Hi all. Hoping for someone to help me out.

I've had my 2004 disco w 118k (current mileage) for 3 months now. I just started noticing coolant and oil externally on the front and rear of the engine. The oil appears to be coming from the VCG's towards the rear. The coolant looks like its coming from where the water pump may be. Not sure tho. I know the best practices are to clean it and watch it, so I'm not going to ask that question.

What I AM asking is.... How common are head gasket failures on the 04's with the 4.6? I though this was isolated to the 4.0's.

I'm hoping that its just the leaking VCG'S and maybe a leaky water pump.

Feel free to speculate !!

Thank you for helping

 

Valve Covers leak. just tighten them up should be ok. As for the coolant leak. YOU NEED to figure this out. If it is indeed from the water pump area you are looking at an easy fix. I would do a pressure test to see if it is the water pump or front cover. Both in comparison to Head gaskets are easy. As for the issue of blown headgaskets. it is an issue for both 4.0 as well as 4.6. it is just the way they run.

 

Head gaskets on the 4.6s, roughly 100%, no difference than the 4.0s.

 

****.... Is it common for coolant to be leaking out instead of into the oil or cylinders ? I though those were more common. I'm not seeing any oil in the coolant and during a recent oil change the used oil looked good.

 

Coolant pathway into head is front and rear, so there is most common leaks, HG is very slim at that point. Coolant pressure test is a good idea.

 

I'll pull a couple plugs out too.

 

Could be valley pan leaking, it has four coolant channels.

 

Head gaskets on Discovery I and II are like a person's shoes.
They wear out and need replaced.

The less you wear your shoes - the longer they will last.
Just flip some new Victor Reinz hand gaskets on there and you'll be worry free.

 

Replacing head gaskets are a PITA on the V8 or the TD5 so worth checking everything before you venture down that route. As has been stated already a coolant pressure test will tell you some of the story and worth doing a cylinder compression test to see if there is any leaks into the cylinders. Check for oil in the water and/or water in the oil with white(ish) scum on or around the oil filler cap. It's all a slow process of elimination but easier than head gaskets. Good luck and keep us posted what happens.

 

Clean all the crud off the engine on the side where the leak is, top to bottom. I use a foaming cleaner and a wheel brush. then check it daily and see if you can spot the trail. Mine was similar to yours. I traced it up past the water pump to the very corner of the HG, right by the manifold. I was adding about a cup of coolant a week and was way too broke to do HG's.

I ordered some K-Seal and havent added any coolant since. Also I guess BG makes a similar product that a lot of people stand by.

That was back in November 2012. I really do need to order myself a HG kit though. Prob take care of that this winter.