Over pressurised coolant system??

[wesacosa]

Hi All

 

I am still in the process of trying to recommission my newly purchased 94 Favorit ahead of my planned 2000 mile European trip in the summer. However I have now found what seems to be a worrying development...

 

I disconnected the heater matrix hoses to look at changing a leaking O ring on the valve , but changed my mind and decided to do it another day along with a more general overhaul of the cooling system. given I have introduced some air into the system I decide I had better try and bleed it.

I set heater control to hot , took off the expansion tank cap and stated engine. All seemed ok at first but when (presumably) the thermostat opened after a few mins there were a few spits of coolant and bubbles flowing back into the expansion tank through the overflow, again as expected. But then there was a constant fairly heavy flow through into the tank . It stayed that way all the way through the warmup to operating temperature.  Based on other cars I have I don't think this is normal

First thought is overpressured system due to failing HG, but based on my one and only 200 mile motorway drive picking the car up from the previous owner...

It ran at normal gauge temp all the way

There is no sign of emulsified oil on dipstick, cap or when I dropped the oil to change it

There does not appear to be any combustion smell in expansion tank or oily residue

The hoses do not seem to be overly hard or swollen

There is a fair bit of exhaust steam when running, and some water from tailpipe but its not particularly overly white and couldn't particularly detect any sweet coolant smell

 

In the paperwork for the car I can see that it had a head skim at about 60k (now on 96k so presumably a HG change too.  But although 60k wasn't many miles ago it was over 15 years

 

So I guess my question is how worried should I be.  Assuming this flow is not normal could anything else be causing it? 

I would also be interested if anyone had experience of using those detection kits for checking for combustion residue in the coolant

something like this

https://www.carparts4less.co.uk/cp4l/p/-/-/-/-/?542770800&0&ws5_0039&gclid=CjwKCAjwiN_mBRBBEiwA9N-e_hgvC3tUsBTvjfhOxijhMHs377r_NvcOROcPEzKExp0PrJqtgvMEYhoCYe4QAvD_BwE

 

Many thanks

Wes

[RicardoM]

48 minutes ago, wesacosa said:

I would also be interested if anyone had experience of using those detection kits for checking for combustion residue in the coolant

something like this

https://www.carparts4less.co.uk/cp4l/p/-/-/-/-/?542770800&0&ws5_0039&gclid=CjwKCAjwiN_mBRBBEiwA9N-e_hgvC3tUsBTvjfhOxijhMHs377r_NvcOROcPEzKExp0PrJqtgvMEYhoCYe4QAvD_BwE

It depends on manufacturer but that kit is insanely expensive. Moreover sometimes the results are irrelevant.

If you want to learn about generic diagnosing a head gasket failure, watch this video in 2 parts:

 

 

As for the unusual flow, for now keep the coolant level in the middle between MIN and MAX (engine cold) and keep an eye on it in the next week.

[wesacosa]

Thanks Ricardo. I will certainly watch those videos

 

Regarding your second point however I am not sure what that would tell me. Do you mean just to check if coolant is dropping (indicating potential HG problem) . Not sure how it would indicate if the flow was normal or not

[wesacosa]

thinking about it some more, I assume you are thinking that an over pressure system would push the level up rather than the excessive flow filling it up.....  But I guess would only learn something if its hot, and when it cools it would just go back to normal?

Edited 12 May, 2019 by wesacosa

[KenONeill]

@wesacosa - Try this. With the engine cold make a note of the coolant level in the expansion tank; maybe put some tape to mark the level. Drive until the gauge shows full temperature. Now go home and check if the level has changed.  Leave the car alone overnight. Check the level again and at this point it should be back at your original mark, then open the pressure cap and listen very carefully for a hiss. Report results.

[wesacosa]

Thanks Ken, I will do exactly that. A couple of things I did notice which may or may not be relevant...

The coolant reservoir was way above max, it was up to the seam on the reservoir. Not sure it it was overfilled. I syringed some out so should be able to keep eye on it. 

second observations is the coolant is bright green. I was expecting blue or pinky/orange if OAT fluid incorrectly used.  Is it correct to be bright green?

 

[KenONeill]

@wesacosa - Bright green is a normal colour for a glycol coolant. I'm not sure if OAT was ever used in the 135/136 engines.

[wesacosa]

thanks. OAT was definitely never used but I guess could have been added in error. I only ever seen blue glycol coolant but good to know its ok

 

[RicardoM]

4 hours ago, wesacosa said:

I was expecting blue or pinky/orange if OAT fluid incorrectly used.

Correct coolant is pink.

[wesacosa]

25 minutes ago, RicardoM said:

Correct coolant is pink.

 

I The replacement fluid I bought is Skoda G11 coolant for Favorit & Felicia according to the label, and is blue.  My question was in the hope that the (new) blue and (existing) green are the same glycol based coolants. I guess the pink you are referring to is the newer G13 fluid which I think is still compatible with the older cars but not what I currently have or intended to change to (assuming the HG isn't gone of course!!)

Edited 12 May, 2019 by wesacosa

[RicardoM]

The blue coolant is indeed recommended by Skoda but in reality it corrodes badly the cooling system.

[Papez]

8 hours ago, RicardoM said:

The blue coolant is indeed recommended by Skoda but in reality it corrodes badly the cooling system.

 

They later (Felicia 98+, Fabia OHV) switched to pink/G12 coolant because of said corrosion. But it cannot be mixed with G11, whole cooling system need to be flushed if you want to change type of coolant.

 

From what I've found, green should be same G11 as blue one.

 

Some flow of coolant through expansion tank is normal. Head gasket failure often increases fluid level (because of the volume of the gas), if yours is constant, it shouldn't be problem.

[wesacosa]

Thanks all. I will mark up the fluid level today and monitor closely.  I ordered a cheapy e bay HG test kit too. Worth a go for the £14 it cost.

 

 Given the car seems to have been running G11 so far I will stick to the blue stuff. It only really needs to get me through my trip this summer , then its at the mercy of the MOT man in October .  Like I say my main worry is the HG because that would probably kill my plans of making the trip. I know its a relatively easy change in theory but given the potential cylinder head horrors I may find, and the age/mileage/condition of the car I would probably have to admit defeat if that were the case

 

[RicardoM]

1 hour ago, wesacosa said:

Given the car seems to have been running G11 so far I will stick to the blue stuff.

 

1 hour ago, wesacosa said:

...but given the potential cylinder head horrors I may find...

 

Food for thought:

Felicia 1.3 Cylinder Head Corrosion Around Coolant Ways

 

You know, technology evolved.

 

Edited 13 May, 2019 by RicardoM

[wesacosa]

Yikes that's not good!!  I assume the corrosion is only an issue if you don't change the coolant regularly?

 

[wesacosa]

1 hour ago, RicardoM said:

 

 

Food for thought:

Felicia 1.3 Cylinder Head Corrosion Around Coolant Ways

 

You know, technology evolved.

 

 

What would you recommend, Ricardo ?   From what I can gather it seems like G12 was used in later Felicia and cannot be mixed with the G11 coolant (I assume a thorough flush with Wynn's or similar would be enough to purge the system)

However I seem to remember reading somewhere that G13 coolant could be mixed with either G11 or G12.   Should I look at that instead ? Or is that too modern for the Favorit ??

 

Cheers

Wes

[KenONeill]

32 minutes ago, wesacosa said:

G13 coolant could be mixed with either G11 or G12

G13 is a replacement for G12++, and should never be mixed with G11, or any other glycol spec.

[Breezy_Pete]

I thought it was only G12 that caused a problem when mixed with G11? G12+ and later versions were modified to be compatible? 

Can't remember where I saw that though...

[wesacosa]

1 minute ago, Wino said:

I thought it was only G12 that caused a problem when mixed with G11? G12+ and later versions were modified to be compatible? 

Can't remember where I saw that though...

I thought I had read somewhere on here the same thing, and this external site seems to confirm

https://www.wolflubes.com/EN_EU/Blog/2016/What-you-need-to-know-about-G13-antifreeze-and-coolant.aspx

[RicardoM]

3 hours ago, wesacosa said:

What would you recommend, Ricardo ?

Since you are worried about your trip, why increase the chances to blow the head gasket from a bad coolant? Yeah, the previous owners used G11 and didn't blow. Yet do you wanna meet Mr. Murphy during your holiday? I guess not. Head pitting occurs from using bad coolant, water instead of coolant, mixed coolant, and from not changing the coolant regularly. Is it so expensive to buy 3 liters of coolant and 3 liters of distilled water? You paid 14 quids for that kit...

[wesacosa]

4 minutes ago, RicardoM said:

Since you are worried about your trip, why increase the chances to blow the head gasket from a bad coolant? Yeah, the previous owners used G11 and didn't blow. Yet do you wanna meet Mr. Murphy during your holiday? I guess not. Head pitting occurs from using bad coolant, water instead of coolant, mixed coolant, and from not changing the coolant regularly. Is it so expensive to buy 3 liters of coolant and 3 liters of distilled water? You paid 14 quids for that kit...

 

Hi Ricardo

I had already accepted your position about not using the G11, I was more thinking if you would recommend the G12 (which seems like it needs every trace of G11 purged from the system) or if G13 would be better which perhaps would not need such a thorough purge as any residue mixing should not cause the same problems as G12 , but may not be as suitable for older car ??

 

I have several old cars so I think the £14 kit will end up getting some use at some point down the line even if not on the Favorit

[wesacosa]

On 12/05/2019 at 15:57, KenONeill said:

@wesacosa - Try this. With the engine cold make a note of the coolant level in the expansion tank; maybe put some tape to mark the level. Drive until the gauge shows full temperature. Now go home and check if the level has changed.  Leave the car alone overnight. Check the level again and at this point it should be back at your original mark, then open the pressure cap and listen very carefully for a hiss. Report results.

took longer to get around to doing this than expected but last night took for 5 mile drive to get up to temperature, about 8pm. No noticeable level increase. hoses firm but not ballooning. Left overnight, open the cap at 9am this morning, no hiss noticed

Edited 26 May, 2019 by wesacosa

[wesacosa]

Hi All

Back to this again I am afraid

 

Car had been behaving itself since the cooling system overhaul, including flush and replace coolant with G13. it's quite warm and humid here in UK at moment and only in some traffic yesterday did it creep above middle gauge, and dropped as soon as we got going. However I did notice the coolant had dropped a few mm in tank so put it down to the residual air after coolant change. Decided to have another go at purging the system today so set the heater valve to max and ran for 15-20 mins with the cap off. All normal at first, no flow into reservoir until stat open then a steady flow as before. However just when I was about to turn off (mid temp gauge) the coolant suddenly stated to spurt out of the open cap like "old faithful". So much so I went from max to min level by the time I could run over and turn engine off.

Does this sound as bad as I am currently imagining?

Perhaps I just left it too long at atmospheric pressure and the coolant was beginning to boil? although as I say gauge was still around normal....

Cheers

Wes

Edited 13 July, 2019 by wesacosa

[RicardoM]

The cooling system is designed to work pressurized. Leave the reservoir cap on all the time.

[wesacosa]

4 minutes ago, RicardoM said:

The cooling system is designed to work pressurized. Leave the reservoir cap on all the time.

but in the case of bleeding the system I had always assumed this was ok so long as I left at idle, and in fact this is also the method Haynes recommend in the manaul