I am relatively new here and new to Discos for sure. I bought an 04 Disco this past May and have been thrilled. Since I have had it, I have been doing the checklist of services on the sticky thread and its going well.
EXCEPT, I have been chasing a Service Engine Soon light for the last month or two. I just happend to have it at the dealer and the tech there pulled up codes P300 and P306. He is suspecting a dropped sleeve along with an estimate well in excess of what I paid for the car ($12K). Aside from a rough idle every once and a while, the truck seems to be running fine.

Sometime around June, it did overheat on me and I drove it a very short distance...about a block or so. I am concerned that I might have caused damage then.
Any thoughts or insight is welcome because I am majorly sweating this over here.

 

Yes you may have caused damage then, driving a rover in the red zone for any distance is very bad.
Now the sleeves do not drop. They do come loose and side up and the back down to position but do not go lower than that. 12k seems like a crock of sh$$ you can buy a used engine for less and pay a Indy shop to do the swap for half that price. Those 300 codes you have are misfires and there is a wide range of thing that could cause that yo happen. 300 is multiple engine misfires and 306 is cylinder 6 misfire could be plugs, wires, coils, mass air flow sensor. Wrong fuel, head gasket leaking into cylinder. Lots of possibilities could be causing you problem.

Please let us know of your mileage?

Also are you loosing any coolant?

 

Silver-
I have 81,000 miles on the truck.
In an attempt to clear the misfire codes, I put in new plugs (Bosch Platinum +4's) and new wires (Magnecor 8mm) following the advice on the sticky thread. I am still getting a misfire/service engine light after installing both.
As for the head gasket, it appears good. Very dry on the bottom of the engine all around. I did an oil change last week and the old oil appeared very normal...nothing unusual.

I am losing coolant, but it is spotty. In the summer when I was running the ac occasionally I would notice a leak on the ground a little. But recently, I dont see anything leaking but I do need to top it off occasionally (however when I open the reservoir it runs back into the tank and I barely need to add any).

I can do almost anything on a car except internal engine/transmission stuff so I am very in the dark on this one. Again, I new to Rovers so I apologize in advance if I am asking dumb questions but its only because I am a little stressed.

 

No apologies need guy, these trucks are a love hate relationship. You more than likely have a very small head gasket leak going on very normal for these trucks the coolant may be leaking in side the cylinders and that is why you don't see it. Good choice on plugs and wires! Mike is very helpful!

 

First thing you need to do is have a coolant pressure test done, if you need help with this give me a shout.

 

I just went through this. I had coolant leaking into cylinder 4 and caused rough starting, misfires and I was losing coolant. I did all the tests and swore I had a loose or cracked liner. I did a test for coolant in the exhaust and it was positive. Also rented a block tester from Motorcars LTD and I did not have coolant leaking from the cylinder walls. I went ahead and did the headgaskets and 1000 mi later she is still running great.

If the headgaskets have never been done, I would just go ahead and do a full HG job. $500 or less if you do it yourself.

By the way, one of the guys I talked to about my problem was a former LR mechanic. He basically told me that if an interior cylinder is misfiring from a coolant leak, they would automatically say it's a slipped liner and replace the block. Whether you can see the headgaskets leaking or not doesn't mean they aren't leaking somewhere. Typically, they will leak into the front or back cylinders, but somehow they can also leak into the middle cylinders. Strange, but true!

 

I would definatley need some help and/or advice with this.

 

If you want some help, PM me your number and I'll walk you thru what to do.

 

I dont suppose there is any noticable symptoms that might indicate a dropped sleeve vs. a head gasket?

 

you are already in tooooo deep

get the head gaskets replaced.

or sell it.

see? easy.

If you have paid $12,000 then what's $2,000 more for head gaskets?
And, piece of mind?

IF you can't spare the thought of losing two grand - then sell it and don't look back.

This is a gamble. Ball on red or black.
You may win.
You may lose.

If you sell it - you don't play the game. And don't look back.

I paid $2,500 for my truck.
Put about $700 into it.
I had a 60% chance head gaskets.
40% chance slipped liner.

I won the bet.

Hold them or fold them.

As you paid a lot more - the $2,000 makes more sense to BET to protect your $12,000 of chips on the table.