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Head Gasket or am i missing something?

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I suspect that rather than a spring, the hose is re-enforced with a fibre composite of some type. Well...all the ones I've ever cut up have been. That'll give it some rigidity, and I'd expect it not to change shape when hot.

I believe the hoses are the only part you haven't checked yet.

Youre right , the hoses are the only thing i havent changed,as they are only 6 months old..... apart from the block :P

I have ordered a new genuine one this morning, so will report once fitted

Thanks for the reply

Tony

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Ok....

So changed bottom hose , all the small bleed of hoses, inlet and outlet heater matrix hosesand bypass hose, for genuine new ones, removed the water pump again and checked, fine, removed thermostat and put in boiling water, again fine, refilled with antifreeze /water mix, bleed system and took for a run..........

Still the same, getting hot under load at 65 up a hill. :angry:

So i am at a complete loss :(

I will take the head off again, but cant see that there is a problem there as no presurisation, brand new head and genuine gasket :unsure:

Any other suggestions would be very gratefull recieved, before it gets a couple of gallons of petrol poured over it and a late bonfire party is held round it!

Thanks

Tony

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i know this is probably a long shot, but what about the injectors? what condition are they in? if they are quite old you may not be getting a full spray pattern under heavy throttle leading to the conditions you are experiencing.

another shot in the dark would be to make sure that all the hoses are connected the right way round, i know it sounds silly, but i've known proffessional "mechanics" reconnect a coolant hose in the wrong place, and even pinch them sometimes, leading to cooling problems.

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i know this is probably a long shot, but what about the injectors? what condition are they in? if they are quite old you may not be getting a full spray pattern under heavy throttle leading to the conditions you are experiencing.

another shot in the dark would be to make sure that all the hoses are connected the right way round, i know it sounds silly, but i've known proffessional "mechanics" reconnect a coolant hose in the wrong place, and even pinch them sometimes, leading to cooling problems.

Thanks for the reply Al

Injectors were tested and are good

Hoses.... well as far as i can see they are all the right way round, only one's that could possibly be round wrong way are heater inlet and outlet, but dont think they are :unsure:

Cheers

Tony

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I know I've posted this before, but have you checked the valve lift for cam lobe wear, specifically the exhaust.

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I know I've posted this before, but have you checked the valve lift for cam lobe wear, specifically the exhaust.

Hi , thanks for the reply.

Yes checked both after i did head gasket last time

Inlet was 9.60 should be 9.67

Exhaust was 9.90 should be 9.97

so i thought these should be ok?

Thanks again

Tony

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Sounds fine, back to scratching my head. Mind you, you did say this problem has developed since the rebuild, might have worn since (blocked oilway etc)

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Sounds fine, back to scratching my head. Mind you, you did say this problem has developed since the rebuild, might have worn since (blocked oilway etc)

Im doing plenty of the head scrating too, i will be bald sooon :D

No the problem started BEFORE i did the head gasket.

I am wondering if it is a blockage in the block waterways, reason i say this is when i turn the heater on to full blast hot , when the engine temp starts to rise, it brings the temp down , not completely but definately helps?

When i did the head gasket i blew out all the water ways.

Since i have flushed the cooling circuit three times, and inbetween used Bars flush, and Holts flush.

Wondering if anyone new of anything more Industrial to flush the cooling system ;)

Thanks

Tony

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dont know about tdi,s but some engines have a restrictor to slow flow through the rad as it cannot cool fast enough usualy the thermostat is enough to do this

did i read correctley that the problem started when the water pump was weeping and got replaced

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dont know about tdi,s but some engines have a restrictor to slow flow through the rad as it cannot cool fast enough usualy the thermostat is enough to do this

did i read correctley that the problem started when the water pump was weeping and got replaced

Yes it was abot the time i noticed the water pump weeping that the problem started, i then changed the pump, but the problem remained......so i ended here totally stumped!!!!!!!!!!!

Thanks

Tony

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I'm stumped too.

I'll be back down your way in January. I hope this doesn't drag on that long, but if it does, I'll come and have a look.

I hope ive got it cured before then, thanks again for the offer, much appreciated :D

Tony

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I've sacked my air con tad off down to it been blocked solid with carp and everything (also it leaks so what's the point) made my disco overheat when towing ridiculously

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I've sacked my air con tad off down to it been blocked solid with carp and everything (also it leaks so what's the point) made my disco overheat when towing ridiculously

Thanks for the reply

Ive got the poor mans Disco...... no aircon! :P

Thanks anyway all suggestions gratefully recieved :D

Tony

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Well... looks like you're more or less out of options... but one thing left to check might be the coolant flow rate

I've got a bit of a risky suggestion if you're feeling brave...

This is based on disconnecting the radiator hoses, then jerry-rigging a static cold water supply to the TOP radiator hose, and disconnecting the bottom radiator hose. The idea is to try and observe the water being expelled from the bottom hose onto the ground - or into a bucket (for measuring the quantity expelled - with a stop watch?).

I've never done this, and obviously make no guarantees etc... Obviously the engine should be cold when you do this...

First up, let's take a stab at guessing the quantity of water that we can expect to see pumped out. I've not been able to find any stats for the 300TDi's water flow rate but... have found 3 websites that may help - so here's 3 guesses based on the 300TDI's power output of 84Kw (113hp):

Flow rate Guess "1":

Conventional cooling needs on smaller engines with mechanically driven water pumps vary between 2.0 to 2.6 L/min/kW. Some advanced engines already run at 1.0 - 1.7 L/min/kW"

So... rough guess: 84kw x 2.0ltrs per minute =
168 ltr
s per minute.

Flow rate Guess "2"

"Assuming the pump was sized for a 320hp (240kW) engine, rejecting a typical 60% of its brake power to coolant, the water flow rate required to keep the temperature rise across the engine to 8degC would be 292litres per minute."

This suggests the flow rate for an 84kw engine should be in the region of
102 litres per minute.

Flow Rate Guess "3"

This next ones from a
:

" Engines with indirect cooling require more flow: about 65-70 litres ... per minute for each 75kW (100bhp) of engine power."

This suggests the flow rate for an 84kw engine should be in the region of
78 litres per minute.
( ( 84kw/75kw = 1.12 ) x 70 litres = 78 litres )

So, if we're talking about running the engine for a few seconds.... in this configuration... a 20 litre jerry can resting on it's side, plumbed into the top radiator hose might work? You'll likely need at least 1 litre of cold water per second of engine running rigged up to the top hose. In theory, the disconnected bottom hose should chuck out at least 1 litre per second too. I would definately get someone to help you - to make sure the engine is turned off as soon as the water supply looks close to empty.

I've also thought about fitting a cheap water flow meter - but that's probably a bit too much hassle! (e.g. water flow meter! £24 )

Finally, i have no idea on how safe this is for the engine - so if it's completely nuts - hopefully someone will say so!

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Thanks for the reply

Today i got some central heating system flush, and have it added in the cooling system and started and stoped engine during the day to warm it up and circulate it round the system, just drained it out and added the neutraliser in for the next couple of hours.

Will fill with water/antifreeze mix and bleed again in the morning and off to green lane day, so will give it a good test to see if it has worked.

If not i will see if i can rig up something as sugested above to see if the water flow is any good.

Thanks for the reply

Tony

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I haven't read all the way through thus I don't know the answer... You've flushed the system,yes... Were there cold spots within the rad face when. Warm? Pointing towards a blockage,

That's a good idea recklessengineer I spose as well as seizing up they can go Slack too

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Did you say that the system isn't pressurising? Have you replaced the header tank cap?

Sorry didnt say correectly, the system isnt over pressurising, ie if head gasket had gone.

Yes Header tank cap new.

Well after flushing the system with Central heating system cleaner, it is definately better, but still not right as under load it still gets hot but only to 10 oclock now not 11 oclock.

So i think im going to flush it again with the Central heating cleaner but leave it in for longer , as first time i chickened out leaving in in for 48 hours .

Cheers

Tony

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I haven't read all the way through thus I don't know the answer... You've flushed the system,yes... Were there cold spots within the rad face when. Warm? Pointing towards a blockage,

That's a good idea recklessengineer I spose as well as seizing up they can go Slack too

Thanks for the reply

No there were no cool spots on the radiator

Cheers

Tony

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If you are thinking the block is restricted why not pull your core plugs out and have a root round inside with welding wire

I sometimes have a problem with gas vaporiser freezing on boat and that is cured by sticking a screwdriver up the block fitting where the water feed is for the vaporiser and having a good root round

But this is raw water cooled and I get debris from the river and no rust prevention

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Right Guys

Its cured!!!!!!!!!!!!!!!!!!!!!!!!!!!!! :D:D:D:D

I Flushed the system again with Central heating flush and left it running and drove it for about 24 hours in total, drained the system out and not alot came out other than slightly discoloured water.

So i thought i would shove some compressed air in the system, so put all the pipes back on except the heater matrix inlet which i stuck a bolt in, and the outlet from the top of the head that i rigged up a pipe with an air line connector on.

Presurised the system up and left it for an hour, came back and was about to de-presurise the system , when BANG WOOSH SPLAT.... the bolt shot out from the heater hose(must use better jubillee clips)The bolt went straight through the side of the workshop wall and there was green gunge and goo all over the engine , workshop walls, me and the dog (when he eventually returned).

So after cleaning the dog me and the workshop walls i put a garden hose on to the outlet from the head , turned the water on, and WOW more and more greeny yellowy gloopy gungey slime kept on coming out.

About ten mins later the water was running clear, so reconnected up the pipes, filled with plain water , bleed and took for a run.... It didn't get hot!!!!!!!!!!!!! :D

So got back drained the system again, only a little dicolouration of the water, so refilled with water/antifreeze mix, bleed and tried again and still good, temp gauge staying at 8 oclock possition,which it never has done before.

That was last week and since then i have towed, driven hard etc and all is fine.

Thanks again for all the sugestions, really apreciated.

Tony

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Woooohooooooooo :D:D

So what do you think the gloop was then ? sort of sounds like congealed antifreeze? ..but why?

nice to have a positive outcome :i-m_so_happy:

cheers

Steveb

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Thanks guys

The gloop i think is a mixture of antifreeze, limescale, cheep system flushing agents, rust and probably other aditives that people have added to the cooling syatem before i got the Disco.

I think the central heating flush loosened/disolved it a bit( its very caustic , burnt my hands neat!)and then the compressed air just pushed it out of the water jackets.

I suppose i will never know exactly what the gloop was, probably years of build up of crud.

I can thoughroughly recomend the central heating stuff, its safe for alumiminium too, and it really cleaned the dogs coat! :P:o

Cheers

Tony

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