Hi all,

I am thinkng about a 55 plate focus ST3 TDCI with 60k on the clock, i love the mk3 chassis in general.

Aside from door rubbers and checking for water ingress, what sort of reputation do these cars have in terms of reliability. I do currently own a mk3 sigma petrol, so I am not totally new to focuses. Cambelt and water pump have been done.

Obviously a huge concern is making sure the Bi-Xenon’s are working ok. I couldn’t get over the £1300 of a piece price of those.

Could anyone please give me a bit of a checklist? Or even their opinions on the STD, in general?

Thanks for your time :)

You've mentioned most of it.

As long as it's not a Powershi*t

That engine, if not abused, is very good

Might be worth a read here:

https://www.focusstoc.com/threads/buyers-guide.580661/

https://www.pistonheads.com/news/ph-buying-guides/ford-focus-st-mk3--ph-used-buying-guide/42709

https://www.fastcar.co.uk/tuning-tech-guides/ford-focus-st-diesel-mk3-buying-guide/

5 hours ago, DaveT70 said:

You've mentioned most of it.

As long as it's not a Powershi*t

That engine, if not abused, is very good

4 hours ago, Eric Bloodaxe said:

Might be worth a read here:

https://www.focusstoc.com/threads/buyers-guide.580661/

https://www.pistonheads.com/news/ph-buying-guides/ford-focus-st-mk3--ph-used-buying-guide/42709

https://www.fastcar.co.uk/tuning-tech-guides/ford-focus-st-diesel-mk3-buying-guide/

Thanks a lot guys, I did try a quick forum search … but maybe it was TOO quick. Sorry about that. Appreciate you digging those out for me.

It’s a manual, thank goodness. I get that little dry heave when I enter an automatic vehicle 😅

The purists get that seeing a diesel engine in an ST. 😆

14 minutes ago, TomsFocus said:

The purists get that seeing a diesel engine in an ST. 😆

🤣I walked into that one didn’t lol

Just on a side note, I noticed it’s MOT history states: “ osr and nsr trailing arm front bushes deteriorated slightly“

What bushes are these exactly, does anyone have a diagram or picture, and how labour intensive are they to do? I tried looking at the Powerflex website’s diagram and just ended up more confused. I would probably just keep it standard rubber, unless it was significantly less work to fit the powerflexes.

Thanks a lot

12 hours ago, Sausage2026 said:

Just on a side note, I noticed it’s MOT history states: “ osr and nsr trailing arm front bushes deteriorated slightly“

What bushes are these exactly, does anyone have a diagram or picture, and how labour intensive are they to do?

The trailing arms are the thin ones that run longways rather than across the axle. Shouldn't particularly labour intensive unless all the bolts are rusty.

FORD FOCUS MK3 C346 Rear Suspension Left Trailing Arm Assy 1773553 NEW GENUINE | eBay UK

Genuine Ford C-Max Grand C-Max Focus Mk3 Kuga I Rear Trailing Arm Bush 1692849 | eBay UK

On 2/13/2026 at 9:01 AM, TomsFocus said:

The trailing arms are the thin ones that run longways rather than across the axle. Shouldn't particularly labour intensive unless all the bolts are rusty.

FORD FOCUS MK3 C346 Rear Suspension Left Trailing Arm Assy 1773553 NEW GENUINE | eBay UK

Genuine Ford C-Max Grand C-Max Focus Mk3 Kuga I Rear Trailing Arm Bush 1692849 | eBay UK

Better late than never, but thank you for clearing that up for me. ST models all have the bolt on arms, don’t they? I’ve seen the ones part of the hub assembly, they looked a nightmare.

I bought it! It’s been a beauty so far. Getting used to driving a diesel again is weird, but I do like it.

I do get a bit of an exhaust fumes smell when first starting her up, but no leaks I can see under the engine cover and no smell of diesel in the bay itself. And no obvious sounding blows or lights on or loss of power/smoke etc when booting it.

Under certain conditions, under heavy braking, it sort of jerks a bit, fairly subtle but I am one that feels everything. Do you reckon this could be down to those TAB’s being worn? MOT next month should be definitive.

Oil is quite black, but it doesn’t smell of diesel. Gonna give a it a full service with all genuine Ford bits next month. Not sure it’s the same with this motor, but most diesels I’ve owned have blackened their oil quite quickly compared to their petrol counterparts

Yes, all ST's should have separate trailing arms. I'm not convinced you'd feel these worn bushes when braking due to their orientation but won't completely rule it out.

Diesel engines do always turn the oil black quickly. That's not a cause for concern.

If it's raw exhaust fumes in the cabin, I would recommend checking the turbo v-band clamp. If it's filtered exhaust, as you'd smell from the tail pipe, then I'd recommend checking underneath. Though the MOT should pick up any exhaust leaks so it might be least hassle just to wait for that.

On 2/23/2026 at 9:43 AM, TomsFocus said:

Yes, all ST's should have separate trailing arms. I'm not convinced you'd feel these worn bushes when braking due to their orientation but won't completely rule it out.

Diesel engines do always turn the oil black quickly. That's not a cause for concern.

If it's raw exhaust fumes in the cabin, I would recommend checking the turbo v-band clamp. If it's filtered exhaust, as you'd smell from the tail pipe, then I'd recommend checking underneath. Though the MOT should pick up any exhaust leaks so it might be least hassle just to wait for that.

On 2/23/2026 at 9:43 AM, TomsFocus said:

Yes, all ST's should have separate trailing arms. I'm not convinced you'd feel these worn bushes when braking due to their orientation but won't completely rule it out.

Diesel engines do always turn the oil black quickly. That's not a cause for concern.

If it's raw exhaust fumes in the cabin, I would recommend checking the turbo v-band clamp. If it's filtered exhaust, as you'd smell from the tail pipe, then I'd recommend checking underneath. Though the MOT should pick up any exhaust leaks so it might be least hassle just to wait for that.

Thanks for that! I’ll see what the tester says, he is also my mechanic so I’ll mention it to him to be on the lookout.

One more thing, since you seem to be a real wealth of knowledge on this car. I am having condensation issues, only under certain weather conditions and on the front screen only, sides and rear are totally clear. It doesn’t happen, even after brutal rain or I’d have suspected an overt leak. It’s usually when it gets cold and damp overnight.

It’s dripping wet on the inside. I’m not losing coolant, all the carpets are bone dry, the boot and spare wheel well also dry.

No leaves in any vents or funny smells. But I am getting the pollen filter changed when it gets serviced. Might pull it out in a bit to see if it’s damp.

A rear door seal had dropped, which I gorilla double sided back on, but that doesn’t seem to have been the issue.

The head liner is 90% dry, although it’s a tiny bit damp where it meets the screen, due to the water on the screen itself.

I’m going to try remembering to turn OFF the climate control when I get out, to see if it makes a difference. As when I’ve been searching someone said the flaps close?

Also just chucked a couple of those desiccant bag things (1kg each) in that are all the rage, on the dash.

My last mk3 zetec often a mist inside, which I class as normal, but wet I do not. This is too much for the AC to clear in a reasonable time, and it’s gonna get tedious wiping it with MF cloths and then taking them back indoors to dry, before setting off.

Do you have any ideas please? Sorry to single you out and plague you 😂

Just changed the pollen filter myself, screw wasn’t in there ofc as most aren’t and the fusebox carpet cover thing wasn’t present so I’ll get one from a scrappy if I can. But it was totally bone dry.

1 hour ago, Sausage2026 said:

Just changed the pollen filter myself, screw wasn’t in there ofc as most aren’t and the fusebox carpet cover thing wasn’t present so I’ll get one from a scrappy if I can. But it was totally bone dry.

Those are surprisingly cheap new from Ford.

Genuine Ford Front Dash Panel Insulator Pad 1703355 | eBay UK

Not sure what to suggest for the condensation. This is the worst time of year for it, but very strange that's it's running down the screen yet not damp anywhere else. Hopefully it will dry out over the next week or so and not come back.

I’m jealous, I would love an ST currently got the Zetec S and love the styling. Even though it’s old ,63 plate. Hope you enjoy it .

On 2/25/2026 at 9:01 PM, Gavemz said:

I’m jealous, I would love an ST currently got the Zetec S and love the styling. Even though it’s old ,63 plate. Hope you enjoy it .

Thanks so much mate, appreciate it! I love the Zetec S, too. Love the bumper etc they always catch my eye. They are all nice handling cars, especially with some good tyres. I really rated my old 2012 Zetec 1.6 petrol. But it had quite a list of jobs on it, not really economical to repair, the engine itself never missed a beat though.

Just gotta do little bits to this one to get it up together, paint isn’t 100% perfect, but tbh I would rather that- because no matter where you park, there’s always the door-openers, shopping bag bandits, and sticking out bushes on country lanes when you’re forced over.

Yeah I agree with you there. I gave mine anreal good deep clean and also clay barred the paint, that made a big difference to the paint. Just waiting for the weather to turn now so i can give it a machine polish. Just to bring back the metallic shine a bit. I’ve done a couple of panels and it lifts it a fair bit and just turns the years back a little. lol . What colour is yours ?

3 hours ago, Gavemz said:

Yeah I agree with you there. I gave mine anreal good deep clean and also clay barred the paint, that made a big difference to the paint. Just waiting for the weather to turn now so i can give it a machine polish. Just to bring back the metallic shine a bit. I’ve done a couple of panels and it lifts it a fair bit and just turns the years back a little. lol . What colour is yours ?

Mine is black, and so was my last one … nightmare for any detailing mistakes lol

I might go over mine when it finally stops raining, if ever haha. I detailed my last one like a mad man for 3 days and it came up lovely, it’s just a huge undertaking and one of those “once you pop, you can’t stop” sort of things. Then there’s the neighbours … “you can do mike next if you want” “missed a bit”

Yeah mine is black as well, looks so much better once it’s done though. I really enjoy detailing mine . With your condensation have you pulled the bungs out the back if they’re still there to see if water is sitting in there. That can often cause condensation but not enough water to run into the carpets etc .

14 hours ago, Gavemz said:

Yeah mine is black as well, looks so much better once it’s done though. I really enjoy detailing mine . With your condensation have you pulled the bungs out the back if they’re still there to see if water is sitting in there. That can often cause condensation but not enough water to run into the carpets etc .

I haven’t pulled the bungs yet. The previous owner did mention water ingress when he first got it, and it turned out to be the rear spoiler washers and the problem didn’t return. But I definitely need to rule those out, thanks for reminding me

On 2/27/2026 at 6:14 PM, Gavemz said:

Yeah mine is black as well, looks so much better once it’s done though. I really enjoy detailing mine . With your condensation have you pulled the bungs out the back if they’re still there to see if water is sitting in there. That can often cause condensation but not enough water to run into the carpets etc .

Well, I just pulled the bungs… you were right. Someone has had them out before because they were upside down. About 250ml ran out of the drivers side (with probably the same again or more trapped in the wadding) passenger side was dry. Since there’s no water in the boot, I assume it was a slow weep in building up over time.

Gonna leave them out for now and let it dry out, I’ll have to get it sorted in due course. First MOT under my ownership due in a couple of weeks, so I wanna make sure that’s not a disaster first. But at least I know that there’s no risk of it sloshing into the boot. Am I right in thinking some people have pulled theirs and had in the order of litres come out?

Ah that’s good news. That may be the cause of your condensation.. All the water sat there. Especially given the cold damp nights we’ve had recently with so much rain fall . I think those who have more water than yours generally seeps in the boot space foot wells etc. so you probably caught it at the right time

The holes on the inside aren't that high up so it leaks into the boot quickly. Fairly sure the space isn't large enough to hold litres, some people like to exaggerate lol!

With mine it travelled forward and soaked the carpet under the rear seats as well as the boot carpet. Car wasn't even 6 years old at the time! 🙄

1 hour ago, TomsFocus said:

The holes on the inside aren't that high up so it leaks into the boot quickly. Fairly sure the space isn't large enough to hold litres, some people like to exaggerate lol!

With mine it travelled forward and soaked the carpet under the rear seats as well as the boot carpet. Car wasn't even 6 years old at the time! 🙄

That’s ***** wild! And bad luck! I can’t believe it was a know issue for so many years and nothing was done about it. Do you reckon I’d be ok with aftermarket vents? There’s a 4 pack on eBay for less than £30, and I’d be silicone sealing them anyways. The original Ford ones I don’t think they even have all of them, and one has a different picture to the rest hmm. And it’s obviously quite a bit cheaper. Just thinking I don’t wanna have to remove it twice, and it would be better to have all the clips present if I want a tight seal with the silicone. Maybe just reuse whatever doesn’t break? I can be a bit of a heavy handed ape when it comes to trip clips 😬

11 minutes ago, Sausage2026 said:

That’s ***** wild! And bad luck! I can’t believe it was a know issue for so many years and nothing was done about it. Do you reckon I’d be ok with aftermarket vents? There’s a 4 pack on eBay for less than £30, and I’d be silicone sealing them anyways. The original Ford ones I don’t think they even have all of them, and one has a different picture to the rest hmm. And it’s obviously quite a bit cheaper. Just thinking I don’t wanna have to remove it twice, and it would be better to have all the clips present if I want a tight seal with the silicone. Maybe just reuse whatever doesn’t break? I can be a bit of a heavy handed ape when it comes to trip clips 😬

Link to the eBay pack?

There weren't any aftermarket ones available when I did mine. Only broke one as far as I remember but did have to buy a replacement from Ford.

Silicone may not be best for this, needs something that can cope with extremes of hot and cold expansion and contraction, as well as the chassis twisting. Silicone will just split eventually. I used butyl gutter sealant on mine.

Yeah I’d not seen after market vents until recently. As long as the clips line up and the seals are good quality should be ok. I’d prob use original if the funds are there. At least they are guaranteed to fit. Like you say don’t wanna do it twice if the aftermarket are a poor fit. I did my friends 1 litre ecoboom( and has gone boom recently). We used Everbuild Everflex roof sealant. Exterior sealant so good for temperature changes and remains flexible .

1 hour ago, Gavemz said:

Yeah I’d not seen after market vents until recently. As long as the clips line up and the seals are good quality should be ok. I’d prob use original if the funds are there. At least they are guaranteed to fit. Like you say don’t wanna do it twice if the aftermarket are a poor fit. I did my friends 1 litre ecoboom( and has gone boom recently). We used Everbuild Everflex roof sealant. Exterior sealant so good for temperature changes and remains flexible .

Out of interest, did you replace the wadding or leave it out? Obviously I want nothing soaking putting back in there. Not sure what that’s even called, Mrs will go bad if any pillows go missing lol