About a month ago I did a routine check of oil, coolant etc and found that the coolant level had dropped to around minimum. It was a surprise to me because since the cylinder head replacement it hadn't lost any until that check.

I did another routine check yesterday and found the level had dropped significantly. It took 750ml of new coolant to get it back to the max level.

There doesn't appear to be any obvious leakage around the engine compartment or any excess steam from the exhaust. Visually checked the dipstick and under the filler cap and see nothing untoward. No bubbles or coolant surging in the expansion tank.

Hopefully it's not another cylinder head crack starting 😪 Will check weekly now. 

If you remove the coolant reservoir cap with cold engine is there any pressure released when you do?

That was a symptom on my previous ST when it cracked a cylinder liner. Or if you pull the spark plugs do they all look the same colour etc?

Had a track bike that ended up needing head gasket replacing due to coolant issues - didn’t show anything up with leak down test etc. Just can’t remember if it was using coolant or putting more into the reservoir 😕

Had that two months ago.

The whole thermostat had to be changed.

Have checked around both thermostat areas, the expansion tank, the carpets inside, the large and small coolant pipes, all around the engine compartment when cold and after reaching full temperature.

In the next day or so I'll have the spark plugs out and take a peek inside.

Might be a spot which is not easy to detect.

37 minutes ago, Bol said:

Might be a spot which is not easy to detect.

I hope so as if not it's the end of a long road for this engine. 

1 hour ago, RayC333 said:

if not it's the end of a long road for this engine. 

Did nobody warn you that trying to save a 1.0 Ecoboost was a lost cause ?

It probably holds the title as the longest lasting rebuilt Ecoboost engine but somethings are just not meant to be. 🙁

Good news (sort of). No sign of coolant getting into the exhaust manifold or cylinder bores, BUT doing a routine inspection in the dark using a torch, the light picked up on red stained deposits in areas around the water pump. I know those deposits were not there when I cleaned everything up for cylinder head and belt replacement.

When I did all the major work on the engine I decided not to replace the pump as I wasn't sure how successful the project would be and secondly I knew that the pump could be replaced without having to disassemble the timing cover again.

More work but not too onerous or costly.

Glad you’ve found the likely cause and it’s not worst case 👍

So I've bought a new water pump ready for the job. It has a ready assembled metal gasket. No vehicle specific installation instructions included.

Online opinion varies as to whether it's necessary, or just a good idea, to also use silicone sealant. I'm tempted to use some sparingly (same type as I used on the timing cover and sump).

The branding is SKF but I believe Ford supply with the same kind of gasket

I'm guessing some of you have fitted many pumps. Any recommendations? 🙂 

Never use RTV sealant (or any other sealant or gasket enhancer) on a coated metal gasket.

When you make sure that the surfaces are absolutely clean and all bolts are torqued at the prescribed torque value the new coated metal gasket will seal perfectly fine.

11 minutes ago, JW1982 said:

Never use RTV sealant (or any other sealant or gasket enhancer) on a coated metal gasket.

... the new coated metal gasket will seal perfectly fine.

I just assumed the gasket was painted rather than seeing it as coated to aid sealing.

Thanks for your reply. Once I get the old pump off I'll clean and check the block surface condition.

I have the torque values: finger tight all bolts then 5x short bolts 10Nm, 2x longer bolts 15Nm+90 degrees.

Pump came supplied with new bolts.

These SKF water pump kits are great value for money. Through the Years I installed several of these SKF water pumps without any problem. My experience is that they last much longer than the factory fitted Pierburg water pumps.


Do not be surprised if the coolant level drops a bit after installing the new water pump. These water pumps have a mechanical seal. This type of seal consists of 1 rotating and 1 stationary  sealing ring that are pushed together by a spring. Both sealing rings are perfectly flat/smooth and are usually made of ceramic or graphite. 

This type of seal is cooled and lubricated by coolant. On a mechanical seal a (very) small amount of coolant loss is perfectly normal. Especially when the pump is new and the seal surfaces are not yet fully bedded in.

This is also why most (if not all) of these water pumps show signs of pink/red coolant residue around the shaft and/or the inside of the pulley.
 

October changed the thermostat, today again found there a drop (lower than minimum).

No visible marks anywhere of leaking. Filled to maximum again with water.

1 hour ago, Bol said:

October changed the thermostat, today again found there a drop (lower than minimum).

No visible marks anywhere of leaking. Filled to maximum again with water.

I've just put a litre in my 2015 Focus ST, been putting in about 500ml every year so far
I'm gonna look into this as an explanation when I get the time, it leaks slowly into the firewall so you don't see it,
the hoses are cheap enough but it's just an O-Ring inside them that fails over time, it's the labour that is gonna be pricey.

 

57 minutes ago, RAIDER32 said:

I've just put a litre in my 2015 Focus ST, been putting in about 500ml every year so far
I'm gonna look into this as an explanation when I get the time, it leaks slowly into the firewall so you don't see it,
the hoses are cheap enough but it's just an O-Ring inside them that fails over time, it's the labour that is gonna be pricey.

 

Did you check any other parts?

4 hours ago, Bol said:

Did you check any other parts?

I've really not had a good inspection yet due to lack of light after work, I keep looking online for possibilities first,
It sounds like the heating matrix is a ticking time bomb, a friend actually did this on his 2011 Focus about 2 years ago,
have you looked inside under the dash as seen in this video?

 

Today after half hour driving (around 30-40 km) the level doesn't seem to drop.

 

Found those spots.

Seemed to be leaking from the lpg system's pipe and vacuum. It required tying.

Checked today. Seems fine. Thank God.