206 GTI coolant blown out

[jgra1]

hi all, chap at work (who doesn't use gauges) drove in today, but 10 mins before he got here, the STOP light was on, guage was on max, and most of the coolant looks to have steamed out..

he carried on driving and got here

what to do? I looked breifly and no mayonaise in the filler cap, and expansion tank smells just like coolant..

He says the fan was working, and the drive is mostly open roads..
I did change his cambelt and water pump early this year..
I haven't started car yet...

ideas welcome..

John

[spider]

Ensure engine is cold* then refill with coolant, carefully bleed it and then run it and watch for leakage.

It may be bad headgasket pressurising coolant blowing it out.

I thought about the belt / pump but an airlock left would of caused a problem at that time not now.


*I saw someone with bad leak pour cold water into an overheated engine, when cranking on the starter it blew coolant out of the expansion tank

[jgra1]

hmm thanks Andy..

yes I bled it ok, many miles ago.

Engine is cold now, I may have to use water only, for testing purposes.. bit stuck here...
A blocked rad, a failed water pump, or thermostat are all I can think of, to cause heat and then spill, assuming it's not HG.. - which it still may well be..

[spider]

Yes no problem with just water for testing, not worth wasting good coolant.

Sorry I did not post thoughts about the cause. A stuck thermostat is probably the most likely cause I think initially, a water pump is possible but I think its the TU units mainly where the impellers can rot or fall off, something I've only seen a few times though.

Rad block, I suppose that's possible but with it having new coolant a while back I would of thought it would of been noticeable by things at the time, thinking back was the coolant that drained when you did the pump then really bad / rusty ?

I think once you've filled it and ran it keeping an eye on it and the top (and bottom) hose / heater / temp gauge you'll be able to determine the cause.

A more rare possibility is a foreign body in one of the water hoses, but I guess as its warming up going around feeling the hoses etc as normal will give a clue to this.

Once it boiled it will eject it due to the pressure as you know, that's pretty normal (but a bit extreme if its that hot)

I'd not worry now until you've filled it and ran it and picked up some more information.

[jgra1]

ok

will report back at 2

[jgra1]

well..

I was about to add coolant, but decided to remove thermo first.. there was a fairly full block of coolant, but not much escaped..

I then added about 4 L of water with some anti mixed in there..
note : the coolant seemed to be orange, he had a small empty bottle of pink in the boot, and I think i used blue! early in the year..

anyway.. got her running and behaved well.. took ages for the gauge to climb, but when it did, it would hover at 90° and the fan would cut in, and back down to 85 or so.. car was running for about 45 mins, with no obvious signs of mass leakage, steam etc..

but..

I noticed a small water/air bubble from the front left at the block/head interface..

my conclusion is : long term coolant loss has gone unchecked, and finally resulted in an overheat today.. now system is full again, all is ok.. for now..
HG failure, ideas...? especially considering types of antifreeze..

I suggested he probably could drive it home and back tomorrrow, I didnt think it was going to do anything major..
I also showed him the temp gauges for the oil and coolant ...

John

[spider]

HG failure if there's visible signs of external leakage from the head / block joint. Possibly slightly warped head although not 100% sure how likely that would be.

I'm sure these have a float for the water level but then again that's not always going to work.

Thermostat is not jammed shut and you verified its not going to boil itself from other factors and the cooling fan(s) function so that's about all that can be done at this stage.

Depending on how many miles are being done, I'd suggest a short journey then examine the coolant level (may be wise to take some water with you) then work from there.

If it was my own I'd just be checking the level daily to gauge (no pun intended) how much water was being lost although it does point towards HG failure due to what you've said about the visible external leakage unfortunately.

Will await others thoughts.

[jgra1]

thanks andy..

theory two.. : the thermo was bad, caused a pressure build up in the block, caused the HG leak, caused the blow out? (I will pop thermo in some water when I can)

I dont think this car has a level sensor.. I had a quick look but couldn't see one.. suprisingly..

So, regarding different types of antifreeze, could this eat a gasket, in the place noticed?

[spider]

Not 100% sure however I know you're not really supposed to mix differing types although any 'effects' would be longer term and probably more related to solidifying at a guess ? , I've never had a problem with mixing though, but we are talking say a litre of another type after I've replaced a hose etc. There might be some reaction however it should not form a corrosive reaction and if it did there would be easier to 'eat' things such as soft rubber hoses rather than a composite material gasket.

A drain / refill although there's some left in the block its probably negligible in most cases, I'd not be concerned that a 'mix' has caused this, I cannot see it.

Coolant should be strong to prevent gasket corrosion (on the Diesel XU at least, not 100% sure on the petrol variant) but you added coolant when you did the pump / belt.

I can't see the stat jamming then working again, unless it got really hot and then it would probably never close again if it got *that* hot. Worth trying it in some water though, iirc they are easy to get at on these anyway.

I've noted a lack of level sensor on some of the newer cars too, possibly a cost cutting exercise.

[jgra1]

thanks Andy..

he drove it in today, it never got above 70.. so think we will keep an eye on it, and get the coolant changed as well..

[CitroJim]

A lucky escape by the looks of it John

[addo]

I'm amazed; it's been a week and apparently this car hasn't come back on the end of a towrope. Talk about good fortune.

[jgra1]

Still running.. a lucky escape for sure..
told him to get a new thermostat, and at least get the coolant checked, and replaced possibly.. winter coming :O

[Junkman]

You can tell him not to play the lotto in the near future.

[spider]

Still running.. a lucky escape for sure..
told him to get a new thermostat, and at least get the coolant checked, and replaced possibly.. winter coming :O

Agree a lucky escape.

Tis getting to that time of year again, coolant / batteries etc if required...

I must go and drain / flush out (its not terribly clean although it tested at about -12c) / refill my coolant before it gets too cold to work outside on the road