I have recently flushed the cooling system on my Plus 8 and have refilled with coolant. I filled it up until I could see the fluid at the top of the radiator then ran the engine for 15 minutes then topped up again. It appears that the level is still adjusting and I keep topping it up since the level drops and is not visible in the top of the radiator (no fluid is seen in the expansion tank yet - the line to it is clear). So far I have added ~6 litres of fluid. There are no leaks in the system and I am sure there are no leaks of coolant into the engine since the oil seen at the dip stick is still clear and bright. Maybe it just takes a while to get all the air out. Maybe a water wetter would have helped. Appreciate any insight from the group. David
Plus 8s were a right nuisance filling with coolant when they first appeared. They were using the first Rover V8s that had a "teapot filler" suspended on the top hose between the rad and the engine. Made quite a mess.They would tell the owners to jack the rear of their car to fill the radiator! Air in the cooling system was inevitable. The bubbles in the system were so large they could even push the coolant away from the coolant temperature sender at the top of the engine. The resultant readings would scare everyone. I occasionally muse wonder whether that is why the MMC placed the rad fan switch at the bottom of the radiator when the temperature sender we read is at the top! Eventually they recalled all UK Plus 8s and that was end of the teapots. I have a picture of the Pickersleigh pile of them somewheres.
Your coolant capacity according to your Manual, is 9 liters. But it is rare you will get in that much.
After a couple of preliminary years of annoyance, a LONG time and 400,000 kms ago, I developed a system for Plus 8s. Never fails me.
1. Firstly, I use a expansion method rather than a recovery one. It merely means placing the pressure cap on the reservoir rather than the radiator. Expansion tanks MUST be higher than the radiator and that is why most +8s have the reservoirs on the bulkhead, the highest point in the engine bay. I cap it with a safety pressure cap at 15 psi, as the manufacturer suggests. I do not use any higher because I have no wish to put any more strain on the water pump than recommended.
And additional benefit is that you will be able to depressurize the system, faster and safer at the reservoir than the rad. But always be careful. 2. The radiator is capped,
not with pressure cap but with a shut-off cap (available at any savvy LR/Rover supplier) These caps are not pressurized and leave the line to the reservoir unobstructed.
3. When filling the rad, I do so to the top with a distilled water solution. (50-50 coolant-to-water to which I add a bottle of Water Wetter (which really does work, just not as enthusiastically as their advertising..figure -2C better).
My goal is to keep my car within the operating range recommended by the manufacturer. My goal is NOT to stop it boiling over when it has to. (only once in 30 years when I joyously blew a head gasket in the Dordogne). Stuff like Waterless Coolants allows the engine to run WAY over the manufacturer recommended limits for engine health. We should WANT the engines to boil over if something is amiss.
4. Once I have the rad filled to the top. I wiggle the car by pushing it to make the rad move a little. Bubbles will stream up to the rad entry. I do that until there is space and I fill again. I repeat the process 3-4 times until there are no bubbles.I close the rad with my non-pressure cap.
5. I then move to the expansion tank. I fill to 1/2-to 2/3ds.
Remember, you will be filling the hose from the rad to the expansion tank as well. I over fill to this level to make sure any air I missed will be filled by the excess over the 1/3 of the reservoir which I am shooting for after the system has adjusted. Anything more will be expelled by the system after a drive or two. Any needed will drain the reservoir, so add a little after chaeck after 2-3 days.
Good luck.
