Peugeot 407 SW 2.0 HDi 136 Thermostat Replacement

[ekjdm14]

I have to agree, now it's looking fairly conclusive that the 'stat is not fully sealing closed. The top hose beginning to warm up too soon is the clincher, still not nice to know such a previously generic cheap part has become one with it's housing and more expensive because of it, but I suppose at least you can replace with confidence it'll be a fix now.

Actually think we may have to replace the one in our 180 too since that drops down to about 70c on a run, albeit gets up there quick enough from cold.

[BadIdea]

I have to agree, now it's looking fairly conclusive that the 'stat is not fully sealing closed. The top hose beginning to warm up too soon is the clincher, still not nice to know such a previously generic cheap part has become one with it's housing and more expensive because of it, but I suppose at least you can replace with confidence it'll be a fix now.

Actually think we may have to replace the one in our 180 too since that drops down to about 70c on a run, albeit gets up there quick enough from cold.

So I really have to buy the full housing, then? Any recommendations on brand?

[Peter.N.]

If its the same as the one on the C5 they all look pretty well the same, I paid 24 pounds for mine on Ebay and its fine. Compare the pictures, I don't see any point in paying twice as much for the same thing.

Peter

[BadIdea]

If its the same as the one on the C5 they all look pretty well the same, I paid 24 pounds for mine on Ebay and its fine. Compare the pictures, I don't see any point in paying twice as much for the same thing.

Peter

Was that with the housing, Peter?

[Peter.N.]

Yes you can't replace just the thermostat by itself - in spite of what the Ebay listings say. The one for the 407 looks pretty well identical to the C5 one but order it for a 407 to be sure.

Peter

https://www.ebay.co.uk/itm/THERMOSTAT-W ... Swp0Rd6jn8

[BadIdea]

Yes you can't replace just the thermostat by itself - in spite of what the Ebay listings say. The one for the 407 looks pretty well identical to the C5 one but order it for a 407 to be sure.

Peter

https://www.ebay.co.uk/itm/THERMOSTAT-W ... Swp0Rd6jn8

That will do me, just a touch cheaper than the Peugeot option

[BadIdea]

I went for a Mahle unit in the end. I didn't want to risk having to do the job twice, but I guess it's luck of the draw anyway.

I stripped away the intake components today while the weather was good, took off the bracket that holds a mass of wiring in place, then saw where the hoses were and promptly put it back together. It looks like a pig of a job! I think I'd need one of those flexible hose tools for a start (which I don't have), but the way I'm feeling about it, I think I'll probably just get a local indie to do it instead.

[Peter.N.]

This is the tool you want. They've gone up since I bought mine a couple of months ago!https://www.ebay.co.uk/itm/Car-Remote-A ... 8207c6085f
Its only the back one that is really difficult if not impossible without the tool but not to difficult with it. Its not essential for the others but does help. Replace them with Jubilee clips.

If you can now get to the hoses don't give up, its not to bad. I'm coming up 81 and I managed it.

Peter

[BadIdea]

Thanks Peter, although I cheated in the end and took it to a trusted mechanic. His words after doing the job (and patching up his bleeding hand) were "I can see why you decided to get a mechanic to do it. I wish I had that option!".

Anyway, the car now gets up to temp after maybe 15 minutes of driving, rather than 30-40 mins / never. Fuel economy still isn't amazing, but to give it the benefit of the doubt, I've only done 5-10 minute trips max. recently in the freezing weather, and it's still managed 25 mpg. I might hit that 30 mpg urban figure if I were to take it into town for example, and I could really do with getting it on the motorway.

The heater is still weak even when the engine gets to temp, but does warm the cabin if set to 26c. So maybe there's something to fix there, too.

[Peter.N.]

If you have the option of a good mechanic that's probably the best way, pleased you got it sorted, being on a state pension I don't really have that option.

Fuel consumption doesn't sound that good but I believe the 407 to be somewhat heavier than the the C5 but where you drive makes all the difference, we live in the sticks and drive mostly country roads and I drive like a grandfather (which I am). My average consumption over the winter is an indicated 48 mpg but I have had over 70 mpg on the motorway in the warmer weather.

Apologies for my absence, we have had no phone or broadband for over two weeks, its come back this morning but I'm, not convinced its going to stay!

Peter

[white exec]

The heater is still weak even when the engine gets to temp, but does warm the cabin if set to 26c. So maybe there's something to fix there, too.

See what it does on a longer journey. Conditions very cold at the moment, so outside air coming in is somewhat chilly. Not unusual to have to dial in a slightly higher cabin temp in the winter.
You might be able to feel one/both of the pipes leading to, or at, the heater matrix. With a fully warmed up engine, they should be too hot to keep hold of.

Possible that the air-mixing flaps of the heater mechanism are not doing their stuff. Hopefully not. I don't know the 407's heater box, so can't advise.

If the car has a cabin temperature sensor, check that isn't clogged with fluff or some other mishap.

[BadIdea]

If you have the option of a good mechanic that's probably the best way, pleased you got it sorted, being on a state pension I don't really have that option.

Fuel consumption doesn't sound that good but I believe the 407 to be somewhat heavier than the the C5 but where you drive makes all the difference, we live in the sticks and drive mostly country roads and I drive like a grandfather (which I am). My average consumption over the winter is an indicated 48 mpg but I have had over 70 mpg on the motorway in the warmer weather.

Apologies for my absence, we have had no phone or broadband for over two weeks, its come back this morning but I'm, not convinced its going to stay!

Peter

Yeah, I've been taking jobs to him that I don't fancy/can't do for the last five years or so. What I like in particular is that when it's me, he ensures that it's him who does the job rather than his employees. I do like to do what I can myself, but having a ten-month-old baby is certainly diminishing the time I have these days. Especially when she's been sick for the last two weeks!

That's some impressive fuel consumption you're getting there, Peter. How long is your average trip in terms of time? Does it get up to temp every time? I drive this one like a granddad too, but the sort of trips I'm doing in it at the moment are not ideal for a diesel. It rarely gets to temp before the end of the journey even with the new thermostat, which I know isn't good for it (especially if it has a DPF, which I believe it does). I'm looking forward to stretching its legs when everyone's well enough to go out for a proper trip. I didn't know that the C5 is lighter, and I'm only just starting to realise how big the 407 SW is. I didn't think much of it to begin with, but now I've had it for a bit and parked it in a few spots I've realised that it's actually quite a beast. I hope my missus will get used to it as it's supposed to be primarily for her. It's really grown on me though; she'd better not prang it!

[BadIdea]

The heater is still weak even when the engine gets to temp, but does warm the cabin if set to 26c. So maybe there's something to fix there, too.

See what it does on a longer journey. Conditions very cold at the moment, so outside air coming in is somewhat chilly. Not unusual to have to dial in a slightly higher cabin temp in the winter.
You might be able to feel one/both of the pipes leading to, or at, the heater matrix. With a fully warmed up engine, they should be too hot to keep hold of.

Possible that the air-mixing flaps of the heater mechanism are not doing their stuff. Hopefully not. I don't know the 407's heater box, so can't advise.

If the car has a cabin temperature sensor, check that isn't clogged with fluff or some other mishap.

Thanks, Chris. I'm hoping to take the car on a bit of a longer trip this weekend, so I'll see what the cabin temperature is like after that.

[Peter.N.]

Apologies for late reply, our broadband and phone have been off for over two weeks and I think only on temporally now.

As we live in the sticks most of our travelling is on rural roads. Our shortest journey is around 14 miles to Axminster and back. We occasionally go to Exeter about 30 miles each way and usually manage in excess of 60 mpg but it is largely dual carriageway. On the motorway in the warmer weather I can get 70 mpg but I rarely drive above 60 mph or 2000 rpm. Our winter average dropped to 47.1 yesterday.

The heater in the C5 is not brilliant, certainly not as good as the XM but it is a big car with a lot of space to heat. One of them has heated seats, but they only work on the wife's side, I let her drive yesterday so I could have the one that works. The auxiliary heating works well though with warm air in a few hundred yards, the temperature gauge does't start to rise for a couple of miles and will drop a little when going down a long hill in the current temperatures.

Fuel economy is governed mostly by how and where you drive but its certainly affected by the cold weather.

Peter

[BadIdea]

Apologies for late reply, our broadband and phone have been off for over two weeks and I think only on temporally now.

As we live in the sticks most of our travelling is on rural roads. Our shortest journey is around 14 miles to Axminster and back. We occasionally go to Exeter about 30 miles each way and usually manage in excess of 60 mpg but it is largely dual carriageway. On the motorway in the warmer weather I can get 70 mpg but I rarely drive above 60 mph or 2000 rpm. Our winter average dropped to 47.1 yesterday.

The heater in the C5 is not brilliant, certainly not as good as the XM but it is a big car with a lot of space to heat. One of them has heated seats, but they only work on the wife's side, I let her drive yesterday so I could have the one that works. The auxiliary heating works well though with warm air in a few hundred yards, the temperature gauge does't start to rise for a couple of miles and will drop a little when going down a long hill in the current temperatures.

Fuel economy is governed mostly by how and where you drive but its certainly affected by the cold weather.

Peter

Oh, no problem. I generally don't find a lot of time to get on the forum regardless of my internet connectivity.

Does your C5 have a manual gearbox?

I managed the elusive 30 mpg urban figure the other day on a ten-mile round trip, all village driving. That matches the consumption figure in the owner's manual for this sort of trip, so I'm pleased with that. I'll have to see what it can manage on a motorway run.

Also, the heater does seem to eventually get up to temp now I've found, even at lower settings like 22c. I wonder if the 407 is supposed to have an electric heater to assist when the engine's cold, though. I'll have to check the manual.