Another Noisy 200Tdi...

Hi all, its been a long time since I needed the collective advice from LZ, but the Defender is acting up...

It going to be one of those, hard to describe, harder to imagine issues that should really be put in front of a professional.

Anyway, the symptoms:

Sounds a bit tractor like at idle, a bit more of a diesel knock than I can remember. Almost a bit slappy/knocky, not like a 1990s fiesta tappety rattle.
When hot, it drops in power and requires more throttle to maintain constant velocity. More throttle means more boost, more heat and high fuel consumption.
Normally running at 60-70 degrees C, but when labouring heads up to 90 deg C.
Just checked fluids - engine, gearbox and transfer box all fine same for diffs and all UJs given a good greasy nipple, water was low but only checked/topped off a few weeks ago, - maybe some consumption or boiling off? No Mayo.

Any ideas where to start? Is it worth pulling the cover off and checking gaps/caps first, or injectors? Or does the coolant usage indicate something a bit more sinister?

BTW, this is a '93 Defender 90, with 140k miles showing. Has a Disco transfer box, high flow air filter and middle box delete. Has a boost pin but only black smokes a little on power as the turbo spools.

Appreciate any insights...

Engine hot and running hand down the back of the cylinder head and see if you can feel any pressure/air moving from blown gasket, always seem to fail at the rear of number four for some reason?
Then check pump timing, mainly to see if crank damper is loose on crank.
Might be worth seeing if any valve lash caps have failed, that may account for the noise but not the temp increase.

Do not forget it might be several small faults rather than one big fault.

Is the temp gauge a proper temp gauge? ie not the silly std one.
Mine runs at pretty much 80/85 all the time.

As above you should be around 80c so either gauge is iffy or stat needs replacing.
Advice about pump timing is also very good, they will knock a lot more if it has shifted.
When timing is set just right you can have very little diesel knock.
There is a thread somewhere on here about a woodruff key failing on a crank pulley, could be a good time to do timing belt kit which will eliminate quite a few things at once?

Have you tried loosening off each injector pipe nut while it’s running to see if noise changes , if dodgy injector is loosened then engine note would be the same
Also has any tappet nuts loosened to allow massive gap so valve doesn’t actually open - that would be noisy

Just checked the coolant again, 2 litres short. I cannot see any leak so I might assume HG has gone.

At least I'll be able to check caps and tappet gaps while I'm at it.

Thanks.

oilydan said:

Just checked the coolant again, 2 litres short. I cannot see any leak so I might assume HG has gone.

At least I'll be able to check caps and tappet gaps while I'm at it.

Thanks.

Click to expand...

Where are you filling the coolant up to
I ask as if to much it will spit it out, if you look inside the header tank there is a plastic cross and this is the level mark, it is pretty much inline with the tanks weld seam, ie half way up the tank is actually the correct full mark.

Head gasket not bad job, reuse head bolts they can be reused 5 times.
Gasket will have a row of holes close together and this is the gasket thickness ie 1/2/3 hole, most play safe and go for the thickest gasket.

To answer some of the questions above....

Cant feel any blowing from the HG down the back.

Yes I have a 'proper' temp gauge.

Coolant is filled to the seam, but after a 30 minute run today it is empty again. There seems to be some white crusty stuff around the thermostat housing and nearby pipes/block. None under the water pump.

I might do the thermostat housing gasket, and whiup the rocker cover off to look at the valves/caps/gaps...