27 replies to this topic

[gazpoole]

Ok, so mine's a little different than any of the others on the forum.. I have looked long and hard...

 

You should know, I'm a rookie mechanic, this is the first car I've wanted to try doing everything myself with so apologies if it's an obvious fix... 

 

I have recently drained all the coolant from the car and installed a replacement Coolant Temp Sensor (GTR206) as the cooling fan was coming on all the time... I have since filled the car back up, but now the radiator fan doesn't come on at all, so the coolant is boiling over.

 

Could it be that now the sensor is fixed, it's apparent there was an issue with the thermostat and this also needs to be changed?

 

The temp gauge in the car sits right in the middle, even when the coolant is boiling over. If I remove the wiring from the Temp Sensor, the cooling fan switches on, so it isn't a problem with he fan.

 

Hoping for an easy fix... Any help appreciated.

[jamesquintin]

Have you looked into this:

 

https://www.minispar.../YMQ105690.aspx

​Had the same issue with my fan not coming on.

 

How long does it take your car to boil over? Is this whilst driving or just idling? The fan pretty much never comes on when I'm driving, just when I'm stuck in traffic.

 

I would be replacing your water pump and the thermostat

 

Q

[gazpoole]

Have you looked into this:
 
https://www.minispar.../YMQ105690.aspx
​Had the same issue with my fan not coming on.
 
How long does it take your car to boil over? Is this whilst driving or just idling? The fan pretty much never comes on when I'm driving, just when I'm stuck in traffic.
 
I would be replacing your water pump and the thermostat
 
Q

Yep. Already replaced the cable.
Fan isn't coming on when idle.
Following the instructions for a coolant replacement, leaving the lid off until the fan kicks in... but it isn't kicking in, just boiling over instead.. gonna have to dig the thermostat out next weekend I think.

[cian]

Replace the cap and try it

[gazpoole]

Replace the cap and try it

 

Do I not need to wait for the Cooling Fan to switch on without the cap on as part of the bleeding process?

The water is boiling over without the cap present. 

[Steve220]

I'm hoping the failed switch wasn't masking a larger problem. If you remove the plug from the switch, does the fan come back on again?

[jamesquintin]

Why are you running it without the cap on??? The cap pressurises the coolant so it doesn't boil over...

[Sprocket]

the ECU starts the cooling fan when the temperature leaving the cylinder head is 105c. Without the rad cap, the system will boil at 100c in atmospheric pressure . If the rad cap or expansion tank are leaking preventing the system pressurising properly the coolant will boil.

[Shep76S]

I think he is leaving the rad cap off to purge the air pockets out.

[Sprocket]

I think he is leaving the rad cap off to purge the air pockets out.

You need to read between the lines and look beyond that....................

[gazpoole]

The manual I'm going on instructs me to leave the cap off to bleed the air out of the system, when the rad fan kicks in, it's time to put the cap on... is that not the case?

Will check the thermostat whilst the system is empty, grab a new cap (I think the one I have has gone) and try again!

[jamesquintin]

I've never left the cap off to bled the system...

[Sprocket]

The manual I'm going on instructs me to leave the cap off to bleed the air out of the system, when the rad fan kicks in, it's time to put the cap on... is that not the case?

Will check the thermostat whilst the system is empty, grab a new cap (I think the one I have has gone) and try again!

 

 

A 50/50% antifreeze mix will boil at 106c. The ECU will turn on the fan at 105c. Unless you can guarantee the entire cooling system Including heater matrix is drained of water after flushing, and re filled with 50/50 mix of antifreeze, it will likely boil before the fan ever comes on if you leave the rad cap off. The Rover workshop manual does not go into detail in this respect as it would be an assumed practice in a commercial dealership workshop.

[gazpoole]

 

The manual I'm going on instructs me to leave the cap off to bleed the air out of the system, when the rad fan kicks in, it's time to put the cap on... is that not the case?

Will check the thermostat whilst the system is empty, grab a new cap (I think the one I have has gone) and try again!

 

 

A 50/50% antifreeze mix will boil at 106c. The ECU will turn on the fan at 105c. Unless you can guarantee the entire cooling system Including heater matrix is drained of water after flushing, and re filled with 50/50 mix of antifreeze, it will likely boil before the fan ever comes on if you leave the rad cap off. The Rover workshop manual does not go into detail in this respect as it would be an assumed practice in a commercial dealership workshop.

 

 

Every day is a school day.

 

OK, good to know.. Let's see what the weekend brings then.

 

Thanks everyone for your advice. 

[gazpoole]

UPDATE: I replaced the thermostat and Expansion tank Lid..

 

The solution now doesn't boil over (50/50 mix), but the rad fan isn't kicking in at all, even when left to run for 30 minutes...

Hopefully, its because it doesn't need to, but I'll have to give it a good run out, see if the Rad Fan kicks in or the car overheats.