Head Gasket or am i missing something?

[fozsug]

I'd be starting to lean this way TBH, you've eliminated just about anything that can cause cooling issues, so the last thing is the block/head itself. As you've done it before you will be well practised at it now, and shouldn't take you long

The head gasket wasn't in a blue box, was it?

Thanks for the reply

I think that i am thinking that way too as the symptoms seem to be getting worse!

No i have been caught out with a lift pump and a water pump on my last disco in the dreaded Blue Boxes so wouldnt ever use their stuff.

The gasket i used was a MLS genuine Landrover main dealer part at 37.00 beer tokens, and genuine headbolts. And yes the block surface was spotless and the head was brand new from a reputable engine company.

I checked the bores with flaw dectector as i had a crack in the bore on my previous disco and they were all fine

The gasket i took off was a genuine composite , and had no visible signs off failure,and the head was the original landrover one, which is down being checked for warping and pressure testing, so i can keep as a spare.

Thanks again, looks like its head off time again, unless anyone else has any other sugestions.

Tony

[mayur]

Hi mate sounds like the cooling systems working what you checked the oil cooler hoses and the oil cooler therostat as that to overheat the engine quite quick or the oil cooler blockage ??

[fozsug]

Hi mate sounds like the cooling systems working what you checked the oil cooler hoses and the oil cooler therostat as that to overheat the engine quite quick or the oil cooler blockage ??

Thanks for the reply

The oil cooler is new on the rad, and plenty of oil came out when i took the rad out the other day, the oil cooler pipes are genuine new about 8 months ago, the oil cooler thermostat? think must be working otherwise oil would not be going in to the oil cooler?

Thanks again

Tony

[Bowie69]

If you have the head off, take the opportunity to blow through all tehe water ways really well with an airline, can only help!

[pinhead]

Just read through the whole thread and it sounds like you have been busy pulling your hair out and all I can think of is with the egt's rising so much when under load this is the cause rather than a faulty cooling system have you checked breathing restrictions inlet and exhaust does boost stay rock solid or does it drop off a tiny bit or fluctuate

Take exhaust off and go for a quick run it will sound like a tank but will tell you if you have a restriction there

Not sure if you have mentioned about fuel and air filter but a restriction in these can cause temps to go up

Good luck and I will keep thinking

[TheRecklessEngineer]

Have you checked the gauge?

I know you've changed the sender, but a *ked gauge isn't unheard of...

[fozsug]

If you have the head off, take the opportunity to blow through all tehe water ways really well with an airline, can only help!

Did that last time it was off but will do again. Someone mentioned about a small breather hole in the block? Any ideas apparently its about 3mm big but i dont remember seeing it last time?

Also is there a drain tap in the block to get every last drop of old water out?

Thanks for the reply

Tony

[fozsug]

Just read through the whole thread and it sounds like you have been busy pulling your hair out and all I can think of is with the egt's rising so much when under load this is the cause rather than a faulty cooling system have you checked breathing restrictions inlet and exhaust does boost stay rock solid or does it drop off a tiny bit or fluctuate

Take exhaust off and go for a quick run it will sound like a tank but will tell you if you have a restriction there

Not sure if you have mentioned about fuel and air filter but a restriction in these can cause temps to go up

Good luck and I will keep thinking

Thanks for the reply

The fuel filter is new and fuel lift pump is new.

Air filter about 3 months old.

It has got a snorkle fitted so maybee i will take it off and go for a run.

The exhaust is only a centre box with a new decat front pipe and a straight through pipe at the rear, but its worth a go , i will take it off and go for a run.

Boost presure rises steadily with aplication of power, and stays rock solid at maximum boost.

Thanks again for the sugestions, all very gratefully recieved

Tony

[fozsug]

Have you checked the gauge?

I know you've changed the sender, but a *ked gauge isn't unheard of...

Thanks for the reply

No i havent checked the gauge , but when i open the bonnet when its got hot on the gauge, you can feel how hot it is under the bonnet , so i think its working ok.

Thanks again

Tony

[pinhead]

http://www.bankspower.com/techarticles/show/25-Why-EGT-is-Important

Makes interesting reading yes it is aimed at big yank trucks but the principles are the same

When you give it full throttle egt's rise sharp that tells me in basic terms either not enough air or too much fuel that is creating combustion heat that the cooling system cannot cope with no.4 cyl seems worst but this could be down to it being the last to get coolant being further back

A diesel specialist has confirmed that injectors and pump and pump timing is good

So it is down to air flow or pump settings ( you say it goes very well you tweaked it and it got worse but what if it was already overfueling you have returned pump settings back how they were but this may be a bit too much )

exhaust sounds like you have taken care of restrictions

So inlet you haven't got a carrier Bag stuck in the snorkel have you? 3 month old paper filter managed to get wet blocking flow

Could you give it a little more air by increasing boost slightly ? What should stock presure be big intercoolers can cause a drop in boost presure

Really feel for you as I had a vette that would run hot at speed even on cruise soon as you slowed down temp dropped it worked almost like a speedo tried loads of things until I hit it

Cam timing was 14 deg out due to a worn chain and cam was like a broom handle changed and it was like a new motor and never ever got hot again diesels work different though And over fueling causes heat where as with petrol lean or under fueling causes heat tricky

[mayur]

It could possibly still be the oil thermostat ( getting jammed ) as you go up hill, you wouldnt get the oil light flicker as when it is on closed it flows internaly which could make the overheat, I know you,ve must be getting annoyed after all this, try remove it and see what happens, it's located on the direct left of the oil pressure switch where the pipe goes in and is held on by two screws, hopefully it might look obvious when you remove it

[TheRecklessEngineer]

I'll re-iterate what I've said before:

To overheat a TDi something major must be wrong. The cooling system is designed to cope with a heavily laden vehicle towing a fully laden trailer across a desert in 50 degree heat. I have done exactly this without a fan . It was fine until I hit a mountain - then I had to pull over and fit the viscous.

To overheat in this weather, something must be nearly totally constricting the water flow around the cooling system.

[fozsug]

I'll re-iterate what I've said before:

To overheat a TDi something major must be wrong. The cooling system is designed to cope with a heavily laden vehicle towing a fully laden trailer across a desert in 50 degree heat. I have done exactly this without a fan . It was fine until I hit a mountain - then I had to pull over and fit the viscous.

To overheat in this weather, something must be nearly totally constricting the water flow around the cooling system.

Thanks again for a reply

I agree there must be a serious fault but where? I do not know where else to look or try?

I havent had a chance to take the head off again yet, but that is going to be my next step unless someone comes up with a brain wave.

Question:- Where is the drain tap/plug on the block so i can flush and blow it completely out?

Thanks

Tony

[fozsug]

http://www.bankspower.com/techarticles/show/25-Why-EGT-is-Important

Makes interesting reading yes it is aimed at big yank trucks but the principles are the same

When you give it full throttle egt's rise sharp that tells me in basic terms either not enough air or too much fuel that is creating combustion heat that the cooling system cannot cope with no.4 cyl seems worst but this could be down to it being the last to get coolant being further back

A diesel specialist has confirmed that injectors and pump and pump timing is good

So it is down to air flow or pump settings ( you say it goes very well you tweaked it and it got worse but what if it was already overfueling you have returned pump settings back how they were but this may be a bit too much )

exhaust sounds like you have taken care of restrictions

So inlet you haven't got a carrier Bag stuck in the snorkel have you? 3 month old paper filter managed to get wet blocking flow

Could you give it a little more air by increasing boost slightly ? What should stock presure be big intercoolers can cause a drop in boost presure

Really feel for you as I had a vette that would run hot at speed even on cruise soon as you slowed down temp dropped it worked almost like a speedo tried loads of things until I hit it

Cam timing was 14 deg out due to a worn chain and cam was like a broom handle changed and it was like a new motor and never ever got hot again diesels work different though And over fueling causes heat where as with petrol lean or under fueling causes heat tricky

Thanks for the reply

Took for drive with the air filter and snorkle disconnected... no change still gets hot

Checked position of ecentric in pump and is where it was originally as the score mark is the deepest

Checked boost pressure 1 bar, uped it to 1.1 bar bit more power but still getting hot under load

Thanks again

Tony

[mahon257]

Still following this thread with interest!

Got another 3 things for ya:

1. Serpentine Belt + Belt Tensioner:

See : http://www.arrowhead...s_and_cures.htm

Specifically " Belts & hoses - Check belt tension and condition. A loose belt that slips may prevent the water pump from circulating coolant fast enough and/or the fan from turning fast for proper cooling. The condition of the hoses should also be checked and replaced if they are over 5 years old."

2. Lower Radiator Hose collapsing (part No. ESR3296 ) (from same site above): "Sometimes a lower radiator hose will collapse under vacuum at high speed and restrict the flow of coolant from the radiator into the engine. This can happen if the reinforcing spring inside the hose is missing or damaged." Or if the hose is made by Britpart?

This topic is also mention here : http://grannys.tripo...leshooting.html

The lower radiator hose is another often overlooked source of high RPM cooling problems. As the water pump speed increases, the pressure inside the lower hose can become very low, as the water must be drawn thru the radiator core. If water flow becomes high enough, the core can become a restriction. When the restriction becomes large enough, the system pressure between the radiator core and the water pump can get low enough to allow the hose to COLLAPSE !!! If the hose collapses, no flow is happening, and overheating is the only outcome.

Most lower (or suction side) radiator hoses come with a spiral wound "spring" like coil inside it's length, which is typically made of stainless wire. If your lower hose does not have one, get one. Even if your hose feels stiff without one, it will become quite soft as the coolant temperature goes up.

The "lower radiator" hose idea seems to fit your symptoms - i.e. over heating only happens at speed - but not at idle / slow driving ... cheap to replace too... (I realise you said you have fitted new hoses...)

3. Replace Expansion Tank Pressure Cap.

"Higher system pressures raise the vapor point of the coolant and subsequently it's ability to absorb heat. A system pressure of 12-17 PSI results from the expansion of the coolant and trapped air going from ambient temperature to operating temperature. "

From: http://www.stewartco...Tech_Tips_6.htm

I reckon number "2" would be your best bet..

Best of luck chap

Nick

[TheRecklessEngineer]

In the words of Sherlock Holmes: "When you have eliminated the impossible, whatever remains, however improbable, must be the truth?"

Interesting the above on radiator hoses. I remember somewhere in this thread you mentioned that you have silicone replacements?

Might be worth replacing the lot with genuine ones...

I'm afraid I can't help with the location of the drain plug. I guess it must be on the side at about the same level as the bottom of the cylinders.

[fozsug]

Still following this thread with interest!

Got another 3 things for ya:

2. Lower Radiator Hose collapsing (part No. [/font]ESR3296 ) (from same site above): "Sometimes a lower radiator hose will collapse under vacuum at high speed and restrict the flow of coolant from the radiator into the engine. This can happen if the reinforcing spring inside the hose is missing or damaged." Or if the hose is made by Britpart?

This topic is also mention here : http://grannys.tripo...leshooting.html

The lower radiator hose is another often overlooked source of high RPM cooling problems. As the water pump speed increases, the pressure inside the lower hose can become very low, as the water must be drawn thru the radiator core. If water flow becomes high enough, the core can become a restriction. When the restriction becomes large enough, the system pressure between the radiator core and the water pump can get low enough to allow the hose to COLLAPSE !!! If the hose collapses, no flow is happening, and overheating is the only outcome.

Most lower (or suction side) radiator hoses come with a spiral wound "spring" like coil inside it's length, which is typically made of stainless wire. If your lower hose does not have one, get one. Even if your hose feels stiff without one, it will become quite soft as the coolant temperature goes up.

The "lower radiator" hose idea seems to fit your symptoms - i.e. over heating only happens at speed - but not at idle / slow driving ... cheap to replace too... (I realise you said you have fitted new hoses...)

I reckon number "2" would be your best bet..

Best of luck chap

Nick

Thanks for the reply Nick

I have just been outside to check and the bottom Silicon hose does not have a spring inside!!!!!!!!!

So i think i will get a genuine one and try

Thanks again i will keep you informed

Tony

[fozsug]

In the words of Sherlock Holmes: "When you have eliminated the impossible, whatever remains, however improbable, must be the truth?"

Interesting the above on radiator hoses. I remember somewhere in this thread you mentioned that you have silicone replacements?

Might be worth replacing the lot with genuine ones...

I'm afraid I can't help with the location of the drain plug. I guess it must be on the side at about the same level as the bottom of the cylinders.

Thanks for the reply

I too think that this is very probable as the silcon bottom hose DOES NOT have a spring in it.

I will be getting a set of genuine hoses and let you know

Thanks again

Tony

[tort172]

hi there just to throw my 2 peneth in, i had the exact same problem on a 200 tdi 110 the guy had done everything you have done to try and cure it to no avail, when i looked at it i used my digital infared temp sensor and found when the gauge read hot the engine was about normal changed the gauge and all good,normally with this amount of constant overheating something will give up if nothing has failed and you dont ever lose water i'd look down that route good luck

[TheRecklessEngineer]

Yes, that does seem to fit quite well. I can imagine silicone going quite floppy when hot too.

[Bowie69]

That's interesting, I was having the same problem on my V8, but noticed it collapsing when ravving it stationary.... Never overheated, as it was just after the rebuild and was still sorting the cooling system out

[mayur]

i brought orignal hoses on my discovery none had a spring on them,

the block drain plug was on the turbo side of the block, and if i remember properly it a 13mm bolt

this diagram might help

like i said check the oil cooling aswell

and when you had the headgasket done how much did you have to skim off it, and why did you have it done apparently 300tdi heads are well known for cracking

[fozsug]

i brought orignal hoses on my discovery none had a spring on them,

the block drain plug was on the turbo side of the block, and if i remember properly it a 13mm bolt

this diagram might help

like i said check the oil cooling aswell

and when you had the headgasket done how much did you have to skim off it, and why did you have it done apparently 300tdi heads are well known for cracking

Thanks for the diagram

The head that was fitted was brand new so no skim.

Will check the hose before i buy

Thanks for the reply

Tony

[mahon257]

Tony - I've actually got a spare bottom hose in my garage (part: ESR3296) - which I've just checked. As mentioned by "mayur" - it indeed does NOT have a spring inside (mine is a Britpart one - ahem ).

Anyway.. that aside, you mentioned you had fitted Silicone hoses to the radiator... Presume these are a different design to the standard ones? My point being - it may be worth fitting the standard bottom hose anyway... just a thought.

[TheRecklessEngineer]

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.