QuestionHi John
My '98 Disco, AKA the Moneypit, has a problem which my mechanics don't seem able to diagnose. The engine overheated a couple of weeks ago on a hot summer's afternoon (I'm in Saudi Arabia, so hot means HOT, about 130F). It happened because the coolant reserve tank has been overspilling occasionally, and this time I forgot to refill it. It wasn't empty, but it wasn't full enough. That's the first time it's overheated to the point of the red temperature gauge warning light being lit in the three months that I've had it. I stoped immediately, let it cool, and refilled it. The problem with the coolant reserve tank seems to a circulation problem - it only usually happens when turning off the engine when parking with the A/C on, or in slow-crawling traffic. If I turn the A/C off about 30 seconds before turning the engine off, there's no overspill.
Anyway, since the overheating episode, the engine has struggled to maintain regular revs at idle, managing a maximum of about 750 rpm which eventually dies off to a splutter if it's not encouraged along with a tap on the gas pedal every few seconds. Same story at traffic lights. Quite a lot of engine and manual gearstick vibration at low speeds, not so bad at higher, though full power is noticeably lacking at all times.
The V8's in a certified Land Rover garage at the moment. It's a new operation and they are struggling to cope with demand without having a full staff or full set of LR tools. They have replaced: fuel pump, fuel filter, spark plugs, spark plug cables, and fixed a couple of holes in the exhaust pipe. Result? Only marginal improvement in revs at idle. They say they ran it at idle for 2 hours without overheating, but I'm not sure that counts for much if the engine wasn't under load (and the overheating wasn't the main issue when driving anyway - it only happened once when driving, the other times were when parking up).
I've read your terrifying post on your blog from Nov 2009 about V8 engine failure in late 1990s Discovery models, and suspect that cylinder liner and/or block failure is what you are going to diagnose. I just wanted to ask if it could possibly be anything else, before I throw in the towel?
Lastly, I'm taking the Discovery I RAVE CD for T4 to the garage tonight (that's right - they didn't have it, so I had to find it for them - God bless the internet) to run a computer check, and we'll see what it spits out. Many thanks and a whole heap of appreciation from me for your work. I've learned a lot more from you online than I have from many a so-called expert face-to-face. Keep it up.
Regards
Adam King
AnswerFirst of all, if the vehicle runs different today than yesterday, you have to ask . . .what changed? In your case, you had an overheat incident, and now the truck does not run the same. To me, that's a pretty ominous sign; one that suggests temperature related damage.
What I would do is look in the spark plug holes with a bore scope, and if I did not have one, I'd pull the plugs and see if one was a different color. You may have already lost this option, though, if they replaced the plugs without looking in a well-meaning repair attempt.
Second, the T4 is a laptop based Land Rover test tool that is entirely separate from Rave, which is the CD based set of workshop manuals used into the mid-2000s. This garage you are talking about needs a T4 or an Autologic or an IDS if they want to be a real LR shop. We have and use all three systems with the T4 and AL being far the best on older cars and IDS being the thing for 2006 and up
