Honda Civic - Blower Heater Issue

[Distorted Vision]

The blower heater on my mum's 7th generation 2005 Honda Civic is blowing cold air when the engine is hot.

I checked for any faults with my Autel ODBII scanner. It came up with this but I think its unrelated:






I checked the fuses in the fuse box in the engine bay:







I then tried checking the coolant level. I know this sounds stupid but I cannot see the coolant level in the expansion tank. It is really awkward trying to look at it but even shining a torch and taking a photo using a flash I wasn't able to tell.



Is the coolant likely to be the cause of the heater blower issue? I'm thinking I should take it to Kwik Fit or ATS Euromaster to get the coolant checked and ask their opinion.

Before I do this does anyone have any suggestions please?

Many thanks!

[owski]

Hi
Losing all the coolant can certainly make the heater cold
Driving with no coolant will cause catastrophic engine damage in short order
Owen

[Super Sonic]

Can you drop a piece of string with a nut tied on down the hole and see if it comes out wet? From the pic, that looks empty, maybe that's why you can't see a level.

[sherman]

I would phoneyour recovery service of choice and get it looked at quick.
Get it towed to a garage after that.
No coolant could be catastrophic engine failure.
Kwikfit or ATS are going to be useless in fixing that. You need an actual garage bot a fast fit place.
At best it cojld neex a collant top up znd a heater matrix.
At worst a whole engine.
Get it in for diagnostics.
Dont drive it with no coolant.

[Krikkit]

If in doubt put some coolant in it

[Distorted Vision]

I already drove the car to my local Kwik Fit before seeing any replies. They topped up with coolant that I supplied.
When I got home I left the car running on the driveway for 5-10 minutes. The heater blower was still cold but I wanted to check. They did say to me before they even checked the coolant that it was unlikely to resolve issue and it was most likely the heater matrix as you all suggested.

The Kwik Fit guy overfilled the expansion tank significantly and had to use a pump to remove the excess. Easy to see as the new coolant is bright pink. But I checked the level myself before driving off and it just blow the maximum fill line so I don't know what's happened.

Now I have a different problem which I don't understand. The temperature gauge of the engine was at maximum after 5-10 minutes running on the drive. I switched off the engine immediately. I've booked a call out with the RAC but their ETA is 17:30-20:30.

[sherman]

I would prepare for the worst if your engine temp is basically off the scale on idle.
Head gasket or water pump could be gone and cooked your engine.

Find your local scrapyards number as its probably not worth going to the garage if the RAC confirm an overheated engine.

[Distorted Vision]

RAC have rescheduled for tomorrow 8am-12pm.

This isn't a bad thing. If the car is repairable I will be get them to tow the garage. This will save me the expense of paying the garage or the local recovery company to recovery back to the garage.

[E-bmw]

If this is something that has recently started I would suggest the coolant level is/was the start of the issue but it is hard to tell from here obviously.

I would like to think a competent AA guy will be able to bleed any air if the low level caused an air lock as that is probably the most likely issue.

I have actually never in over 40 years of working on cars come across a blocked heater matrix, so on my experience alone I think it is unlikely, although I know it can happen.

If there is no airlock then my next checks would be thermostat and water pump.

Either way hopefully they should be able to get a better answer in the hour they allow you to try to get you away.

[GreenV8S]

If it's overheating at idle in cold weather, presumably hot coolant is not circulating through the radiator or the fans are not running. Both of these are trivially easy to check. Once you know which problem you're facing, tracking dowm the cause should be straightforward.

The fact the heater remains cold does point towards it being a coolant flow problem, but I wouldn't assume that since it's so easy to confirm.

[richhead]

seriously, having a code reader doesnt make you a mechanic, take it to someone who is.

[E-bmw]

richhead said:

seriously, having a code reader doesnt make you a mechanic, take it to someone who is.

I have to admit I did chuckle to myself at the irony of someone getting a code reader out as a first step.

[TwinKam]

E-bmw said:

richhead said:

seriously, having a code reader doesnt make you a mechanic, take it to someone who is.

I have to admit I did chuckle to myself at the irony of someone getting a code reader out as a first step.

Especially for an issue where the very first check should be of the coolant level...