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Chat Area => General Car Chat => Topic started by: chrisgixer on 13 May 2014, 16:36:31

Title: Tips on flushing after failed oil cooler.
Post by: chrisgixer on 13 May 2014, 16:36:31
... For Aaronjb

If anyone fancys posting up while we're running hoses...?


Needless to say, there's brown shite everywhere and the heater is week.
Title: Re: Tips on flushing after failed oil cooler.
Post by: Field Marshal Dr. Opti on 13 May 2014, 18:48:47
After my new cooler was fitted by Mark DTM......I repeatedly filled the cooling system with water and a cup full of washing powder. Eventually I managed to get all the shit out.  :y
Title: Re: Tips on flushing after failed oil cooler.
Post by: martin42 on 13 May 2014, 18:50:59
Hope you used a decent brand of washing powder,you know how funny they get when using cheap and cheerful powder that doesnt get the engine clean internally  ;D ;D
Title: Re: Tips on flushing after failed oil cooler.
Post by: al brown on 13 May 2014, 19:07:32
On mine I used dish wash tabs as they don't foam as much. Also I took out as many of the sensors in the coolant system as I could get to and cleaned them as initially the fans didn't work, the sensors in the rad were covered in gunk. That got the fans working again so I was happier running the car with the cleaning solution in it. Took a few flushes, but had been fine for the last few years, coolant comes out clean when I renewed it as year after I had changed the cooler.
Title: Re: Tips on flushing after failed oil cooler.
Post by: aaronjb on 13 May 2014, 19:15:35
That's interesting - the fans in mine aren't running either.. fingers crossed it's as simple[1] as cleaning the sensors.. good to know!

There's a dishwasher tab in there at the moment and I'll run it up to temp tomorrow and drain it again, repeat ad nausea I suspect.

Still, as Al & Chris pointed out today this is probably[2] entirely my own fault for ignoring that little coolant leak (which turns out was likely the oil cooler cover plate and the radiator drain tap; the latter had been previously bodged[3] with a blanked off hose jubileed onto the drain outlet!) and topping it up for, erm.. four years  :-[

[1] As simple as any of the jobs have been!
[2] Ok, not really probably
[3] Not bodged by me, and the last person to touch the cooling system would either have been the previous owner, Vauxhall or Mr Budden, the dealer it came from..
Title: Re: Tips on flushing after failed oil cooler.
Post by: Entwood on 13 May 2014, 19:30:27
When we flushed a mates omega some years back we used a "low suds biological" detergent that his wife "liberated" from the hospital she worked at ...took about 20 flushes but it was extremely clean at the end of that. we reckoned we could do a flush every 4 hours ...

sequence was, with the heater controls set to max heat throughout ...:

Fill with cold water plus detergent. Run engine with the cap off until the thermostat opened, "burping" and topping up as required. Once the 'stat opened fit cap and run engine until temp gauge at normal. Switch off. Leave to stand. After 30 minutes start engine and run for 2 minutes. Switch off and leave until cool. Drain. Repeat ......

Took a while but it worked
Title: Re: Tips on flushing after failed oil cooler.
Post by: TheBoy on 13 May 2014, 21:04:49
The chemist next door suggested a cupful of screenwash, after reading the labels on all the shit in my (then) garage.

IME, the rad switches fail soon after, and keep an eye on rubber hoses and seals...
Title: Re: Tips on flushing after failed oil cooler.
Post by: Varche on 13 May 2014, 21:30:14
I have never tried it but wouldn' t  a degreaser like gunk help?

Garages here have a device that presumably sits in the pipework and sifts out the oil over a period of running. Never seen one.
Title: Re: Tips on flushing after failed oil cooler.
Post by: zirk on 13 May 2014, 21:37:18
Ive tried just about everything including the reccomended Rad Cleaners, best Ive found so far is Industrial Oven Cleaner, which I borrowed from my local Pubs kitchen.  :y
Title: Re: Tips on flushing after failed oil cooler.
Post by: al brown on 13 May 2014, 22:20:48
The chemist next door suggested a cupful of screenwash, after reading the labels on all the shit in my (then) garage.

IME, the rad switches fail soon after, and keep an eye on rubber hoses and seals...


I admit I replaced a couple of hoses afterwards as they felt soft, but the temp switches are still fine several years after my cooler failed but they were cleaned the day after I changed the cooler so maybe I got lucky. Flushed mine on the dive a few times, then the next few times I ran it for a couple of days at a time with a dishwasher tab in it.
I am sure there are many ways to do it, main thing is to make sure it is clean after a few days With the same fluid in it, not just running clear while you flush it.
Title: Re: Tips on flushing after failed oil cooler.
Post by: tigers_gonads on 13 May 2014, 22:29:32
Dishwasher detergent  ;)
Title: Re: Tips on flushing after failed oil cooler.
Post by: tunnie on 13 May 2014, 22:44:50
Omegatoy always recommended a cap full of bleach, but only at idle, never driven  :y
Title: Re: Tips on flushing after failed oil cooler.
Post by: chrisgixer on 14 May 2014, 00:16:27
Funny enough, the moment we put two, yes two, dishwasher tablets in the header tank, and sealed the rad drain properly by replacing the tap o rings, the temp came down and settled at 90(-95?) from the 100c it showed at various stages previously. It cleared a little, bubbled some air into the coolant tank and bought the coolant level warning on.

Engine off. Left to cool, tropped back up, and curry stopped play. Going in the right direction now hopefully. Even got some warm air from the heater.


Very interesting post on the rad fans. Al let some smoke out bridging the contacts to get them working ;D but it made no odds to the temp, as the system wasn't sealed due to the rad drain tap leaking.

Re sensors and cleaning, we did comment that it might need every part of the cooling system dismantling. Hoses, rad, sensors, hbv, and cleaning all the shite out if them.

Unless one of these rad flush products is worth a go....?


...or just stick with the dishwasher tabs and flush daily for a fortnight...?
Title: Re: Tips on flushing after failed oil cooler.
Post by: Kevin Wood on 14 May 2014, 07:32:21
I wouldn't leave dishwasher tablets in there too long as they corrode ali parts.

Plenty of things dissolve oils but you want something not so volatile as to attack the rubber, so stuff like gunk and jizer are out, i reckon. Washing powder or TFR are probably the best, I'd say.
Title: Re: Tips on flushing after failed oil cooler.
Post by: biggriffin on 14 May 2014, 08:58:48
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).

Title: Re: Tips on flushing after failed oil cooler.
Post by: tunnie on 14 May 2014, 11:53:48
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  :o
Title: Re: Tips on flushing after failed oil cooler.
Post by: Blaster Bates on 14 May 2014, 12:14:45
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.
Title: Re: Tips on flushing after failed oil cooler.
Post by: TheBoy on 14 May 2014, 19:56:51
Also beware of mixing alkali and acid as it can catch fire and even explode.
He's going for it today...  >:(
Title: Re: Tips on flushing after failed oil cooler.
Post by: biggriffin on 14 May 2014, 20:49:54
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  :o

whoops had imperial head on,not metric. Litres.
Title: Re: Tips on flushing after failed oil cooler.
Post by: aaronjb on 14 May 2014, 23:54:43
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...
Title: Re: Tips on flushing after failed oil cooler.
Post by: 05omegav6 on 15 May 2014, 09:59:36
The sensors are cheap enough :y 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 :y
Title: Re: Tips on flushing after failed oil cooler.
Post by: chrisgixer on 15 May 2014, 10:20:49
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.
Title: Re: Tips on flushing after failed oil cooler.
Post by: aaronjb on 15 May 2014, 10:38:46
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 ;D

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?
Title: Re: Tips on flushing after failed oil cooler.
Post by: 05omegav6 on 15 May 2014, 10:51:48
It should certainly be on full by then..., 95° as a minimum I would have thought :-\

Worst case, I do have a spare rad :y
Title: Re: Tips on flushing after failed oil cooler.
Post by: aaronjb on 15 May 2014, 13:09:41
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.
Title: Re: Tips on flushing after failed oil cooler.
Post by: Kevin Wood on 15 May 2014, 14:26:17
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. :y
Title: Re: Tips on flushing after failed oil cooler.
Post by: aaronjb on 16 May 2014, 07:37:40
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 ;D

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 ;D
Title: Re: Tips on flushing after failed oil cooler.
Post by: Kevin Wood on 16 May 2014, 10:43:57
Worth massaging the hoses throughout, TBH, including while you initially fill it.  :y

I find the Omega's system just self-bleeds. By far the easiest system I've had to fill.
Title: Re: Tips on flushing after failed oil cooler.
Post by: aaronjb on 16 May 2014, 11:44:38
Ah yes, I omitted the massaging of the pipes in my description  :y 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!
Title: Re: Tips on flushing after failed oil cooler.
Post by: chrisgixer on 16 May 2014, 12:00:42
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. ;)