Best way to "burp" cooling system..

[GTU89]

Okay, I "burped" the system yesterday by taking the rad cap off and loosening the thermostat vent bolt thing. Is that the best way to do it? I may go back and do it again to be sure, and I'd like to know if it is the best way to do it.

[Money pit Beretta]

The cap is the best way, I sure miss having one on the radiator.

[Rettax3]

Another good thing to do after that is to warm the car to operating temp, vent the cap (carefully -don't get burned!) to let out any air from the system, and let the engine cool and draw coolant back in from the reservoir. Doing that twice usually cures it.

[GTU89]

Okay, this is a fairly large bump.

But, I just finished burping it again as it hasn't warmed up since before this thread.

I did as follows:
Ran it for about 25-30 minutes (only 2-3 bars of heat on the digital dash!)
While it was running I slowly loosened the cap to let some air out (helped a bit)
Left it running with the cap off, squeezing the upper rad hose to help it along
It FINALLY got to running temp (45 minutes in?) after adding alot of coolant

But it was still bubbling a bit when I finished, it was getting dark and it is in the single digit to low teens temp wise here, so it was cold lol. Assuming it warms up alright tomorrow, does anyone think I should mess around some more with it? Do the same as before or better suggestions?

How long should it take it to get to operating temp (half way on the digital dash) so I have an idea of if it is good or not?

[Rettax3]

Yes, if you have the time to burp it out again, you should try. Those heads are aluminum, and don't much care for running on steam! Incidentally, both of my operable digi-dash cars only run four bars at full operating temp, five is a little warm, six is ready to boil-over. But my GTU has the temperature sender in a non-stock spot due to the 3800 swap, so that may not count, and I haven't actually over-heated the Yellow Indy, so I may be wrong on the six-bars-is-too-hot thing with that car, but it seems to run about the same indications as the GTU...

[GTU89]

Yes, if you have the time to burp it out again, you should try. Those heads are aluminum, and don't much care for running on steam! Incidentally, both of my operable digi-dash cars only run four bars at full operating temp, five is a little warm, six is ready to boil-over. But my GTU has the temperature sender in a non-stock spot due to the 3800 swap, so that may not count, and I haven't actually over-heated the Yellow Indy, so I may be wrong on the six-bars-is-too-hot thing with that car, but it seems to run about the same indications as the GTU...

Well, hopefully it is better, I'll mess with it again tomorrow to make it right. I'm guessing it never warming up (closed loop?) is why my O2 sensors kept dying (fouled?) and why I am getting 15.5-16mpg avg.

[Rettax3]

That is likely your problem. I mentioned in another thread some 'spirited' driving I did with my Indy recently, and how it dropped the MPG out the bottom, but I think it had as much to do with the fact that the engine (and O2 sensor) was still cold as with the driving conditions and style. These F/I systems don't like short hops. You could upgrade to a heated O2 sensor, that has been discussed recently too...
But, the O2 sensor being at operating temperature has nothing to do with whether or not your engine coolant is at operating temperature, and I think even the OBD-1 systems know if the sensor is not heating up properly and will throw a code, although I don't recall it complaining about taking too long for the engine to warm up, like the OBD-1.5 and OBD-2 does.

[Money pit Beretta]

Is the upper hose getting hot(upper intake too)? I think your gauge is off.

[berettaboi]

if you think that your car takes an obscene/unrealistic amount of time to warm up, (remember that newer cars do warm up a lot quicker), you may have a "stuck open" thermostat. not amount of burping the system will allow it the heat up quicker... it's actually the opposite> more bubbles usually means the coolant is already boiling/or has air bubbles blocking smooth passage, and it can overheat pretty rapidly if the coolant flow is impeded in any way

[GTU89]

Well, I'll look into the t-stat but I'm pretty sure its air in the system. It has gotten better since burped. And I meant maybe the o2 was being fouled or maybe they werent actually bad because it should run richer in closed loop mode, right?

And I dont recall it having warming up issues until we replaced the water pump and had the upper (and maybe lower?) Rad hoses off for a different repair. The upper rad hose was hot/warm this last time, and the plenum was warmish/hotish after todays hour long burping session, neither really got very warm before.

And im sure the gauge is fine, the heater has gotten much warmer.

And sorry if this is incoherant, posted from my phone.

[Rettax3]

Closed loop means that the ECM is receiving usable data from the O2 sensor, meaning it is warm enough to send a signal. Open loop is run off pre-programmed tables in the ECM, and is usually rich -so you have the concept right, just the titles backwards.

As I said though, the O2 sensor is warmed by the exhaust-gases (since it isn't a heated O2 sensor), and until that is hot enough, the ECM cannot use its' data. Whether or not your engine coolant is warm is irrelevant to the temperature of the O2 sensor, and I don't recall that our ECMs are programmed to wait until the coolant reaches a certain temperature before they switch to closed loop mode, although I could be wrong about that. I am pretty sure that our ECMs switch to closed loop mode and adjust the mixture from O2 sensor feedback once the sensor itself is warm enough to provide the Lambda signal to the ECM. For sure, it works the other way, if the ECM tries to receive O2 sensor data and cannot switch to closed-loop mode when it thinks it should, you will receive a check-engine light as it determines your O2 sensor has failed.

[Beretta1234567]

I just left the cap off and ran the engine until it got hot enough for the thermostat to open.

Then I had someone rev it a little as I added coolant and replaced the cap. Not the greatest way as sometimes coolant comes out. But seemed effective enough for me. Only catch is you have to sit there and watch it the whole time.

[GTU89]

Yeah, pretty much what I did, except I "massaged" the rad hoses to help.

But I think most of my problem is actually a kinked coolant hose, the one under the throttle body that is in a L shape, it is kinked, I unkinked it as much as I could and it made a big difference, but it still isn't really close to right, and I don't believe they make that hose new from checking around.

[Rettax3]

If you are talking about one of the hoses going to the TB itself as an anti-icing heater, unless the metal tub running beneath it (as a bypass) is clogged, that little hose shouldn't matter so long as burping air out of the lines is concerned. But if you are referring to the supply line from the lower intake manifold to the piping, then that may have been a big part of your problems all along.

[GTU89]

Nope, doesn't go into the TB, I think its the one you mentioned second. I'll try to get a pic then, its an L shape and there is a straight one beside it that goes into a metal line I think. And yeah, come to think of it, it didn't do any of the warming issues until we replaced those hoses, which apparently weren't close enough. And my original rad cap was leaking too, which wasn't helping anything.