I've read a few threads and was wondering the proper procedure to bleed the system. There is a bleed screw at the top of my thermostat. Opening that with warm, running engine seeps bubbles for a while (10+ minutes)

Do I need to go longer? Is there a better way to properly bleed the system?

 

The engines are supposed to be vacuum bled.

That said, I did what you described about a year ago when I replaced most of my coolant, and it's been fine.

A caution: I only drained the radiator petcock. If someone opens the block drain as well, air bubbles may get trapped in places that don't when only the radiator is drained. So i can't be sure if there's a difference in bleeding effectiveness one way versus the other. Also, I don't know how much more is drained when the block drain is opened. I figured it couldn't be much, so didn't worry about it.

 

Or... from the service manual and completed by me many times....

 

You've got to bleed the SC coolant circuit as well by opening and filling the large hex plug on top of the supercharger.

 

Guy... How would this "non vacuum fill method" be utilized for the non supercharged 5.0 engines? Where are the bleed locations and in what order are they done? Is there a particular step by step procedure?

 

It's dependent upon what parts are being replaced. If the full system's been drained, it's going to be hard to refill without any air trapped and without use of vacuum filling. I know this from personal experience. The screws will be located at the highest points, one at the right rear of the engine and one on the reservoir. Open those, turn heat to max on climate system and fill cooling system through the reservoir, air should be hissing out through the open bleeders. Helpful tip, it's likely you will need new bleed screws so have those handy prior to beginning the procedure. The old plastic ones typically crack, break and leak.

 

jahummer...That's a wealth of great information. Especially on replacing the bleeder screws as I wouldn't have thought of that! Crazy, that even the bleeder screws are plastic! My indy will be replacing almost all the plastics pieces (but not the water pump and the outlet tube) including the front and rear crossovers, thermostat housing including the thermostat, the newer upgraded hose that goes into the front of the water pump bleed, engine coolant overflow hose, throttle body hose (long hose running along the intake, from rear crossover to the front engine/intake area) and all intake gaskets. If anything else is suggested I'll get it. My Indy insists that he won't need the vacuum fill method, and the shop foreman at Jaguar told me that although they use the vacuum fill method at Jag, the coolant fill can be done without it if the tech knows his stuff. If you or anyone is able to supply me with the part numbers of the bleeder screws you have mentioned, that would be great! Thanks again for this great info.

 

For the non-supercharged, 4.2, as per the workshop manual:
1. loosen coolant expansion bleed screw
2. fill expansion tank.
3. when coolant runs bubble free from bleed screw, close it.
4. Fill tank to full mark. replace cap.
5. set heater controls to max and start engine
6. wait for warm air from climate system
7. shut off engine, top up coolant.

There is no mention of ‘under pressure’ or a ‘bleed from engine’. 5.0 engine of course, is different.

 

All of you inspired me… so I read the 5.0 l workshop manual.
Yes, there is the vacuum fill method…. but it is optional. There is the traditional fill method as well. What I found interesting is that in this method, one follows the procedure like we have done for years… While the engine is running, keep filling the expansion tank.
The part about the first fill and raising the expansion tank is interesting and makes perfect sense as the tank is lower than the supercharger.

The part about the Auxiliary Radiator was interesting, too.