25 replies to this topic

[JamesMiniMealor]

Hi, me again.

The final hurdle in replacing the water pump.

Can't get the coolant to circulate properly.

I've idled the car a few times with the expansion cap off (said to in the manual) to get rid of airlocks, but all that happens is the expansion tank boils over when the engine gets to temperature. Is that meant to happen?!

I flushed the cooling system including reverse flushing the heater, i've replaced the pump, reattached all hoses, filled up with coolant, turned on the car with the return pipe from the heater matrix disconnected then reconnected it a few seconds after startup. Heater still blowing cold air.

Pipe going into matrix is hot, pipe out is stone cold. Even the pipes inside the cabin are hot and cold respectively.

I'm out of ideas. What do I do? Will putting the expansion tank cap on solve it?

[nicklouse]

does the water level drop when you rev the engine?

 

yes when water reaches 100C it boils. with the cap on it will boil at a higher temp.

 

Note really.

 

 

sounds like you have issues in the matrix or some pipes.

 

you say you back flushed it. did water flow?

 

have you looked at and checked the thermostat?

 

you did open the heater valve if fitted?

[JamesMiniMealor]

Water flowed fine when I flushed it, lots of gunk came out.

It's not a gradual boil either, just in an instant, the expansion tank fills up then spews out coolant.

Heater worked beautifully until I did the water pump etc.

Thermostat not checked. I'm desperately trying to avoid more work. I've been doing this for a week

Heater set to hot

Only cold pipe in the system is the heater return pipe

Edited by JamesMiniMealor, 16 March 2017 - 03:48 PM.

[Chodosh]

Check the thermostate, but if its not been removed for ages, soak it in WD and or use some heat when removing the bolts. All three snapped on mine and it was a double barrel nuisance. Saying that, the thermostat was £3 and it fixed my problems.

[JamesMiniMealor]

I will change the thermostat if all else fails. But why would it suddenly stop working? What is it not doing properly? 

[panky]

If the heater return was cold then it's probably an air lock in the heater matrix.

[Chodosh]

if you have flushed the system and seen loads of gunk come out, it could have caused a build up in and around the thermostat that caused it to remain permanently open or closed. mine was permanently open, which meant the engine never had a chance to get up to temp. conversely, if perm closed, it will mean the car can't cool down as efficiently as it needs to.

 

my car also had a take off sandwich plate under the thermostat housing, check that this is clear as it feeds the heater matrix.

 

https://axleaddict.c...mostat-is-Stuck

[JamesMiniMealor]

If the heater return was cold then it's probably an air lock in the heater matrix.

 

How does one un-airlock it? 

[panky]

Try disconnecting the heater return hose while the engine is ticking over and see if there's anything coming out. If it isn't then a quick rev should push the coolant through - you will get wet

Remember to stick something over where you pull the hose off or it will draw in air to the pump.

Edited by panky, 16 March 2017 - 04:53 PM.

[JamesMiniMealor]

Try disconnecting the heater return hose while the engine is ticking over and see if there's anything coming out. If it isn't then a quick rev should push the coolant through - you will get wet

 

I did that once... i shall try it again. Only a trickle came out

[panky]

Just in case you missed it I edited my last post to say make sure you put something (finger) over where you take the hose off as  air will ne drawn into the pump otherwise

[JamesMiniMealor]

Just in case you missed it I edited my last post to say make sure you put something (finger) over where you take the hose off as  air will ne drawn into the pump otherwise

 

Ahh that's new to me. thanks

[Steve220]

Does your heater blow hot? I get the feelings it's clogged up with rust silt.

[JamesMiniMealor]

Does your heater blow hot? I get the feelings it's clogged up with rust silt.

 

No. It used to though, before the water pump and coolant change. 

[r3k1355]

Sounds like an airlock.

Having the front of the car slightly higher can help move the bubble, technically the expansion bottle should be the highest point.

 

Here's hoping you've not dislodged a load of gunk and got a blockage.