1.6 156 Fan constantly running - help please

[Daveeoo]

Hi, I’ve read the other threads on this, I feel mines slightly different:
-Fan kicks in full after about 5 minutes idle on the driveway in outside 15deg Temp or hotter
-Fan doesn’t go off again until flat battery or fuse pulled
-Fault related to fan Is then logged due to fuse being removed so I clear this to allow the system to settle before replacing fuse or the fan remains on
-No EML fault comes up
-Slow to reach 90 temp, sometimes never or temp not even about 50 before fan starts

So far I’ve done the following:
- new battery
- replaced oem coolent temp sensor
- checked coolent level correct
- checked oil level correct
- several bsi resets
- read codes, one present other than fan related when the fuse is pulled which is P0172 mixture too rich

I’ve also noticed the ambient temp is -45deg and alternator temp -35deg and coolent temp -10deg on my code reader, this cant be correct when it’s +17deg outside in the uk? Is this another sensor I need to replace? If so where is it?

Any help appreciated to get her back on the road in good health! Thanks

 

[Pedro]

Code P0172 could mean the Thermostat is stuck open & fan full on hence Engine fails to reach correct operating temperature this can affect the ECU getting wrong data combustion signals in Bank 1(cylinder No1) which may be too rich or too lean to the Mass Air flow Ratio
Probability is to change the Thermostat coolant tank this should rectify fault & Fan will go to sleep until needed !

 

[thornebt]

If the thermostat is stuck open would you not just replace the thermostat housing? Why would you change the thermostat coolant tank? Is this the radiator header tank? Cheers. Bruce.

 

[Pedro]

If the thermostat is stuck open would you not just replace the thermostat? Why would you change the thermostat coolant tank? Is this the radiator header tank? Cheers. Bruce.

If the thermostat is stuck open would you not just replace the thermostat? Why would you change the thermostat coolant tank? Is this the radiator header tank? Cheers. Bruce.

My apologise being politically correct it is the Thermostat Housing or if you are in certain countries its been known as a coolant block a coolant thermostat tank or as some of us in the UK put it a thermo housing e

 

[Pedro]

Hi, I’ve read the other threads on this, I feel mines slightly different:
-Fan kicks in full after about 5 minutes idle on the driveway in outside 15deg Temp or hotter
-Fan doesn’t go off again until flat battery or fuse pulled
-Fault related to fan Is then logged due to fuse being removed so I clear this to allow the system to settle before replacing fuse or the fan remains on
-No EML fault comes up
-Slow to reach 90 temp, sometimes never or temp not even about 50 before fan starts

So far I’ve done the following:
- new battery
- replaced oem coolent temp sensor
- checked coolent level correct
- checked oil level correct
- several bsi resets
- read codes, one present other than fan related when the fuse is pulled which is P0172 mixture too rich

I’ve also noticed the ambient temp is -45deg and alternator temp -35deg and coolent temp -10deg on my code reader, this cant be correct when it’s +17deg outside in the uk? Is this another sensor I need to replace? If so where is it?

Any help appreciated to get her back on the road in good health! Thanks

As an addendum to my post its the Thermostat Housing that possibly needs changing as pointed out by another member & not a coolant tank. good luck

 

[Daveeoo]

Hi guys thanks, Im heading to a local specialist for diagnostic end of the week which will hopefully lead us in this direction. Any more input in the meanwhile fire away! I was starting to think a failing thermostat. Thanks