Coolant Level Woes

[mattf4r]

I've had a saga of problems with coolant on my 172 cup!
Mainly the level rising/falling with no obvious cause, it's caused me many a headache and I've thrown every part possible at it with little change so turning to the CS helpline.

Basically I'll fill the header tank to the max level for example, drive the car for about 3 days come back to the header and it's very nearly empty. So you would think it's loosing coolant somewhere? Not that easy. Top it back up to max and then drive the car and there is then evidence around the outside of the header that the level has risen too high and overflowed the tank itself, dumping coolant and causing the level to drop even further when I check it again. So it's as if the level is dropping but after the engine is hot it rises back up and if it's been topped up then there is obviously too much in and it's flowing over the header tank and then loosing some and when its cooled down the level drops back down.

Since the start of the problem I've had the following parts replaced:

Water pump (Genuine Renault)
Coolant Temp Sensor (Genuine Renault)
Thermostat & seal (Gates)
Coolant hoses & clamps (MTC Motorsport Silicone)
Header tank x2 (replaced twice)
Different cup radiator
Coolant cap x2 (Genuine renault twice)

I've ruled out a headgasket with 2 sniff tests courtesy of Bloke.

I've sourced and fixed a fell small weaps from coolant hose clamps, mostly where the upper rad hose joins the stat end and there is no other obvious leaks to indicate that's where its going.

The system has been bled more times than I can remember, it's been pressure tested with a proper Renault kit again courtesy of Bloke.

I've been just topping the level up and checking it every few days but I'm growing tired of doing so and would like to pin point a problem and fix it once and for all as I've racked my brain for months and have no solutions short of a different engine all together.

The car doesn't overheat both on the gauge or when monitored through the OBD. Fan kicks in at 98c as it should, stat opens at 89c as it should. Heaters blow hot (& cold). Car doesn't use an oil or have any mayo/HG signs.

Any suggestions are greatly appreciated both myself and Carl have racked our brains and I've still not pin pointed what the hell is happening and it's getting very annoying now!

 

[imprezaworks]

Does the replacement header tank come with a new cap? Long shot and just a guess tbh

 

[mattf4r]

No buddy but I've not long put another genuine Renault cap on a few weeks back alongside a pattern part header!

 

[mattf4r]

 

[imprezaworks]

Carl will have checked the rad and all that

 

[mattf4r]

Yeah Carl swapped the rad to a spare cup one he had as mine was pretty rusted out but still holding.

 

[bloke]

it's your old car dan.

 

[mattf4r]

it's your old car dan.

This is true. So it's your fault Dan.

 

[Ads29]

I could be completely wide of the mark here but I'll throw in a couple of suggestions

Is the aux belt running correctly and not over/under tensioned?

Possible issue with heater matrix? Very unlikely I know but it's always possible


I know you've mentioned that you've done a sniff test or two, how about compression tests? Again I'm thinking well outside the box, in my head I'm trying to rule more possibilities out as you've covered the vast majority of culprits I can think of

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[imprezaworks]

it's your old car dan.

The cup?

 

[imprezaworks]

This is true. So it's your fault Dan.

Been blamed for worse

 

[mattf4r]

I could be completely wide of the mark here but I'll throw in a couple of suggestions

Is the aux belt running correctly and not over/under tensioned?

Possible issue with heater matrix? Very unlikely I know but it's always possible


I know you've mentioned that you've done a sniff test or two, how about compression tests? Again I'm thinking well outside the box, in my head I'm trying to rule more possibilities out as you've covered the vast majority of culprits I can think of

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I appreciate the comments, anything is taken on board at this stage. I've thought about compression test so will try and do one this week. Aux belt seems fine it's been swapped fairly recently due to an EPAS conversion and like I said has had a new water pump too.

Matrix is a possible culprit but no leaks in the cabin, no funky smell or problems with the heater so reluctant to go digging as it's not a fun job I've read.

The cup?

Aye, ND53 UTU. I got it off a lad Carl sold it to, owned it since feb.

 

[imprezaworks]

Ah cool. Was a decent car that

 

[mattf4r]

Ah cool. Was a decent car that

It's a great car, I love it. Survived the ring in June and a few track days but not been without it's problems!! Just need to get to the bottom of this issue before I spend anymore on it

 

[Ads29]

I appreciate the comments, anything is taken on board at this stage. I've thought about compression test so will try and do one this week. Aux belt seems fine it's been swapped fairly recently due to an EPAS conversion and like I said has had a new water pump too.

Matrix is a possible culprit but no leaks in the cabin, no funky smell or problems with the heater so reluctant to go digging as it's not a fun job I've read.

The heater matrix is a bit of a pain yes, I've removed one or two before and there's definitely easier jobs to do

The only thing I can think of assuming the cooling system isn't at fault is a hairline crack within the engine somewhere, I had an old Golf years ago that had exactly the same symptoms, did the head gasket along with water pump, thermostat etc etc. Wasn't until I put a second head on that I cured the issue.

Hopefully it's not an engine problem with yours and there's something else playing up

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[mattf4r]

The heater matrix is a bit of a pain yes, I've removed one or two before and there's definitely easier jobs to do

The only thing I can think of assuming the cooling system isn't at fault is a hairline crack within the engine somewhere, I had an old Golf years ago that had exactly the same symptoms, did the head gasket along with water pump, thermostat etc etc. Wasn't until I put a second head on that I cured the issue.

Hopefully it's not an engine problem with yours and there's something else playing up

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Yeah all signs would point to a problem in the block. I've drained and bled the coolant today to get a fresh gauge on how much it varies.

Hopefully get a compression test done and see what figures that turns up.

 

[cjgower]

Your problems are almost identical to my DCI 80's. I've tried new thermostat, waterpump, oil cooler. My coolant turns a murky black colour and the header tank pressurises. It passed the sniff test too. The oil appears clear though despite the fact that oil or some other substance is getting into the coolant. I've kind of given up with it and plan on driving it until it no longer starts.

 

[mattf4r]

Your problems are almost identical to my DCI 80's. I've tried new thermostat, waterpump, oil cooler. My coolant turns a murky black colour and the header tank pressurises. It passed the sniff test too. The oil appears clear though despite the fact that oil or some other substance is getting into the coolant. I've kind of given up with it and plan on driving it until it no longer starts.

I feel your pain. My coolant stays clean but some s**t does make its way into the header when I get it stinking hot on track and stick to the sides. It's like a black sticky substance could be someone's put something in the past and it's being pulled through. I'm not sure. Will try and find a picture. Mine doesn't use oil and it's not contaminated. It's just bizarre.

 

[mattf4r]

Flushing and bleeding the coolant system did jack all.

Header was topped to max yesterday from cold. Used the car for about 100 miles and it's near empty with evidence of coolant around the header tank (outside).

Loosing the will to live with it now. Can only image there's a problem somewhere in the block

 

[mattf4r]

Chucking out enough on a 5 mile motorway blast 90mph (header was full when cold) to absolutely soak the subframe etc.

Something is really a miss.

 

[imprezaworks]

Mmm very odd

 

[mattf4r]

Mmm very odd

And horrendously frustrating!! I've thrown every part I can at it and it still does it.

Contemplating cutting my losses, breaking the good bits from the car and turning whats left into coke cans.

 

[imprezaworks]

Would stop the leak to be fair :/

 

[Ads29]

It's a bit drastic though

 

[mattf4r]

It's a bit drastic though

But think of the money I'll save on coolant!!!

In all seriousness I'm fed up of it though

 

[Ads29]

I can understand being fed up with trying to find what's wrong, the only thing I'd say is don't make a rash decision that you regret afterwards.

 

[mattf4r]

I can understand being fed up with trying to find what's wrong, the only thing I'd say is don't make a rash decision that you regret afterwards.

Yeah I would regret breaking it but I can't build it into the car I want with this ongoing issue and I certainly can't sell it as it is so got to keep digging i suppose, sick of throwing money at the cooling system

 

[mattf4r]

Compression test done, nothing out of the ordinary all cylinders the same really.

Not sure what's left to check or swap.
Leaning towards a replacement engine to rid the problem completely.

Could be a cracked block/head or a gasket issue but no real way to know as it's passed sniff tests etc

 

[Ads29]

I know you said you've changed the stat, have you run the car without one at all?

I know it's not advisable, and I wouldn't recommend it for any decent length of time but I reckon by now anything is worth a shot before changing the engine

 

[flebay]

Compression test done, nothing out of the ordinary all cylinders the same really.

Not sure what's left to check or swap.
Leaning towards a replacement engine to rid the problem completely.

Could be a cracked block/head or a gasket issue but no real way to know as it's passed sniff tests etc

This fixes leaks i used it on rovers with blown head gaskets its a pikey fix.
https://www.amazon.co.uk/dp/B00905IR0Q/?tag=cliospnet01-21

 

[imprezaworks]

Yup

 

[mrlee03]

OK I'm going to throw my thoughts in here.
You say it's passed a sniff test, that's great but as I've learned over the years, these sniff testers are fantastic but not 100% sure fire way of diagnosing issues like this.
K-seal is a good product but I have pulled engines apart that have been K-sealed to "fix" a head problem but in my experience it has done more harm than good as it tends to block the coolant channels in the head gasket where it passes from block to head (just doing what it was designed to do I suppose).

I don't normally believe in these magic engine fixing potions but I have had success with one particular brand. It's called STEEL SEAL, it's illuminous yellow and it comes with a money back guarantee if it doesn't work.
It's £40 ish a bottle but it has worked in the past for me.

 

[bloke]

It's had three sniff tests done and all been fine.

Wouldn't use kseal etc on it.

 

[mattf4r]

I appreciate all the comments but I'm staying away from kseal etc, I've seen what it does to engines and it's nasty stuff. I'd do it get out of a pinch of a £200 car maybe but if I do pull the engine I'd like to tear it down and be able to see what went wrong!

As Bloke said we've done multiple sniff tests to no avail, so it's a bizzare one.

I've not tried running without a stat, will give that a go when I get chance.

 

[flebay]

I appreciate all the comments but I'm staying away from kseal etc, I've seen what it does to engines and it's nasty stuff. I'd do it get out of a pinch of a £200 car maybe but if I do pull the engine I'd like to tear it down and be able to see what went wrong!

As Bloke said we've done multiple sniff tests to no avail, so it's a bizzare one.

I've not tried running without a stat, will give that a go when I get chance.

What is the temperature gauge sitting at when it loses water.

 

[mattf4r]

What is the temperature gauge sitting at when it loses water.

Dead middle, I've been monitoring the coolant temp data from OBD and doesn't move above 91c when moving really. Fan kicks in at 99c as it should

 

[mattf4r]

Well a post Christmas update is due...

I've been speaking with my resident renault guru @bloke and decided really the only way to get to the bottom of this is to pull the head. So the plan is have the head off, get it skimmed and tested and inspect the gasket etc, to soften the blow at the same time... (All being well) head will go back on and some 197 cams will be put in and then get mapped by Scoff @EFI.

If something else is a miss that's catastrophic, an engine will be going in. Fingers crossed it's a small crack in the gasket and not the block or something else!

 

[bashracing]

@matt123roll is the aux belt rotating the water pump the wrong way (backwards)

 

[mattf4r]

@matt123roll is the aux belt rotating the water pump the wrong way (backwards)

I'm going to say no as it's had a new pump and belt not long ago and Carl isn't that daft (I hope :tonguewink

 

[bloke]

i'm not that bad :tongueclosed:

was ding it with the old pump as well.