2.3 Duratec coolant plumbing conundrum/puzzle

[wild bill]

OK please bear with me this is complicated to explain. I have a  2.3l Duratec in S3

When i converted fro K series 11 years ago i kept the K series radiator (i tried the ford rad but there were fitting problems and there was no real reason to change so the original rad remained).

I run a raceline water rail and filler neck.

The filler neck has an overflow outlet of 5mm.

Facing towards the rear of the car

The main out from filler neck exits top left and then runs diagonally to the top right inlet on the rad. I have not run an expansion tank and all has been fine however i've been advised that it might be a good idea (by a mechanic that has known the car since 2004 helped with rebuilding bits and that i do trust). In fact since rebuilding the car i now get water overflowing and of course it cant then go back in which means there's less water in the system. This never used to happen and i am stumped as to what has changed. The other day i had lots of steam from under the bonnet on a run which made me pull over to check that a hose hadn't burst and dumped coolant everywhere. (It hadn't) which prompted the thoughts of expansion tank as a solution.

Problem 1) Ordered the rover expansion tank (which is what the car had originally) but the diagonal coolant pipe runs directly over the mounting point. I can order a hose and connector to re route the pipework down the left then right angle turn and along behind the top of the rad and in to the top right. I think this is better than mounting the exp tank elsewhere.

Problem 2) The overflow outlet from filler neck is standard apparently at 5mm but the inlet to the expansion tank is 15mm. Nowhere i've looked so far has a solution (merlin and demon)

1) Am i being mad here? Should i leave as is

2) Has anyone encountered a similar issue

I've searched google for engine bay images but nothing helps. This is as good as i can manage in explaining.

Thx in advance for any help as feeling thick

[7 wonders of the world]

Expansion bottle is required, are you meaning the bulkhead Rover version....?

I run a Skoda spherical on on mine on the bulkhead, with a normal 8mm hoce form the bleed on the engine to the bleed on the bottle.

Where is you thermostat....? in the Raceline alloy rail (not an ideallocation  or are you using the OE stat in the block - albeit in 82 defree format...?

K rad will make no difference I run the same.

Bottle return to the engine needs to connect to the plastic 16mm in the OE stat (NOT onto the metal 16mm in the block) or T inot the heater return pipe which goes to the same place.

[David_Long]

Comments much as #2 - the Ford setup is as good as it gets and I never really understood why people change it. Certainly the Raceline water rail is a pet hate of mine. I suspect what you are seeing is a symptom rather than the cause and it has probably got too hot at some stage. My advice would be to bite the bullet and go back to the standard setup.

[wild bill]

it's not the bulkhead version its the one that mounts on the cross member between the rad and the engine.

My thermostat  threads into the side of the fillerneck on the raceline water rail. I thought the exp tank inlet was the bottom connector which is 15 (ok perhaps 16 makes sense) the bleed is the top outlet (5 or 6 mmm)

If i run from the engine bleed What then attaches to the fillerneck overflow?

Running the return to the heater return will be tricky as there's alot in the way between fron and back. The bulhead expansion position is taken by heater and washer bottle (IYSWIM)

So many questions such minimal brain capacity 

 

[7 wonders of the world]

OK,

Washer bottle can go in a multiple of places, 

Having the stat in the Raceline means its in a dead end and therefore very slow to respond, keep the rail it that helps with your plumbing but take the stat out and get and OE one. (82 degrees)

Are you running the bypass hose from the rear for the head, as you will need this to ensure the system can respond.

Bulkhead mounted bottle is a better solution as the pipe route to the heater return is simpler and the bottle is higher which aids bleeding too.

[wild bill]

Thanks 7 i'm with that. Once xmas is over i need to return the exp tank to Caterham and order the necessary bits.

[7 wonders of the world]

BM with a mobile and if you need any I can ping some photos over via whatsapp   

You can buy Mahle 82 degree stat on ebay for £16 

[Nigel Fox]

Have a look at the car builder solutions video on head tanks and expansion tanks.

[wild bill]

thanks 7 and Nigel. If i put the tank on the bulkhead i'm stumped for space for the washer bottle. It's so tight a config in the s3. The only real space is on the crossmember. Also with the race line water rail im not running a pressurised system so the tank i ordered is un needed in that way.

I'll BM my mobile 7 owver the break. No hurry.

[Molecular--Bob]

If you have 2 points on the water rail where you can add 15mm inlets for the heater loop and the bypass return then you could convert the water rail to a sealed system by using an elbow like this: https://www.burtonpower.com/thermostat-housing-with-boss-cast-alloy-x-flow-rwd-fp612.html

There are ones with a fan switch boss and an overflow if that is the style you need, will depend on if you have a fan switch and bleed hose on your radiator. 

These elbows are pretty expensive for what they are, but would let you use most of what you have with a header tank added in. 

Might be easier to convert to one of the Caterham solutions like the long hose that connects to a standard duratec water outlet: https://caterhamparts.co.uk/hoses/4617-radiator-top-hose-edpm-rubber-r300-r400-r500.html I have the Raceline throttle bodies on mine and couldn't get this to clear the throttle linkage. 

Caterham have a bracket that allows the header tank to be hung from the heater, they use it on the 620s: https://www.autocar.co.uk/car-review/caterham/seven-620s/performance It is 2 parts, sold separately, this fastens to the newstyle heater front : https://caterhamparts.co.uk/expansion-tanks-caps/6200-expansion-bottle-mounting-bkt.html , then this holds the Freelander tank onto the bracket: https://caterhamparts.co.uk/other/5760-mounting-bracket-expansion.html I use just the second part attached to the bulkhead directly. It might be possible to move your washer bottle to just above the gearbox as done on the x/flow supersprints.