Coolant Spewing Out, Lots Of Steam! Whats The Cause?

[GTIAlex 0]

1.6 CTI has recently developed a problem with coolent spewing out of the expansion tank.

 

This started off with the coolant leaking out of the overflow pipe on the back of the expansion tank, I collected a sample of this water to check if it there was oil present and there wasn't.

 

I planned to keep an eye on this, just in case I had over filled the system, however while out and about sitting in traffic, steam began rising from under the bonnet.

 

I opened the bonnet to find water pretty much everywhere under the bonnet.

 

The car has not overheated at any point and still runs well (until the water got in the electrics)

 

The car has been down to my local garage a few times regarding this now and we can't trace the problem.

 

We replaced the radiator cap in the hope that it was at fault, but althought slightly improved, the problem still remains.

 

The garage has assured me that the headgasket is not at fault and that the car is not over heating, it is simply forcing water out of the expansion tank.

 

The rubber pipe on the left side of the expansion tank has a dodgy clip so replaced that but still no luck. The pipe has a very very small split in it, but while running the engine on idle on the drive, no water escapes

 

It is only when driving around that the coolant seems to be escaping, it cant just be viewed from under the bonnet.

 

 

Any suggestions?

 

At the end of my tether with it right now grrr

[Anthony 1,000]

Can only really be two issues that I can see - either the cooling system is excessively pressurising (which would point at head gasket failing) or that the expansion tank cap isn't sealing as it should do (so two faulty caps or something amiss with the expansion tank itself)

[GTIAlex 0]

Iv been assured its not the head gasket doing and just replaced the expansion cap, altho it was from a motor factors and isn't genuine.

[PhilNW 40]

Stuck thermostat?

[allanallen 528 2 Cars]

Stuck thermostat would see it overheating.

How much pressure does there seem to be in the top rad hose when it starts spewing?

If it's definitely not the head gasket I'd say like Anthony that you've got the wrong cap on, easily done.

Is it definitely bled up properly? Blockage in the heater matrix maybe not letting it bleed properly?

What's the temperature doing? Does the fan work and is it on whilst it's spewing?

[GTIAlex 0]

The car doesn't over heat, temp gauge stays as it should. Even in relatively warm weather sitting in traffic a few weeks ago, but that was before the water started properly spewing.

Fan sticks in for short periods of times and goes off.

 

Its hard to say how much pressure is in the rad hose because iv not actually seen it spewing out...by the time u get out the car and open the bonnet, no water can be seen leaking/spewing from anywhere, just small pools of water in places such as on the battery tray and obviously on the engine casing which is creating the steam.

 

Would a Peugeot dealer be able to help me out with a genuine cap?

[allanallen 528 2 Cars]

Have you no pipe on the expansion bottle overflow? Is it defo coming from there?

 

If the waters just stopped spewing when you lift the bonnet there'll still be around 1 bar of pressure in the system so it's worth a squeeze

 

Couple of free checks would be to pull the top right pipe off the expansion bottle and blow down it, if the caps leaking bad you'll not be able to pressurise it. Obviously you'll need your thumb over the other end of the pipe or you'll shower yourself in coolant!

 

Another bit of a check would be to pull the rubber seal off your old cap and fit that in the cap recess before you fit the cap, should seal it up if it's not quite there.

[GTIAlex 0]

OKay thanks for all the info.

Definitely need to source a new cap again so i can 100% eliminate that, and il try the things mentinoned and report back.

[hoodygoodwood 70 3 Cars]

The expansion tank could be cracked , it might not leak until the temperature and pressure got quite high then it might boil and spray out . I had to replace a split one once .

[allanallen 528 2 Cars]

The expansion tank could be cracked , it might not leak until the temperature and pressure got quite high then it might boil and spray out . I had to replace a split one once .

He's not even confirmed it's coming from the expansion tank yet!

[Rob_the_Sparky 9]

Well just applying a little logic:

 

If water is coming out then something must be pushing it and normally there are only two reasons for that:

 

1) air pushed into the water jacket from the pistons, i.e. a bust head gasket

2) water boiling to produce steam

 

You can get steam without the system being hot, localised hot spots can do this. My vote would be on a thermostat or water pump.

 

Rob

 

P.S. I've run cars with no pressure (seal cut on pressure cap) and no problems. Would not recommend this but equally it won't immediately cause it to boil without some obvious signs that the system, has got really hot.

[Tom Fenton 1,526]

One way to help decide if its head gasket, from cold get hold of the top hose and squeeze it together between finger and thumb. Get a helper to start the engine. If you can feel the pressure quickly build in the hose as soon as the engine is started, then it is a head gasket problem. I agree a duff water pump could cause the symptoms, but in my experience if the thermostat is stuck shut you will just find the engine overheating.

[dogboy1066 2 1 Cars]

I had a similar problem which was resolved by a new water pump (and getting all the build up out of the cooling system - so much crap after 25 years).

[PhilNW 40]

try running it without thermostat should give a slower warm up so you possibly see where the problem is

[GTIAlex 0]

Right been investigating all day.

 

Got a new new radiator cap, a modern plastic one which seals loads better than the other two iv tried, although this made the problem worse...i believe the cap sealing better created more pressure in the system which then starting peeing out of a very very small split on the top hose going into the tank.

 

I cut half an inch off the hose and reattached with a new clip and now the problem is almost solved.

 

Went for a long run (the weather is fairly warm today), after id dried out the electrics, the car runs fine, engine pulls well and no overheating.

 

Got home, popped the bonnet to find no steam, and only a very small amount of water dotted around the engine bay.

 

Radiator looks brand new (only had the car 6 months) and iv also replaced the bottom hose and metal pipe and the radiator is clear.

 

Water pump is only a few months old as i had the cambelt, water pump and tensioner changed before christmas.

 

 

 

 

If i wanted to make sure there was no air locked in the system, how would i go about doing this? Iv noticed a valve on the thermostat which can be unscrewed, when is the best time to do this? After a run while the engine is hot or what?

[Miles 331 1 Cars]

Water pumps can fail when new, the impella can rotate on the shaft, but checking the header tank you should see a nice flow of water

[2-Pugs 57]

Interesting issue this one. I have a similiar problem, whereby everything appears to be absoutley normal and the car doesnt overheat, and temperature is, I think OK. But when i switch it off hot (after a long run, esp. in the summer), it then appears to boil over and water flows out of the expansion tank overflow. It doesn't do it when the engine is running.

 

I did replace the HG a few years back as it'd blown (when I first got the car) and did notice a ton of rusty sludgy crap in the engine which i did try my best to clean out. So, my thinking with this is that the radiator is partially blocked, the water pump may be failing, there could be built up crud elsewhere that is causing it to get hot spots as R_T_S mentions.

 

On an annual basis I have used coolant flush and replaced the coolant in an effort to clean out any crud but this has effected no obvious change.

 

My plan, when I get around to it, is to try a new cap, and if that doesn't work, a new radiator.

 

Any other thoughts?

[farmer 327 1 Cars]

Caps are dirt cheap from Pug, try that straight away Rob.

 

Rad's are the same but a wee bit more work to fit.

[GTIAlex 0]

Okay car is running fine but still having a slight issue coolant appearing.

 

Car gets up to temp as normal, stat works and the fan is wroking, no overheating.

 

When i pull up, i notice a small amount of steam and pop the bonnet to find this...

DSC_0765 by alex2327, on Flickr

DSC_0766 by alex2327, on Flickr

DSC_0767 by alex2327, on Flickr

DSC_0768 by alex2327, on Flickr

DSC_0769 by alex2327, on Flickr

Any ideas?

The white foam is oddly straight, cant see any major signs where it might be coming from...its white and foamy and COLD. Freezing cold. Not warm like warm coolant may be.

Really is baffling me now.

Also while driving, i can often hear the sound of water gushing/sloshing around, although the car has always done this during my ownership even before the coolant started pissing out.

[hoodygoodwood 70 3 Cars]

_{When the water is being pumped around the engine it is passing over the hotspots and carrying that heat away to the radiator , when you switch off the engine the water at the hotspots immediately tries to boil . Under normal circumstances this would not matter because the system is pressurised ( which stops it boiling over )but it sounds like you have a leak/split/crack that is stopping the system pressurising.}

_{If you can hear water sloshing around there is clearly an air lock or blockage .Does your heater blow hot air ? , the matrix is well known for sludging up . Have you bled the system at the screw in the heater hose by the bulkhead .}

_{Most 20 year old engines that have never been apart will be well silted up around the bottom of the block and with some peoples love of Radweld etc half of your waterways could be restricted .Flushing it out might not shift scale like that , I would remove the thermostat and check its functioning correctly and have a look inside for a build up of crud , refit it with a new seal if good .The smaller diameter pipes are most likely to block first so remove them and have a poke about with a bit of wire .The foamy water might just cool down quickly as it is 99% air after all . Could the water be spraying onto the flywheel - that might explain the line of foam ?}

_{Get the engine up to temp and go round feeling all the hoses , they should all be equally hot once the thermostat is open .my heater matrix was sludged up and water was barely moving through it so the 2 hoses going thru the bulkhead were cooler .}

 

_{I would -}

_{1. Look for blockages/silting up in - pipes, castings ,heater matrix , radiator .}

_{2. Refill and flush until the water runs clear then bleed to remove all air .}

_{3. Find where the water is spraying from and fix it , that should allow the system to pressurise .}

Edited March 21, 2014 by hoodygoodwood

[GTIAlex 0]

Okay bit more progress on this.

 

Car has a heavily leaking heater matrix which is being replaced tomorrow...i have noticed that the thermostat bleed valve is just a tyre valve cap off a push bike.

 

Cant find any information on whether this is correct...it is the bleed valve that the water seems to be escaping from.

 

its a J reg.

[welshpug 1,626]

that is correct.

 

Don't forget that there is another bleed point on the top of the thermostat housing on a small takeoff, these are often damaged, I think it must have been a plastic screw originally, but its just a normal thread which can be tapped clean and have the brass screw from a later pug engines fitted.

 

the bleed point on the thermostat takeoff/cover will only bleed the top hose and top of the rad, unless you wait for the stat to open.

Edited April 7, 2014 by welshpug

[GTIAlex 0]

Dammit, was hoping it was the wrong cap.

 

Even though the heater matrix is causing coolant leak and the regular topping up is causing air to get trapped...no matter how much i bleed it, it still spurts out and I cant even work out where from.

 

Its seems to be centred around the thermostat bleed cap.

[GTIAlex 0]

OKay thanks il go have another look