peugeot 508 no heating

[BrayanLDZ]

hello. has anyone replaced the air heater in the vents? today I was driving and there was no warm air, the engine held 90 degrees and on the way back the warning light came on to stop the vehicle because the engine temperature was too high. one heater pipe was warm, the other was cold.

[RichardW]

I think you have other problems... Is the coolant level OK? Could be the water pump has failed if level OK.

[BrayanLDZ]

the fluid level is correct. I'm betting on a clogged heater core because one tube is cold and the other is warm. everything was fine on Saturday. the car has 86k miles.

[myglaren]

If you can access the hoses you could try reverse flushing it. If that works I would drain and flush the whole system, then run a flushing agent such as Liqi Moly or Forte Cooling System Flush before refilling with antifreeze mixture.

Is it possible that the system has been topped up with an incompatible antifreeze? Different types are known to coagulate and form gel clumps.

[BrayanLDZ]

I'm going to flush the heater back with a garden hose tomorrow after work and see the effect. On the way home I'll buy a product from the K2 company radiator flush and fill the cooling system with demineralized water. I bought the car a month ago and everything was fine, suddenly I went out today and had a problem with the heating. Nobody refilled the fluid. I have information from Stellantis about the coolant changing color to dark and apparently nothing is being done about it, however I bought the coolant and was supposed to change it in the week for a new one.

[RichardW]

It's unlikely the heater blocked suddenly, and that wouldn't cause it to overheat. So need to get the bottom of why it overheated (or told you it was anyway).

[BrayanLDZ]

when I stopped right after the message that the temperature was too high I opened the hood the pipe from the heater to the thermostat was cold. however the pipe to the heater was warm. of course the pipe from the engine to the thermostat was warm I just didn't look to see if the thermostat had opened. the fan was also on. in any case I will flush the heater from the back and check if everything is back to normal if I don't have to get to the water pump. the question is were there cases where the water pump impeller was damaged? I forgot to add that after turning the car off and on again after about 1 minute, warm air was blowing for a moment, but the heater immediately cooled down and it was cold again.

[RichardW]

What engine is in it? It's not unknown for plastic impellers to break off the shaft on water pumps. Any sign that the head gasket has failed - i.e. still pressurised when cold, or pressuring quickly after start, or bubbles in the header tank?

[BrayanLDZ]

the engine is 2.0 bluehdi 180HP. the cooling system behaved normally there was no pressure when cold in the tank and it does not throw out the liquid. only the heating inside is missing and it seems to me that the thermostat did not open. there were no errors in the engine I connected diagbox.

[myglaren]

Unless something has changed the thermostat not opening should have little or no effect on the heater matrix as the feed for that bypasses the thermostat and water should always flow through the heater matrix and the cabin temperature controlled by the heater flaps.

The only thing that may be noticeable is that when the thermostat opens the cabin heat may reduce slightly as cold water from the radiator starts to flow through the engine and heater.

[BrayanLDZ]

I just drained the coolant....I'll say it's the color I have lds in a citroen c5 x7. There's crap in the reservoir, I'm attaching a photo.

[myglaren]

That doesn't look encouraging. I'd say that a good flush is well overdue.

[BrayanLDZ]

I'll quickly attach a garden hose to the heater at the back, run water through it and then run the water through the tank, I have the hose unhooked on the oil cooler because getting to the fluid cooler hose is bordering on a miracle.

[Stickyfinger]

Those grains are a tell tail sign of "Leak Sealant" having been used. That stuff (such as K_Seal etc) is well known for blocking heater cores & Oil-2-water coolers/Gearbox coolers.

[BrayanLDZ]

I filled the cooling system with demineralized water and added a product to clean radiators from scale, etc....the water pump seems to be working because when I rev the engine, the fluid disappears from the fluid reservoir, so something must be pushing it further.