we are in the process of changing out hoses and thermostat. I'm trying to research the refilling process. I have Jag coolant, and know to blend it 50-50 with water. We keep reading about a "bleeding process" . Do we just fill up the overflow tank, run the engine for a bit, let her cool down, then top it off again? I keep seeing different procedures. This gal is confused. Thank you.

 

Maybe here

https://www.jaguarforums.com/forum/x...system-106516/

 

The system is basically self venting. You need to fill the expansion tank and then start the engine up and let it come to temperature. I also set the temperature control to HI max heat and let it run. Keep the level topped off to the Hot Fill level. When the level stabilizes put the cap on and take it for a drive. That should eliminate all of the air from the system.
When you return from the drive with the check that the level is still at the Hot Fill line. If isn't let it cool down and check it at the Cold Fill line. You want to make sure the level is not overfilled or you can crack the tank when the system coolant expands while hot.

 

micmee1, the idea behind pinching off the coolant hose is to force more coolant through the engine to get the coolant flow as high as possible to flush out the air bubbles. Does it help, that I will leave to the arguments the group has had in the past. I did the flush/refill on my car a few times and I never pinched off the coolant hoses.

What I did do is with the system drained, I filled it to the hot line with the engine cold. From there, I started the engine and got it up to temperature. From there, I rev'ed the engine a few times to increase the coolant flow and flush out a majority of the air bubbles. I then turn off the engine and let the motor cool, leaving the cap off of the overflow bottle. You want to leave the cap loose as the coolant is going to contract some and this will draw a vacuum on the overflow bottle and can potentially lead to damage.

If you look at the overflow bottle (near the firewall), you will see 2 lines coming off of the top of the tank. One goes to the radiator, the other to the left side of the engine (side opposite the tank). These 2 lines are high point vents. So, any air that is in the engine should collect at these points and the system pressure will be higher at these points than in the overflow bottle, so, any air will be pushed to the overflow bottle where it will collect.

The other effect going on is that water wants to absorb air. This is good, this is bad. It is good in the fact that any air bubbles in the engine will be absorbed into the water as it is moving by. It is bad in that it will cause the water pump to cavitate easier, leading to a loss of coolant flow. The good thing is that the overflow tank is at a lower temperature than the rest of the system and this will cause the air to come out of the water and collect there. I use this concept at my nuclear power plant to pull the air out of the coolant that cools the reactor so the main pumps do not cavitate because of too much air in the water. We just have a slightly more complicated way of doing it.

Either way works (ie, just filling it up and leaving a vent path till the engine cools or squeezing the coolant line). You will find that you can drive the car sooner if you pinch the line, but you will also find that you may have to top of the tank more this way too.

 

thank you all for the great information! My Ruby is purring again! Took her down for some detailing, and now she is safely in the garage before these N Texas storms come thru. I apreciate everyone. ��