2.5 V6 heater problem hot>cold>hot

[Roverguest]

Hello,

I have fitted new ECP brushes to the fan motor and it works perfectly, all 3 speeds cut in when they should.

Only issue now is despite it taking a while from start to get to 100 and test the slow speed, it couldn’t take it down to 96 even though the ambient temperature being around 5 degrees.

The fan upped it’s game to medium and fast speed in quick succession even still the temperature continues to rise reaching 114 before we revved it and it fell down to 90 degrees in just a few seconds.

Would this indicate, a relation to the heater issue/ airlock?

Thanks
David

[T-Cut]

It's displaying all the characteristics of an air locked cooling system. In other words, there's insufficient circulation through the engine to lower its temperature. The radiator isn't providing sufficient cooled flow. The heater circuit may well be locked as well, but engine cooling doesn't require the heater loop to receive coolant. Basically, the cooling system needs to be bled of air and topped up using the official MGR proceedure.

If you do a Google custom search (at the top of every page) for 'official MGR bleed refill' I'm sure you'll find it all.

TC

[Roverguest]

Originally Posted by T-Cut

It's displaying all the characteristics of an air locked cooling system. In other words, there's insufficient circulation through the engine to lower its temperature. The radiator isn't providing sufficient cooled flow. The heater circuit may well be locked as well, but engine cooling doesn't require the heater loop to receive coolant. Basically, the cooling system needs to be bled of air and topped up using the official MGR proceedure.

If you do a Google custom search (at the top of every page) for 'official MGR bleed refill' I'm sure you'll find it all.

TC

Yes it does seem that way, and squeezing the top hose with the coolant cap off the hose felt empty and sounds were just like wheezing and no water displacement or movement in the header tank like you’d expect.

[SD1too]

Originally Posted by Roverguest

The fan upped it’s game to medium and fast speed in quick succession even still the temperature continues to rise reaching 114 before we revved it and it fell down to 90 degrees in just a few seconds.

Well done with the repair to the fan motor. Next I'd recommend a complete draining, refilling and bleeding of the cooling system. I gave the procedure in my post no. 19 so there's no need for any Googling.

Originally Posted by Roverguest

... squeezing the top hose with the coolant cap off the hose felt empty and ... no water displacement or movement in the header tank like you’d expect.

Your top radiator hose is normal and you shouldn't expect any movement in the expansion tank because the full circulation does not pass through it. The only flow you should see is from the tiny cylinder head bleed hose which discharges into the neck of the expansion tank. You can check that when starting the engine from cold and removing the expansion tank cap.

Simon

[vitesse]

Originally Posted by Roverguest

Yes it does seem that way, and squeezing the top hose with the coolant cap off the hose felt empty and sounds were just like wheezing and no water displacement or movement in the header tank like you’d expect.

Sounds a bit similar to what I’ve experienced with my latest V6, some bleed easily some like mine require multiple bleeds to get that last bit of air out.

Just been out to test my top hose with a stone cold engine. When squeezing the hose and with the expansion tank cap off, most of the difference is a gurgling sound but there is a very slight difference in the level in the tank. Mine is exactly on the max mark, if I compress the top hose it will rise one or two mm, release it and then back to max. But I should stress the difference is minimal and barely visible.

I found that despite following the procedure, air remained in mine and when I, against the recommend advice, eased the bleed screw some air came out before the coolant. Another test drive, same again, air out - then coolant. Took a few trips to expel all the air but then settled on 95 degs.

Regards