Coolant leak from mystery hose . P0115 error

[stevepicasso]

Hi, I was in traffic and got engine temperature warning, i saw the level of water temp was at max, i parked up and found the cooling tank almost empty. I waited to cool down, added water and drove home as emergency, the engine temps were 90 normal but I drove on motorway and turned engine off at stoplights. i found the coolant empty when I reached home.

I ran diagnostics and found error p0115 (22)
I looked for leaks and found nothing on the bottle cap or around engine. I looked under and found coolant seems to be coming from this mystery small transparent hose behind the oil pan.

Car had new original belt and water pump a month ago, ran perfectly since. Water level was checked during the month and it was okay.

I still don’t know what is causing this coolant dump.

[Huskyxantia]

I Think That's the hose from the fuel filter, when the filter has water in it there's a leak off point and this is connected to it it stays connected

[Huskyxantia]

My c3 had a leak from that area and it ended up being a core plug

[Huskyxantia]

And here's how it was repaired as I couldn't get the core plugs so did it the old school way , still works and dont lose coolant either

[stevepicasso]

My c3 had a leak from that area and it ended up being a core plug

How easy for a normal mechanic to do this? How expensive is it too?

[Huskyxantia]

We're to begin.. ok, my car began with a slow leak over a month it got worse, one morning I checked the coolant level before using the car and I saw a puddle under the car and the coolant bottle was empty. So took the car off the road to get it done, I knew the head gasket was beginning to show signs of failing so once the head came off and the manifolds front and back were removed bingo I spotted the core plug which was passenger side rear of engine and this would show up as a leak as shown in the attached photos of this post . Coolant is useful for tracing leaks because it stains . The coin 1p was slightly oversized but ideal and was pressed into the head with a socket and that socket was tapped with a hammer till it was firmly in place and hasn't leaked ever since , but this simple job is only simple when the head comes off and is all cleaned and put on a bench . If you have a good home mechanic id say having the gasket done aswell and all works involved and if you have a good friendly local mechanic 260 labor and what ever the gasket kit is.

[Huskyxantia]

Oh there's core plug on the front of the engine too, as ever it's removal of manifolds, turbo set up and so on. And as these are covered by manifolds you won't see the rusty little hole till there removed.

[RichardW]

Need to get under it when it's hot and see where it's coming from. Suspicion always falls on recent work...I'd be paying close attention to the water pump.

[stevepicasso]

Today i put it on jack stand and let the engine run for about an hour and could not see any drips , i revved the engine also, then i drove in town for an hour and temps are stable at 90 as well as coolant level has not gone down dramatically if at all.

After two hours drive i noticed tiny leak under where that fuel pipe is but i can not see the source, it doesn’t seem to come from water pump housing either.

I can’t seem to find water sensor for this model on its own or I have to buy a whole thermostat to get it?
I can supply vin number if needed
It’s a Picasso 1.6hdi blue 120bhp 2015

[Huskyxantia]

Need to get under it when it's hot and see where it's coming from. Suspicion always falls on recent work...I'd be paying close attention to the water pump.

Oh so true I've seen them pack up in under 2000 miles . Even incorrectly tighten up bolts

[Huskyxantia]

Id say if your thinking water sensor then yes the whole thermostat housing has to be replaced , check ebay and I will say if you can get to yours do so as there are more than one variant, and to be honest anything over the 100k mile mark with this plastic parts will start to fail, some have a sensor on the front some one the back a silly design as a clip hold it in place and the sensor has an o ring aswell https://ebay.us/m/9cjUcb (different car possibly same but picture shows what i mean )which this o ring gets old and fails, my 207 has 1.6hdi and I replaced the thermostat housing as my temperature gauge was reading then dropping to nothing so instead of swapping the sensor i did the whole unit , im glad I did as whe I removed the original one the thermostat was stuck open the gasket was a mess and when the new one was fitted and coolant topped back up and system bleed all was like new, my old one was also leaking all be it very slow , due to the gasket failing. Another place they lose coolant is oil pump cooler , but them leaks are more noticeable,

Check this out for the thermostat housing it comes with sensor too
https://ebay.us/m/nCRruJ the sellers should be able to compare your vin with it , but looking at that it looks to be the correct one. Think this is where my one came from as I did get a new on when I was working on my picassso last April

[RichardW]

The stat housing is on the other end of the engine - they do have a tendency to leak, you can easily check by putting your hand under it (under the air pipes) to see if it is wet. They're not cheap, or easy to change.... I doubt this is why you have a leak at the other end of the engine, however. If it's not pressurising or boiling over from the cap, then there is a failure somewhere - there is a manifold all across the back of the engine that could be the source, but it's difficult to see and even harder to change! Really you will need to get it on a ramp - it appears to be a fairly significant leak when it does happen, so shouldn't be that hard to find.

[stevepicasso]

The stat housing is on the other end of the engine - they do have a tendency to leak, you can easily check by putting your hand under it (under the air pipes) to see if it is wet. They're not cheap, or easy to change.... I doubt this is why you have a leak at the other end of the engine, however. If it's not pressurising or boiling over from the cap, then there is a failure somewhere - there is a manifold all across the back of the engine that could be the source, but it's difficult to see and even harder to change! Really you will need to get it on a ramp - it appears to be a fairly significant leak when it does happen, so shouldn't be that hard to find.

yes I doubt it too, I checked all the hoses and pipes from that end they're dry. the leak is on the other side for sure, I just suspected the water temp sensor since the error did come up when it overheated.
do you know if this engine has an EGR cooler? someone said his one leaked but his was an old peugeot 307. so it's either that or the last job wasn't done properly, I do admit I took it to a ford specialist he is my mechanic I used for years, and I do know this dv6 engine is used on some fords. so perhaps he didn't tighten the pump properly to psa specs or something, I am taking it to him next week and see what he finds.
the car has done 75k miles btw.

[Huskyxantia]

The water pump bolts are not overly tight to be honest , I know some people still use mastic this isnt needed as it has a metal gasket in with the kit, ive heard that the mastic can fail then your have a leak.