Rad cap; Blowing pressure seal! update?

dieseldoggy · Post by **dieseldoggy** » 08 Aug 2009, 03:14

hi all having a bit of a problem with seal being blown on rad cap the pressure one in middle of cap!.
Results in no pressure in system.as can air hear getting past cap if you squeeze hose.got new one from citroen as others where a bit manky from oil contam after engine change.it only seams to do it after you have given it a bit of welly/loading.see temp creep up a bit never been high.(fans not working atmo)but only use either when road not to biz or not to far from home.so never hot enough for fan anyway? going to do them tomorrow and have all front of&rads.don't seam to be much happening when warm if you look in header tank.Wondering if it could be thermostat stuck or rad bunged up abit?did have hose running through it for quite a while(in header tank and small hose on rad to wash out hyperclean to get all oil out of system!) there is so cack between rads that has accumalated i saw when looked other day so will have them out and try some rad cleaner inside aswell.

Old-Guy · Post by **Old-Guy** » 08 Aug 2009, 09:51

If you're in doubt about the thermostat, it's best to change it - should be under a fiver from your local motor factor. If it fails (nearly) shut, the engine will overheat under heavy (ish) load - been there, done that but at least all the rest of the cooling system was working properly so soaring temp gauge and STOP light on. If it fails open, the engine will never get properly hot which leads to excessive wear, poor fuel consumption and bad running.

dieseldoggy · Post by **dieseldoggy** » 08 Aug 2009, 11:56

thanks for getting back so prompt.yes stat was what was in engine and no housing over it when it was installed in car&he left it on.it does warm up quickly and sitt's around 70 line down from middle did creep up when had foot down etc even on open road/late night etc so should run cooler then? when running hose through it all to flush out and block cold as had been off for good few hours&cold water.i was still getting water coming through stat.so was thinking that it was stuck part open open?.
When i first put new cap on and we run car up to get fan switchs to work to it took yonks to get temp up so dont think rest of system to bad/ and it wouldn't have been under load though. thanks again

Post by **CitroJim** » 08 Aug 2009, 17:47

Have a look at this thread for a bit more on rad caps.

I'd be inclined, along with the 'stat, to change yours.

dieseldoggy · Post by **dieseldoggy** » 09 Aug 2009, 02:44

Hi cheers for that jim.Just been having a poke around.water level was just at bottom of plastic tube.Had it running for awhile to check it did push water up abit after i filled it to top to see if anything happening and to float any crud still in header tank odd bubble could be from under edge in tank?.I took stat out and stuck in a glass with boiling water!.It did open about around a pencil thickness?.went back later and repeated and didn't seam to open much atall after few minutes and same again after repeating?.opened to about 6mmish quite quickly then didn't seam to go anymore watch for another minutish?.the cap was new few weeks ago from citroen.Their does seem to be more than one type/pressure they said?. But like everywhere else that lives with a pc strapped to their face? can't tell you diddly all about it unless it say's on the screen!.LOL Then give you wrong part?. Found green&white one's so far?.not sure what diff is or what model they are for etc? might have a dismantle to see what's inside and what i can do with it?.
good mind to take it back for exchange?
Did find out that it won't seal without stat/rubber inside?mmm.lol.

having some fun trying to type this as got new gaming mouse which is pretty quick.4000dpi.and trying to click pointer on things is abit like getting the pea with fork?lol

anyway thanks for info.

Post by **CitroJim** » 10 Aug 2009, 08:43

I thought all rad caps were much of a muchness but that'll be worth looking into. citroen.service or Laser will be forthcoming on the differences as it should give the pressure value for each type of cap.

One thing I have always noticed about all engines in Xantias is that they will never hold a coolant level above the minimum marker in the expansion tank, however hard you try. The level will always fall and stay at the bottom marker in those with the expansion tank mounted on the RH inner wing and at the mid-section seam on those (2.1 and V6) with the expansion tank on the bulkhead. This bothered me a lot at one time but no longer. I live with it.

One very important thing to do on any engine is make sure it is really well bled. I leave the cap off for a long time to allow air to bleed out and nowadays leave the cap of until the engine has cooled down again. This is in fact, recommended when bleeding a V6 and is pretty vital to getting a good, effective bleed.

dieseldoggy · Post by **dieseldoggy** » 10 Aug 2009, 23:58

Hi lol. not much chance of it making much difference with cap on as not holding pressure with any i have?.
went to Halfrauds and got a new stat.QH one.they are a nightmare in there! don't know left from right? Another if it's on pc i can do!.fished through that book on shelf as don't list/do a zanty 1.9td one. Did non turbo and zx 1.9 td plus synergie 1.9td and even 2.0 td zanty? hurrah and gives same part number for all! so i got that one! Same temp as old one but got abit on the back of it like an opposite flange/spring bit?.fitted in so used it.
what temperature should it stay at on gauge? used to be on 70 one line done from middle now it's on 80 halfway is that correct? also given it a bottle of rad flush to clean it all out. as theres still some oil crap still in header tank? and wondering if that could be blocking bottom/cores of rad? or atleast slowing it down!

they did ask me which one when i went there so gathered that there could be different types for them?. has ive a green one and others are white. going back there tomorrow and will ask them! halfrauds book i only saw one for most of the engines listed so may'be it's just colour? but you did used to get different pressures on fords when i had them!

how does those caps work? as it lets it through middle of cap. i thought it normally pushed rubber seal up against spring pressure?
Has could i put something in the hole ie blob of glue?

yes it was still sitting at bottom of the plastic bit inside header tank.

It is abit worrying that you go into a dealers to get/buy/service etc and you clue up knowing more than them?lmao
anyway cheers for that.

Xantidote · Post by **Xantidote** » 11 Aug 2009, 00:29

You asked about temperature readings on gauge.

With my original thermostat, gauge used to hold at about 80 line on the gauge, until thermostat then failed open, and engine then ran at 70, exactly as you describe.

Very recently fitted new thermostat from GSF (markings suggest 83 degrees, as did original), and temperature gauge now sits at bottom of the thick 80 line, so temperature seems to have returned to original reading.

I'm happy with the the 80 reading, though I don't take too much notice of the numeric value on the gauge, as IMHO gauges can be a bit suspect. However, the fans do cut in when the gauge reads 90, which is what I've read elsewhere on the forum should happen.

Sorry no useful comments on your other points raised

Martin

dieseldoggy · Post by **dieseldoggy** » 11 Aug 2009, 11:58

hi no just wondering where it should be etc. the one i took out did close and opened fully when i boiled it! well got to make sure it's cooked?lol. put thermonitor in pot to see what temp read over 90+.
QH one has like a rubber type flange round gate of stat! old one was just metal.

this thing with cap's giving me the pip! going to givem other one back tell um it's no good if enough people took them back they would have to make them better!

Xantidote · Post by **Xantidote** » 12 Aug 2009, 10:58

[quote][/quote]

"the rubber type flange" you refer to: there should be a rubber seal around the thermostat where it sits in it's housing

Martin

dieseldoggy · Post by **dieseldoggy** » 12 Aug 2009, 13:52

hi yes but where talking about the plastic bit in the middle as thats where it lets pressure through? wether ment to or not is what i'm trying to establish or could blob it up if it's not???

dieseldoggy · Post by **dieseldoggy** » 12 Aug 2009, 18:53

Hey just took cap back to dealer.said he would return to citroen has never heard of them failing?

.and when i said it had a another engine he practily threw me out of shop and gave cash back and didn't want to sell me another?
because it had been changed well it is same engine code.ok few years newer so what diff would there be between them? apart from cam pulley?

Had to laugh when he tried to tell me he was into engine design/tech! and tell me that it could alter the temp if not got right headgasket onit.yes but reason for that is that pistons run proud of the block and to allow for manufacture diff they do various gaskets.

Pleiades · Post by **Pleiades** » 12 Aug 2009, 19:19

He is correct, the pistons do protrude from the block, but this will not effect the running temp, only the compression of the cylinders.

When doing a head gasket on a diesel, you should measure the piston protrusion at top dead center on each piston, then taking the maximum measurement, order the correct gasket, this is usually found in nothces at the bit poking out of the gerbox end of the head. The more notches, the thicker the gasket.

Having said that, most folks just go for the thickest gasket!!

Is your problem just a heat one or a pressure problem, if it is pressure blowing the rad cap, then I would be supicious of head gasket problems. Try running the engine without the cap on for a while and see if the water starts to rise and overflow, if it does then I would say most likely the head gasket is fubarred or at worse the head cracked.

Regards
Martin.

dieseldoggy · Post by **dieseldoggy** » 12 Aug 2009, 20:18

hi just changed engine.dont overheat as fans are not working yet but temp nevers goes over halfway. if it does get up i just run heater fans. only use occasionally and keep out of traffic so fans would never need to be working anyway? we was thinking about rad having some crap init from when other engine filled waterways with all the oil out off sump.ive left so rad flush init till i take them out to flush and replace fans. only time temp go's up is when ive got it underload ie 70's it will come up abit!
Yes it was me thinking about headgasket not him! i didn't say anything just left him to it!

dieseldoggy · Post by **dieseldoggy** » 13 Aug 2009, 22:54

Hi all took one apart today.to stick me nebbet into it? I think but not 100% sure? that if you push centre in and turn abit it resets valve as both work now and hold pressure?.
Also think that part of problem was stat not opening fully all the time.as did notice that it had been scoring one side of brass piece in middle.