GUIDE. Replacing thermostat mk3 Ford focus TDCI

[@tomdonoghue5623]

Hi, just after seeing this video, I have something similar but what happens with me is that I would be driving for about 20 minutes or so, I don't have any heat and the gauge doesn't move, then all of a sudden after awhile driving the gauge straight to about 80 degrees and the heat works mighty. So I dumbfounded as to what is wrong. I'm thinking it may be the thermostat but not sure. So fingers crossed it will work when I change it. Cheers

[@mike_themechanic]

I'll keep my fingers crossed for you as well. I filled my expansion tank over the max mark by a couple of cm so that it always had pressure in the system and hopefully didn't go below empty

[@Wardy75]

The Mk4/5 Fiestas suffer badly with the heater control valves, when they do fail it causes issues with the engine temperature and also the heater inside the car. Not sure if it would be a similar story with the Focus'.

[@mike_themechanic]

Where is this valve?

[@Wardy75]

@@mike_themechanic I had a look on eBay and it was called a heater valve or coolant control valve, the pictures might help to identify if the car has one. I don't suggest that it will be problem, but seems a relatively cheap part to try before head gasket or water pump.

[@mike_themechanic]

@@Wardy75 thanks I'll have a look for it 👍👍

[@bigsquatchsasfoot1964]

Is there a heater control valve on it ? Sometimes they get stuck there like a plunger that goes up and down and they get a bit crappy and stuck 🤔

[@mike_themechanic]

Not that I'm aware of

[@bigsquatchsasfoot1964]

@@mike_themechanic I have absolutely no real mechanical skills as such only I’ve just replaced one doing similar things on my streetka but I’m certainly no mechanic anyway it was just a thought ..good luck with it 👍

[@mike_themechanic]

@bigsquatchsasfoot1964 no worries. All imput is welcome 😊

[@Hollaendaren]

I have the same problem on my Audi, but only when it's really cold and slightly low on coolant. I'm 99% certain for me the problem is air, my Audi has a petrol heater and some additional heating hoses that are routed at about the same level as the coolant reservoir. I think when coolant drops below max those 2 hoses or one of them is causing trouble. Weird thing is it only happens when it's really cold and I'll be freezing my ass off halfway to town before I get heat from the vents.

[@mike_themechanic]

I don't seam to be loosing coolant it just seams like it's not circulating. My next job is to change the water pump again I think

[@mikle65]

cabin temperature sensor, right side under the steering wheel there is a round vent, pop the trim off and see if the senor is full of dust (there is a fan in it collecting dust) see if you have a fault code for it as well. Also if the cabin temp reached the set temperature it won't necessarily blow hot air, but in -30 it is unlikely. After replacing the thermostat does you coolant temperature still movind down after reaching 90c*?

[@MickSchiavone]

I have the same issue, and Carried out the same repair. The only other thing I can change is the water pump, because the seal might be swollen....

[@mike_themechanic]

I changed it not long ago when I did the cambelt but I also think that I might have to do it again

[@MickSchiavone]

That's what my local ford dealer said anyway. I was under the impression that there was another sensor at the rear of the engine, but they confirmed no . Let us know if you resolve this issue with the new pump...

[@mike_themechanic]

@user-qh8yz3ej6b thankyou I will 😊

[@OritanoVero]

Did you check internal temp sensor near the steering wheel?

[@mike_themechanic]

I know it's there but how do I check it?

[@OritanoVero]

@@mike_themechanic You should have to try fitting a new one or try to clean it

[@mike_themechanic]

@@OritanoVero thanks. I'll try cleaning it

[@chrismcerlain1664]

My temp gauge doesnt move at all usually. when it does decide to move, it reads normal,( just below half way ). The car heater warms up in a timely manner and appears normal other than the guage. very strange. Im wondering if themostat is playing up somehow, of maybe sensor ?? anyone got any ideas ?? thanks 👍

[@mike_themechanic]

If you are getting heat in to the cabin I would say the sensor is at fault if not then possibly the thermostat is at fault. When I changed my thermostat housing it came with a new sensor so it might be worth changing both.

[@Daveyboyo14]

Why didn’t you show taking bolts out

[@mike_themechanic]

That's a very good point and something I have realised after making this and a few other films that you as viewers want to see how I did the job not just I've done it. Thank you for taking the time to share your thoughts I really appreciate it 👍👍🙏

[@jassimadnan9635]

Which is the same engine and the exact same problem, which is very confusing. I hope you find the problem and tell me. Thank you!!

[@mike_themechanic]

When I find the answer I'll be sure to let everyone know. Thanks for watching

[@norbertpalhegyi8780]

Have you found what caused this issue, and how to fix it?

[@mike_themechanic]

Not really, now it's warmer outside I don't notice any difference but as soon as it was cold it did play up

[@fulcrum811]

If you feel that new bubble is being formed over and over again….. I hate to say it but, it might be a leaking head gasket😢

[@mike_themechanic]

That idea has been talked about. Don't want to go there just yet as I have no other signs of a blown head gasket

[@fulcrum811]

@@mike_themechanic the only other place in a coolant system where pressure is low and air could be drawn into the coolant is at the water pump shaft. Or at least i cannot think of anything else 🤔

[@davidnorton5887]

Cant you use a block tester where the fluid changes colour?

[@davidnorton5887]

Just use a vacuum filler for the glykol instead of all the fannying about filling, revving, bleeding. 2 minutes and its done properly.

[@mike_themechanic]

I changed the water pump when I changed the cambelt. I have wondered if that could be not working in some way and not pushing the water around the system as it should

[@ade3101]

Back pressure could be a cracked head or bad head gasket

[@mike_themechanic]

My thoughts as well. Video coming soon 😉😉

[@kevincarter4163]

Iv got the same problem. Had the egr cooler changed and didnt solve it

[@mike_themechanic]

Have you tried the thermostat housing?

[@kevincarter4163]

Hello, going to get that done with the mot next week mate. I will update on here if you like

[@kevincarter4163]

My coolant also goes below minimum but when I unscrew the cap the coolant rushes back upto max level

[@mike_themechanic]

@@kevincarter4163 yeah do that 👍👍

[@mike_themechanic]

@kevincarter4163 mine does that as well. It keeps pressure for ages. Don't know if it's supposed to do that as its not normal for engines to do so

[@shahzadgigi]

So what was the issue?

[@mike_themechanic]

The issue was it loosing heat. Very mysterious 🤔.

[@fergucas]

Same problem, did you solve it?

[@mike_themechanic]

Not really, it is better now but it's also warm outside. When it was cold out side I lived it's own life going up and down all the time

[@yyabay]

Head gasket leaking.

[@mike_themechanic]

I hope not

[@coolrider91]

@@mike_themechanic Hello!! En tout cas, 🤔 tout les symptômes indiquent un joint de culasse défectueux, (ou plus grave, une culasse fendue 😟) fuite de compression entre cylindre et chambre du circuit de refroidissement, du coup, une partie des gaz comprimés passe dans le circuit de refroidissement, le circuit de refroidissement monte en pression, des poches d'air se formes, la circulation du liquide devient chaotique tout comme le chauffage dans l'habitacle... J'espère que depuis le temps ton problème à été solutionné😅😅

[@coolrider91]

Dis moi, mon diagnostique est correcte ?😉😉

[@robertjohnson8489]

Does it work now in -30 hahah

[@mike_themechanic]

Don't know I haven't dared to try it when it's this cold. - 36 yesterday 😂😂😂

[@robertjohnson8489]

Hahah smart idea :)

[@robertjohnson8489]

Now that I've watched all the way through. Why not plug it in and have the engine heater on and bleed it. (Maybe both at the same time as it may push air into the main system?) Should have brought a petrol.

[@mike_themechanic]

@robertjohnson8489 the electricity engine heater has no pump its just a block heater that heats the oil. The diesel heater has its own pump and I've had that started a few times and I do get heat when that starts. I'm starting to wonder if it's the water pump that's not pumping properly

[@simel192]

water pump impeller

[@mike_themechanic]

The water pump was changed just before this video was made so I don't think so, unless it spins on its axel at certain times 🤔🤔🤷🤷