Hi guys I've given up trying now with this bloody car. First things first it's an X reg 6n2 automatic, 1.4 16valve, AUA engine code

Originally the car came to me with a water leak from the pump so this was replaced along with the timing belt kit nearly two months ago. I was not made aware that the heaters started to fail earlier in the summer, since the pump being replace I have learnt that the coolant is not flowing what so ever. Obviously the girl was not happy with the car so I have carried out more work to try and correct the issue. I replaced the complete thermostat housing and fitted another new water pump. This still made no difference and the engine still overheats, the heaters only come luke warm when the engine is at 3,000rpm or more and the fan does not cut in, no coolant flow still and this is where I started to check flow through things. Tested the matrix and radiator both ways, perfect. Visually checked all the hosses and coolers and all check out perfect also. I am still at this stage scratching my head at what is causing this issue of no circulation. As requested by the customer after a discussion that it's a possibility that the engine has a blockage internally I have now fitted a second hand engine that was removed from a running car with no heating issues what so ever. After completing the work I have been put back to square one with it and am still none the wiser. I'm hoping and praying that one of you guys on here has had this issue or can tell me weather I'm missing a trick to bleeding the air from the system, I have tried numerous times to fill the system but having no joy with it making any difference. Thanks a lot guys in advance. I know it's a big type up but I'd rather give all the details instead of leaving blanks.

Cheers, Dean.

This is the method I use to bleed the system.

Cold engine, remove expansion pressure cap top up with antifreeze mix to max line, start engine, hold rpm @ 2/2.5K for 20 mins, with heater selected to full hot, fan on low, by this time it should be indicating 90deg and pipes to/from radiator & heater should be all the same temp, stop the engine, top up to max again, refit pressure cap, run engine again for 15~20 mins, switch off and allow to cool, when cool enough top up to between min & max

Are you sure the thermostat is opening at around 90deg and it's not blocked? I had once a similar problem with the thermostat not opening and alowing circulation throught the radiator.

Ended up cooking it in a pot to see if it works (a new one didn't work)

If the pipe that goes to the lower part of the matrix stays cold there is no flow through it.

If the heather in the cabin is working, heating, than you have flow through the engine but not to the matrix.

if this doesn't help you can take down the thermostat housing and sticking a water pipe in the tube that goes to the w. pump and see if the water comes out on the head.

In this case the engine w ways are clear and you can concentrate on other things.

I think it's something with the thermostat...

Fitting another engine seems a bit drastic!!

When you say that you have 'visually' checked the hoses, did you check the INSIDE? It is always possible (but not very common) for a 'flap' of rubber to be acting as a one-way-valve.

If the impeller vanes on the second pump that you removed were in good condition, then it is likely that there was nothing wrong with that pump.

I would be tempted to temporarily run it without a thermostat and see if you can get circulation around the block,head and radiator.

I know that you say that you have changed the thermostat housing, but if the cross piece in there is broken, there is nothing for the thermostat capsule to react against, so the 'stat can't possibly open, resulting in NO circulation through the radiator, although (providing that you have got ALL of the air out) the heater should get hot providing that (1) the matrix isn't 'blocked. (2) the heater temperature control valve is working.

A simple way to check that there isn't a blockage in the heater matrix, is to disconnect both hoses and blow through the matrix by mouth. Do not use compressed air or you will need a new matrix!!

Regards

blocked radiator...

id try it without the thermostat in so it's free flowing first and if that fails id be flushing the radiator out with a hose pipe to see if water can flow through it or not

The cylinder block will not have a blockage, it's an aluminium moulding, the waterways are huge.

The head gasket is another matter - the holes in that are relatively small, so if any plastic breaks away from the inside of the rear supply tube around the seal (this does happen), breaks away from the thermostat housing walls (this happens too), or from the plastic thermostat cage itself (you guessed it, these also break up), then these bits of plastic will end up wedged in the head gasket's holes. All the coolant has to pass through the head gasket.

But before you whip the head off, determine where the water is going. Take the thermostat out, run the engine until it starts to warm up and feel top and bottom radiator hoses for which one heats up first, if one heats up at all (obvious), and how long it takes the second one to heat up, bearing in mind there's no thermostat so it should follow suit quickly.

As you have replaced the engine and the fault is still there, it must mean the problem is with the "car" side of the waterworks/plumbing

Just a quick addition when I say there is no circulation I am talking even at the return hose to the header tank there is none what so ever. When I originally started the car after the engine swap it started to circulate into the header tank and I thought I was into a winner but shortly after this circulation stopped and it's back to not circulating what so ever. As if the pump has failed (I know it hasn't as its not even done any actually driving mileage) I can't understand why it would just stop circulating the start then stop again, the heater matrix pipes are only warm half way up and when I take them off there is no pressure behind any of the coolant system which I'm sure it should be pumping to there? Unless of course I'm wrong and someone can inform me of how to correctly test if I'm getting any flow.

I have used a hose to check the radiator both ways and also the matrix both ways.

One question I do have is when I fill the system should I expect the pump to push the air out of the system? If so is there any way you could recommend I can try and force bleed the system?

Ta again

dean

Here's the method from the dealers manual 6N2 cooling system drain refill.doc

If you grab hold of the top and bottom hoses whilst the engine is on a fast idle, you should find; (1) With a good thermostat in place - the top hose will start to get warm, followed by the bottom hose, when the thermostat opens, the top hose will become hot and the bottom hose cooler due to the cold coolant in the radiator moving into it. (2) Without a thermostat, the top and bottom hoses will warm up together.

What you saw going into the header tank MAY have been bubbles, but as the air started to dissipate, the bubbles ceased, leading you to think that the circulation may have stopped.

Regards.

Take the thermostat housing right away from the cylinder head. This is done by three bolts (5mm Allen key) and a clip for the rear pipe. Takes just a few mins.

Now you have just two holes, one in, one out, of the engine. This test will check the pump and engine are okay, so this 5min test will save you having to change the pump or head gasket or engine..

Put a hose pipe in the rear pipe, run the engine, and if water gushes out the big hole in the end of the cylinder head then you know it's not the engine at fault.

You now only have to check the plumbing outside the engine. You can rule out the heater matrix because a blockage there would make no difference - you block it by turning the dial to blue, after all.

Take the thermostat housing right away from the cylinder head. This is done by three bolts (5mm Allen key) and a clip for the rear pipe. Takes just a few mins.

Now you have just two holes, one in, one out, of the engine. This test will check the pump and engine are okay, so this 5min test will save you having to change the pump or head gasket or engine..

Put a hose pipe in the rear pipe, run the engine, and if water gushes out the big hole in the end of the cylinder head then you know it's not the engine at fault.

You now only have to check the plumbing outside the engine. You can rule out the heater matrix because a blockage there would make no difference - you block it by turning the dial to blue, after all.

Mikey I have done this on the old engine with a bad result hence why I changed the pump again then ended up going with the engine as it still made no difference. I really can't understand why the coolant is not circulating as everything should be ok 😐 Staring at a blank page with this one and can't understand it now because it's just like it should be working!

Is there a possibility that someone used some kind of radiator sealant mixed with the coolant? That could block waterways in the engine when it get's hot and in contact with air.

I would go step by step starting with the engine as mikey said...