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Roccoguy: Yeah that's what i normally do as well except that the fan never kicks in.. And it is working, i've tested it and it has a new sender, as soon as i put the stat in, the bottom of the radiator just won't get warm enough.
Chasr: It's a Gates thermostat, supposedly OEM quality. I've used them before and they seem good. I'm not sure if the mk2 stat is meant to have a hole/ jiggle pin, i don't think so.. Would it hurt to drill one to prevent any airlocks?
Thanks for the help everyone.
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Use hot water when bleeding. It will open the stat and prevent any air locks as the system will be in full circulation. And I say lemon because it cuts through grease. And it's £1
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bortaf
Posted a lot
Posts: 4,549
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Sept 2, 2013 13:48:04 GMT
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Not really sure on this particular layout but is there a small bore pipe near the stat housing that returns to the header tank? if there is and these block they make the exact same problems you are describing (at least in most fords of the 80s/90s), they usually have a restrictor in the pipe or header tank return that usually blocks with limescale and needs clearing/drilling out. Worht a look although i may be well off the mark ?
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R.I.P photobucket
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Sept 2, 2013 14:16:32 GMT
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Ah well I used dishwasher tablets this time.. I'll keep it in mind though, cheers.
bortaf: I think it's a bit different on the mk2 but the pipe you mean goes from the top hose to the header tank. That's a good point i'll check it out. Thanks.
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Sept 2, 2013 14:41:46 GMT
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Have you checked condition of the heater matrix only ask as Havnt seen it mentioned in thread and have also experienced personally were the matrix has a tiny pinhole in it which leaks just barely but also causes airlocks and all sorts of problems .....depending on if its routed before or after stat Took me an eternity to suss it out lol but worth a punt . Easy enough to check by just bypassing it via joining pipes together
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Sept 3, 2013 16:56:06 GMT
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Thanks for all the suggestions, I drilled a wee hole in the stat to allow any air to get past the stat and guess what: The bottom hose now heats up and the heaters are blowing hot! However the car still overheats.. The fan kicks in now as the bottom of the rad is heating up which brings the temp back down but it's still not right. It does take a lot longer to get too hot though!
I reckon the pump is also on it's way out, can't think what else it could be. I think the airlock was only part of it..
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Reckon you still have an air leak somewere in that case Jerry rig a pressure test up and see if you can spot were it is
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Nov 11, 2013 18:31:23 GMT
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Sorry to resurrect this ancient thread but i am still having the same issues- To recap:
What is wrong- Car overheats, bottom rad hose stays cold til temp is well over half way
What I have done so far- changed water pump, stat changed twice, hoses, heater matrix, coolant, flushed system.
It seems I still have a major air lock in the engine. I have absolutely no idea what to do about it though.. Tried all the usual methods.
I also find that the coolant never boils over with the cap off no matter how hot the gauge reads. What could that mean?
Any help would be great.. thanks!
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Dave_Q
Part of things
Posts: 32
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Nov 11, 2013 21:37:45 GMT
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Are you sure the gauge is accurate? On my gf's mk1 the gauge is very variable and I have come to the conclusion that is is not actually overheating.
Any way of checking the actual temperature?
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andyf
South West
Posts: 415
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Dink has just posted what I was thinking. See if you can get hold of one of those infra red temperature guns that you point at hoses to check temperature. May even be the sender unit for the gauge.
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1980 Triumph TR7.
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Dave_Q
Part of things
Posts: 32
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Nov 14, 2013 11:01:07 GMT
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Even a thermometer in the expansion tank will give you an idea.
Obviously it will be at a lower temp than the engine but if it's at less than 90C when the gauge says its overheating you're probably fine.
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Nov 14, 2013 18:27:26 GMT
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Is it possible to put the thermostat in upside down?
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Nov 16, 2013 11:02:57 GMT
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Hmm, I'm not 100% the gauge is accurate but it's definitely getting hot... The thing is it stays low with the stat out so I reckon it is reflecting the temp.. I'll try a thermometer when I can get hold of one. One other question- could this possibly be due to the expansion tank cap? It's one of the old black ones.. Also, the overflow pipe that runs from the top hose to header tank pours water out into tank the whole time.. I thought it should only do that under load? Is it possible to put the thermostat in upside down? Why would I want to put it in upside down?
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RobinJI
Posted a lot
"Driven by the irony that only being shackled to the road could ever I be free"
Posts: 2,995
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Nov 16, 2013 11:12:09 GMT
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I think he means if it's possible, then you could have done it by accident. My VW's have always had flow through the header tank when the coolant level's high, a slight trickle on idle and jet coming out at anything 1000rpm+.
Personally I'd be tempted to blame the rad if you're sure the rest of the system's up to scratch.
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Nov 16, 2013 12:00:22 GMT
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Haha I know, sorry bad joke.
Forgot to mention, I flushed the rad a couple of times and flow seems to be fine.. Not sure how to test for certain though?
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RobinJI
Posted a lot
"Driven by the irony that only being shackled to the road could ever I be free"
Posts: 2,995
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Nov 16, 2013 13:02:24 GMT
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The next thing to check's probably the flow through the hard-line that goes from the stat housing around the front of the block and over the bell-housing to the heater matrix. The stat relies on this as it's source of hot water to tell it to open, so if it's blocked the stat could be sat in cold water while the block and other pipe-work heats up.
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Nov 17, 2013 21:54:20 GMT
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The next thing to check's probably the flow through the hard-line that goes from the stat housing around the front of the block and over the bell-housing to the heater matrix. The stat relies on this as it's source of hot water to tell it to open, so if it's blocked the stat could be sat in cold water while the block and other pipe-work heats up. Yeah, that pipe gets hot, in fact even the part of the waterpump that the stat sits in gets hot.. So it SHOULD be opening. Weird. Wish I had a thermometer, I'm starting to doubt that gauge. Thanks for the help, it's appreciated.
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Nov 18, 2013 16:05:24 GMT
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have you got mfa? you should be able to tell oil temps on there which will a better indication to engine temps.
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Nov 18, 2013 19:54:55 GMT
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have you got mfa? you should be able to tell oil temps on there which will a better indication to engine temps. Unfortunately not, don't think any of the diesels have it..
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Nov 19, 2013 15:10:25 GMT
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Ok, bought one of those cooking thermometers with a probe and stuck it in the expansion tank- getting a reading of 163*F/ 73*C.
I don't know how much cooler the expansion tank is than the engine but I imagine not much?
So, given that this was the reading when the gauge was over 3/4 am I correct in concluding that the gauge is not accurate and the car isn't overheating at all?
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