Civic mk8 temperature issues

mccarf · 17 Jan 2019 at 15:33

My civic over the last couple of days has several problems with temperatures and I was wondering if anybody had any suggestions:

1)The heater fluctuates between hot and cold air but blows mostly cold air. It's -7 atm in Finland so I would really like to get this fixed asap.
2)The oil temperature gauge can quickly rise when I try to turn the heating on. This started just a day or so ago at the same time as the heater going kaput.

Any suggestions would be much appreciated!

Dup · 17 Jan 2019 at 15:54

The temp gauge is the water temp, not oil so it's likely your issues are related.

I'd hazard a guess that the thermostat is stuck or sticking occasionally. Or worst case a head gasket issue.

There is a way of reading error codes on the dash by bridging two pins on the OBD-II port with a paperclip or some wire. This is dangerous though as bridging the wrong ones can fry things proper but might give some indication.

mccarf · 17 Jan 2019 at 16:01

Dup said:
The temp gauge is the water temp, not oil so it's likely your issues are related.

I'd hazard a guess that the thermostat is stuck or sticking occasionally. Or worst case a head gasket issue.

There is a way of reading error codes on the dash by bridging two pins on the OBD-II port with a paperclip or some wire. This is dangerous though as bridging the wrong ones can fry things proper but might give some indication.

Ah okay that's good to know! I didn't know that this sort of thing would throw up error codes. I did buy a little OBD2 reader from ebay a while back that I haven't used yet so maybe that can give me the answer. Thanks.

Swifty55 · 17 Jan 2019 at 21:36

Will be thermostat.

Have a read up as it may be easy to change yourself.

Haggisman · 17 Jan 2019 at 22:11

There's a coolant temperature sensor at the bottom of the radiator which may be responsible, had to replace mine with similar symptoms, it's about a 10 minute job if you have a safe way of lifting the front of the car enough to get underneath

Part no (for 1.8 petrol) VE375108

mccarf · 29 Jan 2019 at 17:03

Just a mention to say big thanks for the help on this. Just had my thermostat changed and I am now driving in a nice warm car again

rjk · 29 Jan 2019 at 18:24

Thermostat common on 8th gen. Start with that and go from there. Edit* Derp didn't read you fixed it.

mccarf · 18 Feb 2019 at 17:17

So a bit of a development. It's seemed to be fine since it was done but today I noticed every time the car stops the coolant temperature starts creeping up and the heating cools down. It doesn't do it when the car is driving on a fast road. I also noticed the fans at the front never spin, even when it's overheating so am I right in thinking they are to blame for this?

Phemo · 18 Feb 2019 at 17:39

Sounds like it could well be a knackered radiator fan, or associated electrics. The natural airflow through the radiator when you're driving would be what kept the coolant temp down. As soon as you're slowed down there's no airflow through the radiator so the coolant just keeps heating up.

I had this with one of my cars a few years back. I do almost all motorway miles so never noticed a problem until a few occasions where I was stuck in traffic and I saw the car saying the outside temperature was climbing. One time when I was in Belgium in mid December and I was stuck on the Brussels ring road I remember seeing the car reporting the ambient temperature as 35 degrees C. When it cleared up a bit the temp started dropping but for whatever reason I never thought much of it at the time.

Another time the temperature warning light came on and as I was about to move over to the hard shoulder, the traffic cleared up and the light had gone off before I even had a chance to get over. It was only at that point that I realised I hadn't heard the radiator fan kick in for a long time and on that car it usually always kicks in as soon as you turn the AC on.

I spun the fan with my finger and it made a knackered grinding and squealing sound so it was safe to assume that it was dead. Replaced the fan myself in 15-20 minutes with one I bought from Ebay for £40 and it's still fine to this day, over 4 years later.

I'd suggest trying to spin the fan by hand (with engine off of course) and seeing if it moves freely. If it does then check the associated fuses for it.

Dogbreath · 18 Feb 2019 at 18:02

The interior heating getting cooler and the engine temperature increasing at low engine speeds suggests something is impeding the flow of coolant through the system. Could be a failing water pump or a build up of crud in the system. Has it has coolant changes performed to the correct schedule? It's not unknown for the blades on the water pump impeller to get sheared off due to aged coolant freezing in the block during cold weather.

mccarf · 18 Feb 2019 at 18:47

Phemo said:
Sounds like it could well be a knackered radiator fan, or associated electrics. The natural airflow through the radiator when you're driving would be what kept the coolant temp down. As soon as you're slowed down there's no airflow through the radiator so the coolant just keeps heating up.

I had this with one of my cars a few years back. I do almost all motorway miles so never noticed a problem until a few occasions where I was stuck in traffic and I saw the car saying the outside temperature was climbing. One time when I was in Belgium in mid December and I was stuck on the Brussels ring road I remember seeing the car reporting the ambient temperature as 35 degrees C. When it cleared up a bit the temp started dropping but for whatever reason I never thought much of it at the time.

Another time the temperature warning light came on and as I was about to move over to the hard shoulder, the traffic cleared up and the light had gone off before I even had a chance to get over. It was only at that point that I realised I hadn't heard the radiator fan kick in for a long time and on that car it usually always kicks in as soon as you turn the AC on.

I spun the fan with my finger and it made a knackered grinding and squealing sound so it was safe to assume that it was dead. Replaced the fan myself in 15-20 minutes with one I bought from Ebay for £40 and it's still fine to this day, over 4 years later.

I'd suggest trying to spin the fan by hand (with engine off of course) and seeing if it moves freely. If it does then check the associated fuses for it.

Thanks! I'll try and spin the fan tomorrow. I did try turning on AC earlier and it didn't do anything. I'm hoping it's this because it seems easier than some of the other possibilities. Good to know it should be cheap too.

Dogbreath said:
The interior heating getting cooler and the engine temperature increasing at low engine speeds suggests something is impeding the flow of coolant through the system. Could be a failing water pump or a build up of crud in the system. Has it has coolant changes performed to the correct schedule? It's not unknown for the blades on the water pump impeller to get sheared off due to aged coolant freezing in the block during cold weather.

This does sound like it could also be the problem. I've owned it for two years and the first coolant change that it's had during my ownership was when I had the thermostat changed a few weeks ago. It's also been the car's first really cold winter because I moved from the UK to Finland in the summer and brought the car with me. Again, to my knowledge it's never had the water pump changed.