Isuzu Trooper Owners Club UK™

Gribble · Posted: Sat Jun 06, 2009 14:51 Post subject: A fault with ?

So its a wet saturday and I thought I would share this puzzel with you Smile

Got Kia 2.9 turbo diesel engine (normal bosh rotary pump and injectors ,4 cyl in line ,DOHC) which starts and runs fine no smoke at all of any colour . Compressions are all spot on and within 5% of each other.
Its a bit different in that the pressure cap sits on the theromostat housing which sits on the head ,now if you fill it with water and start up in 3 seconds its blowing out the expansion tank like a good un , run it with the cap off and it goes up over a foot high in a jet and thats with the 'stat in Shocked

Run it with the stat out the same .Run it with the rad out the same .

Now yer all saying ' head gasket or cracked head ,whys he posting it ? ' well , there is no ,as in none whatsoever water in the oil not even a hint of white mist on the filler cap not even a tiny drip in the sump.

Ah ! yer all saying its just blowing from the leak into the cooling system under pressure , well fill the system up up with boiling water pump it up to 30psi and leave it for a day or so and its still got 30psi Confused

Ah you say its a tiny leak only compression pressure gets through , nope it throws the water out a foot high with the stat in on starting up and the compressions are right . Now I have decided that the head will have to come off but I just cant belive that the head or gasket is acting as a perfect one way valve .

This seems a common fault on kia diesels and many have had gaskets changed and heads skimmed but the fault wont go !
Its not an air lock they dont make water leap out the cap .

Any comments and observations welcome from all .
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Red Robbo · Posted: Sat Jun 06, 2009 15:36 Post subject:

Gribble you have now forced me to go out and buy more beer,all the better to ponder.. Laughing

Putting aside any head/gasket issue,if you made an analogy to a hydraulic system,where the stat is acting as the relief v/v,then the system somehow is dead-headed........or how else may extra pressure be applied to the system ? Water p/p on steroids Shocked

Anything to do with aircon Confused

Going to get some more brainfood now..... Idea

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Wirdy · Posted: Sat Jun 06, 2009 16:00 Post subject:

I reckon you or the owner has caught the fault before it can develop into a full blown HG failure, that's why the symptoms are confusing - this stage doesn't normally last very long and could possibly measured in seconds!

I can imagine a small warpage of the head, or a slight imperfection on the casting, just enough to cause blowing past the gasket that would act like a one way valve as you say. Then under cooling system test pressure the small portion of HG flips back the other way and seals up the tiny gap.

If you could run the car up to full temp and take for a drive ( I know you can't because the water squirts)....but if you could, I reckon the HG would fail good & proper after a run.

An interesting one to ponder this Smile

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rallymarshall · Posted: Sat Jun 06, 2009 16:32 Post subject:

DYLAN · Posted: Sat Jun 06, 2009 18:36 Post subject:

The guy's answer on the bottom of page, Could it be your answer? Dont know that much about engines but sounds plausible

http://www.kia-forums.com/kia-carnival-sedona/47739-kia-sedona-overheating-issue.html
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2002 S-TYPE JAGUAR 3.0 SPORT

Gribble · Posted: Sun Jun 07, 2009 23:32 Post subject:

Ah ! Thanks for the input lads but Robbo Crying or Very sad

an excuse to buy beer , oh dear cheers

Simon Gamble said you were a teetotaler ?
No airconn , and its the same stat in or out

Wirdy - if the compressions are matched then whats the cause of the cooling system pressure, it has to lose comp psi on the one blowing into the cooling system as thats not restricted ? do you suggest the head gasket is doing the check valve number on each cylinder , most odd if thats the case.

Rallymarshall - good point but its (the water ) not even halfway up the rad . I could go with the air/expansion thing but . . .

Dylan - thanks for the link but after reading that post but he got no further than me .
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Red Robbo · Posted: Mon Jun 08, 2009 7:46 Post subject:

It were Julian I worked for and he knew full well I was no tee-totaller.. Laughing

Back to your engine,assuming head is 100% ok,no porosity etc,,are they wet or dry liners ?
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Khotso...........

Gribble · Posted: Mon Jun 08, 2009 10:40 Post subject:

Ah, I was close Smile

The 2.9 Tdi Kia is just a block engine no liners been told its a copy of the mazda engine ? . Cant say the head is ok as its not been off for seperate pressure test yet but it would appear to be ok since it hold pressure . The most odd thing is the engine runs fine ,dead steady at idle and cracking each injector off a tiny amount gets a change in note but has no effect on the rate of pressurisation Confused

It does have a watercooled turbo same as a 3.0 but cant see how that would get pressure in to the cooling system if it failed somehow ?

Much scratching of head .
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Red Robbo · Posted: Mon Jun 08, 2009 11:15 Post subject:

Exhaust gas in cooling water test kit ???
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gary820 · Posted: Mon Jun 08, 2009 20:47 Post subject:

Is the water pump turning, has the impeller broken off the back of it? older bmw's do that as have a plastic impeller, they 'boil' over very quickly when that happens?! Is the cooling system blocked anywhere causing it to pressurise?
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