Suzuki SX4 2008 - temp gauge drops while driving

chops018

Hi all,

So we got the above car a couple of months ago as a second car, just a run around.

Just passed the NCT when we bought it and it drives really well.

Only thing is if the car is idle and running for a few minutes it heats up fine and the temp gauge goes up to the middle where it should be, but as soon as you start to drive it the temp gauge goes back down to the bottom and the air blowing out of the car then isn't that warm.

Do you reckon this could be a simple fix? If not then we might just plough on and drive it for a few months as hopefully be coming into warmer weather for a few months soon. Bought it as a cheap run around so ideally don't want to be spending much on it.

cml387

It's possible the fan is running constantly and with increased airflow around the radiator it can't come up to temp. Is the fan running constantly or does it cut out after a while.

If it's on constantly the thermostatic control could be busted.

teediddlyeye

Thermostat stuck open is the only thing it could be. Nothing else causes over cooling.

chops018

@cml387 Not sure tbh. How can I check this?

I'm not great with cars to be honest.

If you mean the blower fan then once this is turned off I don't hear anything running but I'm guessing I need to open the bonnet and check?

Are either issues an expensive fix? If so, we will just drive it on for a few months and get rid. Was only a cheap run around. But if it's nothing expensive to fix might get it done.

Also, it shouldn't affect the driving should it? I mean it will still be ok to drive and safe? So long as we don't mind the air temp dropping a bit. We would have our toddler in it sometimes so if it's uncomfortable for her I'd consider getting it fixed or use it as to trade in for something else. As mentioned, we should be coming into warmer months soon so might get another while from it?

chops018

Thanks @teediddlyeye - any idea on estimate cost to fix? Have a mate who's a mechanic so I could ask them to do it but would be waiting a good few weeks for him to do the job.

teediddlyeye

It's a cheap part €15/20 max. Can't comment on labour for your particular car.

Won't do any harm in the short term. Your fuel consumption will be higher.

It's nothing to do with your fan, think about all the cold air passing through your radiator at 120kph on a day like today and it's still supposed to be hot.

chops018

https://www.boards.ie/discussion/comment/120335554#Comment_120335554

Not too bad so. Might try get it fixed. So long as it's not more than €150 for parts and labour as the car drives very well.

Might look into it so.

chops018

@teediddlyeye my friend who's a mechanic is going to price the thermostat part. Just one question, is it not odd that the temp gauge goes up to halfway as normal and blows out fully hot air while the car is just sitting running on idle? Then as soon as you go driving it the temp gauge goes right down.

L1011

No, that would be what happens if its stuck open. All the coolant is being sent to the radiator to cool, but it isn't cooling much when sitting idle; but it is when you're driving and blasting it with (currently cold) air.

chops018

https://www.boards.ie/discussion/comment/120337889#Comment_120337889

Ok makes sense. Thanks for the reply.

10-10-20

You can test this.

Start the car from cold and leave it running for 10 mins; then put you hand on the top radiator hose nearest the radiator and see if it's warm. 10 mins is not enough time for the engine to fully heat up and for the stat to open. So if it's warm, then the stat is faulty as it should be closed till the engine hits ~72 degrees C.

chops018

https://www.boards.ie/discussion/comment/120338263#Comment_120338263

Thanks. I'll give this a try!

honda boi

My 08 Octavia did the exact same thing.

Changed thermostat and now it's fine.