To stat or not to stat?
Discussion
Have an old MK4 Ibiza running a 1.9 130 PD and this past week I've noticed its not getting up to temp as quickly as it normally would.
It gets up to 70 no bother but then fluctuates between 70-90 depending on the driving.
Motorway it gets to 90 and tends to stay
Town it is closer to 70
On any incline or decline (especially) if it's at 90 it drops to 70 and takes a while to come back up.
The last service about 5k miles ago was big one so had waterpump changed, not sure if it is that?
Could also be the thermostat or even the sensor but not sure where to begin to diagnose or just change them both. Car is pushing 254k and I've not change the stat before so it could be that?
It gets up to 70 no bother but then fluctuates between 70-90 depending on the driving.
Motorway it gets to 90 and tends to stay
Town it is closer to 70
On any incline or decline (especially) if it's at 90 it drops to 70 and takes a while to come back up.
The last service about 5k miles ago was big one so had waterpump changed, not sure if it is that?
Could also be the thermostat or even the sensor but not sure where to begin to diagnose or just change them both. Car is pushing 254k and I've not change the stat before so it could be that?
Definitely the thermostat.
Get it changed as it will think you are not up to temp and will be over fuelling.
Also, MK4 could have a DPF, if it has it won't be doing a regen and will block up really quickly. Even if it hasn't your EGR and inlet manifolds will be getting gunked up if it is running cool.
Just buy a whole unit, but make sure it is a decent brand, such forums for the recommended one.
Get it changed as it will think you are not up to temp and will be over fuelling.
Also, MK4 could have a DPF, if it has it won't be doing a regen and will block up really quickly. Even if it hasn't your EGR and inlet manifolds will be getting gunked up if it is running cool.
Just buy a whole unit, but make sure it is a decent brand, such forums for the recommended one.
gizlaroc said:
Definitely the thermostat.
Get it changed as it will think you are not up to temp and will be over fuelling.
Also, MK4 could have a DPF, if it has it won't be doing a regen and will block up really quickly. Even if it hasn't your EGR and inlet manifolds will be getting gunked up if it is running cool.
Just buy a whole unit, but make sure it is a decent brand, such forums for the recommended one.
No dpf just an EGR.Get it changed as it will think you are not up to temp and will be over fuelling.
Also, MK4 could have a DPF, if it has it won't be doing a regen and will block up really quickly. Even if it hasn't your EGR and inlet manifolds will be getting gunked up if it is running cool.
Just buy a whole unit, but make sure it is a decent brand, such forums for the recommended one.
My thoughts were sensor as it fluctuates as I drive. Stats fail open so I understand why it wouldn't get to temp but if it does then drops within seconds could it be just the sensor?
I'm probably going to change both but just asking
With a thermostat that’s stuck open, the actual temperature of the coolant, not just the gauge on the dash, will fluctuate a lot. This will depend on engine load and speed of air flow through the radiator.
Go for a drive until the needle on the temp gauge has settled, then stop with the engine idling. If the stat is stuck open, the needle will rise to ‘normal’. Then go for a ‘spirited’ drive. Again, with enough load on the engine, the needle will settle at normal.
And the final proof: find a long downhill stretch of road, and at about 60mph take your foot off the throttle pedal and let the car coast for a minute or so... the needle will drop due to no load and lots of cooling air. The knackered stat won’t close to keep the temp up.
Go for a drive until the needle on the temp gauge has settled, then stop with the engine idling. If the stat is stuck open, the needle will rise to ‘normal’. Then go for a ‘spirited’ drive. Again, with enough load on the engine, the needle will settle at normal.
And the final proof: find a long downhill stretch of road, and at about 60mph take your foot off the throttle pedal and let the car coast for a minute or so... the needle will drop due to no load and lots of cooling air. The knackered stat won’t close to keep the temp up.
Edited by Tony1963 on Saturday 21st November 15:53
Edited by Tony1963 on Saturday 21st November 16:01
No damage to leaving it for a week - I've been meaning to look at mine for about 5 years now!! Your thread has spurred me on - mines an AWX engine (PD130) so this is what I've watched - bit long winded so I skipped to the bits I wanted to watch. https://www.youtube.com/watch?v=LOr80QZVlE4
S6PNJ said:
No damage to leaving it for a week - I've been meaning to look at mine for about 5 years now!! Your thread has spurred me on - mines an AWX engine (PD130) so this is what I've watched - bit long winded so I skipped to the bits I wanted to watch. https://www.youtube.com/watch?v=LOr80QZVlE4
Awesome gives an idea where, although mine is transverse and zero space.i might need to remove the alternator to get better access Gassing Station | Home Mechanics | Top of Page | What's New | My Stuff