Club 80-90 Forums

i have been chasing this one around for a while. it appears to be coming from the top of the coolant resevoir, the one behind the inspection flap. its spraying upwards an all over the dizzy. does not do it with the engine ticking over, also tried revving it and it behaves, take it for a run though and i have coolant everywhere. its a late wbx. any idea.s fella,s

It sounds like its pressurizing buddy the Dalek cap on the header tank ( in the engine bay ) is a one way valve, if you take it off you should be able to blow air through it but not suck air back. it also sounds like you may have a lill split / hole in the coolant resevoir which is why its spraying over your engine.

If it's coming from the tank behind the flap, remember that tank is not under any pressure.

My guess is either the tank or the feed pipe is leaking and the water is getting chucked around by the fan belt and / or pulleys.

The plastic spigot in the bottom side of the top up tank where the hose from the dalek cap feeds in is very thin, I'd be checking there. The system allows coolant above a certain pressure from the header tank to pass to the top up tank and then be sucked back into the header tank as the system pressure drops again. The top up tank has a breather hole to stop it too becoming pressurised.

Also have you checked the pipe from the pump behind the crank pulley, the flange on the right bank and the short connecting hose ? These are known weak points and if these leak the coolant is thrown by the fan belt.

Ian

You need access to a coolant pressure tester so you can actually see where this leak is coming from...otherwise it's just guesswork.

Martin

if not a leaky pipe then it sounds like stuffed darlek cap
just buy a new one from baxter
if that doesn't fix it then it's poc in coolant, sniff test time

thanks guys, new cap should be with me tomorrow, i will give it a go and report back.

new cap on and no better. i decided to bleed it out again, started at the rear then got her up on the ramps, left her running to get her up to temp, i was having one of those moments of staring at my engine and noticed a constant steam of airbubbles being fed into the main tank. now i have been having dark thoughts about the system being pressured by combustion gasses so i swithed her off and took out the plugs expecting to find one very clean one. all looking good. so back to bleeding it through again. as the motor got to temp it bubbled over and lost a liter or so. i bled lots of air out of the rad, hoping i had cracked it i went back to looking for air bubbles. still there, back to the front and i see a waft of steam from the rad. i cleaned the rad up and waited for it to dry completly then started her up again. still wafts of steam. the bottom of the rad is kippered, can it be drawing in all the air to cause that amount of bubbles?

I am afraid that sounds like a head seal/cracked head problem .. if a new pressure cap hasnt helped and air is still appearing especially under a little load..

Only other thing could be that the water pump is not moving the water or there is a blockage.. but from cold it would not pressurise until hot... if air is getting in there from cold.. head area issue...

does it bubble from cold start ? with the tstat closed there should be no flow from the radiator to the engine
sounds like sniff test time if only to rule out poc in the coolant

new rad for tomorrow. from what you are saying as soon as the thermostat opens it lets in all the air from the rad and pressures the system up. it then has been dumping all the exess into the filler tank and has been spraying out of the top(this is most certainly where it has been coming from) heads were pressure tested after recent rebuild so hoping all is well there. thanks for the info guys. slowly understanding my cooling system.oh and new pump and thermostat.

No, thermostat doesnt "let air in" from rad or anywhere..

if the heads are leaking, it will be putting presure into the system (air/combustion gasses) this will force the coolant out.. "air" will get transported around the system and sit in the rad etc...

If its "boiling" the coolant and creating steam, the pressure wont build until the engine has heated up somewhat..

If you bleed it down and leave to cool (several hours/over night) does it build pressure and create air very quickly after driving off? or only when it gets towards normal temp?

If there are any leaks in the system and it is succking air back in when cooling, then this could also cause problems as the air wont cool the engine and what coolant is there will boil and create a lot of pressure..

only spits it out when warm. i bled out the back end when it was cool, got it running through without bubbles as it warmed up loads of big bubbles came through spitting coolant out. i am hoping that that happened when the stat opened intoducing the coolant from the rad that was full of air coz of the hole in it. new rad on today and keep fingers crossed.

Whilst your at it, good idea tho check this (snipped from another post of mine)

Whilst you are there I would check all those thinner pipes, both the bleed ring around the engine bay and the "T" pieces on it, and the thin rubber pipes around the stat, and the one that goes from the rear of the nearside head to the bleed ring, check them all for blockages.

The blockage causes the water in the left hand head to boil and this causes symptoms like a blown head gasket.

I am aware of at least 3 instances were one or more of the above have been blocked.

here is a pic (courtesy of KarlT) of what it looks like

One had disastrous consequences according to the owner, and when mine was blocked it very nearly had disastrous consequences, in fact I reckon it was what caused my original WBX to seize up on the nearside rear cylinder - just glad I discovered it before it had chance to do the same to my low mileage recon I got to replace the original with.

thanks for that tip, i have renewed most of those hoses and now have rechecked them. i have fitted the new rad and its not improved things at all. i will take the van into a garage to have the coolant tested for combustion gases.i guess now it can only be that the heads have failed