Cars eating coolant!

[Oddesy]

So I changed the coolant system on my 172 cup a few weeks ago, new radiator, new expansion tank and new silicone hoses, I put just over 5 litres of Type D coolant in and pretty sure I got all the air out of the system.

Since then my coolant level has been all over the place, It was just under max when I added the coolant originally, I took it for a drive and it dropped so I topped it up a little then just monitored it over the next couple of days, the level went up and down when I'd been driving it, which is expected, if it dropped below half way I topped it up a little. Used the car for work a few days, was fine.

Checked it last night, it was sitting just above half, drove to the petrol station and back, probably like 4-5 miles, level had dropped to half, as it was still hot I thought I'd top it up in the morning. Checked it this morning, level was pretty much on min, so just left it and ended up taking my girlfriends car to work.

The only difference I've noticed is the cars been getting up to temperature quicker, but that's probably down to the weather, and if anything it's been running a little cooler than it used to.
There are no leaks, there's no moisture anywhere in the engine bay around any of the hoses or the radiator. I've put almost 6 litres of coolant in now.

Could there still be air in the system? Does it just need time to level itself out? The cars probably done less than 100 miles since the change.

Does anyone know what's going on here?

Cheers!

 

[imprezaworks]

Top it up and leave it running with the cap off for a little while.

 

[Amos91]

Sounds like air is trapped, have you re-opened the bleeder to check?

Do the heaters work okay?

 

[Oddesy]

@imprezaworks I left it running with the cap off when i first topped it up, worth doing it again?

@Amos91 I've not re-opened the bleeder, no, I'll try that, yeah the heaters work fine.

 

[JamesBryan]

Still got air somewhere.

If you top the tank right up and then start the car and crack the bleed screw open again it should get the air out.

Careful though as it will piss out much quicker than with the engine off.

 

[Oddesy]

@JamesBryan I'll try that at the weekend, better doing this with the expansion cap on or off?

 

[imprezaworks]

@JamesBryan I'll try that at the weekend, better doing this with the expansion cap on or off?

How long did you leave it for when you topped it up?.

 

[Oddesy]

@imprezaworks probably about 10-15mins

 

[JamesBryan]

@JamesBryan I'll try that at the weekend, better doing this with the expansion cap on or off?

Can leave it off.

 

[imprezaworks]

Assuming it was ok before this, there will be air in the system.

Try bleeding it again as above and see how you get on. I’ve read they can be buggers sometimes.

 

[JamesBryan]

Run the engine for 20 minutes at 2,500 rpm, until the fan cuts in (time required for automatic degassing).

That's the wording on the workshop manual.

 

[Oddesy]

I'll bleed it again if I get time this week or at the weekend, hopefully that will sort it. Cheers!!!

 

[Oddesy]

Just had a go at bleeding again. How far am I meant to take the bleed screw out? Had to stop as the engine was getting too hot. Took the screw out about 10mm. Surely it’s not meant to come all the way out?

 

[Brigsy]

Bleed it on cold engine when not running. I took it all the way out until good stream of coolant came out with no air bubbles.

 

[Oddesy]

@Brigsy cheers. I’ll try that

 

[Brigsy]

Make sure the header tank does not run low. If the coolant does not really come out give the header tank a blow.

 

[imprezaworks]

If the coolant does not really come out give the header tank a blow.[/QUOTE]

Giggles.

 

[bloke]

from empty or low, cold engine, cap off, bolt all the way out, coolant in until it comes out of the bolt hole, bolt in, top coolant off to max, squeeze top hose few times, top to max again.

cap back on and use car, get it to temp and then leave it alone until next morning, should of dropped no lower than min, top up to max and that's it.

 

[Oddesy]

I've had some developments with this.....

I re bled the system as suggested before and it seemed OK, but my cars been off the road for a few weeks, due to waiting for parts, painting stuff, etc. I've been driving it for the past few days and it was running fine, temps were all OK.

Checked my coolant level this morning before leaving for work, the tank was completely empty, I've put like 6 litres in now, where's it gone?

There's no leaks from anywhere, nothings wet, no puddles, starting to think someone has come in the night and stolen my coolant.

 

[imprezaworks]

Headgasket maybe.

 

[bloke]

Sniffer test, probably wont show anythong, Compression test, probably won't show anything, then leakdown test, again probably won't show anything as is always the way.

Then borescope, if it's gasket you should see a lovely clean piston crown.

Only ever known one gasket fail, passed all tests even three or four separate sniffer tests and was only when head came off we found where it was blowing, even then it was only a very slight blow.

 

[Oddesy]

So it's just coincidence that this has only started happening since i changed the coolant system?

 

[flebay]

new radiator, new expansion tank and new silicone hoses

Out of those 3 i would say the silicone hoses are most likely to leak around one or more of the clamps.

 

[RIC172]

My 172 cup had been getting through lots of coolant too, with no obvious signs of a leak from any hoses, thermostat housing, expansion tank, rad etc. Kept topping it up but eventually the head gasket went so I ended up putting another engine in.

 

[Oddesy]

Out of those 3 i would say the silicone hoses are most likely to leak around one or more of the clamps.

I'll check around all the new hoses again to see if there's any leaks, already checked 3 times, pretty sure there is't

 

[bloke]

So it's just coincidence that this has only started happening since i changed the coolant system?

Possibly, but may not be head gasket. 6 litres is a lot to get through without a sign of it leaking anywhere.

 

[Oddesy]

Possibly, but may not be head gasket. 6 litres is a lot to get through without a sign of it leaking anywhere.

It's them coolant thieves!

I'll have a through check when i get home later

 

[mattf4r]

Only ever known one gasket fail, passed all tests even three or four separate sniffer tests and was only when head came off we found where it was blowing, even then it was only a very slight blow.

And it still survived a ring trip and track day without melting ?

 

[robmuns]

Had headgasket failure on my old ph1 1.. Coolant kept dropping without a sign off leaks, car ran fine.. when the oil was drained from the engine when the car was broken for parts it had alot of water in it.. On my ph1 now I renewed the coolant in the system and it didn't settle until the bleed screw was taken all the way out when hot and a constant stream coolant was coming out of it.. Topped it up and been fine since..

 

[Oddesy]

Got home from work to find a puddle under my car, there were some drops of coolant around the bottom radiator hose, but no where near enough to drain the tank. I've filled it back up, ran the engine for a bit and a couple of drops came out, but barely anything. I left a tub under the car it over night to see how much came out when it was left standing, must have been about 4-5 drops in the tub.

So the coolant is either pooling some where or it needs to be under load for it to leak more.

I'll do some more investigating over the weekend