TRD problems

toddao · Post by **toddao** » Mon Dec 15, 2008 4:26 pm

Today I started up the TRD ( 1.9 n/a) after its new head gasket. Everything started well - good oil pressure, warning light went out.
But then as it warmed up, on comes the warning light before doing its old trick of squirting water out of the radiator.

I know this means that there's gas in the system which I thought was the head gasket. Does this mean a cracked head? I didn't have the thing pressure tested.. any other suggestions?

I've got my TÜV (MoT) booked for this week - looks as though it was
premature!

CitroXim · Post by **CitroXim** » Mon Dec 15, 2008 4:52 pm

Sorry to ehar this Todd

What warning light Todd?

Good way to check for a cracked head is to start up from cold and feel the top hose. If it goes rock-hard after a few seconds then that means there's gas escaping from somewhere to pressurise the coolant.

It's pretty vital to have the head both skimmed (or at least check it's in tolerance) and have a quick pressure test.

N/As in my experience do carry their heads and gaskets fairly well. Sorry if I'm asking something that's already been said but what prompted you to do the head?

EDIT: Is the system well bled? That can cause strange things like this sometimes...

toddao · Post by **toddao** » Mon Dec 15, 2008 5:16 pm

Hello Jim, I did the head gasket because it was doing this very thing before -blowing water out of the radiator ( with the cap off ) after about 2 minutes of being started when the coolant hadn't even warmed up.

When I took the head off, the gasket had indeed failed on number one cylinder. I took the head to be skimmed but I didn't realise that I should have pressure tested it too.

I thought that bleeding might have been the problem but why the warning light ( the big one that says : STOP in red!) and I don't think air in the system would cause such an eruption!

I'm trying to be Cool(ant) about it! (quite hard)

CitroXim · Post by **CitroXim** » Mon Dec 15, 2008 5:23 pm

You're being remarkably cool Todd. If it were me my post would be full of

Another test is to run with the expansion tank cap off. Can you see loads of bubbles and eruptions in there?

Another possibility is a blocked bypass passage. You know the little plate on the LH front side of the head (as you look at it) with a little pipe coming from it. The little aluminium spigot sometimes blocks and upsets the water flow around the head and causes an exceedingly rapid rise in local temperature leading to steam and big bubbles. In fact worth checking all the small diamater pipes on the cooling system to check they're clear.

In fact, running with the cap off will tell you quite a lot.

I sincerely hope the head is OK...

toddao · Post by **toddao** » Mon Dec 15, 2008 5:44 pm

Thanks Jim, I'm trying to write this with my little 6 week old daughter balanced on my knee - it could be worse!

I'm determined to get this car back on the road but probably not this week now. Spent quite a few €€€s and got special insurance and red plates for this week to test drive it and take it for its test. It's the wife who's

because I've given it all my spare time! And the yellow one's out of TüV this week!

Let's assume it's the head that's cracked, if I fitted another good head, could I then find out that it's the block that's cracked?

I just wonder what is lighting the warning light ( the 'it's ferked' sensor?)

BX Bandit · Post by **BX Bandit** » Mon Dec 15, 2008 5:59 pm

Hi Toddao.
It was the block in my case I'm sad to say but I have it on good authority that is was a year or two of manufacturing around 1990 using some dodgy steel.
If it's still air in the cooling system then the level will gradually drop as the air is purged out. Remember to use the bleed points (one on thermostat housing - not sure where or if there is another on an n/a) and put the cabin heating on to help everything circulate. 30 mins on tickover or elevated revs now and again should see it sorted.
If it's still bubbling after that and the water level isn't going down then you probably have a porous head.

Another pointer: When hot and with the rad cap fitted (i.e. coolant system under pressure) turn the engine off and leave overnight. The pressure within the cooling system can force water back through the porous passage (

). On starting the water doesn't compress and the engine idles rough but very hard. This is how life was with mine with a porous block. BUT, if sufficient water has escaped and is trying to be compressed as you start the engine it may well........ um .........break things!!!!

Check for water in the oil too!

CitroXim · Post by **CitroXim** » Mon Dec 15, 2008 6:09 pm

A daughter Todd! Congratulations

She'll be almost exactly 16 years younger than one of ours! What's she called? Something good and German I hope? Our 16 year old is called Robyn. A very popular girls name in the place she was born - Australia

Chances of a cracked block are exceedingly rare. It's a big lump of cast iron and very tough

I see your thoughts, have the head off the yellow one when it's TUV runs out? Should be a goer although I'd be tempted to source another head and leave the yellow one intact. Those heads are common enough and there is an awful lot of interchangability between various XUDs.

The "It's Freked" light could be either the over temperature warning or the low coolant warning - the latter being confused with all the turmoil going on in the expansion tank...

I'd still doubly check all parts of the coolant circuit before condemming the head.

CitroXim · Post by **CitroXim** » Mon Dec 15, 2008 6:13 pm

BX Bandit wrote:I have it on good authority that is was a year or two of manufacturing around 1990 using some dodgy steel.

Todd,

I'll withdraw my statement in light of information from Mr. Bandit.

jonathan_dyane · Post by **jonathan_dyane** » Mon Dec 15, 2008 6:17 pm

Sorry to hear that you're still having problems! I'd be royally pissed off by this point...

On the good news front though, the old head gasket was definately knackered. Are you 100% sure that you are bleeding the thing effectively? For some reason *some* XUD engines are absolute pigs to bleed properly, and the symptoms of trapped air can be just as you describe.

You *must* use a funnel/pop bottle with the bottom cut off etc. sealed to the radiator filler to create a good head of water, I usually fill it too the very top, heater on hot and both radiator and thermostat housing bleeds open.

After water starts coming out of the bleed points, let it continue to run out for a good 10 secs or so, often more air will emerge.

Start engine and observe, feeling hoses and checking for circulation. If the heater hoses don't get warm and the head is clearly getting warm, stop the engine and have another go at the bleed points.

After the thermostat opens I always stop the engine briefly to crack open the bleeds again. Often more air emerges... Also, when the 'stat opens expect to see more bubbles appear in the header and the level to drop. Top it up to maintain head.

Run engine like this with the header still in place until the cooling fan(s) come on and all bubbles have stopped emerging in the header. Hopefully all is now well. I usually stop the engine and crack bleeds one last time to be 100%, which is good for a light scalding

Have another shot at the bleeding, and I hope all will be well!

toddao · Post by **toddao** » Mon Dec 15, 2008 6:57 pm

Thanks for replies everyone. Without the support offered here, I probably would have given up before!

I can't do anymore tonight because I'm left holding the baby ( her name is Sovay, by the way, Jim!) who is displaying symptons of trapped air too, but I can't find the bleed screw!

Jonathan, tomorrow I will try again with the bleeding - I hope you're right.

As regards the oil pressure gauge - should this give a constant reading or is it only effective on start up? I don't have one on my yellow BX. Also re the warning lamp - what symptoms normally light this?

ken newbold · Post by **ken newbold** » Mon Dec 15, 2008 7:07 pm

Sorry and I know this is of little use now, but I've never had the head off one of these engines as there are so many very likely causes, cracked head being the most IMHO. I've always taken the easier and quicker and cheaper option od pulling the engine out and replacing it with a know good one.

Mind you last time I did this, there were still plenty of BX's around to donate

toddao · Post by **toddao** » Mon Dec 15, 2008 7:28 pm

Ken, if all is lost with this motor, that is what I'll have to do - if I can find one. There's two on Ebay here for €600 each - tested with 12 months guarantee but that's too much for me right now.

It's just a shame that this car otherwise is immaculate - it was Citroen serviced up to 36,000 miles then when the 90yr old owner passed away it was taken on by a monkey of a mechanic who didn't understand it - a thousand miles later it was shafted. Just changed the oil today and seeing the way the sump plug had been bodged open gives me a clue..

Way2go · Post by **Way2go** » Mon Dec 15, 2008 7:31 pm

citrojim wrote:
Another possibility is a blocked bypass passage. You know the little plate on the LH front side of the head (as you look at it) with a little pipe coming from it. The little aluminium spigot sometimes blocks and upsets the water flow around the head and causes an exceedingly rapid rise in local temperature leading to steam and big bubbles. In fact worth checking all the small diamater pipes on the cooling system to check they're clear.

I believe this bypass suggestion is worth looking at because if it's similar on my petrol, I had the red light come on whilst the temperature gauge was reading normal at 90 degrees. Rad flow seemed OK and thermostat had opened. I managed to sort it by running Wynn's Professional flush in the system for a days journey after a normal flush and backflush had made no difference.
However you know diesels better than me so whether Wynn's flush is likely to work in your case I don't know but it can't hurt to try I guess, before dismantling again.

jonathan_dyane · Post by **jonathan_dyane** » Mon Dec 15, 2008 7:32 pm

toddao wrote:As regards the oil pressure gauge - should this give a constant reading or is it only effective on start up? I don't have one on my yellow BX. Also re the warning lamp - what symptoms normally light this?

This isn't actually an oil pressure gauge, but rather an oil *level* gauge, and indeed is supposed to go off after a few seconds as it cannot provide an accurate reading with the engine running.

As far as the other warning lights go, not being familiar with the Mk1 I cannot say what light does what, however the Mk2 has three cooling related lights.

1) Light is an image of a radiator and lights together with stop light to inform of low coolant.

2) Amber temperature light, lights at about 105 degrees centigrade. When lit means stop now and you might *just* get away with things.

3) Red temperature light, lights at 112 degrees centigrade together with stop light. By this point you're usually in trouble.

I dunno if the Mk1 is the same, but clearly the light you have coming on is either low coolant (because some has blown out?) or too hot (due to trapped air or lack of circulation in this case.) Which leads me on to ask; have you done the timing belt and water pump on this car? If not now would be an excellent time, and if the impellor of the pump has fallen off/disintegrated this could be what caused the HG to fail in the first place.

If tomorrow you still can't sort it with bleeding, I would be looking at the water pump...

Way2go · Post by **Way2go** » Mon Dec 15, 2008 7:37 pm

toddao wrote:
As regards the oil pressure gauge - should this give a constant reading or is it only effective on start up? I don't have one on my yellow BX. Also re the warning lamp - what symptoms normally light this?

Oil pressure gauge reads constantly once the illumination goes off after a few seconds and it has finished reading oil level.

Edit: The above is the case if the gauge is a retrofit from the GTi etc but otherwise Jonathan's posting which crossed with mine is more applicable.