Pressure In Coolant System

[matt.leese3]

It seems that I have found the culprit, checked immediately after the drive and still a full bottle of coolant rising above max while hot! Checked this morning and coolant level is consistent to where I topped it up. I'm assuming it is a combination of the thermostat housing sealing with the block and/or the thermostat o-ring. I am surprised at the difference in the two thermostat o-rings available as I posted above 

I owe a big thank you to everyone who has contributed here, It has saved me money avoiding garage prices!

[btmaldon]

Well done for persisting with it and I'm pleased you finally got it sorted.

[james1089]

Great, Ford want £133 for the housing alone, the very cheap ones don't last long, so the one you got should be ok but won't last as long as Fords.

[matt.leese3]

Hi guys,

Unfortunately she is back to loosing coolant again! no drips or leaks, had an MOT last week I asked the garage to have a look whilst they were replacing the brakes and they could see no evidence of leaks while running with the under tray removed, they advised that the problem may not be easily identifiable until it develops further.

Any further ideas?

Thanks in advance!

[leaky econectic]

hey Matt, did you get a fix for this; I seem to have the same problem. 

[gavin shaw]

hi all iv got same prob with my 18tdci but iv changed head gasket water pump stat header tank and still water is coming out header tank its like brown water 

 

[Lotus6007]

Any news mine has a similar problem 

[ashy401]

Hi I am having the same problem. 

Car has had head gasket, thermostat and housing, header tank and cap, water pump over the last 18months  

and it is still pushing coolant out of header tank.

any help is appreciated

[ifloochies]

Did anyone ever find a solution to these issues, and what was it?

[Dan.t]

Hi everyone, any news related to this topic? I'm also into this and did not found the answer yet.

[alex111111]

On 11/29/2015 at 11:19 PM, artscot79 said:

Its a closed system so theres always pressure in the system even when cold just less than when its hot simple car basics they really should teach the cooling system is a closed loop and is pressurised the pressure raises the boiling point of the coolant without it the coolant would boil away this is why in the manual it will tell you to use a rag and slowly release the pressure http://auto.howstuffworks.com/cooling-system7.h

Hi, Im all new to Ford tdci. A friend gave me his 1.6 tdci econetic to service. The worrying thing I saw first was black soot/oily splatter on bulckhead arround the headder tank. After lifting the tank out of its position I noticed a hole in the tank underneath at the back. My guess is its just the coolant dump/overflow for when its got pressure build up. So i kind of guessed the pressure before I even looked further.I took the cap off and noticed where the seal should be someone had put a few elastic bands round it. I noticed two seal areas with partition in between and this is where the opening is for the overflow/dump.. Basically when started from cold it bubbles like mad from the header tank filler with the cap off. I am sure this is never meant to happen. Only thing I can conclude is either major blockage somewhere in coolant system or thermostat housing. or head gasket. I never like to go straight for head gasked. Anyone have anything for me?

 

[nicam49]

I wonder if the thermostat is missing. Looks like someone has done some bodging with the elastic bands instead of the cap seal. Has your friend only just acquired this tdci?  Does that hole look like factory?  You know about the sniff test... it's not as conclusive with a diesel due to the different gasses produced. 

[alex111111]

3 hours ago, nicam49 said:

I wonder if the thermostat is missing. Looks like someone has done some bodging with the elastic bands instead of the cap seal. Has your friend only just acquired this tdci?  Does that hole look like factory?  You know about the sniff test... it's not as conclusive with a diesel due to the different gasses produced. 

Thanks for the reply, Yes he only had it a while now. The overflow is a bit wierd as its just a hole with no hose atatched (Im 99% its factory) that opens up between the first and second seals by the filler cap. And the fact there is loads of black sooty residue inside the header tank and all over the body where it is positioned and has sprayed everything is very concerning. I might have a second look at the thermostat and housing etc, but Im not very hopeful at this point. Shame as the engine sounds pretty good after a service. Might even be worth doing the head gasket? It does look a bore though.

 

[nicam49]

Try raising your query on talkford.com. You might get a bigger response there.  I know the Mondeo mk3 tdci hg seems almost bulletproof.... not seen one reported in all the years I've been on the forum,  usually it's corroded oil cooler or egr cooler that causes that sort of issue. 

[Kevin#95]

Alex

When it bubbles from startup is the water cold? If it is cold then it might be the head gasket leaking air into the water. I would change the expansion cap as the rubber bands may not be holding the pressure. Does the exhaust sound smooth? If you put some paper near the exhaust does it get sucked in? Or is it constantly flapping away from the exhaust?

[alex111111]

Hi, yes it bubbles like mad from cold (water cold too). I found some seals that fit the coolant cap and when I tightened it up I was worried it was going ao blow up as the overflow started whistling like a distressed baby elephant. So I wished I hadnt bothered wasting time finding seals to fit. I took the whole tank out to inspect. The two small hoses had pressure build up. One goes straight to radiator (high/top) and the other goes to the thermostat housing. Both had pressure one way or the other. And the main large hose linking to the bottom of tank was pushing water out fast.. Car is overheating. Black sooty looking stuff inside tank and wherever its splashed outside the tank. All I can think is  - thermostst stuck, temp sensor broken, something lodged in coolant hose creating massive blockage, water pump propeller broken/seazed. Or finally head gasket. you can see Im clutching at straws.

[Davey_boy]

did anyone get an answer to the coolant being pushed out the header tank issue? i've changed thermostat, exp vessel, cap, waterpump, i'm tempted to change the radiator but it doesn't overheat so im dubious (stays at ~90C on guage, also confirmed by plugging the laptop in). Plenty of heat from the cabin heater and water seems to be circulating back to the exp vessel through the small pipe from the thermostat housing. I did a compression test and it looks nice and even across all cylinders, also passed multiple sniffer/chemical tests at the exp vessel. You can pretty much run it around town all day and its fine, but put it under load >2000 rpm and it starts to throw coolant out. Any help greatly appreciated. Loathed to take the head off as the more people i speak to the more i'm inclined to believe the HG is unlikely on these, obviously coupled with the compression and sniffer test results

[driftwood]

any joy on this? I have the exact same problem, could it be a blocked oil cooler? or corroded egr cooler?

[Dan100892]

Hi. Have a similar problem with my 1.8 tdci focus, 2007. Too much pressure in the system and water escapes through the pressure relief hole on the expansion tank. Replaced expansion tank, thermostat but still same issue. Looses 2-3 litres in 10-15 minutes drive and the temp. Gauge goes all the way upto red. Restarting sorts the problem out for a few minutes( Coolant is gone by this time) . Any help would be appreciated. 

Cheers

[Kevwrightuk]

It appears that there are many things that could cause this. My Galaxy 1.8 is doing the same thing. So far I’ve changed water pump, thermostat housing and thermostat, bypassed EGR and oil cooler. No joy. Still too much gas getting into coolant and causing excess pressure. 
radiator replaced. Heater matrix completely clear. Small pipes to header clear. 
only thing left is HG. 
job for tomorrow. Will report back. 

[Kevwrightuk]

Update….

head off today. No.2 cylinder was full of coolant. Slight spill into number 3 also. Clearly exhaust gasses getting pumped into coolant and causing excess pressure which in turn caused airlocks and lack of flow through the heater. No cracks or distortion so will smooth off mating surfaces and re-gasket. 
Tempted to change oil cooler while I can easily get at it but no sign of blockage or leakage there. 
may even bypass it anyway. 
will rebuild this weekend and hopefully that will be end of problems. 

[Kevwrightuk]

2nd update. 
head gasket now replaced. Hasn’t fixed anything. 
Sniff test passed. Lots of pressure builds up and forces coolant level way down below the min. Comes back up when cool and cap removed. But I think it may still be losing some. 
So what is left now? 
New thermostat housing on. New thermostat. New expansion cap. New radiator. New water pump. No water in the oil. No oil in the water. Very little heat from heater still. Pipes in and out of matrix not that warm. 
no airlocks. No obstruction through block/ matrix/ oil cooler. EGR cooler bypassed. 
I’ve run out of ideas. 

[unofix]

There has to be air trapped somewhere in the system. The basic laws of fluid dynamics states you can not compress a liquid. So with that in mind, I would assume since you have ruled out most things that the increase in pressure is due to heat from the engine which is normal and to be expected. If the coolant is disappearing from the expansion bottle but then returns when the engine cools the liquid must be getting forced in to an air pocket.

Since the heater seems not to be getting as hot as you would expect then my guess is that is where the problem lies. Can you disconnect the pipes in and out of the heater matrix and join them together with a bit of hose, some copper pipe and half a dozen jubilee clips? With heater matrix disconnected and the system refilled see if the coolant level remains fairly constant. If it does then further investigation of the heater matrix is needed.  

[Kevwrightuk]

On 2/15/2022 at 5:50 PM, unofix said:

There has to be air trapped somewhere in the system. The basic laws of fluid dynamics states you can not compress a liquid. So with that in mind, I would assume since you have ruled out most things that the increase in pressure is due to heat from the engine which is normal and to be expected. If the coolant is disappearing from the expansion bottle but then returns when the engine cools the liquid must be getting forced in to an air pocket.

Since the heater seems not to be getting as hot as you would expect then my guess is that is where the problem lies. Can you disconnect the pipes in and out of the heater matrix and join them together with a bit of hose, some copper pipe and half a dozen jubilee clips? With heater matrix disconnected and the system refilled see if the coolant level remains fairly constant. If it does then further investigation of the heater matrix is needed.  

Thanks for the reply. So todays update goes like this:

Bought a Sealey flush gun and using compressed air, blasted the heater matrix first. The amount of crap that came out was unreal considering a garden hose ran clear yesterday. 
Did same with oil cooler, then the engine block. Plenty of rubbish came out. 
Ran engine and heater is now hot again and level in expansion tank is stable. So you were right. It was able to clear air from the matrix and was completely air locked. 
now all I have to solve is the issue of the fuel pressure going between 17000 and 40000 in a perfect sine wave. 
I’ve put a new pressure sensor on. No difference.  I’m sure it wasn’t doing this before I changed the head gasket. 
 

[Kevwrightuk]

Further update re the fluctuating fuel pressure: I had connected the 2 plugs to the fuel pump the wrong way around. This was due to an insert getting stuck inside and not realising. Once I had changed to plugs around (one to the PCV and not sure what the other one does - something to do with fuel return?) then car runs perfectly.