Flushing coolant...Zetec

[Cloud 9]

Have just removed the thermostat, as it is not opening until approaching the red ,to find lots of rust coloured water and the stat was rusty as well. It looks as if there has never been any anti freeze in the system.I have bought the red stuff which was recommended by Ford dealer, which leads me to ask............

 

Whats the best method of draining and flushing the system without getting airlocks?

 

It is a raceline engine with heater

 

Many thanks

 

John

[Manxseven]

Didn't read the title 😳

 

Caterham Fireblade here

 

Edited by - Manxseven on 14 Mar 2006 13:48:59

[philwaters]

The best place to drain it is probably from the bottom hose connection of the radiator - I think this would be the lowest point. You may have a drain plug on the rad which can be used to avoid a mess (crack the top hex hd nut on the rad to allow air in and a faster flow). Then just get the remained by undoing the hose joint...

 

Phil Waters

[I.Mupferit]

You mention that the stat wasn't opening until the temperature reached the red. Has it always done this and I presume you have a Raceline water rail fitted 🤔

 

If the answer is yes to both these questions you may find it beneficial to drill a 2mm hole in the top plate of the thermostat, alongside the bulb. The position of the stat in relation to the head causes the temperature to see-saw as it warms up since the stat isn't sensing the temperature in the cylinder head early enough. A small hole will allow some water to flow past the stat thus allowing it to read the temperature in the engine earlier and react accordingly.

 

Brent

 

2.3 DURATEC SV Reassuringly Expensive

R 417.39 😬

 

Edited by - Brent Chiswick on 14 Mar 2006 14:05:55

[I.Mupferit]

Forgot to add that assuming you have got a Raceline water rail, you will have no problem with filling and bleeding as the cap on the water rail above the thermostat is the highest point for the engine. You may, however, need to loosen the highest hose at the heater and just ease it off enough to let any air escape before quickly pushing it back on and tightening the clamp.

 

Brent

 

2.3 DURATEC SV Reassuringly Expensive

R 417.39 😬

[Cloud 9]

Brent...yes it has a Raceline water rail, it has gradually got worse over time,it goes nearly into the red then drops suddenly to 60 deg , looking at the stat I think it has been sticking due to a bit of corrosion on it, hopefully the other ingredients in the anti freeze will stop this.

Many thanks to you and Phil for your advice

[I.Mupferit]

If you still see the temperature see-sawing albeit to a lesser extent, I would definitely recommend drilling the little hole in the thermostat plate. This is a well known cure for the Raceline see-saw syndrome.

 

My old Zetec 7 suffered with this and it is quite alarming to watch as the car is warming up. It won't do the engine any good either for the temperature to get nearly into the red and then receive a great slug of relatively cold water as the stat opens. The drilling cures that once and for all.

 

Brent

 

2.3 DURATEC SV Reassuringly Expensive

R 417.39 😬

[Cloud 9]

Thanks again....I think I`ll drill it whilst its out, as thinking about it, it used to get fairly hot before it opened anyway.

 

 

Cheers

 

John