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[tunnie]

On DAF XF 430/480/530. Oil coolers and rear head gaskets are a common fault,thus allowing 10 gallons each of oil and water to mix and its like thick black sludge.

to clean use liquid dishwasher detergent,run round the system,drain and flush,re-do if necessary,.
try some detergent from local pub or restaurant,as that's a bit stronger (industrial).

10 Gallons, that's a lot of sludge 

[Blaster Bates]

Beware of using alkali products in the cooling system for extended period as it will attack the alloy components such as cylinder heads etc.

Also beware of mixing alkali and acid as it can catch fire and even explode.

[TheBoy]

Also beware of mixing alkali and acid as it can catch fire and even explode.

He's going for it today... 

[biggriffin]

On DAF XF 430/480/530. Oil coolers and rear head gaskets are a common fault,thus allowing 10 gallons each of oil and water to mix and its like thick black sludge.

to clean use liquid dishwasher detergent,run round the system,drain and flush,re-do if necessary,.
try some detergent from local pub or restaurant,as that's a bit stronger (industrial).

10 Gallons, that's a lot of sludge 

whoops had imperial head on,not metric. Litres.

[aaronjb]

Ran it up to temp again tonight, drained, flushed, refilled and burped the system - I could provoke it to 100C on the gauge but it took a lot of revving and turning off the heater to do it.

Still no action from the fans, though.

Will do it all again tomorrow night...

[05omegav6]

The sensors are cheap enough leave the ones on the coolant bridge as the gauge works and the ecu isn't flooding it with fuel, so would suggest they're both fine...

Swap the two on the radiator out the final time you drain it prior to refilling with the correct mix

[chrisgixer]

I rekon a clean is all they need. The sensor on the coolant side is just a brass lump. There's nothing to break from that point of view, and they don't often fail.

Rad comes out easy enough, although I know the screws on the plastic cover will need drilling out.

[aaronjb]

A clean is likely all they need - when it's cold (so, tonight) I should be able to test that it's just the sensor by pulling the connector on the upper one and bridging the contacts, I think. Lower one being a little harder to get to - and I don't know which set of fans they control, but I guess there's a good chance I'll find out

I'm a little worried that the rad casing could crack on trying to remove them as the end tanks are plastic..

Anyone know off the top of their head what temperature the fan(s) should come on at? Main fan at 100C, is it?

[05omegav6]

It should certainly be on full by then..., 95° as a minimum I would have thought

Worst case, I do have a spare rad

[aaronjb]

Cheers Al - there shall be more flushing action tonight and I'll have a poke at the upper sensor as that's easy to get at.

Ooh, more for Chris this, but - the two new O-rings have completely fixed the drippy drain plug.  So if anyone else is watching, a 6mmx2mm O-ring on both O-ring locations works perfectly.

[Kevin Wood]

Cheers Al - there shall be more flushing action tonight and I'll have a poke at the upper sensor as that's easy to get at.

Ooh, more for Chris this, but - the two new O-rings have completely fixed the drippy drain plug.  So if anyone else is watching, a 6mmx2mm O-ring on both O-ring locations works perfectly.

PM sent.

[aaronjb]

Right, thanks to Kev's PM I proved the fans work if you bridge the contacts on the switch, so the only thing stopping them turning on is the switch itself not seeing hot enough water - probably due to an insulating layer of gunk

Ran it up to temperature again last night (takes a long time to get it to the point that the fans should come on, actually - it rockets to the stat opening point and then needs a lot of provoking to get higher, which must be a good sign), drained it, refilled it and added another dishwasher tablet.  What comes out now is more or less .. well, cloudy water. More flushing needed then.


Just to check, the correct procedure for bleeding the system is;

With the engine off, fill the header tank until no more will go in
Run the engine with the cap off and heater matrix open (heater on Hi), topping up as required

As it gets up to temp the coolant starts to overflow and puke lots of big bubbles out - I presume that's the point you stick the cap back on and massage the hoses?


These new fangled self bleeding cars .. my last one(s) just had bleed nipples to open

[Kevin Wood]

Worth massaging the hoses throughout, TBH, including while you initially fill it. 

I find the Omega's system just self-bleeds. By far the easiest system I've had to fill.

[aaronjb]

Ah yes, I omitted the massaging of the pipes in my description  Although I did do plenty of that last night

Thought I'd best check as after the last fill last night everything was hunky dory until suddenly the coolant bottle was empty - I'm guessing a big slug of air shot round from somewhere to somewhere and ate the remaining coolant level.  It was roasty toasty at that point though so opening the lid to add water wasn't an option until the whole thing cooled down a bit!

[chrisgixer]

Yep it's self bleeding. Ordinarily, just fill to the level, run the car until hot, maybe use it for a day. Top it up ,as the air rises to the top with use, job done.

However, with that much gloop in there, we did have trouble with circulation initially. While I suspect it's well passed that stage by now, I'd keep a close eye on the coolant level and temp. If the level drops, stop the engine and let it cool before topping up, or it will boil instantly and overflow the moment the cap is opened.

There is a guide on flushing, maybe worth a read up on disconnecting the heater hoses in order to flush the matrix. The water ways are quite narrow in there.

Edit, missed your last post.