Peugeot 407 SW 2.0 HDi 136 Thermostat Replacement

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Peter.N.
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Re: Peugeot 407 SW 2.0 HDi 136 Thermostat Replacement

Post by Peter.N. »

Take your pick from here. I recently replaced one in my C5 which was very similar, think it was about 24 pounds and worked perfectly. Yours looks a bit easier to fit as it doesn't have any pipes at the rear.

You might need a hose clamp removing tool unless you can get to them easily. Replace them with Jubilee clips, much easier to get off again.

Peter

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Re: Peugeot 407 SW 2.0 HDi 136 Thermostat Replacement

Post by ekjdm14 »

Was just about to mention the Citroen thread you posted in, Peter! I only saw it because of the "most liked" box haha, it should be stickied in all the brand fora I think since it applies to all "water" cooled cars. This thread here viewtopic.php?t=61901 :)

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Re: Peugeot 407 SW 2.0 HDi 136 Thermostat Replacement

Post by GiveMeABreak »

I'd agree - and especially as both scenarios Outlet Coolant tank or Matrix require coolant to be drained, refilled and degassed.....

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Re: Peugeot 407 SW 2.0 HDi 136 Thermostat Replacement

Post by white exec »

You can check whether the 'stat is working properly or not, before buying new:
viewtopic.php?p=600484#p600484
See section at the end of the article on How to Test.
Details there about checking heater matrix, too.

If you look on Mister Auto (owned by PSA), you'll find several makes of the item.
You can key in the original part number 1336Y9.
Photos of each there too.
https://www.mister-auto.co.uk/search/?q ... _search=1/

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Re: Peugeot 407 SW 2.0 HDi 136 Thermostat Replacement

Post by Peter.N. »

Didn't do any of that 'degassing' with mine, just filled it with coolant and kept topping it up until it stopped going down and bled it with the valve on the housing. Done quite a few miles with it since with no problems.

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Re: Peugeot 407 SW 2.0 HDi 136 Thermostat Replacement

Post by GiveMeABreak »

That's probably one reason why many people have problems down the line with poor heating output due to airlocks. Ends up being twice the cost in time and resources having to do the job again.

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Re: Peugeot 407 SW 2.0 HDi 136 Thermostat Replacement

Post by Peter.N. »

My heating is 100%

Peter

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Re: Peugeot 407 SW 2.0 HDi 136 Thermostat Replacement

Post by GiveMeABreak »

Good for you Peter, I'm pleased.

On this 407 there was an earlier version of the outlet cooling housing unit with additional degassing pipes and 2 control solenoids to aid in the degassing. These have been superseded now with a replacement part - but IIRC the OP has a build date after the modification, so should have the newer unit on.

I only go on what is supposed to be done (officially), in most cases as my philosophy is if it didn't need to be done, then it wouldn't be included in the procedure. It's my intention to avoid causing any potential additional problems by including at least what is supposed to be done and then the OP can make his choice bearing this in mind.

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Re: Peugeot 407 SW 2.0 HDi 136 Thermostat Replacement

Post by white exec »

Just a couple of observations on the need to 'de-gas' (bleed out air)...

Some cooling systems are more prone than others to air in the cooling system getting trapped in 'pockets'. Some of these likely to be at 'high points' in the system, where air would accumulate. Some vehicles don't help with this sort of thing, because the header tank/filler cap, and bleed-points, can actually be lower than some other parts of the system, and trapped air will rise.

XM 2.5 is a good example of this, and there is a mandatory procedure for purging trapped air, which simply involves using an inverted open bottle (half filled with coolant) on the header tank - to create extra "head" for the system, while it is brought up to full working temperature, and the bleed screws are opened several times.
Coolant top-up bottle.jpg
For a lot of systems, if coolant is being replaced, or the system in an way drained, the chances are that air will have got into the system. It is important that this is got rid of, which may, or may not, happen with just some normal driving after refilling.

In the worst case, an un-spotted air pocket can be in the cylinder head (often a high point) and this can create a hot-spot, and localised boiling. If this happens, coolant can be thrown out. BX XUDs were susceptible to this (inadequate or absent header tank), and the overheating could warp the cylinder heads and ruin head gaskets.

As Marc says, the recommendation to 'de-gas' is there for a reason. My own view is that whenever a vehicle has its coolant drained/replaced, attention should be given to removing inevitably trapped air, rather than just hoping it will find its way out. Even new coolant will contain some dissolved air, which will come out of solution as it approaches boiling point.

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Re: Peugeot 407 SW 2.0 HDi 136 Thermostat Replacement

Post by Peter.N. »

I'm afraid I'm still back in the '50s. :)

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Re: Peugeot 407 SW 2.0 HDi 136 Thermostat Replacement

Post by BadIdea »

ekjdm14 wrote:
15 Jan 2020, 11:07
The MPG figure does seem more than a tad low & that'd be my primary concern (our GTi180 manages about 29mpg on a run), but it'd be helpful to see what the coolant temperature really is (IR gun measurement at the thermostat housing) compared to what the ECU is seeing/reporting. If you have a cheap temperature gun you could check it yourself, they're less than a tenner on ebay & very useful little tools. You can even get an idea of flow by checking either side of the 'stat housing and comparing the readings. Obviously if it's stuck open then both sides will warm up equally slowly from a cold start whereas if it's functional you should see the head side getting warmer and then eventually see the top hose start to heat up as it opens.

Honestly I wouldn't spend even the £20-150 (+ the time and hassle) to replace the thermostat without a clearer picture of what was going on, tempting as it may be to leap in and shoot the prime suspect, that approach can lead down an expensive road. For what it's worth, I'd suggest the money would be better put towards a diagnostic session at a dealer or specialist if there's no-one local able to help with that. Offer of my help still stands as per the other post, if you happen to be down this way, fingers crossed there's someone a little closer though as it's not a short trip.
You're right; I was jumping the gun as it was one issue with the car I felt more comfortable in being able to rectify. Low-hanging fruit if you will, but I've reined in my enthusiasm a little and have ordered an IR thermometer. The fuel economy is concerning, assuming the reading is anywhere near accurate. I had to cringe last night when I was cruising at a steady 30 mph on a slight incline, and the instantaneous figure read 12 mpg. Of course, it's very efficient going downhill :-D

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Re: Peugeot 407 SW 2.0 HDi 136 Thermostat Replacement

Post by BadIdea »

GiveMeABreak wrote:
15 Jan 2020, 18:41
Good for you Peter, I'm pleased.

On this 407 there was an earlier version of the outlet cooling housing unit with additional degassing pipes and 2 control solenoids to aid in the degassing. These have been superseded now with a replacement part - but IIRC the OP has a build date after the modification, so should have the newer unit on.

I only go on what is supposed to be done (officially), in most cases as my philosophy is if it didn't need to be done, then it wouldn't be included in the procedure. It's my intention to avoid causing any potential additional problems by including at least what is supposed to be done and then the OP can make his choice bearing this in mind.
vindecoderz.com says 14.02.2006, is that correct? What are the implications of this manufacture date for degassing?

The E36 beemers (six cylinder, at least) are notorious for air locks if not bled properly. I used to remove the top hose from the radiator, stretch it up as high as it would go, then pour coolant into the block, as the bleed screw was never sufficient.

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Re: Peugeot 407 SW 2.0 HDi 136 Thermostat Replacement

Post by doctle »

If the coolant temperature sensor is faulty it can give a false reading on the gauge and cause fuelling issues. They are like women, good ones aren't cheap and cheap ones aren't good :-D

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Re: Peugeot 407 SW 2.0 HDi 136 Thermostat Replacement

Post by ekjdm14 »

Indeed it can, and cheap anything on a modern car tends to be a false economy (well, maybe not cheap fuel haha, but then again, remember the silicone in supermarket petrol a few years ago?)

Diagnosing the true issue before spending wisely on quality repairs is key to enjoying the thing as much as possible, hopefully the temperature comparison from the IR gun will highlight the true culprit and then more confidence placed in buying a decent replacement part as needed.

The Mk3 Supras with the 7M engine are also horrendous for air locks in the cylinder head, not helped by the whole radiator and expansion tank assembly being a good few inches lower than the head, as well as the heater matrix. Main issue though IIRC was that with the car on level ground, the back of the head was actually higher than the front too! No prizes for guessing where the majority of MA70 head gaskets fail... usually soon after a new owner's coolant change to protect the engine... (procedure on those was to run the front up some ramps plus the "header bottle" trick & I used to bleed by loosening the heater hoses a little).

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Re: Peugeot 407 SW 2.0 HDi 136 Thermostat Replacement

Post by GiveMeABreak »

BadIdea wrote:
16 Jan 2020, 10:05
GiveMeABreak wrote:
15 Jan 2020, 18:41
Good for you Peter, I'm pleased.

On this 407 there was an earlier version of the outlet cooling housing unit with additional degassing pipes and 2 control solenoids to aid in the degassing. These have been superseded now with a replacement part - but IIRC the OP has a build date after the modification, so should have the newer unit on.

I only go on what is supposed to be done (officially), in most cases as my philosophy is if it didn't need to be done, then it wouldn't be included in the procedure. It's my intention to avoid causing any potential additional problems by including at least what is supposed to be done and then the OP can make his choice bearing this in mind.
vindecoderz.com says 14.02.2006, is that correct? What are the implications of this manufacture date for degassing?

The E36 beemers (six cylinder, at least) are notorious for air locks if not bled properly. I used to remove the top hose from the radiator, stretch it up as high as it would go, then pour coolant into the block, as the bleed screw was never sufficient.
The modification was made with the new Coolant Outlet Housing from models built from 30th January 2005. Yours was built 2nd February 2006, so will have the new one fitted.

For those others who may be reading this and are interested:
Coolant Outlet 407.PNG
(A) Old Assembly <= 30/01/2005
(B) New Assembly => 31/01/2005

The following parts have been discontinued:
  • (1) Venting electrovalve
  • (2) Degas pipes
  • (3) Bypass solenoid valve
  • (4) Coolant outlet housing (piloted thermostat)
The connectors of the following components are disconnected:
  • Bypass solenoid valve (at "a")
  • Coolant outlet housing (piloted thermostat) (at "b")
  • Venting electrovalve (at "c")
Replacement Parts Available:
  • (5) Coolant outlet housing
  • (6) Degassing pipe
  • 3 plastic tie wraps
  • 3 connector protectors
The tie wraps and connection protectors are to protect the electrical harness.

Note: The elimination of the solenoid valves will result in the following 2 fault codes:
  • P1579: Cooling circuit degas solenoid valve
  • P1597: Cooling circuit by-pass electrovalve
If the solenoid valves are missing, then these 2 codes can be ignored.

There are no documented reasons why the modification was made going forward, but there would be little point, I feel, in going into the workings of the older system being that it is no longer relevant.

So if, when you get a diagnostic done, make a note of these 2 codes which can be ignored on vehicles without the solenoids fitted / disconnected.