Engine Coolant Recurring Leak

[niallgavinuk]

Good morning all,

Newbie to the forum, so please excuse any unitended niaivity...

I have a 55 Reg Octavia II Diesel DSG Auto with which I have been very pleased. Have a problem which my local Skoda Service Centre can't replicate and therefore fix! Wondered if any other owners have come across this one?

I get the Engine Coolant warning indicator. On checking the coolant levels, it does appear to have dropped. I have topped up accordingly. However, after a week or so, I get the same issue.

Car has been into our local service centre and they have pressure tested and investigated for leaks - with no result. They cannot make it leak. I am now seriously concerned as to where - if at all - the coolant is leaking. Is it into the engine and therefore untraceable (big job to investigate and repair?) or is it evaporating somehow?

Anyone else experienced this problem, and if so, how did you get it resolved? Be grateful for any experience or ideas.

Thanks.

N.

[andyvee]

Normally it is the EGR cooler, Oil cooler or the header tank itself.

The cylinder heads have been known to go porous as well.

Get a bottle of K-seal from a motor factors, cures most small leaks for a tenner. You just put it in the header tank and then go for a drive to get up to temperature.

[haribo(felicia)]

before trying k-seal you could try running the engine up to temp then tighten the hoses up if they arnt them silly spring clips the reason i say this is i had a leak on my delica and it took ages to find the culprit turned out that when the hoses got hot one leaked but only when engine was running and it evaporated on the engine instead of pooling on the ground you could also look at the pipes for signs of whitish powder which could indicate a similar leak on your car hth nigel.

[skodacarman]

I bet it's the water pump leaking.

[niallgavinuk]

Thank you all. Will investigate further and report back.

[07 vRS Taxi]

The pump would leave evidence of a leak like that, I bet the head has a tiny leak into the combustion chamber.

Sent from my LT26i using Tapatalk 2

[skodacarman]

You're right a leaking pump will leave evidence, but not obvious signs such as puddles. It collects inside the cam belt covers and evaporates away with the heat of the engine. You have to strip off the covers to find it.

[07 vRS Taxi]

Yes a pink crust should be around the pump, I would've thought Skoda would've removed the covers....then again they can't find the source of the leak either.

Sent from my LT26i using Tapatalk 2

[dieselV6]

+1 on various leak locations, but it is worth (or laziest ) to check first right under the coolant bottle.

If you see coolant leaking from under the bottle, clean the coolant cap seal and the bottle opening first, replace the cap.

Be careful when opening the cap on a hot engine.

If it is still leaking from the bottle after cleaning the cap, either the coolant cap is opening under lower pressure than it should (?1.5bar, but do not quote me on that) and needs to be replaced, or your engine's head gasket is leaking exhaust into the coolant. At early stages, it looks exactly as you described, and coolant still looks clean. Had it on the 1,9 after dealership did not refill engine's head properly with coolant (TB/WP job) . Only later you notice exhaust dirt in the coolant, but by then the engine used more coolant then water :(

[jeallen01]

Normally it is the EGR cooler, Oil cooler or the header tank itself.

---

Get a bottle of K-seal from a motor factors, cures most small leaks for a tenner. You just put it in the header tank and then go for a drive to get up to temperature.

 

I had my 140 BKD engine remapped a couple of months ago (and it spent a long time on the rolling road, so probably got quite hot for a sustained period) and then I started noticing a slow drop in coolant level - first time I got the warning light but not afterwards because I kept the level topped up once or twice a week (about 1/2 pint each time)  during the hotter weather, but less often now the weather is cooler.

 

Still no sign of crap in the coolant header tank or contamination of the sump oil, but, 5 mins after I start the car from cold, there is white condensation smoke from the exhaust for a couple of minutes and then it stops - so I think it is probably a leak in the EGR cooler, and the "smoke" is from a small amount of coolant  which collects in the exhaust part of the cooler as the engine temperature drops. Is it worth trying "K-seal" to seal this leak, or would that do more harm than good?

 

Thanks in advance.

 

John

 

PS: OTOH, the "economy" remap from Perfect Touch in Hoddesdon was pretty successful - about an extra 30-35BHP from about 1500 revs upwards, revs cleanly a lot higher and has lots more torque across the range, so it drives much more smoothly at low revs (spun the front wheels in 3rd at a slightly damp roundabout recently), and I'm not blaming them for the leak problem as it could probably have happened anytime on an engine with more than 100k miles on the clock.

 

Edited 17 October, 2014 by jeallen01

[Guest]

I'd try another pressure cap first.

It would likely not be tested and if allowing pressure to escape will lower the boiling point of the coolant and allow hot vapour to escape eventually depleting the coolant.

You'll find one at a scrappy for pennies, most VAG items will be the same, check any part numbers to be sure.

The white smoke is actually water vapour/steam and is due to the cooling effect of a cold exhaust system on hot exhaust gases.

Perfectly normal until the exhaust system heats up and more noticeable on cool damp days.

For the detectives among you it's a telltale sign of a car recently started and a pet hate of mine when you see it on films where the vehicle has supposedly been on the go for miles but clearly has just been started for the shot.

[jeallen01]

I'd try another pressure cap first.

It would likely not be tested and if allowing pressure to escape will lower the boiling point of the coolant and allow hot vapour to escape eventually depleting the coolant.

You'll find one at a scrappy for pennies, most VAG items will be the same, check any part numbers to be sure.

The white smoke is actually water vapour/steam and is due to the cooling effect of a cold exhaust system on hot exhaust gases.

Perfectly normal until the exhaust system heats up and more noticeable on cool damp days.

For the detectives among you it's a telltale sign of a car recently started and a pet hate of mine when you see it on films where the vehicle has supposedly been on the go for miles but clearly has just been started for the shot.

Good suggestion about the pressure cap, and a replacement can't hurt - so I'll get one from TPS next time I visit - Thanks.

 

As for the "white smoke", I would agree with you except for the fact that this was not happening before the remap, and, anyway, the weather was very warm at the time (early September) that I first noticed it, so I still think it's probably what I described in my earlier post!

 

John

[FLAPPERJACK7]

Egr cooler usually, or if it's leaking inside the cylinder head a good way to find it is pressure test the cooling system remove inlet manifold leave for 24 hours re check and you usually find coolant around the valves looking through the cylinder head inlet ports. ..im assuming that your engine is the 2.0 ?

[Guest]

re white smoke.

Coolant has a distinctive smell when part of the combustion mix and you should be able to tell by the bouquet from the tailpipe.

Off hand it's difficult to describe, thankfully it's been a while since I've had a cylinder head gasket let go... from recollection I'd say it was a dry, powdery, plasticy smell.

[jeallen01]

Thanks.

Just to return to my original question about leak-stoppers - now that the weather has cooled down somewhat, the leakage seems to have almost stopped and I haven't added any more coolant for about a week, but I'm still wondering if some leak-stopper would help the seepage not to recur when the weather warms up again.

 

If so, which one might be best, and should I add a whole container or just a small amount in order to avoid clogging up the cooling system unnecessarily?

 

Thanks in advance

[Guest]

I can't see how a few degrees change in ambient temperature would cause coolant loss.

Perhaps your temperature gauge/cooling fan(s) aren't operating correctly and causing the overheated coolant to vent via the reservoir cap as vapour.

re sealant

I've had very good results in the past using Silver Seal.

Personal experience would advise against liquid type sealers, the powder/granulated types being better at filling small holes.

The instructions will detail how to use, usually the container is used completely with multiple doses only required for large engines/BAD leaks.

[jeallen01]

Thanks

 

I think the coolant losses generally occurred when the car was stationary or moving very slowly for substantial periods in traffic queues in hot weather. 

 

During those times the temperature gauge stayed at the normal 90C mark, but you could be on to something when referencing the fan system so I'll try to run some tests of letting the car idle for long periods to see if the fan does cut in when it should (and that might also be another pointer to the header tank cap being faulty and blowing off too early) 

 

OTOH that still does not explain those clouds of steam (which I have not noticed for the last few weeks, and so I will see if I can find some Silver Seal although I have not come across it before.

 

John

[jaysskoda07]

probably EGR cooler.....

[jeallen01]

probably EGR cooler.....

 

That's what I said in my first post of 17th Oct - and then I asked if some sealant might help!

[Guest]

Test radiator fans by switching heater to 16C/fan off and foot on loud pedal to idle at 2K rpm.

My temperature gauge never goes above 90C regardless off engine speed/load, however the fans work fine, I think it's a design issues.

This is the stuff I used with great success on an 18 year old Peugeot with a holed radiator.

http://www.ebay.co.uk/itm/Silver-Seal-Leak-Stopper-radiator-sealer-sealant-works-/380195408068?pt=LH_DefaultDomain_3&hash=item58856988c4

Fingers crossed it's not a head gasket failure you've got, coolant loss and white smoke are indicators.

If you don't regularly boot it perhaps any small failure sealed itself and is just waiting to blow again given provocation.

PS the product I mentioned will not help a head gasket failure, it works on positive pressure environments where it is forced into the leak.

In HG failure chances are the leak goes both ways, exhaust gases into coolant and coolant into combustion chamber(s)

May help a bit but only buying you time.

[smileonimpact]

When my mk1 started losing coolant without trace of leak it turned out to be from the heater matrix, but the warning signs did appear eventually, misted up windscreen and the smell of coolant, got a new matrix fitted, no small job! 6 months later coolant loss started again but this time it was the head gasket, had a recommendation of "steel seal" liquid head gasket repair to keep me going until I sourced a replacement car, worked a treat and it comes with a money back guarantee.

[daemon]

I had a similar problem on my VRS, I was losing coolant, therefore warning light for coolant came on.

I also changed egr cooler, but it wasn't a problem.

 

In the end it was a cracked cylinder head!

[jeallen01]

Well, the coolant loss and the white steam from the exhaust after starting from cold has virtually, if not completely disappeared :sun:, so I don't think it is anything worse than a slight leak in the EGR cooler (and certainly not a head gasket or the head itself) - but it might be the heater matrix because there was some misting on the windscreen this morning but not this evening (having been switched off for 5 hrs).

Think I will get some Silver Seal and try that as the first step.

 

Thanks for all the comments.

 

John

[Guest]

It's that time of year again where Octavia windscreens mist up internally due to the design of the heating system.

Even on full demist it takes longer to clear than any other car I've had and you're left with a fine mottled pattern on the windscreen which requires wiping weekly otherwise the film messes with vision in bright light conditions.

I think I'll try switching the system to ECON for a while and see if it helps.

[jeallen01]

Thanks to all - some Silver Seal is on its way but I hope I won't need it soon.

 

BTW - no  mist on the screen this morning :sun: