Hi everyone.

I purchased an overheating 2004 Discovery in an attempt to fix it.

After testing positive for exhaust gas in the coolant I decided to replace the head gaskets. After removing the passenger side head, I noticed significant carbon (I think) buildup on the pistons and the heads.

I am trying to look for signs of head gasket failure in hopes that it isn't a block problem.

Top of block:

(see link below for more pictures)

Head: https://imgur.com/a/X3pvyw1

I took a video and some pictures and would appreciate some input from anyone who has more experience than I. Does this build-up tell us anything?

Thanks!

 

One of the interesting things was as I removed the last head bolt in the very back, a lot of coolant started dripping out. Like probably 1/2 gallon. Also, the rear cylinders were full of coolant. Is this just due to the system not being fully drained and the removal of the head allowing coolant from the passages to flow into the cylinder? Thanks again.

 

Some coolant is going to pour into the cylinders when you remove the heads, no way around it.
The carbon build up is likely from low octane gas.
These have no egr valve, and require premium gas to prevent or at least cut down on the carbon.
If any of the cylinders, especially the middle 2, are nice and clean, with no visible stains or damage to the gaskets, then you may have a crack in the block behind the cylinder liner, but that doesn't mean it definately does either.
The coolant leak could have been external only too.
If you haven't bought parts yet, everything for the head gasket job from Lucky8 is $88, minus oil change and coolant. New thermostat, $30, injectors, $80, and coil packs $50 are also a good idea too.

 

IMHO that looks OK including sealing of the HG from just seeing photos. That amount of carbon is equivalent to around 50K to 100K miles so IMHO no problems as the only thing seems the exhaust valves seem a bit pale and maybe the mixture is weak. I would certainly clean out the coolant from the cylinder bores asap. The amount of coolant present is representative of not draining the block and cooling system properly first.

How many miles on the odo and who owned it, it's never been driven hard IMO ?.

 

Great, thanks for the response OffradFrance and Sixpack577.

Offroad: The previous owner was not a "car person" so to speak and I do not know what type of gas he used. It is possible that I did not drain the system properly, I thought I was removing the bottom-most hose, but maybe not.

Sixpack: Thanks. I am pulling off the other head tonight and I will look for those things. I already got the thermostat, the head gasket kit, and the studs. I am of two minds about replacing a lot of parts. If I knew the block was good, I would have no problem replacing injectors, cams, ect.... but I hate to spend a lot of money and then scrap the engine for replacement.

I do appreciate the input.

 

Looks like carbon build-up...nothing looks out of the ordinary...
Like sixpack and France said....some coolant will fall into cylinders....
Just clean everything up thoroughly......probably have heads checked..
slap it back together..
Good luck...keep us updated

 

Can you post a couple pics of the head gaskets? Look at the rear most section and look for any cracking.

 

Head gasket looked pretty good. I will post pictures this afternoon. One thing I did notice was some material transferred from the gasket to the head.

I am pulling the other head this evening and will post pictures from both.

Thanks again for all the assistance.

 

Also to follow up to Offroad, the odometer has 134k miles and headgaskets were previously done at 80k miles.

 

Update with findings! Okay, so I pulled off the other head and noticed that inside cylinder 5, it is steamed cleaned.




One interesting thing is that there is a pretty big gob of what seems to be RTV on the lower left of that cylinder.




So, one important piece of information is the following picture. These are the valves for the steam cleaned cylinder:


Here is the head gasket near the valves where it was steam cleaned.




As requested, here are some pictures of both head gaskets. Things look pretty good, except for some material transfer as I mentioned earlier.













What do we think? Cracked block or new head gaskets should do the trick?

Thanks again, you guys are great.