Technical Losing water with no visible leak

[VitaPepe]

Hello guys,

as title says, my MK1 is losing water with no visible leak, but it's not overheating (checked with scan tool, when temperature goes above 90 celsius fan kicks in and keeping it at that level). Here are some things I did/checked:

- bleeded system several time
- checked every single part for leaks
- no bubbles in expansion tank
- no heating in cabin as of now
- no steam out of exhaust
- both hoses are warm
- when you turn off the car water coming out of expansion tank
- scan tool showing "System MAX Rich" (recently)
- car is running smoothly, no hesitation

Temperature gadget (not sure that's right word) in cabin showing that car is warmer than actually is. Before, fan would kick in just above middle line, now way above, although scan tool is showing that temperate is not that high as gadget says. I believe some air is tricking gadget and that same air could lead to "System MAX Rich" condition?

Thanks in advance,
Greetings from Croatia.

 

[Peter Pick-Up]

Have the cooling system presurized at a good workshop.

 

[VitaPepe]

Have the cooling system presurized at a good workshop.

I like to do things on my own, so I think I could make pressure tester from bicycle pump.

 

[Peter Pick-Up]

You need a pump like this:

https://www.ebay.com/itm/14PC-Car-C...964388&hash=item1ecdd92c7c:g:XEoAAOSwWLFZmukB

 

[Peter Pick-Up]

Or this, together with your own air compressor:

https://www.ebay.com/itm/Car-Coolin...ash=item33c9742ff1:g:LfoAAOSwXYtYs5ET&vxp=mtr

 

[VitaPepe]

You need a pump like this:

Yeah, just saw that one on ebay. Though, it's pretty expensive cause it comes in package for more car manufactures. Then I stumbled upon DIY bicycle pump tester which I would connect to that little hose on side of the expansion tank, I don't think it needs to be connected to expansion tank cap or i'm wrong!?

http://prntscr.com/h92bbd

Something like this.

 

[VitaPepe]

Yeah, we're thinking the same. Thank you for idea.

 

[Peter Pick-Up]

Don't put to much pressure on the system though, no more than ~2 bar I suggest.
It should keep pressure for at least 10 minutes or more.
If coolant seeps out visible, you know what to do.
If it looses presure with no visible leaks, I suspect headgasket...

 

[VitaPepe]

Don't put to much pressure on the system though, no more than ~2 bar I suggest.
It should keep pressure for at least 10 minutes or more.
If coolant seeps out visible, you know what to do.
If it looses presure with no visible leaks, I suspect headgasket...

Thank you for advises. Will test it tomorrow and reply with results.

 

[digger58]

I would suspect head gasket.

 

[Puntonaka]

I had a slight leak in my MK1 a few years ago, only sign was a slight mark down the side of the passenger side carpet where the heater matrix is.
I put some K seal in and it stopped the leak.
Now when I flush the cooling system I put a fresh bottle of K seal in " just in case" as it will seal any small leaks as they develop.

 

[digger58]

I replaced my heater matrix in the cabrio, a real b..ch of a job but worth it, they are very cheap as well, Not a fan of any of the quick fix stuff.

 

[rolandbrindley]

Cylinder head gasket

 

[VitaPepe]

Okay. Went to mechanic, actually not mechanic, but parts changer. As soon as I told him I didn't do machine work on cylinder head, he said it's 100% head gasket. Although I was pretty sure it's not, since I checked it for straightness, I gave it a try. He did machine work on it and changed all of the gaskets, radiator cap, some plastics, added antifreeze etc. 150€ total work, for... NOTHING!

Next day I saw green spot under the car, it was radiator that was bleeding heavily. Now i'm going to get a new radiator and replace it myself.
Question, will Punto 55 radiator fit on my Punto 75? I have cheap used one from friend of mine, almost new. But from what I saw on internet dimensions are different, just double checking.

Next time I'll listen ScannerDanner:
http://prntscr.com/hcs55d

 

[bluejohn125]

Did you make any progress? I imagine a 55 radiator would work in a 75 car if it can be fitted, the size may be smaller?

To me your problem sounds like a leaking heater matrix, this would explain the heater problem inside the cabin. You should notice condensation in the cabin on a cold morning, and there can be a bad smell also from the coolant.

Putting a sealant in the system is an OK solution but not the best, and I would certainly only do it ONCE but certainly not after you have changed / serviced the cylinder head and put nice new coolant in the car.

I don't know the Punto design but I had this problem with my Brava (FIRE) a few years ago, first I sealed the leak then changed the matrix (not an easy job).

 

[dekinstoke]

If it's throwing coolant out of expansion tank when you turn it off then the coolant system is being pressurised from the cylinders i.e head gasket failure

 

[rolandbrindley]

Run it to temperature with the radiator pressure cap off and look for air bubbling up inside the expansion tank, which indicates the head gasket is leaking. They can be pigs to cure. You have to ask yourself why it blew if there is no obvious reason such as overheating.

I have a Mk1 head in my garage that I replaced because after 2 new gaskets carefully fitted I still could not cure the leaks, I now think it's cracked.

I fitted a Mk2 head on my Mk1 block as I couldn't find the right head in the scrappers, see my guide on this, I also fitted 10mm studs in the block and shoulder nuts in place of the standard 9mm bolts. That was a few years ago, no water loss from that day to this, problem solved.

 

[blu73]

the expansion tank not holding water could also just be down to the cap failing. Had it on several fiats where they lose a little water with no visible leaks and its been the cap on the rad/expansion tank.

 

[Ralf S.]

You have to ask yourself why it blew if there is no obvious reason such as overheating.

Head gaskets can rust internally. If the car has been run on water or very weak coolant (antifreeze) mix, then the metal mesh inside the gasket will gradually weaken and split, so the gasket material becomes unsupported and will burst eventually.


Ralf S.