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coolant flow and rad problems. Pug 306td - r1ch1e
Please help, I am having a coolant flow problem as I have an extra pipe that I dont know where to put. I will try and paint a picture in your head with what I am working with in the hope you will understand it and know how to advise me best.
ok, This is how I\'ve worked it out, start at the radiator and ther are two hose bottom left, one is the degassing pipe from thermostat housing, then thereis the big bayonet type pipe that runs to the pump, from the pump there are 3 external pipes, one to heater matrix, one to oil cooler and one to underside of thermostat housing, the heater matrix then comes back out to the back of the cylinder head, which in turn goes back through the block to the thermo house, which all makes sense. there is then the radiator top hose which goes from thermo housing direct to top of radiator opposite side to expansion tank. I am then left with one hose coming from the oil cooler which presumably is water coming out of the cooler as the pump is sending in on the other pipe. On my old engine this pipe went straight into the top hose between the thermo and the rad. Effectivley that would be putting it straight back to the radiator to then cool again. On the engine I have got now however it wasnt spliced that way and from what I\'ve seen of pictures when it was in the old car (written off) the pipe went to the expansion tank but on its own fitting next to the degassing pipe. Stupidly enough I didnt realise this was a degassing pipe at the time and had originally t\'d the pipe into the degassing pipe so it still flowed to the expansion tank, however this is putting a lot of pressure into the expansion tank even when cold and I think may of been the cause of the blown head gasket within a mile problem I had. I am really looking for a vote of confidence that putting it back to the top hose and effectively back to radiator makes sense. To me it sounds right as that way it is then cooled down again and makes a complete circuit, however the last thing I want is another problem occuring that may result in being more serious than a blown gasket such as broken oil cooler, cracked radiator etc. Someone else has told me it makes no sense being in the top hose as it would create a back pressure to the thermo hoousing and effectiveley stop the water flowing out of the cylinder head, but I cant see it as the pump is still drawing coolant from the rad therefore creating a vacuum effect that will pull the coolant the right way??
Sorry if I went on one there but trying to give as much detail as possible to get a good accurate response.
coolant flow and rad problems - solara
car model might help.
coolant flow and rad problems - r1ch1e
sorry, 306 td, phase one (pre 97)

{added to subject header. DD}

coolant flow and rad problems - solara
I know that there are two types of expansion vessels fitted to the rads on these pugs (mines a 306 td 93). One has an extra pipe connection. Couldn't you pipe it up to the existing rad/vessel?

Apologies if this doesn't answer your problem, but your description is too verbose for me on a Friday afternoon.
coolant flow and rad problems - r1ch1e
That is what appears to be the problem, the donor car had two pipes on the expansion vessel, but mine only has one. I tried using a t piece into the degassing pipe but it created a hell of a lot of pressure in the vessel even when cold and started overflowing. I believe thjis may of been the cause of my head gasket blowing within 1 mile of driving it. I want to try and t it into the rad top hose instead as it makes more sense as it then does a circuit through the rad and back to the pump. If it goes back to the vessel it doesnt get cooled again properly. I just need a bit of ressurance this wont cause false pressures elsewhere and create more problems.
coolant flow and rad problems - pienmash
dont mean to sound sarky,best bet on a pug td is to get the right rad,this placed i used in crystal palace are well cheap for pug rads ,there called aaron radiators,they only sell orig rads for pugs as well not them cheapie copy ones.
coolant flow and rad problems. Pug 306td - Civic8
sorry your point about oil cooler.it is part of rad/but a seperate part.the two are not connected only as a material section of rad.degassing pipe will be the breather pipe to expansion tank.ie as you fill with water it should get rid of any air in system./before I go any further is the rad correct for your car it doesnt sound it.and there wont be any answers if it is wrong.I may have missed something in your post?
coolant flow and rad problems. Pug 306td - r1ch1e
It is the right rad for the car but as I have bought a new engine it would appear the rad should be slightly different as the oil cooler is plumbed slightly different. On the old engine it drew water from the underside of the thermo housing and put it back out through the top hose. On the new engine it appears to draw water out of the oil cooler and push it back through the block and then out through the top hose. Where I had previously gone wrong was in thinking the pump pushed water through the oil cooler, not sucked it out. Hence why I had some plumbing wrong and effectivley had created a loop forcing air back into the system.
It now looks likely I know where the error lies, as the oil cooler feed pipe needs placing into a direct cold feed hence why the other radiator has 2 connections on the rad not one. The radiators themselves are the same, the difference is the expansion tank has 2 fitments not one. After serious checks of flow direction and pressures I have now found that the most efficient way for me to plumb this until funds allow a new radiator with correct expansion tank is to take a feed direct from the radiators main outlet hose straight to the oil cooler.
Thanks for everyones advice on this one, all help combined has probably saved me at least another blown head gasket, if not worse.
306td, normal behaviour? - r1ch1e
Ok, finally got the car back together all plumbed up and full of coolant. Does this sound like normal operation of the cooling system as test 2 will be going out in it to actually drive it and see how it runs, but dont fancy getting 1 mile again.
Ok, started engine and stuck it at 2.5 to 3k rpm to warm it up. once up to about 45 degrees you could feel, oil cooler pipes are warm, matrix is warm, thermo housing back to pump is warm and rad top return hose is cold. Gets to about 60 degrees thermo opens rad top hose gets warm, as does radiator. gets to 95 degrees fans kick in, within 30 seconds to 1 minute the temp is back down to 85 ish (normal op temp for derv).
I let it fully cool down from there, took rad cap off and level in expansion tank has dropped by half, which seems as though the degassing pipe is functional and all airlocks have been pushed out and replaced with coolant, so topped it up. Re ran back up to 95 fans kick in let it cool again to 85 kept running back to 95 again fans back to 85, switched off and left it. checked levels in tank again and the level has remained the same in the expansion tank so no more air being pushed through.
Just wanted to know, does this sound like it is all functioning correctly??
P.S, 60 through to 95 took ages so would think it wont reach 95 with air flow around engine on open road.
Cheers for any advice / comments in advance. I SO do not want another blown head gasket!!!
306td, normal behaviour? - DL
Sounds OK to me!

Well done.
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306td, normal behaviour? - Civic8
sounds good to me.hope it stays that way.good luck
306td, normal behaviour? - solara
Shouldn't the thermostat open at 83 degress C (not 60 ish), as stamped on thermostat? Atleast it did on mine when I recently changed it for a new one.