Water Pressure - Expansion Tank - El Leako Mondo

[Waxman]

soooooo...

the HDI 110 I got hold of the other week..

Had a bit of a water leak around the lower rad hose, noticed crack in plastic section.

x 1 new radiator - New lower hose required as well due to old one corroded - for the sake of it, ordered an OEM from main dealer ( not expensive, £20 or so )

Then for next day spent time faffing around the lower hose connection as kept leaking from the bottom.

Rad out again, fully lock into place lower hose, add a bit of flex sealant to 0-ring ensure nice fix, wrap external around with self amalgamating tape, then cover area with hose tape. - Jobs a goodun.

Fill expansion tank with coolant ( 10th time in two days ) - release air locks from bleed nipples at rear by matrix, side by thermostat and top of rad.

Top up select amount and run on idle until temp got to about 80

No leaks.

Take for 5 mile drive up road watching temp level, got to 90 and stayed there.

Pulled back on the drive, lift bonnet and notice the water/steam forcing out of the expansion tank.

ok. - leave to cool down, undo lid of expansion tank, refill with coolant, go for another 5 mile drive

Come back, same thing, water pressure out of expansion tank lid. - When unscrewing the lid, you can hear a pressure pop too.

me thinks Head Gasket ?? -

Throw open to the forum as you all know these cars a lot better than me.

Thoughts ?

thx

[lozz]

You might be best to have a sniff test done,

It couid be a fubard water pump/thermostat. Or even the expansion cap fubard,
Hard to guess..

How's the heat from the heater is it blowing out nice and warm

[Waxman]

Yes, heater blower working well. no probs there.

Guess it's the painful process of elimination checking the parts through the system i.e thermostat etc.

[davew]

i had a similar problem on a passat tdi and it was the water pump, the impeller was spinning on the shaft.

[lozz]

Id.Try changing the cap first, might not be that but for what they cost
Its not much of a gamble.

[crackpotterpig]

i would take thermostat out and try again if it still presuurises its the head and or gasket, i would of thought if it was a water pump issue it would overheat straight away.

[puggy]

Did you tilt the car over so the expansion side was higher when you
reffilled and bled , if not might be worth giving it a try ....

[jasper5]

As above, but bleed the radiator first as you fill the system.

If the pressure wasn't there before you did the work then correct bleeding may be the answer.

[Waxman]

Thx for the info guys.

ok - rechecked everything and it does indeed appear that it is still dripping from the lower hose connection ( doing my head in ) - when I say drips, I mean it loses about a litre of coolant on a 10 mile run.

The radiator was one that I got from ebay, a company that have been making cooling systems for 30 years apparently so it is not an OEM part.

The lower hose is brand new that I picked up from a Peugeot dealer so no issue there. I think the rads at fault as it's not holding the hose correct i.e plastic connection dimensions etc. These things only need to be 1mm diff and that could cause it.

Next port of call is that I'm going to swallow the ££ and get a OEM rad from the dealers, - once hooked up I'll take it from there. ( Unless anyone on here has a working one available ? )

My tip of the day... don't buy crap parts - even after sending the guy 4 emails to say, 'you sure it will work ?' etc.


soooo.. if the bottom hose is leaking and causing air back in the system, this could result in the pressure at the cap ?? ( my assumption there )

And, has anyone had any hassles before fitting an OEM hose to an OEM rad ?


Thx

As above, but bleed the radiator first as you fill the system.

If the pressure wasn't there before you did the work then correct bleeding may be the answer.

It's a new car to me, came to me with cracked/corroded rad so actually never seen it work properly yet

[mjb]

Pulled back on the drive, lift bonnet and notice the water/steam forcing out of the expansion tank.

ok. - leave to cool down, undo lid of expansion tank, refill with coolant, go for another 5 mile drive

Come back, same thing, water pressure out of expansion tank lid.

Are you filling it to the top? If so, then it may well be working properly. The pressure cap should spit out any excess coolant so that when cold it sits at the right level. On my 406s I tend to fill to the brim (helps with bleeding) then allow the cap to chuck out the excess. After a good run at operating temperature, the pressure should have stabilised.

If you're losing coolant by the litre though, it's not this.

When unscrewing the lid, you can hear a pressure pop too

If the cap's spit out coolant while hot, when the coolant cools it'll create a vacuum, which is likely what you're hearing - air escaping out would be more a 'psssst' than a pop

Don't attempt to unscrew the lid when the engine's hot. The pressure can rip the cap out of your hand, dent the bonnet and fly off for some distance, accompanied by a fountain of scalding coolant (substantially hotter than boiling water!!!) which will shoot off the underside of the bonnet and spray everything in the area.

Good luck with the OEM radiator.

[Waxman]

Well possibly this could be a short lived peugeot experience

New Rad + New Bottom Hose + New Expansion tank cap + Thermostat Check + Bleed method correct.

Small almost 'fizz' type bubbles coming up through expansion tank when cap is off and it's idling, then nice clean white froth.

With the cap back on and when you move the car and as it's coming up to temp it start to chuck it out of the expansion tank cap. 10 minutes later the coolant light is back on.

Both upper and lower pipes are getting hot so that's ok.

So my inexperience is saying either a Head Gasket or Cracked Cylinder head. - the last owner says he had the head gasket done about 10k ago.

It's going into the garage this week so I'll guess I'll find out. The only niggle I have is, could it be caused by a water pump that's on it's way out ? - I've not asked if it was changed prior.

Car currently owes me about £200 + the time I've spent cleaning it up - would seem a shame to scrap it etc but not going to throw big money at it.

Thx

[steve_earwig]

Oh blimey I don't think we hear much about impellers falling off of water pumps on these, leaking seals yes, but not that kind of failure (BMW has that one covered though).

Makes you wonder why the previous owner had the head done and was it done properly

[crackpotterpig]

I would of said more than likely head gasket rather than head cracked as these engines are pretty good........you need a nice genuine 406 like mine.....by coincidence its for sale now

[Welly]

Sounds like head gasket to me, the last HG was probably fitted 'on the cheap' without skimming the head or without replacing the head bolts with new ones (are they stretch bolts on these?) a cheap repair will only last a while especially if the coolant is in poor condition it seems to eat away at things.

[Waxman]

ok. Update.

spoken to the last owner who has kinda said, "yeah it always did that"

He basically said that once he brimmed it, it would always spit out a certain amount. - Enough to get the coolant light on. But what he's saying is that it was only ever a certain amount and the temp gauge / car worked fine etc and never overheated.

He used to top the coolant once a month.

Looking at the handbook, there is a note that the HG and belts were done at 156k - the car now is on 211k

So basically it may be the case of going back to oldschool way of driving - i.e keeping an eye on the temp gauge and just having the coollant light on

A trait of the car I guess - I need to do a long run to test it.


EDIT > Just did a 40 miles return trip on the car on a local dual carriageway so average speed 70mph - Temp didn't go above 85