02 Bravada dies on Interstate....Cause?

[Mooseman]

IIRC, OEM rads did not have the drain. Or maybe certain years. Most aftermarket ones do. This is GM's idea of cutting costs. They did the same on the rear diff.

For the clip. if you have a pick-n-pull nearby, just go for a walk and grab one.

 

[1968Case580CK]

Question for Thermostat experts:

The new Thermostat arrived, and I did a side-by-side comparison of them (pics below). I was expecting the new one to have a "shut" valve, especially since it was 35 degrees outside on the porch where UPS left the box......but when I opened it, the thermostat valve was in the same position as the old (bad) thermostat. Old on left, and new on right:





Shouldnt the brass stopper be totally "shut" and resting on the round metal flange just below it? Or, is the "stopper" action taking place up inside, at the other end of the thermostat?

The only other difference is that it "appears" that the spring is wound with one more twist on the old therm.

Since the check engine light has been on, and indicating a Code P0128 (coolant temp too low), how do you verify that the therm is actually bad?

MRRSM.......Good video on how to remove those fuel line metal connections.....now I know its best to have those proper removal tools. I will go tell Homer to stop pulling on the rope.

 

[TollKeeper]

The way to test your thermostat is to get a boiling pan of water, remove from the stove, and place the thermostat in the water, and watch for movement, the internal wax should melt, causing the spring to open the thermostat.

 

[1968Case580CK]

TollKeep.......I guess you could use a thermometer and when watch as the water gets around 190 degrees, as thats when they are supposed to open up.
Just wondering if I install the new thermostat, and the check engine light still comes on and warns "coolant temp too low", then what else could be the problem?

 

[Blckshdw]

@1968Case580CK I just replaced my t-stat a couple weeks ago, my old one (on the left) was stuck open, the new one looked the same as yours, so I'm thinking both of yours are closed?

 

[1968Case580CK]

Blckshadow...Great pic there. Well, your pic confirms that "stuck open" is when the brass core is about flush to the lower flat plate.......so the closing "gate" portion of the thermostat is up inside the pipe, not at the bottom that we see in the pic.
Im guessing that maybe my thermostat was just wearing out and opening around 175 degrees instead of 190.......so it was working, but not as it should....and causing the engine light to come on.

 

[Blckshdw]

My truck was getting over 190 (eventually) due to the FL heat, but once November rolled around, I noticed a drastic change, and it never warmed up. Now I get up to 195 pretty quickly, no more than 5 minutes of neighborhood driving, and it stays between 195 and 200 after that. No CEL came on though.

 

[1968Case580CK]

Blckshadow......Well, I hope my new therm does as your is, and with no CEL coming on. I sure could use some of that FL heat now.....up here in Va, got some snow flurries today, about 35 all day.

 

[mrrsm]

If your Repair Sequence leads up to THIS issue... These Two Videos cover "How-To" R&R ...First The Fuel Tank...

...and then he has another "How to R&R The TB Fuel Pump".... However... The VOP (Video Original Poster) SHOULD Have Chocked the TB Front Wheels with the SUV sitting on an Incline... and of course... He chose the WRONG, CHEAP NON-OEM QUALITY FUEL PUMP ... instead of getting a DELPHI or BOSCH Replacement Version:

Check out that BROKEN GROUND-BONDING STRAP for Breaks or Rusted and Poor Contacts with the Body. THIS is the only thing that prevents an external Static Electric Shock from sparking into the Open Gas Tank Neck and it deserves an immediate repair.

 

[1968Case580CK]

MRSSM......Good videos of the tank removal.....not something I really want to do. I agree......sure could use some wheel blocks on those front tires.....hopefully he did not leave it in neutral. But I think you will cringe when you see how I was supporting my old Case backhoe when tearing off the front wheel spindles......do I hear the sound of cinder blocks cracking? I guess we all take unnecessary risks when dealing with stubborn projects..........

 

[NJTB]

While you're in there replacing the thermostat, put a coolant temp sensor in it too. It's right above the thermostat. A few wraps of teflon tape will help ensure there's no leaks. Ask me how I know.

 

[1968Case580CK]

NJTB.....That was a good idea, but I already put it all back together, and luckily the temp sender is working perfect.....did a test drive last night, and now the operating temp is getting back up to 190-200, while it had been only getting to 175 with the old thermostat. So, now the mixture can lean out properly and not clog up the catastrophic converter.

Now gotta remove the throttle body and clean it properly, and the Mass Air Sensor....got the proper CRC sprays for each.

 

[1968Case580CK]

Pics of the Throttle Body before/after cleaning:

Throttle Body before removing:



Airbox side before cleaning:



Intake manifold side before cleaning: (Almost as dirty as the inside of my chimney)



Airbox side after cleaning: I found that using an old toothbrush along with the Throttle Body Spray works great.....spray, brush, wipe off, and repeat until clean.



Intake manifold side after cleaning:
Clean enough to eat off of, I suppose. After seeing the huge amount of soot on the inside of this Throttle Body, I cant see how people claim to clean these just by spraying cleaner on them while it is still installed on the engine.





I thought this 02 Bravada had a Mass Air Flow sensor to clean, but today I learned that apparently the 02s did not have them. This sensor to the right side of the Throttle Body is apparently a "MAP" (manifold pressure) sensor. Can these be cleaned by spraying cleaner into the hole?



Hope these pics help someone else who wants to clean the Throttle Body.

 

[1968Case580CK]

Another question:
Here is a pic of the plastic "intake manifold" to the right of the Throttle Body. It is pretty fouled-up with oily/dirty residue. I used a rag soaked in gas to reach inside and remove alot of the black mess. Is it reccomended to remove this box for a thorough cleaning, or not really necessary? If this is just air intake, where does all the oily crapola come from?

 

[Blckshdw]

If this is just air intake, where does all the oily crapola come from?

On the intake resonator box that sits on top of the ignition coils (you probably have some buildup inside there as well), you'll notice a small rubber hose that connects to a port on the front passenger side of the engine... That's your source.

 

[Mooseman]

And it's considered "normal" for this engine. It's part of the PCV system. In fact, the engineers built-in some trickery that over time, it will adjust the idle air to compensate for this crud but if you disconnect the battery, it will lose that and idle like crap. You have to disconnect the battery for 30 minutes to reset it after cleaning or it will run almost as bad.

 

[1968Case580CK]

Blackshadow......I had already cleaned the intake resonator box above the coils, but the innards were not that dirty.....its on the right-hand manifold box that really gets that oily grim. Seems to me that a patriotic non-EPA-complying guy could just route that little vacuum tube downward near the base of the oil pan, and just put a cap on the manifold box nipple.......that would keep that box nice-n-clean. But does this adversely affect the vacuum pressures and computer data?

Mooseman......Instead of disconnecting the battery, I got Youtube info on unplugging two fuses for 30 minutes which does the same thing. I used the code reader to delete the Check Engine Light, took her for a test drive, and so far the light is not coming back on.

Another question: If the Catastrophic Converter is getting clogged-up, will I get a Check Engine Light to alert me?

 

[Mooseman]

Mooseman......Instead of disconnecting the battery, I got Youtube info on unplugging two fuses for 30 minutes which does the same thing. I used the code reader to delete the Check Engine Light, took her for a test drive, and so far the light is not coming back on.

Yep. that'll work. That should also clear the codes at the same time.

Another question: If the Catastrophic Converter is getting clogged-up, will I get a Check Engine Light to alert me?

Not if it's just clogged. The downstream O2 sensor just checks for efficiency, not flow. Only a backpressure test or pulling the upstream O2 sensor can confirm this.

 

[mrrsm]

JFTHOI... If your Air Box Feed Tube sports one of those "Warning Devices" with the Colored Warning Bars to alert you as to when its time to "Change The Air Filter"...besides changing that filter out just as a matter of course...given the condition of the Carbon/Dirt/Gas Vapor Lacquer build-up on the Throttle Body Butterfly Baffle... take a minute and look very carefully at that Damned Plastic Thingy... with a very jaundiced eye. You would be surprised how often the Cap on those devices can easily get unscrewed ...and just fall off.

This of course allows for Un-Filtered Air to sneak around and bring in a ton of airborne Silicate particulates that will accelerate Piston Ring(s) and Cylinder Wall wear and tear. If it is missing in your case... its's absence might also explain why your Brass TB Baffle Plate was so mottled with solid stuff glued in place with all of the other crap that the Half-Assed PCV system allows to recirculate back into the Intake side of the Engine. This becomes a greater real nuisance for anyone living where dust blown sand is more prevalent as well.

 

[1968Case580CK]

MRRSM......Sorry for the delayed reply (not sure if I got an email alerting me). Thats a good suggestion about checking the "Colored Warning Device". I forgot the proper name of that rascal, but its that green/red colored devide that looks like a fuel filter and plugs into the black air intake line (upper left corner of 1st pic, and to left of big white air filter in 2nd pic).





You are right.....if that cap falls off, it will suck a ton of crap right into the air intake, totally unfiltered. Mine still has the top on it, but I will definately inspect it more often.

Speak of bringing in "unfiltered air", I forgot to plug in the front vacuum line (small line with the 90 degree elbow, top left of Pic 3) after doing all the throttle body cleaning and reseting the computer, I drove it with that vacuum line off for the first trip. Maybe this is why the idle was a bit higher than normal. (I used to be able to pop the tranny into neutral while going 55 and let the car glide down the off ramp, and the tach would go down to around 800, and then drop to 600 when I came to a stop. Now, the tach wants to stay up around 1600 when I pop her into neutral, but does come down as I slow down, and then hits 600 when I come to a stop. I guess the computer is re-learning, and will eventually allow me to coast at high speeds at a lower RPMs?



Thanks again for all the help from everyone at this site.
(I did buy a infrared thermometer, and will check the temps at the front and rear of the catastrophic converter to see if it is still good.......I will post the results when I do it). Car seems to be running great, but I have not tried towing 5000 lbs up some long mountain grades.