side by side, you'll probably find the old one will take longer to open and the disk will not move as far. If the old one doesn't budge even in boiling water then you know your diagnosis was correct. My gut feeling is that it will actually be ok. Report back on your findings.



Here, the new one on the left and the extra movement on the disk is clear to see. Both are starting to close as they cool down when the photo was taken.

[mikeonb4c]

My advice would be to test old and new 'stat in a pan of boiling water so you can see what works or doesn't. If you have bought a new Mazda one then it WILL work correctly. When you test them both side by side, you'll probably find the old one will take longer to open and the disk will not move as far. If the old one doesn't budge even in boiling water then you know your diagnosis was correct. My gut feeling is that i
t will actually be ok. Report back on your findings.



Here, the new one on the left and the extra movement on the disk is clear to see. Both are starting to close as they cool down when the photo was taken.

I'd have thought they failsafed in the open position. When mine was tired, the engine was slow to warm, for that reason I supposed. Would explain cold bottom hose maybe? Sorry if I'm getting the wrong end of the stick - haven't re-read all the posts

[Northern Bongolow]

ive just taken chells gen mazda stat out today, and fitted new gen mazda stat, new rad and new 5 year coolant.

the 18 year old rad was wet around the crimped edge top and bottom, but when tested the 4 and a half year old mazda stat was still perfect when pan tested.

neither of the stats in simons picture are mazda stats as they dont have the rubber cleaning band around the top of the spindle.

sorry to highjack the thread but i thought important to mention to fit a gen mazda stat as they really work.

click on this pic to enlarge it.
http://www.ebay.co.uk/itm/like/17104162 ... 108&ff19=0

[Simon Jones]

The one on the left is genuine Mazda according to the box (as it came from club shop) but bear in mind it's for a V6 so it is different .

In answer to previous question, there is no fail safe mode: it will remain in the state it was prior to failure which in most likely to be closed.

[Northern Bongolow]

.

looks like all the petrols have no rubber cleaning ring simon, apologies

http://www.mazdabongo.com/catalog/cooli ... ls-genuine

[Simon Jones]

That's cos petrol Bongos are so much cleaner than diesel ones . Interesting that they are different though.

[volamoose]

Sorry all, I should have got back to you sooner. The taking the revs up did it ( I didn't actually read it here, as, just a thought) 'course had I returned to this page I'd have read it, but hadn't had any replies at the time of trying. So bled as per video, then when up to temp I increased revs to between 2500 & 3000, when steam erupted I backed off till it settled down, and repeated till no more eruptions and taking no more coolant...shazzam...job's a goodun. Thanks all!!

[Simon Jones]

Sounds good. Did you test the old 'stat out of interest just to see if duff?

[volamoose]

Nope, that's one new water pump & thermostat(passed the kettle test) I didn't need.So they're both cleaned up & on standby!