206 overheating

[jsp]

Hi, I have a 206 1.6 NFU 2003 engine and the engine overheats only when I am on the motorway.

So far I dont know which tool to buy to diagnose the headgasket

some gurgelling noise is audible when turned off the engine

[myglaren]

It may need a thorough bleeding to get any residual air from the system.

[jsp]

Been bled many times, the weird thing is only over 60mph I get overheating and at the traffic light

[myglaren]

Well, I hate to say it but that was a symptom my daughter's C3 had. Had a new head gasket fitted and the block and head surfaces skimmed but they were pitted and we were warned that the engine was about shot.
It was pressurising and blew the top hose, that was replaced and it continued to chuck the coolant out.
Bought her a replacement C3 last week.

Gurgling was air bleeding into the cooling system of course.

[jsp]

? so a replacement radiator is not enough?

its only doing at higher speed.

[myglaren]

Not saying that your problem is the same, just similar symptoms and the gurgling would seem to indicate air in the cooling system. Some cars can be very difficult to bleed and there are some clever ways of doing it, from parking on a hill so the reservoir is at the h point, to fabricating an extended reservoir using a 2L drinks (Coke) bottle. It may be worthwhile to try that.
Take some time to look for leaks when it is hot and pressurised as it may draw air in through the same breaches as it cools.

[ozvtr]

Are you loosing coolant from the expansion tank (the cooling system)?

Overheating at speed is typically a blocked radiator...but only if you are not loosing coolant. If you are loosing coolant it's probably the head gasket (cooling jacket leaking into a cylinder) .
Gurgling is probably bubbles from the return pipe into the expansion tank (for one reason or another). Check that expansion tank cap is forming a good seal. If it's hissing tighten or replace the cap. Gurgling can be the cooling system being pressurized by compression from a cylinder (bad head gasket).

Could be a "blown" head gasket (between the cylinders) but you need to do a compression test to check that. Again, you wouldn't loose any coolant with a blown head gasket but the compression would be down on (typically) 2 adjacent cylinders.

You can get a tool and liquid that check for exhaust gasses in the coolant, indication of a leak from a cylinder into the cooling system.

So It comes down to: are you loosing coolant or not?

I would take the car to a radiator repair company. They should be able to diagnose the fault very quickly. They wont fix head gaskets, if that's the problem, but they should be able to tell you what's wrong.

I cant see anything wrong with your pictures!? 90'C (85'C? Hard to tell) is just fine at speed, then 95'C when stopped is not unusual. Is that as bad as it gets?

[jsp]

its not losing any coolant now, it was because I overfilled the expansion tank too much. Now its fine, I will replace the radiator and see what happens.

[MattBLancs]

? so a replacement radiator is not enough?

its only doing at higher speed.

Is that as hot as it gets at speed? As 90°C isn't that hot really.

Agree stationary image is rather on the hot side of things. Radiator fan working when at that temperature?

[PaulC5]

The temperatures shown in the photos do not look wrong to me, it ought to be running between about 90 and 96°C once warmed up. Below about 90°C once warm can indicate the thermostat is faulty opening too soon/too much. Above 96°C by a lot and the engine fan might not be running.

If you plug in a code reader that gives live data you can check the coolant temperature and also see if the dash gauge is correct. Typically you ought to get about 90°C the thermostat opens and the radiator top hose gets warm, 96°C the engine fan will start, a bit higher the fan speed will increase further if it is a 2 speed fan, about 110°C you will get a high temperature message, about 120°C the expansion tank cap will open to vent steam.
If the coolant temp is not at ambient (around 20°C) before the engine is first started on a morning, then the sensor might be faulty. If the engine fan is not running above 96°C then it might be faulty - if you have air con it should also run with the air con on. If you think it is over heating then putting the cabin heater on max temp and the blower on max should help to drop the temp.

[jsp]

yes the fan runs only with A/C on. Not with A/C off? Where is the fan switch on the 206?

So the overheating is now only at stationary?

??

[PaulC5]

As far as I can tell, the photo with the car stationary does not show it overheating, it shows the temperature about 95°C and not in the red part of the gauge. At this temperature the engine fan might not need to come on. Switching on the fan might be using the coolant temperature sensor so you need to use a code reader with live data to check what it is giving if you suspect the dash gauge is not accurate. With the car stationary and the bonnet closed, let the engine warm up and see if the gauge goes above 96°C to check if the engine fan runs.

[jsp]

ended up with a clogged radiator

[MattBLancs]

ended up with a clogged radiator

Cured by a good flushing, or replaced and found the old one gummed up when removed?

Glad it's sorted

[jsp]

replaced with a Valeo one. was already crusty from outside