Water rail replacement

[edh]

Hi, Following on from my earlier thread, I've got a new water rail turning up today (hopefully).

 

Anyone want to tell my on the best way of changing it. IE, how to drain the coolant, how refill the coolant, how to bleed the system etc, and any other things I should know????

 

Ed

😬

[Stationary M25 Traveller]

Probably do a search in TechTalk - and maybe FAQ - loads of topics about this !!!

 

******************

And you run and you run to catch up with the sun, but it's sinking...

 

And racing around to come up behind you again. new link to photos

[edh]

Thanks SM25T, I have searched the archives but can't find anything conclusive, I've also had a look on 7FAQ but couldn't find anything.

- I'm don't mind being proved wrong 😬

 

Ed

😬

[John Howe]

No real problem, just a matter of draining the radiator into a container (assuming you want to reuse the coolant), removing the existing rail and refitting the new one.

 

You will of course require a new gasket, where the rail mates with the block, and because of the leaning angle of the engine, make sure you don't cross the thread to two 8M bolts that hold it in place.

 

Yes, the system will need bleeding but there is enough in "search" to guide you through this.

 

JH

Deliveries by Saffron, the yellow 230bhp Sausage delivery machine

[Englishmaninwales]

In addition to the radiator, you'll need to drain off some coolant from the bypass hose otherwise the engine/heater will still be full when you take the coolant rail off

[Stationary M25 Traveller]

Try a search in Techtalk over the last 2 years and search for (type it just like this):-

 

bleeding and radiator

 

or

 

airlock and radiator

 

******************

And you run and you run to catch up with the sun, but it's sinking...

 

And racing around to come up behind you again. new link to photos

[MartinWoodham]

drain coolant from bottom of rad.

Drain from the bypass hose if you've got a thermostat (all(?) non-race cars) - low point is where it joins the stat housing but this might be inaccessible depending on plenum/ throttle bodies etc. You can omit this but will get some spillage when you take the rail off as has been noted.

 

take water rail off and replace using new gasket as stated, also swapping over the temp sensors. These are different sizes, they'll only go in 1 way round. IIRC one of them is on a tapered thread so don't over-tighten. Leave the bypass hose loose where it joins the water rail.

 

Do everything up again, take the bolt out of the top of the radiator and fill with coolant through the expansion bottle. When the rad air bleed starts to leak coolant, replace the bolt.

Ease the bypass hose off the water rail, top up expansion bottle if necessary, wait until all air is all evacuated from the bypass before sliding the hose back onto the water rail and tightening the clamp. If you've got a heater do this with the heater on full.

 

If the quantity of coolant put in is sensible ie none left over from what you drained (!), fire the car up with the expansion tank off, let it warm and hopefully evacuate more air, replace the cap as it comes up to maybe 50 deg, then check that it warms fully up to fans cycling on and off. Check coolant level and top up as necessary.

 

Some people swear by hoisting the car up in the air front then back, but I've always managed on the flat - as long as you get the air out of the rad and then bleed the air from the bypass hose - this latter is the highest point in the system so once that's free of air you should be fine.

 

 

 

Martin

Aero'd supersported ex-Roadsports B...anyone got a cheap LSD/ 6 speed box?

[PAUL MARRIOTT]

EDH

 

Couple of things

 

The water rail flanges aren't always flat - best to check that you get a good mate between the flange and the cylinder head.

 

Check that the flange bolts aren't to long and prevent the flange being tightened properly.

 

The rail has a 3rd mounting point forward of the flange you need to make sure that when the flange is tightened that this mounting point is hard against the head. If there is a gap between it and the head pack it with washers to ensure that when tightening you don't put leverage on the flange.

 

Coolant refill - do it exactly as the manual tells you, if the cars plumbing is installed properly then you'll have no problems.

 

Good luck

 

Paul M