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Cooling Issue


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Hi all

 

Quick piece of advice needed please (I hope)

 

My 2B is overheating when running, this can be as simple as just ticking over, just before the fan kicks in i have noticed that the header tank starts to boil and inevitably lose some water.

 

I'm pretty happy the pipes are 99% correct, and hopefully the stat is not knackered, i believe this issue is this;

 

I have the top pipe on the header tank as an overflow

I have the top pipe on the rad as an overflow

Solution - connect the two together to pressurize the system?

 

Given it is glorious outside and the lack of extra heater hose, does anyone see an issue with just blocking these two pipes up as an interim solution?

 

Thanks

Simon

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Guest mcramsay

Top connection on the radiator should vent back to the header tank, top connection on the header tank ( just below the pressure cap) should feed into an overflow bottle.

 

If the coolant is boiling before the fan kicks in either the fan is cutting in too late, or you have pressure entering the system from the exhaust.

 

What reading does the temp gauge give? And how long does it start to boil.

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Guest Gargoil

Are top and bottom hoses hot when the fan kicks in and why do you need two overflows?

 

The more info you can give, the better the answer you get.

:pardon:

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First things first, have you checked the thermostat? put it in a cup, pour boiling water over it and it should open up fairly quickly. Next, is it fitted into the housing the right way round? They will fit either way. The bulb should be in the water of the engine side, not the hose side. Now we can look at hoses and tanks.

Start with you rad cap, is it a 13lb cap? is it a double acting cap and does it have a seal under the large fitting face?

Now there are a couple of ways of doing the next bit.

The leak off pipe from the radiator needs to go either to the bottom of an overflow bottle (1/3 full of water) the cap of the overflow bottle will just vent to air.

Or to the bottom of a header tank (so that it can return back to the rad) the overflow pipe from the header tank should just vent to air. If you have a pressure cap on the header tank, then change it for the lowest pressure that you can find. (I use this system with a 5lb cap on the header tank, it helps to push the water back into the rad when it cools)

 

If your stat & plumbing are correct, then you've either got: A) air lock . B) Head gasket problems. C) blocked pipe / radiator.

Edited by Big Jim
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Guest evildave

I'd not bother testing the stat and just put a new low temp one in. if you have electric fan you can get adjustable temp switches for about £12 just turn the dial.

I don't run an overflow bottle and have no heater etc so not a lot of fluid in the system 2litre Cortina rad running a cammed 2.1pinto that gets thrashed, on the move drives around 86degrees, fan comes in at 90.

I'll be fitting an oil cooler soon as well just to help.

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  • 1 month later...

Hi all

 

Thanks for the response, apologies for the lack of feedback, pretty rude of me but I've been far too busy with work to play with the car!

 

Anyhow took it back out tonight and after a five mile stint it lost 1.5L of water. Whilst the header tank is boiling the water seems to be coming out of the rad cap. Fan kicks in at 85 which is in the top rad hose. Water boils in the header so obviously a lot hotter here!

 

The above gives me some stuff to go on as my set up is listed below which differs a bit so I'll try and align to the above.

 

Rad overflow to header overflow

Top rad to top engine thermostat

Bottom rad to water pump and bottom thermostat and bottom header

Top header to very top small outlet on engine thermostat

Header has a pressure cap, not sure on rating (140? Maybe)

Rad has 13LB one

 

I'd upload some pics but can't seem to on here, if anyone has anymore advice then great

 

Thanks

Simon

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