So far haven't found anything on this:

1) Heater in auto is delayed until engine warms (normal). Mine has always cycled a little once it starts, usually just past the blue on the temp gauge.
2) Last year, took a little longer to start. This year, can start as soon as needle starts moving, but will turn off. Now it must be mid range to work, and then cycles the fans on and off for a while. Eventually warms up OK, but something's up.
3) I had a leak last year at the throttle body & fixed it.
4) No testbook (!) on display unless on highway for 1/2 hour or so, then it lights. It might be less effective after that. Resets on startup.
5) I see nothing here about air in the system, but suspect that could be it. Is there a way to bleed any air out on a 2002 P38?
6) I noticed under hard acceleration the heater will tend to cycle back on.
7) Probably unrelated, but the right night light on the heater display (for the auto **** and right controls) is out. Has done this before and comes back on. Once or twice whole display was out and came back on. Anyone know what connector to reconnect / check for that?

Any advice? Thanks.

 

I would suspect a blend motor failure. It is a fairly common problem with the P38 and would explain the test book symbol.

Your Rover will not fire right up (maybe it did in the past, but now its old like mine ). I ALWAYS, doesn't matter what vehicle it is, turn the ignition to the II position for a few seconds to let it "boot up". Doing this turns the fuel pump on which primes the engine, as well as giving the computer a chance to read sensor data. Mine starts up within .5 seconds every time. I have tried just turning it over, and noticed it HATES it. And will sputter and hesitate.

Have you checked your coolant level? I suppose it is possible that there is air in the system, and I would recommended doing a coolant flush just for the sake of it. As well as doing the bleed procedure. Make sure you follow the RAVE manual directions EXACTLY.

 

There is definitely air in the system. Last night I found a little in RAVE and saw the bleeder hose. The upper hose is full of air. Once warm, if I rev up the engine, I can feel the air being flushed away, only to return. The bleeder is working in that there is a small stream of coolant going into the reservoir with the cap off, but no air is coming out. The air is way above the radiator. It's a really bad design if you ask me...

I didn't see anything special in RAVE. Know what section I should be following exactly?

 

I would also suggest that you go to NAPA and buy a block tester to see if you have hydrocarbons in your coolant It costs 50.00 but you can quickly determine if you need a head gasket job or the cooling system is in good condition

 

I fitted a 5/16 ID clear PVC hose to the bleeder and tank just to see what's going on. Looked like a little air came out, but the big hose is still full of air. Didn't work. The system holds pressure and vacuum OK. Now I think I will drive the vehicle up the steepest ramp I can find, so the right front is up in the air a few feet. That should make it so the upper hose can leak the air to the bleeder. Then I can rev the engine and hopefully the bleeder will pump the air to the tank. If I can get it sideways and vertical about 30° each, it should release the air.

 

I have a recording thermometer I put in the dash vent just to see whether the sensor was bad. I put the fans on a non-auto setting and the temperature started rising immediately and linearly as soon as I started the engine. So the cycling must have been from the sensor being bad. It measured open circuit. Now the auto feature works normally with a new sensor, which was easy to change (remove 5 screws from glove box & lower it). So I guess plenty of coolant is reaching the heater core, now I just wish I could make that big air bubble in the upper hose go away. Tilting the car at a severe angle and running it didn't work. Might try a good off-road trail and just try to jiggle the air out. So far don't see any signs of a head gasket leak, other than the fact that there is air in the coolant that I can't get out.

 

try removing the coolant bottle from its mount and lift it up a bit higher than the engine, you should be able to do this cold with cap off see if you can add more coolant with bottle up a bit higher