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geobloke

Member Since: 06 Nov 2012
Location: Nottinghamshire
Posts: 4395

2003 TD5 Coolant System over pressurising

Well what a cruddy way to start the day... well if I am honest this began last night on the way back from a site survey. Cruising along the A55 having a great time, the delicious sound of a TD5 exhaust note through the Conwy and Pen tunnels... Life as they say was good...

..then... Oh

the temp gauge needle is in the red!

Immediately rev down and head off a very handy slip road. Pop the bonnet to find the coolant has discharged out of the expansion cap. Everywhere.

Let the temp go down for a while and thank goodness for dog water

Saved me this time pup.

Managed to get home by rolling gently down the road being careful not to stress the engine out any further whilst keeping the air flowing through the rad. Thank goodness for having a nanocom in the car. The LR gauge really is utterly useless. It appears to only have 3 positions: Off, on and death imminent...

Home safely I find that the coolant tophose bleed screw has arrived from Island4x4 and just in time. Really I urge folks to replace those terrible plastic LR one, the alli alternatives are just leagues ahead.

Bleed the system and apart from the expansion cap drenching there were no leaks from the piping or rad. So why the over pressurising?

Air being drawn in to the system? Head Gasket? Any other culprits I should be aware of?

So after a short drive this morning to drop the wife off at the station (total 15 minutes of mixed driving) I check the system again in the work carpark...

Click image to enlarge

Uh-Oh...

I must have missed something last night...

https://youtu.be/AfXLr4G9VaI

Oh yes missed that little drip.

So the question is. Is this actually a core plug? looks to be threaded and thought core plugs were push-fit. Either way could air be drawn in here to over pressurise the coolant system?

How does one go about replacing the plug, or plugs seal?

Looks like I may be able to get to it without unbolting the manifold.

The other scenario I am all too fearful of is a problem with the head gasket and that maybe the plug is just a symptom. From what I understand if the gasket has gone then it is likely that combustion fumes will be evident in the coolant and/or oil. Is that right?

Any and all help/experience is gratefully received.

And as a kick in the 'nads some scroat has walked off with me snorkel top...

Click image to enlarge

14th Mar 2017 7:56am

ian series 1

Member Since: 17 Nov 2014
Location: south
Posts: 3127

2008 Defender 90 Puma 2.4 CSW Bonatti Grey

I had exactly the same symptoms with my 03 disco.

Overheating, pressure in the system, needle in the red, etc etc...
A sniff test proved negative, but still suspected H/G failure.

Early TD5 used plastic locating dowels in the head, these are prone to break, causing the head to move.
So head off and you could clearly see the problem!

Replaced with upgraded steel dowels, new H/G and all was back to normal.
You can undo the bung behind the manifold when the head and manifold is off, always worth while replacing manifold studs while your there, unscrew it seal it, I used PTFE tape.

Common problem on the early TD5 I'm afraid. 80" 80" 86" 88" 90"

Wanted, Forward Control Anything considered.

14th Mar 2017 8:22am

geobloke

Member Since: 06 Nov 2012
Location: Nottinghamshire
Posts: 4395

Hi Ian. Thanks for the reply. Any idea when did LR stop using the plastic locating dowels? Mine is a 15p engine.

14th Mar 2017 8:34am

Disco_Mikey

Member Since: 16 Nov 2014
Location: Dundee
Posts: 531

2009 Defender 110 Puma 2.4 DCPU Keswick Green

Replaced h/g's on 03/04 cars, and still had plastic dowels...

14th Mar 2017 8:43am

geobloke

Member Since: 06 Nov 2012
Location: Nottinghamshire
Posts: 4395

Ok just found the LR Notice on this;

Quote:
AFFECTED RANGE:

All Td5 derivatives within VIN ranges:
Discovery Series II (02 Model Year) 2A 736340 to 3A 793895
Defender (02 Model Year) 2A 622424 to 3A 647705

SUBJECT:
CYLINDER HEAD LOCATING DOWELS
Td5 engines fitted to vehicles in the above VIN range are fitted with plastic dowels to locate the cylinder head onto the cylinder block.

Land Rover Engineering has introduced steel locating dowels from the following VIN numbers:
Discovery Series II: 3A 793895
Defender: 3A 647705

INFORMATION:
If a cylinder head is removed from a vehicle in the above VIN range, the plastic dowels must be replaced with new specification steel dowels, which are now available from Land Rover Parts.

CAUTION:
Td5 derivatives prior to the above VIN ranges must not, under any
circumstances, be fitted with the new steel dowels. If steel dowels are fitted to earlier engines, cylinder head cracking may result.

In theroy mine should have metal dowels being a 3A651$$$

In theroy...

14th Mar 2017 8:43am

geobloke

Member Since: 06 Nov 2012
Location: Nottinghamshire
Posts: 4395

Disco_Mikey wrote:
Replaced h/g's on 03/04 cars, and still had plastic dowels...

THat is really appalling considering LRs notice above.

14th Mar 2017 8:44am

Disco_Mikey

Member Since: 16 Nov 2014
Location: Dundee
Posts: 531

Bear in mind, an 04 plate car can still be a late registered 03MY

14th Mar 2017 8:56am

geobloke

Member Since: 06 Nov 2012
Location: Nottinghamshire
Posts: 4395

True enough Mikey.

So onwards. I have just been back out to the Ol' Gal and canot see any more leaks and nothing has made it to the ground underneath either. That core plug under the exhaust manifold is still weeping and there is now no fluid in the top hose where the bleed screw is. The exapnsion tank though is still at the correct level, so an air lock. Aewesome way to start a Tuesday.

Beginning to look an awful lot like a head gasket failure...

And on top of that I am meant to be heading to Devon this weekend.

14th Mar 2017 9:31am

geobloke

Member Since: 06 Nov 2012
Location: Nottinghamshire
Posts: 4395

Ok Booked in for a pressure test today. Entirely expecting the result to be inconclusive as it appears that others who have had head gasket failure this is the case.

So time to put a bet on:

What are the odds do you reckon that A: I have plastic dowels and B: they have either snapped or bent allowing the head to shift?!

14th Mar 2017 10:29am

ian series 1

Member Since: 17 Nov 2014
Location: south
Posts: 3127

Both!

80" 80" 86" 88" 90"

Wanted, Forward Control Anything considered.

14th Mar 2017 11:26am

geobloke

Member Since: 06 Nov 2012
Location: Nottinghamshire
Posts: 4395

I was hoping for secret answer C: it is all in your head you're just imagining it...

14th Mar 2017 12:03pm

stigomery

Member Since: 10 May 2016
Location: Cambridge
Posts: 277

Symptoms very similar to mine last month... it was HGF detected by exhaust traces in coolant. Head and gasket looked damn near new and the '04 TD5 engine has only done 80k miles... £900 later and she runs sweet as a nut but my wallet is very light this month...

I can understand the running gear and transmission etc. taking a hammering on these 4x4 contraptions, but HGF is inexcusable in a sub 100k engine...

14th Mar 2017 12:53pm

ian series 1

Member Since: 17 Nov 2014
Location: south
Posts: 3127

I managed to get my disco to 74,000 miles before it went,
The head had moved very slightly, enough to damage the H/G.

The plastic dowels were (and still are) a problem on the K series engine used in the Freelander 1 and other Rovers.
You thought they would have learnt?.... 80" 80" 86" 88" 90"

Wanted, Forward Control Anything considered.

14th Mar 2017 2:44pm

sgilmour

Member Since: 21 Jul 2015
Location: Essex
Posts: 232

Hate to say it but I'd lean towards HGF. I had exactly the same symptoms with my TD5 Disco and it took me a couple of months of methodically working through the car, replacing loads of parts to not solve the problem. Always had it in mind but was last resort because there were no common HGF symptoms.

Was exactly what you have described, plastic dowels shifted and failed the gasket. New HG and all was good. Just make sure you/the garage time it properly! I had it running fine but starting badly, spent ages in the garage while they tried to work on it, got fed up and I sent to a specialist. They hadn't timed it correctly and the result was poor fueling.

Good luck! 1994 Defender 90 300TDi
2002 Disco II ES Td5 Auto (SOLD)
2011 BMW 120d M Sport
2012 Audi A5 Coupe 2.0 TDI (Other halfs)

14th Mar 2017 4:29pm

hplp

Member Since: 17 Nov 2014
Location: Cirencester
Posts: 15

Sorry mate.....Id be leaning towards HGF caused by low water.....

Unfortunately thats not the first time Ive seen that core plug leaking....

H

14th Mar 2017 5:19pm

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