Overheating 2.5 Diesel

Hi Gents

So after 11000 miles of trouble free journeys,the old boy overheated today.

Hoses were rock solid, red light on and steam coming form expansion tank.

VC, water pump (metal impeller) and stat all changed about a year (11K) ago.

We were in stop start traffic when he blew.

Could it be the head gasket and is there a test I can do to establish this?

The oil is uncontaminated

It's a 2001 2.5 diesel

Many thanks

Ash

Static test for leaks and then for pressure build whilst running.

Hi Wammers

Thank you for replying, for pressure build do I just hold my hand over the expansion tank cap.

The hoses were very hard, I'm guessing that's a bit of a giveaway, since posting late last night I have been doing a bit of research.

Thanks again

Head Gasket Failure

AP90 said:

Hi Wammers

Thank you for replying, for pressure build do I just hold my hand over the expansion tank cap.

The hoses were very hard, I'm guessing that's a bit of a giveaway, since posting late last night I have been doing a bit of research.

Thanks again

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You need a static test rig. Top coolant up, blow the system up to 15 PSI and check for leaks or pressure drop. It maybe a slow coolant leak causing the problem. Or connect rig up without any pressure and start engine, a rapid increase in pressure would indicate head gasket or cracked head problems. Normally the system should be at about 5 or 6 PSI with engine at normal temp. Losing coolant from the head circuit via the horse shoe shaped hose at the rear of head will give you what you have as an air lock is formed in the head.

Hoses will go hard just from the overheat. HGF is not common on the diesel. Just as likely to be the viscous fan has given up especially if it was Britpart or even the waterpump if it had a plastic impeller.
Before jumping to conclusions, best do all the basic tests, just because something has been replaced doesn't mean it will not fail, ****part are notorious.

Hi Keith

Thanks

Sure, I will check but the impeller was a metal one and not brit part, the VC was an expensive part as I remember but not sure which manufacturer.

Reading through a few posts the HG appears a common failure and I think that the engine in this car has been messed with and not very competently, although it starts on the button and has been backwards and forwards London to Cornwall loads of times.

Sorry, just remind me of the VC test? as it get the thing warm and then stick a rolled up newspaper in it and see if it stops it?

AP90 said:

Thanks for the info, apologies for my ignorance.

I think the head gasket is too bigger job for me to attempt and with the special tools needed not sure I want to.

I'll get a price from my specialist and see what he says.

On the whole this has been a pretty good car only ruined by previous owners neglect and lash ups.

Including purchase price, it has been a best part of 7k project, seems a shame to scrap it now but it my be the only course to take as I may be throwing good money after bad

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You are not listening, HGF is pretty rare on the M51 engine, if it's not the viscous fan, water pump stat expansion tank cap or RAD, it's more likely to be a cracked head than HGF.
Check the basics.

7K sounds a lot of money to be thinking of scrapping. Renewing head gasket or even head itself is not too big a job and I'm sure your specialist will be able to sort it.

Most garages can do a 'block test' for you.
This involves a blue chemical in a container on the top of the coolant header tank, fumes from the cooling system are then drawn in through the chemical.
If the head gasket has failed (or the cylinder head cracked) and hydrocarbons are getting into the cooling system the chemical will change colour to yellow.

Usually your local garage won't charge much for this. (perhaps just enough to cover a couple of pints for later).

Great, thank you for the advice everyone, hopefully the guys at Cranbourne will sort it for me, doing a few projects at home so can't face ripping it apart on the drive.

Sorry to hear you're having problems Ash, the first thing I'd do is change the expansion reservoir cap for an OEM one bought from Land Rover - not eBay - or any other supplier claiming to be OEM.

StuckAgainSteve said:

Sorry to hear you're having problems Ash, the first thing I'd do is change the expansion reservoir cap for an OEM one bought from Land Rover - not eBay - or any other supplier claiming to be OEM.

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+1!!

had a cheap one on mine that didn't release any pressure, so something else had too

JohnnyCrash said:

+1!!

had a cheap one on mine that didn't release any pressure, so something else had too

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The caps are designed to bleed off pressure above 15 psi and give total pressure release at 22 psi to protect the system. However the system should not get anywhere near 15 psi in normal use. That would only happen if the engine overheated, various reasons for that, or ingress into the system of HP combustion gas. Head gasket failure is pretty rare on the M51, heads crack but that is usually down to an overheat caused by some other occurrence, they don't usually crack spontaneously.

wammers said:

The caps are designed to bleed off pressure above 15 psi and give total pressure release at 22 psi to protect the system. However the system should not get anywhere near 15 psi in normal use. That would only happen if the engine overheated, various reasons for that, or ingress into the system of HP combustion gas. Head gasket failure is pretty rare on the M51, heads crack but that is usually down to an overheat caused by some other occurrence, they don't usually crack spontaneously.

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using home made diesel with double the amount of petrol because you forgot you had already added the petrol?

that good enough to cause it to crack??

anyway, now I'm out of hospital and my face is healing well after my fall I need to get "cracking" and sort the new head out

JohnnyCrash said:

using home made diesel with double the amount of petrol because you forgot you had already added the petrol?

that good enough to cause it to crack??

anyway, now I'm out of hospital and my face is healing well after my fall I need to get "cracking" and sort the new head out

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Think you may have been told your witches mix would do something eventually.

wammers said:

Think you may have been told your witches mix would do something eventually.

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mmm true

but it's been fun trying ;-) and covered a hell of a lot of miles on very little money

JohnnyCrash said:

mmm true

but it's been fun trying ;-) and covered a hell of a lot of miles on very little money

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You should with all the money you saved be able to get a proper service exchange head from Land rover then. A snip at £2091.89 plus a refundable exchange deposit of only £240.00.

wammers said:

You should with all the money you saved be able to get a proper service exchange head from Land rover then. A snip at £2091.89 plus a refundable exchange deposit of only £240.00.

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I'll buy two so I have a spare for next time

JohnnyCrash said:

I'll buy two so I have a spare for next time

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Way to go be prepared.