Xn6 head gasket

[NinaYo401]

I’m experiencing white smoke on startup, which eventually evolves into pressure in the radiator.

i don’t think I’m bleeding it wrong.

how difficult is the gasket on these?  Do I need the head removal  tool or cylinder liner holding tool?

is there a gasket between the Maifold and down pipe?  Is there much involved in removing the intake?  
 

I added a 4.4oz bottle of “Subaru coolant conditioner” to my radiator today and since noticed easier starting, but then I hard accelerated to stop at a uturn and returned it to rough.

[NinaYo401]

It’s probably a crack in the head.

I loose heat after initial start.  Changed from a 167 to a new 167, then tried a 180° thermostat, had a little heat for a bit, and now I’m struggling to reach 1/3 temperature on the dash.  The radiator fan is triggering, but I’m guessing my temp probe isn’t getting fully submerged, due to cooling system pressurization from exhaust gas.

changed coolant recently, along with a new lower hose, and the expansion cap isn’t too old

something tells me, rear arms and heads are tough to source.  So, I see why these cars aren’t too common these days.

[NinaYo401]

i don’t know.  Maybe it’s a valve.  Anyway, no overheating. White on start, then loss of heat.  Nothing out of the expansion.

i opened the radiator, after only 30 minutes of cooling, and the system was under pressure,  and puked at me.

squoze the hoses, added a dash of distilled, and pipe wrenched the cap tight.
 

it’s either been burped, the Subaru coolant’s active ingredient is doing something, or the crack seals when hot.  Maybe some combination.
 

My luck with Peugeot seems one step forward, two steps backward.  Took me a three or 4 point to pull away from a curb today.  
 

I should take a look at fixing my steering ram line leak 

it runs rough at 1/4 temperature.  Maybe I could try a new temp sensor.  But if there’s air in there, it would explain the temp.

[NinaYo401]

There’s a chance my temperature sensor is bad.  I cleaned it today, because the replacement I received from rockauto is the wrong part.  M14x1.25, according to the friendly autozone kid, who’s hopefully correct.  The old one came out with a 16mm deep, barely cute in there

rockauto sent a bigger thread sensor, which wanted 22mm.  I don’t even have that size metric socket.  Figure I’ll buy 6 point of anything larger than that, but might like to have a deep 22mm, and an impact 19

starting to think rich fuel mix from temp sensor to ecu is illuminating orange ring on my dash cluster for predetonation from hot fat plugs triggering emissions or worse.

[Mr_rye]

The rich running is probably from the control pressure being too low (defective Warm Up Regulator) or the fuel metering vane/plunger being stuck or adjusted wrong. The temperature sensors (I think) tell the ECU when the engine has warmed up enough to read the O2 sensor. The big sensor on the bottom of the radiator near the lower hose is the fan switch. You may have to rig up a fuel pressure meter to see if the fuel pressure is correct according to the engine/ambient temperature. Also a compression test and leak down test may be in order to determine if the headgasket is bad.

Hopefully someone more knowledgable that I will chime in, this car seems to have a lot of sensors on the coolant, maybe one of them provides feedback to the frequency valve/ECU but from what I understand the frequency valve, which does a fine trim control on the fuel mixture is controlled by the O2 sensor.

[Ducaati]

I got super lucky and found a rebuilt head on eBay. Replaced it, car is ok now, no special tools required. Think about it- with the head on, what would a tool to hold the cylinder liners in place do? Answer-nothing! I did use a torque wrench. The torque pattern is weird, use the book! Also, be sure to match the head gasket holes to the passages in the head. This should take precedence over any labels or markings to the contrary. The French word “dessus” was on the bottom of it. That means top. You’ve been warned.