I recently had a alternator repalced, along with that a surpetine belt, since then my temp gaugegoes up and down and in the red, there is no steam and does not appear in any way that it is overheating. I checked the routing of the surpetine belt, and replaced the thermostat. I want to try changing the coolant temp sensor as it is my next move. I have no idea where it is located. I have a 98 Landrover discovery 1, help and could anyone send me a pic or instructions. I am female and need help! Thanks so much!

 

You main in fact have another problem in the form of a major over heat issue, so verify the temp sensor, replace it, they are cheap and if still there, quit driving it before you toast the engine.

 

well my veh isnt overheating the guage is just going up and down I dont know where the coolant temp sensor is located to change it

 

This description is a basic as it gets...

Look for the Large hose coming out of the top of the radiator at the left / front of the truck. Follow that large hose back toward the middle of the engine. It will be clamped to a part called the thermostat housing. That large cooling fan at the front of the engine is attached to a shaft coming out of the front of the water pump. On top of that T-stat housing where the large hose is clamped you will see two sensors with wires coming out of them. One of them has only a single wire and the other will have two wires. The single wire sensor is for the temp gague in your instrument cluster, (the part you say is going up and down). the other (two wire) sensor is the temperature sensor which tells the engine management computer (ECM or ECU) how hot the engine is.

As Mike was saying, you may have an actual issue with the cooling system. Just because you don't see steam or any other visible clues does NOT mean you have a normal running cooling system.

 

you have coolant temp sensor that feeds info to the computer, AND a coolant temp "sender" that feeds info to the gauge on the dash. On top of the motor...near where the top radiator hose fastens to the engine...you will see 2 small upright senders, the one with 2 wires hooked to it is the temp sensor for the computer, the one with 1 wire hooked to it is the sender for the temp gauge. unhooking the 1 wire should make the gauge go/ stay cold....you may just have a bad connection there.
Having said all that....these trucks do have a reputation for cooling system leaks and thus overheat issues....check your coolant level in the reservoir when cold....as long as its to the full mark you should be ok...
if the coolant level were low...the flow of coolant through the engine could be sporadic enough to cause the temp sender to give you wild readings..
let us know how it goes

 

Also see if you can borrow an infrared point and shoot thermometer, which will give you some idea of the temp around that sensor or the thermostat housing. Even better is a code scanner that will read the coolant temp from the other sensor. Don't drive the truck until you check these out, use another vehicle to fetch parts.

If you did the thermostat, it might be possible that you disturbed the wiring going to the single wire sensor. A "skinned" place will make a ground that could cause the gauge to go high. I would suppose if you take off that single wire the meter should change, but certainly should not go from one end and back to the other unless a wiring problem. The speed of the changes might be an indicator - very rapid changes (a second or two or less) can not normally be accomplished by water alone.

 

Well I had the alternator replaced but now it is acting the same as it did before sluggish to start and almost not starting, this is very frustrating especially when you are a single female trying to figure it out

 

Well, poor starting can be a lot of things; like weak fuel pump or fuel pressure regulator - but you used the word "sluggish" - so would that mean "slow", like how your starter sounds with a weak battery (groaning, then finally increasing in speed as the engine turns over)? The voltage on the battery teminals should be a little over 14 volts when engine is running and battery is charged up. The black wire from the battery runs down to a bolt clamped on the frame (passenger side just below radiator on my Disco). That main ground, if loose, could account for all kinds of wierd electrical problems. Has your temp gauge stabilized?

 

No we are putting the coolant sensor in today, so im anxious to see how than pans out. I will check that wire to see if it is loose. Thanks for your help!

 

Two things that will and does cause starting problems on these:
1. The battery to chassis ground connection (especially at the connection to the frame)..
2. The starter to chassis ground cable/connection to the frame.

Corrosion at these ground coonections where they bolt to the frame os often the root cause and is misdiagnosed as bad starters, bad alternators, battery won't charge, etc.

One of our members ( screenname Antichrist aka Tom Rowe) manufacures and sells a fantastic replacement cable at a great price. I am putting mine on today.

Send him a PM and get you a set, you will be happy you did.