Pam here again, with an issue with my 2001 Disco - "Sally".

Now that the weather has cooled down, I have been attempting to use my heat only to find that it worksintermitently and more often than not, blows cold air. Additionally, the temperature gauge keeps shooting upand the temperature warning light comes on periodically.And the RPM measurement device jumps around quite a bit.

How big of a problem is this?

 

Wow! I'm no expert but I hope you at least know to shut down your engine if your temp. warning light comes on. overheating can ruin an engine. Maybe you alrerady did! You say it keeps shooting up...you should chek it out after the 1st time it shoots up.
If your engine gets hot but no hot air from your heater sounds like maybe the heater core is blocked so no engine coolant is passing throughit. Or...are you low on coolant?
Can't see how the tachometer has anything to do with this . that must be a seperate issue. I'm sure someone here can offer better advice
Good luck

 

Pam,
Sally needs some help and it is all related. I'll be out for a couple of hours but would like to talk to you and point you in a direction to resolve this.
Call me after 2:00 pm Colorado time and have a pencil and paper ready.
303-862-7680
Colorado

 

Check the coolant it is low.

 

Hey discomike
Don't leave the rest of us up in the air. How can the tach jumping around be related to the overheating issue? unless the engine is overheated and misfiring madly. great of you to help out 'sally'
Fill us in

 

Low on coolant Pam. Take it right to the oil change place and have them check it for you.
And then you need to figure out why it was low.

 

If the tach is not steady, this is an electrical issue coming from the alternator, either a dirty/loose wire or the alternator is on it's way out.
I suggest Pam call me cause it is sometimes easier to walk people who are less familiar with their truck to correct the problems.

 

That's correct. I actually had the same thing happen to me (when I was in Colorado, ironically). The tach would go bezerk and at the same time the Temp gauge would rise/fall. Went to Autozonelike Mike suggested (in Montrose) and had my Batt/Alt tested. The diagnosis was a bad diod in the Alternator. So, it could be what is happening here.

It's possible to be low water or thermostat problems. In my case I had a bad thermostat too and it wouldn't heat up very much. Now, it could heat a house!