engine knock - 2002 Defender Extreme TD5

[applesbrew]

Gday all, first post and its one I really dont want to make but anyway.....

In the last week I became the owner of a 2002 Defender Extreme TD5. The motor has had a full rebuild (its done 3000ks since) and I believe that the turbo is new as well. It has also been chipped at M R Automotive at Redcliffe.

I was exiting a roundabout in 2nd, and then changed into 3rd (prob 50 - 60kph) . I was accelerating, but I would not say harshly. A loud knocking sound from under the bonnet developed. I immediately treid to switch off the ignition and move over to the emergency lane. The engine was revving very harshly by itself (no input from my right foot). It then shut down.

I opened the bonnet and saw that coolant has sprayed in a circular patch onto the hood lining (I am guessing that there is a pressure relief valve in the cap). Other than that There is no other fluid loss of any type.

I let it cool down (2hrs), have checked the coolant level and it is pretty much still on the cold mark, so I lost very very minimal coolant.

It is still parked on the side of the road, I am unsure what it may be at this stage, I will be giving M R Automotive a call in the morning.

I dont want to chance driving it if it is a serious problem, but at the same time dont want to spend a gazillion dollars on a tow truck and find out that it is a minor issue...

Any ideas?

[strangy]

Well welcome sorry this how you had to make your first post.
Some more info would be helpful.
Firstly IMO dont drive it.

How fast was it revving? Are we talking over 4000.
When did the knock start, post or pre uncommanded revs?

Symptoms you describe i.e Revving without your input and your coolant loss are an indicator of head gasket failure, head failure and associated engine runaway, knocking caused from bearing failure due lack of oil and extreme revs.

The engine revving without your input is usually caused by oil from a turbo, bad rings or more commonly with the TD5, cracked head and leaking injectors, diluting the oil enough for the motor to be self sustaining without fuel and then destructing.

Since it has been rebuilt you may be able to rule out rings and turbo (rebuilt is different to reconditioned) and are left with most likely head problem.

Please note that is an extreme case scenario, but the symptoms are indicative.

The coolant spray is most likely (if it has runaway) from the head gasket failing and comprssion gases pressurising the coolant system.

How is the oil level and colour/smell?

Probably most significant is Why was the engine rebuilt in the first place and what was done to the head?

This thread is probably best in the Technical section so mods will likely move it.


cheers

[spudboy]

Hi AppleBrew - bit of a sad first post :(

If you do a search here on "TD5 runaway" you will find a number of posts to give you an idea of what happens, like this one: http://www.aulro.com/afvb/general-chat/109383-runaway-td5.html

Hope that is nothing as serious as this for you.

Yours stopped on it's own, so maybe not a runaway.

Cheers, and welcome to the forum
David

[applesbrew]

Gday spudboy, I think its pretty much going to be as Strangy described.

I towed it to MR Automotive, upon a very brief initial inspection the mechanic has indicated it will either be simple (injector seals approx $400), or it will be BAD (new head, etc etc approx $5500.)

I read the associated post runaway TD5, hopefully mine is not as bad, I dint notice any plumage of smoke (it was at night though) mine only ran on for about 5 seconds.... It felt like an eternity though.

Fingers crossed.