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Query on PSA 1.9 cooling system


pogweasel

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Eyeing up some old grot on eBay....Seems said vehicle has a couple of issues...

SUSPECTED HEAD GASKET (BUT NOT SURE). THESE ARE THE SYMPTOMS:THE WATER IS BUILDING UP PRESSURE IN THE EXPANSION TANK, BUT DON'T GET HOT ON THE TEMPERATURE GAUGE.

Deffo HGF? I'd have thought it would have gone thundering up the gauge if it was parped???Vehicle in question is ~150 miles away, would be nice to get it back without RAC assistance!!
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It'd only overheat if it was actually loosing coolant, surely? As long as the system contains the pressure without dumping the coolant, I expect it'd stay cool. If that's the case, i wouldn't trust it over any distance.

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It'd only overheat if it was actually loosing coolant, surely? As long as the system contains the pressure without dumping the coolant, I expect it'd stay cool. If that's the case, i wouldn't trust it over any distance.

No it will overheat if the system is being pressurised with air regardless of coolant loss or not. If its pressurising, it can only be getting air from the combustion chambers, this air in the system not only causes pressure build up, but also causes overheating as air isnt a very effective coolant. If its pressurising its only a matter of time before something gives up and it loses its coolant anyway. Hes obviously not driven it far because it doesnt take long to boil over, i had a BMW with the same problem a few years ago, and that didnt take long to pressurise and overheat. Interestingly it would tick over all day with no bother though
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OK, second question then!Supposing we go for it, and grind to a halt shortly afterwards on the hard shoulder of the M4, with a RAC piggy-back home, how hard is doing the HG on these engines? Two fairly inept blokes with plenty of time on their hands... DIY-able?Bearing in mind that the engine isn't necessarily in it's natural environment, being N-S, gearbox behind then prop to rear axle :wink:

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No it will overheat if the system is being pressurised with air regardless of coolant loss or not. If its pressurising, it can only be getting air from the combustion chambers, this air in the system not only causes pressure build up, but also causes overheating as air isnt a very effective coolant. If its pressurising its only a matter of time before something gives up and it loses its coolant anyway. Hes obviously not driven it far because it doesnt take long to boil over, i had a BMW with the same problem a few years ago, and that didnt take long to pressurise and overheat. Interestingly it would tick over all day with no bother though

Not entirely true, because gasses can only enter the coolant system if there's space for it. If no coolant is being lost or consumed then gasses cannot enter the cooling system as water isn't compressable. But as you say, it is only a matter of time before it gives up the ghost which is why I wouldn't trust it to go far.That said, I've had two Nissan L series six pots that both had a problem with pressurising the cooling system and both went for months before the inevitable sudden catastrophic headgasket failure. Anyway, if you do drive it and it dies en-route, you may do it no favours and render the head useless. Bust out the A frame I say.
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OK, second question then!Supposing we go for it, and grind to a halt shortly afterwards on the hard shoulder of the M4, with a RAC piggy-back home, how hard is doing the HG on these engines? Two fairly inept blokes with plenty of time on their hands... DIY-able?Bearing in mind that the engine isn't necessarily in it's natural environment, being N-S, gearbox behind then prop to rear axle :wink:

What is it? Some sort of Shitroen? Or a Pug?Headgaskets are straight forward enough if its a bit of old Pig Iron that wont need to be pressure tested and skimmed etc, and if theres no valve timing units to fiddle with etc. Just a ratchet set, and torque wrench, ive done loads of CVH headgaskets no problems.Always use new head bolts, aswell as the new gasket set (obviously), new waterpump while you're there and a timing belt.
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No it will overheat if the system is being pressurised with air regardless of coolant loss or not. If its pressurising, it can only be getting air from the combustion chambers, this air in the system not only causes pressure build up, but also causes overheating as air isnt a very effective coolant. If its pressurising its only a matter of time before something gives up and it loses its coolant anyway. Hes obviously not driven it far because it doesnt take long to boil over, i had a BMW with the same problem a few years ago, and that didnt take long to pressurise and overheat. Interestingly it would tick over all day with no bother though

Not entirely true, because gasses can only enter the coolant system if there's space for it. If no coolant is being lost or consumed then gasses cannot enter the cooling system as water isn't compressable. But as you say, it is only a matter of time before it gives up the ghost which is why I wouldn't trust it to go far.That said, I've had two Nissan L series six pots that both had a problem with pressurising the cooling system and both went for months before the inevitable sudden catastrophic headgasket failure. Anyway, if you do drive it and it dies en-route, you may do it no favours and render the head useless. Bust out the A frame I say.
No water isnt compressable, but the radiator cap will release pressure from the top of the expansion tank and allow airlocks to be created by the exhaust gasses, allowing it to overheat if coolant is lost or not.Then when there is no more room in the expansion tank due to the airlocks lower in the system, thats when it usually blows the cap off. Seen this on a few Straight 6 BMW's
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Basically if an XUD displays any kind of coolant system issues I would be running away from it.Ask him if it's losing coolant. Could be as simple as a duff rad cap, but I doubt it. I very, very much doubt it.Book time for a head gasket change is something like 9.5 hours on the 405. A pound to a penny you'll need a head skim as well. And they can also crack, too.

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I see what you're getting at but in my experience, cars with an expansion tank will also dump the coolant when the pressure gets too much. I've had two Sunny ZX's and a Sunny estate behave that way. The ZX's are undrivable when the HG lets go but the E16 Sunny would go 40 miles plus before needing a top up. With those they'd only overheat once the coolant went. Funnily enough, years ago I modified the coolant system on my Austin A40 to a sealed expansion tank type system and when the HG went on that it just kept dumping it's water every 30 miles until I got it home. The older cars without an expansion system just seem to chug on until they eventually go pop.

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I see what you're getting at but in my experience, cars with an expansion tank will also dump the coolant when the pressure gets too much. I've had two Sunny ZX's and a Sunny estate behave that way. The ZX's are undrivable when the HG lets go but the E16 Sunny would go 40 miles plus before needing a top up. With those they'd only overheat once the coolant went. Funnily enough, years ago I modified the coolant system on my Austin A40 to a sealed expansion tank type system and when the HG went on that it just kept dumping it's water every 30 miles until I got it home. The older cars without an expansion system just seem to chug on until they eventually go pop.

I guess it depends on the type, and the degree of failiure experienced then. Seem to me yours have been mild failiure allowing you to continue using the vehicles. The failiures ive experienced as mentioned rendered the vehicle immediately undrivable (although pressure builds immensly quickly at 100mph on the M4)
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I guess it depends on the type, and the degree of failiure experienced then. Seem to me yours have been mild failiure allowing you to continue using the vehicles. The failiures ive experienced as mentioned rendered the vehicle immediately undrivable (although pressure builds immensly quickly at 100mph on the M4)

The only one I've had that failed immeadiately without warning and rendered the car undrivable was my '76 Civic. The open water jacket at the block deck doesn't help there. The Nissan CA and E engines will run just fine until the water has gone but both will warp the head massively if they get too hot (CA's do the rings too). If that happens then it's goodnight engine. The old L series just lumbers on regardless. I've only ever known one of those engines to ever fail terminally and I've had dozens of them. Modern engines (by which I mean anything 80's onward) seem fragile by comparison. My old 280C ran four about 4 months with a slightly leaky head gasket. I had to fix it in the end because it did actually start filling a cylinder with water overnight and would hydraulic in the morning. Once a new gasket went in it was fine. No damage done..no head skims needed. Amazingly tough old engines.
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The failiures ive experienced as mentioned rendered the vehicle immediately undrivable (although pressure builds immensly quickly at 100mph on the M4)

I don't think doing 100mph on the M4 (or anywhere else for that matter) is likely to enter the equation where an LDV Pilot is concerned...I've only ever had three cars with blown head gaskets - a Proton Persona, a Mk1 Tranny with a 2-litre V4, and the Mazda 323 that is currently in the process of being disembowelled by Mr. Scrapman. All three ran quite sweetly, although the Proton would overheat quite quickly; the Tranny, on the other hand, could be left idling for half an hour with no untoward consequences, and both head gaskets were comprehensively Donald Ducked on that, to the extent that after leaving it sat for ten days, when I went to start it again all four cylinders were full of water. I don't know whether the ability of an engine to keep on running depends more on the engine itself or on where exactly the head gasket has blown - although all three cars had engine oil like chocolate milkshake and threw out clouds of steam from the exhaust so water must have been getting into the oil ways and the bores.
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I once had a very similar problem with a BX19RD (i.e. the non-turbo XUD engine). The head had cracked, iirc near one of the injector prechambers, but I drove it 70 miles without incident. I'd rigged a modified electonic cooking thermometer up to the cylinder head so I could make sure it wasn't in any danger of warping and it remained cool throughout. I swapping the head for one from a scrapyard with 200k on it. They're apparently prone to cracking, and I was glad to get hold of even a mileagey one becuse they seemed quite scarce at the time - but the engines are reputedly good for 300k so I thought it might have some life in it still.Swapping the heads was a real mission and I did it in a number of sessions over several weekends - much more involved than the other head swaps I'd done, but much of this was due to the way the BX appears almost to to be constructed around its engine - there was a LOT of dismantling. Replacement head gaskets come in different thicknesses, and you have to take some pretty accurate measurements using a dial gauge to get the right one - good excuse to buy more tools, and probably the highlight of the job for me.Personally, I'd run a mile.(I've just noticed tontops' post about a spare engine. Could be an easier option than a head swap, but I have a funny feeling that the blocks designed for longitudinal installation have different mounting points - when the BX died I considered nicking its engine for another of the fleet and istr this was why I didn't do it).

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The only one I've had that failed immeadiately without warning and rendered the car undrivable was my '76 Civic. The open water jacket at the block deck doesn't help there.

Ha ha - my '78 Civic did the same - started it up at the roadside one day and the engine just turned into a water pump - shot a jet of water ten foot out the exhaust!
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One of my previous 405's used to lose enough coolant to bring on the warning light within 200 miles or so. The temp gauge used to do funny things as well, dropping to zero then jumping up to 110 before stabilising at 90, dropping to zero again and repeating. I bled it numerous times and lobbed some K-Seal in as a last resort then sold it, apparently the new owner fitted a new waterpump and it is fine now, so it could be as simple as that with this Sherpa. I did do about 2000 miles in it, just topping it up and bleeding it all the time (did I mention that bleeding XUD's is an absolute faff? And that most installations (406 and possibly Xantia are different) don't have an expansion tank?), and it certainly performed well enough, so maybe I was lucky.Problem is that the XUD is very susceptible to damage when overheating, and I'd be wary of this one. Ally head usually warps and needs a skim, loadsa different HG thicknesses as previously stated, rads block over time, etc. That said, as also pointed out, LDV engine bay access might be easier than in a 405. Personally though given the seller's pretty meaningless description, I would say "caveat emptor" on this one.I had a 3-litre Mitsi Sigma that was similar, which had already suffered HGF and was thrown back together as cheap as poss by a Mitsi dealer - Hermetite was everywhere in the engine bay. Unfortunately they hadn't thought to change the waterpump on that, which I suspect was at fault. Didn't harm the performance mind, but did freak out other road users at traffic lights when steam would shoot out of the grill...

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I had a Rover 111GSI (why-o-why!) with a foobared headgasket, but blimey it took some abuse! I swapped it for two pints of Stella one sunday afternoon, ran it for 4 months with the headgasket gone, it was ok if you bimbled about, but give it any stick and it would blow the contents of the radiator all over the road. As I was forever topping it up it never had any antifreeze in it, cue a cold snap, and each morning I used to have to pour boiling water all over the engine and radiator to thaw it out, then for the first couple of miles it would sound like a Mr Frosty machine :lol: Given all that, it never once refused to start, and got me from Stoke to Leeds and back several times over the peak district! I pretty much knew every pond and beck on route for topping up the water!Funnily enough I only got rid of it when the head warping got to such a stage that if you revved it whilst stationary it would piss water straight out the joint between head and block. At such an angle that if you were trying to bleed the system to get the heater to work for the couple of miles jaunt to work, it would hit you straight in the crotch. :lol:

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I had a Rover 111GSI (why-o-why!) with a foobared headgasket, but blimey it took some abuse! I swapped it for two pints of Stella one sunday afternoon, ran it for 4 months with the headgasket gone, it was ok if you bimbled about, but give it any stick and it would blow the contents of the radiator all over the road. As I was forever topping it up it never had any antifreeze in it, cue a cold snap, and each morning I used to have to pour boiling water all over the engine and radiator to thaw it out, then for the first couple of miles it would sound like a Mr Frosty machine :lol: Given all that, it never once refused to start, and got me from Stoke to Leeds and back several times over the peak district! I pretty much knew every pond and beck on route for topping up the water!Funnily enough I only got rid of it when the head warping got to such a stage that if you revved it whilst stationary it would piss water straight out the joint between head and block. At such an angle that if you were trying to bleed the system to get the heater to work for the couple of miles jaunt to work, it would hit you straight in the crotch. :lol:

LOL!! Thats class.My worst experience of headgasket faliure is on fairly recent 24v BMW engine (my previous e36), it pressurised on the M4 returning from london near bristol, and big style cooked as i wouldent pull over on the motorway and carried on to the services. I didnt bother looking into a repair and sold it as seen for more than i paid for it, id heard that the alloy blocks can be a pain with pulling threads when re-torquing the head down so decided not to bother and bought another (my current) that had been well looked after!Guy i sold it to reckoned he was gona repair it himself, however despite my warnings still a-framed and automatic from cardiff to milton keynes (berk), its not been taxed since i owned it :lol:
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