more cooling problems

[stevek9815]

afternoon folks,

following on from this thread \/\/\/\/\/
https://www.volvoforums.org.uk/showthread.php?t=293348

i'm still having problems.

the car is a V reg v70 2.4.

brief rundown of the problems.

car started to run a little to "warm" for my liking, it was creeping over half way on the temp gauge whether i was sat in traffic or moving, had to turn the heater & fan on full to bring it back down.

got a fault code reader to see if there were any codes stored, one in particular.
the ECT (engine coolant temp sensor) was faulty,

so i changed that for a brand new one, but before that i checked the state of the coolant which turned out to be nothing but water,

so that was changed as well also i checked the thermostat was working correctly (tested in a pan of boiling water) and that was faulty (struggling to open) so that was changed too.

also there was a code for the cooling fan relay, that was swapped for a brand new one,

i also checked the fan was working by putting 12V straight to it, & it span up straight away,

so, so fat it's had a new thermostat, ECT, coolant flush & change, & cooling fan elay yet STILL (!!!!) it runs to hot in either traffic or moving.

also the top rad hose gets nice & warn (nearly hot) & the bottom hose gets warm as well.

as far as i can see the head gasket is ok (no mayo/oil & water mixing) & as far as i know the water pump was changed at the same time as the cambelt (not long before i got the car) so fingers crossed it not those as i really can't afford to get those changed if it overheats at the moment.

i'm beginning to suspect either the radiator or the fan wiring are at fault,
has anyone else on here had a similar problem to mine?? if so how did you go about sorting it??

i need the car back on the road asap as it is my only transport at the moment.

thanks in advance.

[stevek9815]

right, a little update.

just been out to the car, unplugged the ECT & started the car.

the fan came on as soon as the engine started, plugged the sensor back in & the fan stopped.

i then unplugged it again & the fan started again, so i then got the old sensor plugged that in with the sensor end out in the fresh air & the fan stopped, so when i unplugged it again the fan started.


when i stopped the engine the can continued to run with the ignition key in my pocket!!! i had to disconnect the battery to get the fan to stop.

so, anyone know any causes &/or cures for this??

[Dippydog]

How high on the gauge are you letting it get before turning on interior fan?Although the gauge on mine doesn't move far from normal before the rad fan kicks in it could be that it's not getting to the point of firing the fan up before you turn on the interior fan?Other than that I'd suggest that there's a partial blockage somewhere-most probably the radiator,flushing agents don't always work,but you could try flushing and back flushing to see if that helps,no doubt if it's been run on plain water for any length of time before you bought it the system could be clogged with limescale.

[stevek9815]

Originally Posted by Dippydog

How high on the gauge are you letting it get before turning on interior fan?Although the gauge on mine doesn't move far from normal before the rad fan kicks in it could be that it's not getting to the point of firing the fan up before you turn on the interior fan?Other than that I'd suggest that there's a partial blockage somewhere-most probably the radiator,flushing agents don't always work,but you could try flushing and back flushing to see if that helps,no doubt if it's been run on plain water for any length of time before you bought it the system could be clogged with limescale.

thanks for that dippydog, i'll take the rad off & flush it through both ways & see if anything comes out, if the rad has had it then it's time for a new one.

still doesn't explain why the fan runs with the ECT unplugged then stops with it plugged back in.

[stevek9815]

dippydog, i let the gauge get to about just over half way then turn the fan on to try & bring it down again.

[Luxobarge]

Originally Posted by stevek9815

still doesn't explain why the fan runs with the ECT unplugged then stops with it plugged back in.

With it unplugged, the ECU detects a fault with it and as it has no idea what the real temperature of the engine is, it switches the fan on as a safety precaution - this looks to me like it's doing what it's supposed to do.

Looks to me like a clogged radiator. If it's been there some time, I know I'd be changing it anyway, these rads have a limited life span and if you replace it you'll a) probably cure the problem and b) have a nice new one that will last a long time. I changed mine, they're not that expensive really, and it's peace of mind.

[Bob Meadows]

If you aren’t already aware then domestic central heating descaler & cleaner is ideal for cleaning the cars radiator/block: ~ far more effective than the product sold via car factors- compatible with mixed metal systems (used it for a long time on classic cars) available from DIY sheds/ plumbing merchants. Once done go back to the correct ratio mix of engine coolant/antifreeze.
Good Luck
Bob

[volvo again]

Originally Posted by Bob Meadows

If you aren’t already aware then domestic central heating descaler & cleaner is ideal for cleaning the cars radiator/block: ~ far more effective than the product sold via car factors- compatible with mixed metal systems (used it for a long time on classic cars) available from DIY sheds/ plumbing merchants.
Bob

Never realised this, great tip. Thanks.

[stevek9815]

thanks for the replies folks,

new radiator on order, as for the descaler? got some somewhere will dig it out & have a go.

fingers crossed this solves the problem.

[stevek9815]

well i've got the new radiator, going to be changing it today,

fingers crossed it cures the problem.