2002 Discovery II

Hi, I've been dealing with this same problem for the last 2 months now with a Land Rover repair shop in Tucson called Falconworks. I got 2 codes from the scan which were for random multiple misfire and #6 cylinder misfire. This is a tricky problem for me because it is also causing overheating. The head gasket seemed to have gone bad (coolant in cylinder 6) so I replaced that and overheating continued. Replaced cylinder head and things got better for a couple of weeks. It didn't overheat after replacing the cylinder head but service engine light came on. I took it back to the shop and they switched out the 4 and 6 spark plugs, cleared the codes and it ran great for another 2 weeks.

This last saturday I started it up after it ran incredibly smooth the day before and the check engine light came on, started blinking, and then it overheated. I'm completely stumped on what is causing the overheat. Suggestions, guesses, hypotheses welcome!

 

Did you replace BOTH head gaskets?
Did they properly bleed the cooling system?
Are you still getting the mis fire codes?

 

I replaced both head gaskets. I don't know if they bled the cooling system, but I would think so. And I am still getting the misfire codes.

 

When did you last change your wires?

 

The shop just changed them when i first brought it in.

 

Was the engine inspected for a crack or dropped sleeve, how about the replacement head, new, used or rebuild and was it inspected first? Were new head bolts used when you replaced the head?

 

the engine has been thoroughly inspected for a crack, none were found. the replacement head was an inspected used head in good condition. They also specifically told me that they would use new bolts when installing the new head.

 

If you are no longer loosing coolant then it has to be something else.
So they need to double check all of their work and make sure that they have all the plug wires in the right places.
Do you know what brand of plug wires they used?

 

The coolant is a little low, when I took the cap off right now it released a lot of air and i haven't driven it for a few days. The wires are STI (spark transfer international). Could an ignition problem even cause overheating?

 

No not on your truck.
If your truck still had a distributor then the timing being way off can cause a hot run situation.
But you have electronic ignition, which is controlled by a computer.
Find the "how to bleed a DII" sticky on the top of the page, follow it and see if that fixes your overheating.
A big air bubble inside the engines cooling system will cause it to overheat.