Hey scotty, firstly thanks for all the great Youtube vids, real great source of information.
Last week I broke down on the Motorway in the UK with my Peugeot 206 flashing the trusty STOP sign on the dash, to my horror my rad had split at the point it met the hose (I believe it was the original rad) and the cooling loop was 100% empty and due to the cost of getting someone out to the vehicle (£159 before repair or tow) I decided I had no choice but to rig something. And so I did, I rigged a small seal by getting the hose further onto the pipe right up to the leak, filled it with coolant and water from a nearby services and drove the 42 miles home with a leaky rad at under 50mph and watched that the rev's didn't go above 2000rpm to keep the engine temp down.
I suspect I drove for about 3-5 miles at 70mph without any cooling in the engine.
Getting home was no issue, I had no warning lights and the engine was smooth as it normally is, once home I bought and installed a new rad and properly fitted it and ensured I bled the hoses properly.
However since then I have had rough idling (normal about 800) and what feels like a cylinder is not firing. The abnormality goes away above 2000rpm.
This week I plan on checking it out properly as I have a long drive next week. I am going to check the sparks which are all new (2 months) check and clean the ignition coils check for a vac leak and check the PCV valve (if this car has one - never checked and don't know). ODBII is showing the O2 sensor has a fault so I will check that as well but I don't see why that would cause a rough idle.
Would greatly appreciate your input as to where you think I should start and what else I might want to check.
Make sure the engine didn't suffer any damage due to losing coolant. Do a compression test and check for a blown head gasket.
https://www.youtube.com/watch?v=QA7KVQq9vKA
Yes.
I now concur, the O2 sensor issue has gone away after cleaning the connectors and I now have oil coming from what appears to be the gasket, so definitely a gasket in my mind. I will start the disassembly this week and then order the new parts once I can actually inspect it. I will report back when and if it's all fixed.
ODBII is showing the O2 sensor has a fault so I will check that as well but I don't see why that would cause a rough idle
That could be the reason, electronic ignition on old French cars are one huge nightmare.
The oxygen sensor is used to set the correct fuel-air mixture, it affects emissions and idle quality.
To really understand if the sensor has anything to do with idle you need to perform the obvious maintenance,
make sure the car's overheating didn't blow the head gaskets, and that it didn't cause compression loss,
Also check the Idle air control actuator, clean the throttle, and possibly adjust the valves, ...
(I'm about 90% sure that's a TU, if has more or less than 75 horses, that's a different engine)
reset the ECU values, and if it doesn't set it back correctly - analyze the live data.
I'm unsure how to verify a bad O2 on an old French car, old euro electronic ignition systems on these are unpredictable.
On a Japanese car, when we think the oxygen sensor is causing it to misbehave, we unplug it and see how it runs -
on a 21 year old PSA? I do not know - local mechanics in your area probably may know how to check...
Thanks, that's really weird I just watched that vid before you messaged me!
So I don't have the kit to do a compression test, however after I removed all the plugs / ignition coil, check the valves etc etc I noticed that the coolant level was low again, although there is no leak or water pool under the car.
I also found there was a 'fumy' smelling gas in the pipework when bleeding again, I assume this is a good indication of a blown head gasket from over heating? I have no 'white gas' coming out of the exhaust as I know you can get, but I am now seeing liquid out of the exhaust which I never saw before.
Still thinking head gasket ?