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Discussion Starter #1
after a phone call from my OH to say the PH2 GTV was overheating I thought I knew what was going on....


symptoms.

overheating under load, overheating afert about 10 mins of idle from cold, fans kicking as and when they are supposed to but has no effect, burped the system just to make sure it wasn't an airlock and still the same issue...scratched head and had a think.

next step after spocking it through I popped the return hose off the header tank to see if there was anything coming out..not a thing!

top hose was warm, bottom hose not so much, coolant cool, rad cold..engine temp 110!

bought some radflush just in case the rad was blocked, flushed through and refilled rad confirmed not blocked, no change though, obvious no circulation, it must be water pump..surely? if not a blocked rad..?

so camcovers off and I thought I may as well do a cambelt and replace the water pump etc etc...all done but the old water pump looked in very good nick, certainly not the cause.


the culprit..? the thing I ruled out at the front end as it very rarely if ever happens, the stat had failed closed!

new one fitted from ECP and all good.


BTW the stat opened in a pan of boiling water but I had a feeling it was not opening fast enough allowing the engine temp to run away, this turned out to be exactly spot on.


so the next time you have overheating issues that look like a blocked rad or failed water pump , have a good look at the stat first.


I am very surprised at this as I have never seen it before.

you live an learn!
 

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Thanks for posting, thats useful to know. I have only had thermostats stuck in the open position so I would have guessed at water pump too.
 

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I had this the other day on my sisters Mini but I'd already fitted a new thermostat a few weeks before so ruled it out :banghead:
 

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Discussion Starter #4
Thanks for posting, thats useful to know. I have only had thermostats stuck in the open position so I would have guessed at water pump too.
well, thanks for that back up, and that is exactly why I posted, had i readanywhere it had happended I would have speculated it ''could'' be the stat and changed it first.

I felt like a dummy yesterday as it would have been 4 hours faster to change the stat! I am still not speedy at TS cambelts having only done about 4 ...I have one more to do in the next couple of weeks so I will get faster..
 

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Wow thats very rare. Never even crossed my mind while we were speaking.
 

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Discussion Starter #6
Wow thats very rare. Never even crossed my mind while we were speaking.

Nor mine Dan, I had all but ruled it out , hence going through the process of doing a cambelt before even considering the stat!


only ruling out the waterpump gave me no other possible option, I checked the resistance of the temp sensor when removed from the stat both hot and cold but it did what it was supposed to do, nice and linear reading as the temp went up.

besides the temp gauge and the point at which the fans were kicking in indicated that the temp sensor and gauge were reporting ''correctly'' so they confirmed each other really.

the real kicker was no coolant coming through the return hose to the header tank, that was such a strong indicator of pump I couldn't believe it when it came off looking very healthy!

however after I established it was the stat I could see how that could happen.


worth posting as it did open in a pan of boiling water, just not very quickly and it closed pretty quickly after the water stopped boiling.

I think the stat was opening but late and not enough so that the temp had runaway to a point where it couldn't be recovered with the flow available.

so 2 ''myths busted'' really


1) stats do fail closed

2) they can work in a pan of boiling water but still be operating insiufficiently on the car to be be effective.


the moral of the story..check your stat first!:rotate::rotate::rotate:
 
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