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Bleeding Hell.

Gingerbread Man

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The car used to run at 80ish degrees happily.


Lately it gets up near to 100 degrees. Sometimes it'll kick back down to 90, sometimes it'll stay around 100 degrees. Never gone over 100 and coolant level stays happy.


Today I removed the stat (what a pain that was to get out!) to find (as expected) an 88 degree stat. I had brought an 82 degree replacement from Halfords ready to go in.


I also removed the heater matrix. Then ran a new hose from the water rail round to the stat housing. I hope this is right???


Replaced the stat and filled up the system. and got my bleeding hat on. Shook the bottom rad hose like mad and the J hose. Air came out and topped up as necessary.


Now. The temp gauge continued to rise and 80 came and went, the stat still not opening. When 95 appeared, I turned off the engine.



The new hose I ran from the water rail to the stat housing was piping hot. Too hot to hold. The bottom rad hose never got hot. Seems that the problem is with the stat not opening.


Could I have put the stat in wrong? Will it go in back to front? Have I bypassed the heater incorrectly?


I think my bleeding wasn't too bad. If it's still likely to be air, I'll get cracking on with it again.







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Are you always online Ian!!? Never bad with my mechanical skills!


I took out the heater and hoses. Brought a new hose from Halfords.


Ran this from the water rail above the primary's around the back of the engine to the stat housing/ J tube location.


This new hose is red hot as it goes into the stat housing, but the big J hose coming out isn't boiling hot. So the stat isn't letting the water through - right?


If I disconnect the new hose from the water rail and hold up in the air. Any air trapped by the stat housing should rise up? This would take the air problem away from there and hopefully move it on to an easy bleed location - rad bleed valve.



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I made the whole bleeding experience less bleeding tricky with a single small hole in the 'skirt' of the stat when I refitted an 82 degree halfords item into my K-Series - would you consider that?


It helps a number of things including bleeding if air is trapped at the thermostat.


It won't go in the wrong way round assuming it's a K-series we're talking about.


When I checked mine in a pot of boiling water I used water from our taps and covered it in a white scale after just 2 boil cycles.. (Oxfordshire water!!!)




Edited by - Rich N on 30 Mar 2009 08:47:13


Edited by - Rich N on 30 Mar 2009 17:08:44

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The joys of bleeding! Should be easier without a heater though *confused*, typical as you've removed it and still having problems.


Try raising the front of the car, unbolting expansion tank and holding this higher. I also bleeded from the top of the radiator WHILST running which I think many will shake there head at 😔 *confused*


Heater bypass sounds fine. Not sure whether the stat can go in the wrong way round.

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Stat... Temp sender... What's the difference amongst friends eh? *wink*


Don't disconnect the bypass hose at the water rail. Jack up the front of the car, and massage until your hands hurt. The air is probably stuck nearest the stat, because some dipstick designed it to be higher than the submarine *tongue*





Bugsy: '82 2cv6 (Back on the road!!! 😬)

Talloulah: '08 1.6K Classic (Grubby )

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Massaged over and over two nights in a row now and no air coming now. I think the air has all gone. I thought it had yesterday, no big gulps or much difference today.


So ran it up and the stat didn't open. I even unbolted the header tank and held it up higher whilst massaging away.


While turning away defeated again, I took the old stat with me (88 degree) and put it in a pan. This started opening at 88/ 90 degrees. So this one works. I still found temps running near to 100 degrees on any run/ basic drive anyway. I planned to change to an 82 degree stat anyway so all is not lost.


I'll check to see if the 82 degree stat works tomorrow when I take it out. If It does, I'll drill a hole in it's skirt and try one last time.


What size hole and how many?


If this stat also works, what are my problems.


a: I think I've got rid of most of the air if not all. Might be some in there causing problems still but I've tried over and over.


b: Could the stat be obstructed in some way? I'll take it out tomorrow but I'm grasping at straws here.


c: My temp gauge is lying to me. Easiest way to find out? Do I need an infra-red thermometer or will strapping a cooking thermometer to the black hose be sufficient?

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c: re the gauge lying to you .... there are two parts to this ... the gauge and the water temperature sender that measures the water temp from the water rail (exhaust side of engine, smaller of the two senders) and supplies associated value to the gauge. The sender fails quicker than the gauge......


Edited to include link to Sender


airborne tweaked supersport


My New Tow Car



Edited by - wavydavy on 30 Mar 2009 21:25:02

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I've replaced the sender top corner of the rad before. 6 months ago max.


I've never replaced the sender on the water rail. Does this report the water temp?


Still doesn't explain why the stat isn't opening. Unless it's out by ~20 degrees and 100 degrees (on the gauge) is ~80 degrees actual? Therefore it's running at normal temps and not too high.


I doubt this though. This bottom hose still doesn't get hot and the fan doesn't come on. What triggers the fan?



Ian - I'm not coming to Wight Blat I'm afraid. I do plan to go over to Wales and hoon about the Evo Triangle - Elan Valley and the Black Mountains come the long Easter weekend. But not if my cars likely to overheat!


Best bet to trying measuring the coolant temps and ignore the gauge? Order a new sender - Water Rail one as linked above?


Edited by - Gingerbread Man on 30 Mar 2009 21:32:38

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The temp sensor for the display is the brass one in the water rail. They fail frequently.


You can confirm the gauge is working by unplugging it at the sensor end, and touching the contact to a metal part of the engine - the gauge should go 'full scale' all the way to the right.


Hole in the thermostat skirt helped my tricky bleed + seemed to be the done thing in some cases. Did I mention that? 😬




Edited by - Rich N on 30 Mar 2009 21:41:08

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If it were me, I would prove the 82 degree stat works as described avove, if if does you might as well fit it. Check the gauge as described and fit a new temp sender, the one I linked to looks correct.


When the temp sender fails, it can make the gauge reading very unreliable, sometimes over or under reading or not at all! ....... I run a standard ali radiator on a 1900 cc K series with a dry sump and struggle to get the fan to kick in during the winter .... as you say the 88 degree stat is working fine, perhaps its the temp sender or gauge that are at fault?


airborne tweaked supersport


My New Tow Car


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There are two senders in the water rail - the single wire one is the temperature gauge sender, the other connects to the ECU I believe. As post above, remove the single wire connector and touch it on to something metal on the engine with the ignition on - it should go to full scale, to show this is the right sender ! And it 'proves' the gauge works.


Fan triggered by the large temperature sensor with 2 wires - in the top of the radiator. Test the fan by removing both those wires and touching them together with the ignition on.



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Just a few points. The engine designer who specced the pistons also chose the thermostat to suit the pistons.


I've never had a problem bleeding a K coolant system. I remove the small plug from the rad and allow the engine to tickover whilst topping up the colant via the removed plug. When coolant is running out this plug it appear all the air has been expelled.


Norman Verona, 1989 BDR 220bhp, Reg: B16BDR, Mem No 2166, the full story here

You and your seven toThe French Blatting Company Limited

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Touching the two wires from the read stat make the fan come on.


Touching the single wire for the water rail stat to the engine makes the gauge temp read full.


I'm thinking that I'll order a new water rail stat as recommended above. I'm busy in the evenings for a few days so when this arrives I'll get cracking. See if this cures it.


If not I'll re-drain the coolant and test the 82 degree stat. May also drill a few holes in the stat. What is the normal - two or three 2 mm holes in it's skirt?


The reason that I'm not going to test the stat first is A: I'm busy and won't be working on the car for a few evenings.

B: It's showing the same behaviour as the old 88 degree stat which is working. This makes me think it's something else telling lies.


Also the fan doesn't come on to cool the car down (when testing in garage). Is this because the water isn't yet up to 80ish degrees and I'm reading the temp from a dodgy reading?


I'm putting hopes on a new water rail sensor. Wish me luck! I'll reply back in a few days.


Edited to say that I just went to check 100% what water rail stat I had. The electrical spade connection that sticks out of the top happily spins around and around. Not leaking water but could this be a sign that it is knacked?


Edited by - Gingerbread Man on 31 Mar 2009 18:30:44

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Certainly sounds like it!


Re the stat, read Norms post re the engine designer specification of the original stat. FWIW I have not had to butcher my stat, neither have I suspect the many other million of k series owners..... if you have a functioning water temperature sensor/gauge then you will be able to judge the water temps a little more accurately *tongue* As you say the radiator fan kicks in when you short the electrics, which means the fan is working ..... if you fit the working 88 degree stat, new temp sender, fill and bleed the system correctly you will be back to state where you can properly assess your next steps. Best lof luck 😬


airborne tweaked supersport


My New Tow Car


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I hoped that my sender would arrive today, alas it hasn't.


I did how ever borrow a differential thermometer temperature gauge from work and wrapped the sensors around the rubber hose (round the corner from the primaries).


Now I appreciate that there will be a bit of insulation from the actual water temp and the outer hose temp but I can't see it being much!


When my temp gauge read just below 90 degrees, the thermometer displayed just above 50. 40 degrees difference!!


This would explain why the stat is not opening when my gauge displays 100 degrees!



Hopefully this'll all be the same tomorrow when I replace the water rail stat.


I'll confirm then. Thanks for the help guys.

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