My plastic tee/coolant hoses are fairly new as is the water pump. Put a brass bleeder screw in as well on the tee.

In a new development, when the heat is running full blast my temps idle at or below 206. When I shut it off it'll go back up to 217-221. Before today the heat had no effect on temps. The difference today being after I pressure tested twice, I re-pressurized the system to 20psi and turned the truck on with heat blasting and bled some coolant from the bleeder screw. This was from complete cold start so it was pretty controlled.

Tomorrow morning I'm going to do my final procedure and reverse flush the heater core and rebleed the system.

Will get back with any changes

 

You're describing what I did to my 04 disco.


It would pass a pressure test. No leaks. As soon as it was driven the temp would spike whooshing sound at the heater core and mine would over heat.


It turned out to be a slipped liner and I had the engine replaced.

good luck.

 

So I did the flush of the heater core today and it is still running the same. I've come to terms with the fact it may have finally slipped a liner. Tried to pinpoint it with mechanics stethoscope but they all honestly sound like they are ticking. My plan now is to just run it until it dies and not invest any further money or time into it.

Thanks for the help and suggestions everyone.

 

A lot of people really try and over complicate things with over heating Rovers. Especially the 03 and 04's which are prone to slipped liners.

If you have no leaks and you're holding pressure but still over heating or seeing spikes then coolant is more likely than not, bypassing the liners and causing steam in your cooling system thus causing spikes and over heating.

I went through 2 weeks of HELL trying to get my Rover to run with out over heating. Would idle for hours with out over heating (Still had temp spikes tho) Whooshing sound in heater core. Flushed drained bleed it till MY fingers bleed. Nothing worked.


Had the engine replaced saw the offending LINERS plural. 2 liners were slipped my engine was TOAST.

Hope you get some more miles out of it.

 

just a quick note.... Ive been working on a cooling issue and I am kind of convinced mine was a Previous Owner's invention to add a metal tube for overflow and kink it just enough to slow down return pressure... this I would believe could cause more pressure in radiator preventing the thermostat from opening properly since it was being pressurized from both sides... ( just a guess) ... a clogged top of radiator or something in there could be your culprit... or.. I read that a water pump from a member possibly impeller was spinning free inside thus not pumping... anyway.. food for though... as far as mine.. its all new and I ended up using a 5/16" fuel line for the overflow tube for 13$ at auto zone and that was for 10 ft of it! I still have 4ft for other things lol was far as bleeding... I t believe its not that hard... not many places for air if you lift expansion tank and bleed it properly.. Ive bled mine when almost cold but slightly warm and still had no issues... but its best to bleed stone cold if you have that luxury... however that IS the proper way I understand lol

 

This happened to me. Changed radiator, hoses, water pump and thermostat. Still occasionally temp spikes. Turns out it was the brass plug... Slipped threads causing slight air penetration. The plastic joint has a tendency to crack where the plug is located. Changed the joint. Extra careful with screwing in brass plug. All okay now.

 

The Inline Mod totally solved my problem!! wow... an old style cooling system with an old style engine! who'd a thunk!? my temps on highway for 20 mins several different times today were a solid 183deg and at stop lights it would go up to 188-190( once) its basically running I didn't check heater but its so dang humid and hot here I figured I was hot enough lol A/C blows nice n cold though

 

This is exactly the operating temps that I am getting with the same setup. I'm slightly perplexed by the temps spikes though. For the first few days it would stay at 183-185 regardless of speed, AC, ambient air temps. Then one day I looked down and it was at 194 with the cold AC on, when it had been at 183 a half-minute or less before. Now if I'm driving with the AC on it will spike like that the whole time. AC off, 189 the highest and just every so often. I don't really know what it could be, I'm just slightly paranoid about it, because there is always an accident waiting to happen on the 4.6 cooling system. It just loves any excuse to OVERHEAT and can't wait to find a reason to do so.
Anyways, I'm starting to believe that 10-degree temp spikes aren't isolated to the Rover and probably happen with 98 percent of vehicles on the road. I wish I could stop worrying about it but I know I could look at that handheld at any time and read 220 F like what happened the other day when a coolant hose let loose of the radiator because I forgot to tighten the clamp. I've had the coolant tank crack, water pump go out, the Tee break on top hose and then this last one so I never take my eyes off of that OBD reader until the day I install a Gauge to the sender that produces an audible and visual warning to an overheating incident.

 

Chubbs if the highest you get is 194 I would not worry. Before I put the 180 t-stat I would run 212-215. After I run 188 cruising and at idle 195,197,199 then it goes back down when cruising. Actually when the weather warmed up and my AC was on my new fan kicked in and kept it around 190.

Relax unless you're seeing 200 or more regularly. But good job keeping an eye.

 

I can't relax! Every time I chill out on it, the sumb**** tries to self-destruct! I'm dead serious when I say this engine has a death wish.