Our Land Rover Discovery is a 1998. It seems to have two problems or maybe the problems are connected, we can't figure it out.

First it will overheat after driving for about an hour, especially if we drive it on the highway, my husband changed the thermostat last summer and we just bought another one to see if it helps. We also put some of the radiator fluid in that helps keep the temp lower. The vehicle idles to high when driving and then when we put it in park it shoots up to almost 2,000 rpms.

The other problem is weird. During driving it will all of a sudden loose all electrical, lights, wipers, radio, windows, everything. Then when we go to turn if off and put it in park, it will make this grinding noise, that my husband finally got to hear, because it happens very randomly, he said it sounded like the starter trying to start even though it was already running. Let it sit for an hour or two and then everything is normal again, electrical works again, it doesn't make the grinding noise when put in park. We can't figure out what it could possibly be and we don't want to leave it in park and on for very long (long enough to check where the sound is coming from) because the grinding sound sounds so bad.

Last problem, the anti-lock brakes light is on and sometimes when I push on the brake it resists and makes a fast bumping I can feel in the brake pedal and it gets very hard sometimes to get the car to stop you really have to push hard on the brake. Thanks for anyone who has some advice.

 

If it only overheats on the highway then most likely the viscous fan clutch is faulty, also good idea to completely drain the cooling system and radiator and re-fill with fresh 50/50 ethylene glycol (green ) coolant mix.
If within budget i would seriously consider removing the radiator and having it professionally cleaned , only then can you eliminate that from the overheating issue.

Electrical issues are usually traced back to bad earth connections and corroded wiring , start by disconnecting the battery and going over all the main cable connections and checking for corrosion than clean with sand paper and a wire brush if found.
I can really help with the brakes since i dont have ABS on my diesel disco but faulty/dirty wheel sensors and modulator faults are the general cause but search here for better answers.

 

1. temps... question...are you "losing" coolant? Is it necessary to 'top up' the level in the overflow tank periodically? If so, how often?

a) drain and refill with fresh coolant. b) check that fan shroud, top and bottom are in place. c) replace viscous fan clutch d) have radiator serviced

2. electrics... check for solid ground connections

3. ABS. replace sensors with these
New ABS Wheel Speed Sensor Front Left & Right for Land Rover Discovery STC1749

 

The Park-grinding noise, are you saying that when you stop, with the engine running, and put it in Park there is a grinding noise as long as the engine is running?

High idle could be a vac leak or possibly a wacky IAC. Check all those vac lines. Easy and cheap.

Maybe the grinding noise and the high idle are connected. Revving engine could be rattling a cat or some loose thingy.

Regarding the electrics, like the others say, it is more than likely grounding issues. Grab a copy of the Electronic Troubleshooting Manual from Walt's Rave manual link, labeled etlj970x...

As far as the brakes go, unplug the ABS fuse and the brakes will revert to Vintage style brakes. Get the other stuff figured out first, IMO. Then deal with the brakes. I have the fuse pulled and the abs dash bulb pulled on mine.

 

Thank you, my husband will read this when he gets home from work and try out your ideas.

 

No, I don't think we are loosing coolant, he did put in more a couple of weeks ago and he put in that treatment, but the level seems to be staying there.

Good a place to find sensors. We wanted to fix the anti-lock brakes, not pull the fuse.

 

Yes, when I loose all electrical and then go to stop and turn the car off, when I switch the gear shifter into park while it is running, it makes a grinding noise in the park position and then I quickly turn it off because it sounds like a horrible bad grinding. Turn it back on again and it is usually just fine. I have all electrical back and no grinding when in park.

My husband was out checking the vacuum lines last night and found one that was "iffy" and he is going to replace it this weekend. Also when we bought the thermostat the guy at the checkout counter said to buy the low heat one rather than the high heat one, he said the high heat one can mess up signals. Last year the thermostat he put in was the high heat one right at the end of summer, so that could be some of the problem, we just recently started driving it again this summer, it sat all winter, needing new tires for snow. Fine for driving in the summer.

I think we would rather fix the brakes but he may pull the fuse for now because it is getting much worse just in the last two days. I have strong legs and I have to really stomp on the pedal to get it to stop (when it does it) and if its hard for me then its bad, former soccer player. Last trip to town it did it almost every time I braked (the thumping in the pedal) but only "really bad" three times. My husband will read all this when he gets home and decide what to do, thank you.

 

Is it idling, in park, at 2000 rpm at this point also?

 

Thinking out loud;
Maybe your overheating & grinding in park are related. Wonder if the viscous clutch is failing in such a way that it is causing it to overheat on the highway and making the grinding noise after you put it in park and the idle revs up to 2000.

 

If you want to fix the ABS, try using the "blink test" to accurately diagnose the problem rather than throwing money and parts at it. If you google Rover ABS Blink Test you'll come up with the procedure. The connector for doing the test is up under the dash on below the steering column on later DI's.