Peugeot 406 Thermostat Leak

[derbyshirewhaley]

Hi all, my trusty 406 (HDi 90) has had a coolant leak for several years now. I love the car and it's taken me and my family everywhere, so I want to get this addressed.

I've identified the source of the leak at the thermostat housing. The housing itself looks fine (from the angle I've looked at) and the leak seems to be coming from where a pipe goes into the housing (possibly just push fit?)

You can buy the housing, but I thought I'd ask here to see if others have had the same issue and if so, what they did to fix it.

[mickthemaverick]

Difficult to tell from the pics but if that is a metal pipe going into a housing then it probably has an O ring around it which has perished. If the housing and pipe are in good condition you may just need to replace the O ring.

[ozfrog]

You seem to identify engines differently in England compared to how we do in Australia! This is the second time this week that someone has referred to an engine in a 406 in terms that I don't use. I've worked out that the HDi 90 means that it has 90 horsepower- well, 89 to be exact. But I haven't found out what engine it is.

We didn't get the same range of engines here, as far as I know, that you did. The engine in both of my 406 HDi cars is what we call the RHZ engine. Or some people might call it DW10ATED. Again, from my searches, I don't think that your engine is the same as mine, but I'm not certain.

All of that to say that I was going to look at one of my 406s to get a better look, but if it isn't the same engine …

[derbyshirewhaley]

Difficult to tell from the pics but if that is a metal pipe going into a housing then it probably has an O ring around it which has perished. If the housing and pipe are in good condition you may just need to replace the O ring.

So sorry I didn't see this reply..!
It is a metal pipe and I agree it's not a great photograph. I've had other looks around there and the leak definitely animates from the junction of the housing and pipe. I now need to source an O-ring, I'll ring Peugeot as I don't have PP2000 anymore.

It happens in cold weather much more often, in the Summer I might get away with topping up every month, so possibly swelling rubber?

You seem to identify engines differently in England compared to how we do in Australia! This is the second time this week that someone has referred to an engine in a 406 in terms that I don't use. I've worked out that the HDi 90 means that it has 90 horsepower- well, 89 to be exact. But I haven't found out what engine it is.

We didn't get the same range of engines here, as far as I know, that you did. The engine in both of my 406 HDi cars is what we call the RHZ engine. Or some people might call it DW10ATED. Again, from my searches, I don't think that your engine is the same as mine, but I'm not certain.

All of that to say that I was going to look at one of my 406s to get a better look, but if it isn't the same engine …

The HDi element is standard (obviously the successor to the XUD), however I've found that most people here will then differentiate the two offerings into either the HDi 90 (for for the 88bhp one) or the HDi 110. Some will quote the engine number as you have.

No idea where it started, but I'm sure there is a sticker on the driver side B-pillar which states this "HDi 90" I'm quoting.