Kia Picanto coolant loss

Kia Picanto coolant loss

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jamesson

Original Poster:

2,584 posts

190 months

Thursday 8th July
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Hello all,

I have a 2012 1.0 Kia Picanto which suffers from a coolant loss. It's quite slow and I'm having trouble finding it. I've done a pressure test and the pressure drops very, very slowly. No evidence seen in the engine bay anywhere and I've been underneath the car too but still couldn't see any leaks.

I took off the front bumper to have a closer look and thought the radiator didn't look in the best shape after nine years and 83,000 miles so after I drained the coolant I changed the radiator along with the upper and lower hoses and thermostat (a might-as-well-since-you're-in-there type job).

All went back together OK with no obvious leaks to be seen but I'm still losing coolant.

The carpets are dry so I don't think it's the heater matrix and when I spoke to my local Kia garage the service manager said he'd never heard of a head gasket going on this engine.

The only thing which I think is a bit weird is the neck of the expansion tank. I know it's not a pressurised system so what I'm about to explain shouldn't be an issue particularly, but there's a gouge out of the top of the neck which is something I've never seen before in other cars.

Is this normal for this era and model of Kia? It doesn't look like it's supposed to be there and a mechanic friend of mine said it wouldn't have any effect on the loss so I'm a bit stumped. All ideas gratefully received!



Collectingbrass

1,475 posts

164 months

Friday 9th July
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I might get shot for this, but I come from the shed end of mechanicing... Given the cars age and mileage I would throw some Rad Weld in it and keep an eye on it. I did this on a 1.8 Mondeo of similar age & mileage and it both stopped the coolant loss and didn't seem to suffer any adverse consequences.

Going a bit further I might have changed the expansion bottle and the pump, but you say you haven't seen any signs so that might be spending money for no reason

jamesson

Original Poster:

2,584 posts

190 months

Saturday 10th July
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I'd rather get it sorted properly than throw some radweld in it, but I appreciate the suggestion.

GreenV8S

28,964 posts

253 months

Sunday 11th July
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Given that it is not pressurised and is well above the coolant level I don't see how that can be relevant to a leak that shows up on the cold engine.

Given that you seem to have ruled out any likely external leaks, an internal leak seems the next most likely cause. You could do a block / sniff test on the coolant to see whether you have an internal leak in the engine.

Can you get a sense of how fast the leak is by leaving the cold system pressurised overnight and seeing how much coolant is needed to top it back up? If you're only looking for a trace amount per day, it's pretty unlikely that you would spot that since it would evaporate as fast as it's leaking so you would need to be looking right at the leak to see any witness of it.

jamesson

Original Poster:

2,584 posts

190 months

Monday 12th July
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I don't think I'd be able to track it down as I can only do basic mechanic stuff. I've booked it in with my local friendly mechanic for 2 August so I'll report back when he's had a look at it.

jamesson

Original Poster:

2,584 posts

190 months

Monday 2nd August
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Hello all. I thought I'd update you on the conclusion to this one.

My Picanto went to the mechanic today and he couldn't find any external leak either, which is sort of gratifying because it means I put it all back together properly after I changed the radiator, thermostat and hoses.

But it's also annoying because if there is no external leak then there must be an internal leak. He did a pressure test which showed a slow drop and his best guess is the head gasket is faulty. He said he's never come across a petrol Kia with a dodgy head gasket and the Kia service manager I spoke said he'd never encountered one on my engine either but that doesn't mean it's impossible.

Two options: change the head gasket but there's no guarantee that will solve the issue despite potentially a large labour bill. Or just carry on as I am. The engine has had this problem for tens of thousands of miles and it doesn't seem to be getting any worse so I think I'll just keep topping up the coolant as I go.

I appreciate it could very well overheat one day and that could mean a new engine, but it's a nine year old Picanto with 85,000 miles on it so it's not worth much anyway. In the event that happens I'll sell it for spares or repair and buy something else.

Unsatisfying not to reach a definitive conclusion but there we go.

GreenV8S

28,964 posts

253 months

Monday 2nd August
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jamesson said:
He did a pressure test which showed a slow drop and his best guess is the head gasket is faulty.
If there is a leak, it should be possible to prove it by a block test aka sniff test. You definitely wouldn't be planning major work without a definitive diagnosis but I'm surprised the mechanic didn't do the test as a matter of course under the circumstances. It is quick and cheap to do.

SRAutoSolutions

5 posts

1 month

Monday 2nd August
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GreenV8S said:
If there is a leak, it should be possible to prove it by a block test aka sniff test. You definitely wouldn't be planning major work without a definitive diagnosis but I'm surprised the mechanic didn't do the test as a matter of course under the circumstances. It is quick and cheap to do.
This exactly.

There are a load of other tests that can be done before you start throwing parts/money at the car. A sniff test can be done for an hours labour and will give you a better idea of whats happening and an idea of which way to go from here.

out of curiosity, what pressure was the system tested to?

jamesson

Original Poster:

2,584 posts

190 months

Friday 6th August
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SRAutoSolutions said:
out of curiosity, what pressure was the system tested to?
Sorry, no idea, but I imagine it was whatever is written on the radiator cap.

Maxdecel

97 posts

2 months

Wednesday 11th August
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jamesson said:
Hello all,
The only thing which I think is a bit weird is the neck of the expansion tank. I know it's not a pressurised system so what I'm about to explain shouldn't be an issue particularly, but there's a gouge out of the top of the neck which is something I've never seen before in other cars.
Think that cut out maybe an overflow should the expansion tank be overfilled ?

jamesson

Original Poster:

2,584 posts

190 months

Wednesday 11th August
quotequote all
Maxdecel said:
Think that cut out maybe an overflow should the expansion tank be overfilled ?
Could well be, I'd just never seen that before. According to another Picanto owner of the same model, it is the same as his.

Maxdecel

97 posts

2 months

Wednesday 11th August
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As these things do idea tend to wander in to my brain cell given due time - Water Pump ? Inaccessible to diagnose ? (guess) slight leak that dries up with eng. heat so no trace from front cover area or underneath ?
Just a thought, it'll have done some rotations during those miles.