bleeding the air out of coolant system

[jerrymadd]

Hi

would anyone know how to bleed the air out of the coolant system on the 2001 aurora 4.0. I had the heater hose changed and ever since then the coolant is not circulating throughout the system. As many of you know, there is no air bleed valve on the 4.0.

I haven't been able to use my car for 4 days now because it overheats since the coolant is not circulating. I took it to Pep boys and they stated that it is not the thermostat or the water pump; and that there is air in the system, but they didn't know how to bleed the air from that type of engine.

any help would greatly be appreciated.


jerry

[1996autobahn]

1 after servicing cooling system, use this procedure to ensure all air has been bled from the system. If the system was drained,disconnect lower radiator hose, add 3 pallets of coolant supplement (3634621) into lower radiator hose and reconnect hose.
2 add a 50/50 mix of coolant to surge tank until system (including surge tank) is full. start engine. set climate control to any mode except MAX. set temperature to highest setting.
3 run engine at idle until lower radiator hose is hot. Add coolant to surge tank until tank is full. Install surge tank cap (align arrows on cap with overflow hose). allow engine to cool. Fill overflow reservoir to FULL COLD mark. ;D ;D ;D

[renaldo0613]

I always thought the N* were self burping systems.

[ntrenn]

The problem seems to be hit and miss. The 4.0 never had an issue. The 3.5 was a beaoch.

Adding to the post above - running the engine at 2500 rpm with the surge tank cap off has been known to clear air bubbles.

[renaldo0613]

not self burping, but self purging

[1996autobahn]

Jul 3, 2012 12:38:21 GMT -6 renaldo0613 said:

I always thought the N* were self burping systems.

so did I, but after hearing that there was an issue I checked Mitchell on demand and thought that I would see if it might help. when i replaced my radiator and hose i didn't burp the system, also when i rebuilt my water pump housing there was no burp needed. was kind of surprised to find an actual procedure but there it is.

[jerrymadd]

Thank you all for your comments...much appreciated.

The Master Tech at Pep Boys stated that he bled the system, and that it's most likely the head gasket, which I won't be able to afford. I'm not too sure if he knows Cadillac engines, though. Therefore, I'm taking the car to my old mechanic for a 2nd opinion.

Would anyone know the symptoms of a blown head gasket?

I'm really nervous because the Aurora takes me everywhere, especially to work and back.

Looking forward to a reply. Thanks.

Jerry

[jeremy1980]

I'll throw out some ideas, but someone else might want to correct me if the V8 in the 2nd Gen is much different. I drove a '97 for a while that had a blown head gasket. I've got a '98 now, but the system should bleed itself and remove air in the system.

Need more specifics though on your problem. What kind of temps have you been getting when it has overheated? Does it shoot up real quick, or just start creeping up? I don't know where you are, but considering we've had heatwaves all over the place, even here in Minnesota it was about 95 today and humid. So we're seeing a ton of topics in recent months/weeks of people thinking the car is overheating, but it's just to about 220. These engines run hot anyway, so although I don't like to see it going from 200 to 220, that isn't a concern when the car is sitting for a while or in traffic on these hot days.

As for head gasket, here's what I noticed when the '97 I drove had trouble with that. If it's the head gasket/pulled head bolts what you might notice is the temp shooting up seemingly out of no where. It wouldn't just creep up, I'd be on the freeway and start hearing a dinging. And it doesn't ding unless it is REALLY overheating bad. Won't matter whether you're on the freeway on a cool day or hot. Exhaust gas would be mixing with the coolant due to blown head gasket / pulled head bolts, and since your coolant sensor isn't designed to measure the temp of exhaust gas it's going to throw it for a loop.

Is your tailpipe exhaust more white smoke than it should be? Their is a relatively cheap test to check for exhaust gas in the system. I think they call it a "sniff kit", you could buy it yourself or have a shop do it for you. It uses a special liquid that will change color if it detects exhaust gas in your coolant system while the car is running and the tube will just be placed on where your radiator cap goes. Speaking of which, that's another thing that can cause issues, double check and make sure the guys at Pep boys closed that properly. Are your cooling fans running when it's been overheating, easy way to test them is if your a/c works turn it on and if the a/c is cycling you should hear or feel the cooling fan(s) going to pull air through the radiator. They should be on if it was really overheating. Feel the radiator hoses to see if it's hot after the car is at operating temp for a bit. If they're not, then I'd question whether the thermostat is functioning properly and circulating coolant from the radiator to the engine.

When I replaced the radiator and thermostat on my '98 I refilled the coolant and the system bled itself. As long as your hoses are clear on the top going from the throttle body area back to your overflow, it should remove trapped air quite well.

Those are just a bunch of different ideas on things to check on your own. If you haven't done the "sniff test" before with the fluid that changes color, have your old mechanic do it if he has experience on the Northstars. A lot of mechanics have worked on these engines by now, but if I go to a shop I'd ask a couple questions to make sure whoever is working on it know their way around a Northstar engine. I often say, "this ain't your granddaddies Oldsmobile." These Aurora engines are a tad different.

This got pretty long, sorry for rambling but I'm up late. Good luck!

[ntrenn]

2G head gasket failures are rare. Less than a hand full reported here.

Echoing Jeremy....if you see the needle just JUMP toward the red, it's probably an air bubble, tstat, water pump, clogged rad or some other malady.

My car has NEVER had the needle go past the middle mark. It just sat in 100F weather with the air on while in a store for 15 minutes. If it's working right, that's what you should have.

Most systems need to cycle hot-cold to settle in to the right level too...

[oldwino]

Back when I replaced the radiator on my '02, I didn't have to "bleed" or "burp" the coolant system. Just filled it to capacity and topped up the reservoir a time or two between heat/cool cycles.

[ntrenn]

Are you absolutely sure that the Pep Boys did their job correctly?
No cracked overflow tank
OEM pressure cap
50/50 or better Dexcool or equivalent
Fans coming on correctly


Your symptoms sound more and more like what I had with the LX5 - the water pump just flat out was not putting out enough head pressure at low speeds. Check your water pump belt tensioner.

[aurora2001tan]

Jul 3, 2012 11:31:37 GMT -6 1996autobahn said:

1 after servicing cooling system, use this procedure to ensure all air has been bled from the system. If the system was drained,disconnect lower radiator hose, add 3 pallets of coolant supplement (3634621) into lower radiator hose and reconnect hose.
2 add a 50/50 mix of coolant to surge tank until system (including surge tank) is full. start engine. set climate control to any mode except MAX. set temperature to highest setting.
3 run engine at idle until lower radiator hose is hot. Add coolant to surge tank until tank is full. Install surge tank cap (align arrows on cap with overflow hose). allow engine to cool. Fill overflow reservoir to FULL COLD mark. ;D ;D ;D

Yeah better take it to a real dealer. Pep boys are wrong again. this system bleeds itself. Your pump is what circulates the water....so.......

[jerrymadd]

To be quite honest, Pep Boys had an ASE certified mechanic look at the car, and he couldn't figure out why the coolant wasn't circulating. I spent all day on Saturday at the shop on June 31st. They told me that their Master Tech will look at it on Monday, because he doesn't work on Sundays. I took the car in on Monday, spent all day there, and the Master Tech told me that I would have to leave it overnight. I did. I went there the next day, and the Master Tech stated that he bled the system; however the coolant still wasn't circulating. He stated that it was most likely a blown head gasket and that I should junk the car because it would be too expensive to fix. I asked them if the knew Northstar engines and they said that they were familiar with it. However, it took the first mechanic a long time to figure out the problem because he didn't know how to find the bleed air valve. I told them that it doesn't have a bleed air valve and that there is a procedure that must be followed, but I didn't know how to do it. I'm assuming that the Master Tech knew the procedure.

As for symptoms:
-- no white smoke from exhaust; as a matter of fact the exhaust is working as normally as it did since I owned the car...you can't see anything coming out of the exhaust at all.
-- the oil doesn't look like 'mayonnaise'
-- the oil still has its consistency; I only use Castrol Synthec
-- the fan comes on as usual
-- there is no strange or burning odor either; the only smell of coolant comes from the reside because of the spill from when the coolant reservoir had the leak.
-- no leaks, oil or coolant, after the reservoir was changed.
-- after I drive the car for about 1 mile, the needle begins to move from the mid point to the red; this happens quickly...I don't know if that would be defined as creeping

The first mechanic at Pep Boys stated that it wasn't the stat or the water pump. I really know if either of them, the first mechanic or the master tech really knows Northstar.

The temperature problem began in January. I drove the car for 70,000 miles and the temp needle remained at the normal temp. It never moved. In January, my old mechanic stated that there was oil in the coolant reservoir. He changed the radiator. After I drove the car for a few days, it started to overheat. I needed a tow truck. I complained to him about paying for the tow truck, but he said that it was my responsibility. He stated that the problem was the upper hose, the really big, long one. I asked him how was it possible for that hose to last for 70,000 miles, and the engine never overheated; but after changing the radiator, the engine overheats. He said that these things happen when you remove hoses, and I was responsible for the price of the hose and the labor. I took the car home, and again after a few days, it began to overheat again. There wasn't any more oil in the coolant reservoir tank, and there still isn't any. After that, I took the car at Strauss Auto, and they changed the thermostat. That was in February. The car never overheated again until June when the lower spout of the coolant reservoir had a crack, and coolant was leaking out. After removing the heater hose so that the reservoir can be changed, that was when all this circulation problem started.

A few words about my old mechanic and why I decided to take the car back to him. He was my mechanic ever since I owned the car. Here's a list of repairs on the car ever since I owned it in the fall of '07, bought it used with 68,000 miles (I'm not including regular oil change, or brakes. As I have stated, I only use Castrol Synthec, and Bendix brakes):
- rear ignition coil because of misfire; months later, the front ignition coil was replaced, too, for the same reason
- wheel bearings, front
- that summer, I tried to use the A/C, it didn't work; he told me that it wasn't good and that it was leaking gas. I never bothered to get it fixed because the total parts, labor, and freeon would have been about $1000...and I still don't have A/C since then.
- transmission blew, $1600...$1900 if you count all the taxis I had to take to and from work. I had to take the car back to him a number of times over the course of two months because the tranny wasn't working properly. It has worked fine since then, January 2009.
- tensioner and pulley
- serpentine belt
- engine mounts replaced...twice...over a span of a few years
- electrical problem, car wouldn't start, everything faulted...$550 to fix everything...electrical has been fine since then
- a few years later, the front ignition coil misfired again...had to replace that
- front wheel bearings went again, had to replace it
- last June 2011, the tire iron snapped...and I don't race the car. They tried to do a wheel balance, but the steering is off slightly. It was straight before they changed the tire iron, and ever since then it's been off; and it was balanced twice.
- oil was found in the reservoir, so he changed the radiator (this story is described above).

And so here I am, stuck without a car, with over $9000 worth of repairs over the last 4 years from the same mechanic. I don't know what to do.

I am sure that if it is the head gasket, I'm not going to repair it or change the engine for these reasons: only the driver side window works; the A/C doesn't work; the steering is off ever since the tire iron was replaced; and there seems to be water coming under the driver side carpet.

I've never heard of a car having so much problems.

...and I can't afford a new or used car.

jerry

[jerrymadd]

* I really know if either of them, the first mechanic or the master tech really knows Northstar.

I really don't know if either of them, the first mechanic or the master tech knows Northstar. In truth, I'm not too confident with how they took such a long time to figure out what to do.

[ntrenn]

Jerry,
Sorry your story sounds like a lot of others here. Sounds like you've had more than your share of issues, though.
You're in the right place to commisurate and get the help to get you back on the road.

Your first batch of information all says things are probably good with the head gasket.
Oil in the coolant was most likely transmission fluid.
Upper radiator hose - poppycock!!
N* water pumps don't fail often, but your symptoms really sound like a water pump problem. These engines use quite a bit of head to circulate the coolant, and you can't tell from the outside.

Suggest doing the 2500 rpm in neutral test. Warm the car up by running it at 2500 rpm in neutral until it gets to normal temperature. Have somebody watch the temp gage. If it comes up to the middle mark and stays put - so far so good. Then take the car out and drive at a steady 30 mph. If it overheats (needle shooting toward the red), pop the car into neutral and rev the engine to 2500 rpm. If the temperature comes back down almost immediately, you have a water pump problem. If it doesn't overheat, try a steady 50 mph and repeat the engine revving procedure.

As far as the other maladies - we've all had them. Once you get the overheating behind you, we'll help you through them....

If you bought the car with 68 and have put 60 on it, you're not too far behind me. I bought mine with 43 and have put 120 on it.

[bobsblue95]

Jul 5, 2012 17:48:28 GMT -6 jerrymadd said:

To be quite honest, Pep Boys had an ASE certified mechanic look at the car, and he couldn't figure out why the coolant wasn't circulating.

I heard that ASE stands for Ask Somebody Else!
It sounds like they don't know it well enough to trust them with it (any of your mechanics.) I don't trust anyone with my car. I won't even valet.

[oldwino]

Any reputable parts store will probably have a test kit you can buy that will verify the presence of exhaust gases in the coolant. It should tell you with a fair amount of certaincy whether or not the head gasket is leaking exhaust gases into the coolant, causing your overheating issue.

[jeremy1980]

Water pump suggestion by ntrenn might be your best bet, but I'd suggest replacing the overflow pressure cap to see if it acts the same. Never had issues with them myself, but heard some do and they can cause a lot of mayhem with temp for how cheap and easy it is to replace. Also, feel the radiator hoses to see if they're hot after it reaches operating temp for a bit. Can't recall which one is from the engine after tstat, been a few years since I've dug in there. You may have replaced the thermostat in the past, but we'd want to rule that out anyway. Be careful as your engine will be VERY HOT, and make sure the cooling fans and engine are off before you put your hands down there. That's obvious, but I don't want to get an angry email saying I owe you a prosthetic finger or two.

If you can find a better shop/mechanic and want to further rule out the head gasket, the "sniff test" might cost $50.

Check your auto insurance on that towing thing. It's definitely your responsibility to pay for all that: tow, labor, parts. But many insurance policies include "tow insurance" where they'll reimburse you for towing. Depends on policies, but if you have full coverage or something above the bare bones liability there's a good chance it's covered. In the past I have brought in the tow receipt that I paid and they'll mail me a check for the cost.

In the future I'd also recommend you get other quotes on the expensive stuff. Like your a/c issue, depending on how well the mechanic checked it and how bad the leak is it could be needing to replace all those parts and evac/recharge, or just hook a can or two up and at least hold a charge the rest of the time you've got the car. If it's over a hundred bucks and you're in doubt, I'd check elsewhere just to see what they say. It's amazing how often mechanics (even supposedly "good" ones) are wrong and just throwing darts when it comes to changing parts until they find the right one.

I took my car in for freeway speed vibration. One mechanic said my rack and pinion needed to be replaced, another shop said tie rods, another said nothing was wrong and didn't know what was causing it. I checked around on here and other websites and decided to have the wheels balanced. That solved it! A problem that two guys said would cost several hundred dollars fixed for $24. Stuff like that happens all the time.

[jerrymadd]

Thank you all for your help. I'm still waiting for my old mechanic to check the car. I'll let you know the diagnosis as soon as I have it.

If it's the head gasket, would Steel Seal help?

I'm considering looking for a 2003 Aurora. Is that a good idea, considering all the issues I've had with this car? That is if my current car's head gasket is blown.

Jerry

[ntrenn]

I'm a believer of fix what you have, but sometimes the money pit gets too big.
I've spent less money but lots of time on mine, but it's still the best car I've ever owned.
Wheel bearings - only name brand can be trusted. I buy Timken
Transmissions - change the fluid and screens every 50,000 miles or less whether it needs it or not.
Motor mounts - they fail and take 8+ hours to replace.
Water leaks - sunroof drains leak. Evaporator drains plug. Trunk seals leak. All easy fixes
Doors stop working because of the water leaks. Easy fix, but kinda involved (thanks boldsmobile)
Coils fail.
Intake plenums split.
window regulators fail.
Steering wheel sensors fail
AC systems break and are expensive to fix, even if you do it yourself.

Cars are flipping expensive to repair....$30 part, $500 labor is common....

[bobsblue95]

Jul 6, 2012 10:54:02 GMT -6 jerrymadd said:

Thank you all for your help. I'm still waiting for my old mechanic to check the car. I'll let you know the diagnosis as soon as I have it.

If it's the head gasket, would Steel Seal help?

If it really is HG it *might* help a minor leak, but HG leaks typically get bad fast. I tried the expensive Bar's Leak 3 stage stuff, like $80. I think it bought me about 10,000 miles on my last engine that turned out to have a cracked (porous casting) block.

I'm considering looking for a 2003 Aurora. Is that a good idea, considering all the issues I've had with this car? That is if my current car's head gasket is blown.

Jerry

You know you could probably find someone to swap in a used engine for 2-3 grand. It's no worse of an idea than buying another unknown car with who-knows-what problems looming. All used cars come with their own personality and issues. Are you technically/mechanically inclined?

[bobsblue95]

So this is interesting... I'm changing my oil today because even after gutting my thermostat, the gauge is reading like 220 on up, kinda worrying me. Switching to Mobil1 to make sure it doesn't break down. Anyway, this morning I go to start her to get her up on my "ramps" (don't ask... basically piled wood lol) and as soon as I turn the key on I notice the temp gauge jump to about 115. It was only 85 out, so I hook the Tech1 up and sure enough the ECT shows 118 after sitting overnight. Not cool! (no pun intended.) God I hope I don't have to replace that freakin' sensor!!! Of course I'll start by checking the wiring, but even that is a PITA on the ECT!

[Randy T.]

"after I drive the car for about 1 mile, the needle begins to move from the mid point to the red; this happens quickly...I don't know if that would be defined as creeping"


Sounds like a bad thermostat. If it's overheating that quick something is blocking it. Get a new one from the dealer or pull it out and drive it and see what happens. Someone can say a thermostat is good all day but the symptoms sound like a bad one.

[renaldo0613]

Jul 8, 2012 9:04:31 GMT -6 Randy T. said:

"after I drive the car for about 1 mile, the needle begins to move from the mid point to the red; this happens quickly...I don't know if that would be defined as creeping"


Sounds like a bad thermostat. If it's overheating that quick something is blocking it. Get a new one from the dealer or pull it out and drive it and see what happens. Someone can say a thermostat is good all day but the symptoms sound like a bad one.

Not to jack this thread. But when you pull the T-stat out and drive without it what are we looking for?? To See if it still over heats with t-stat out?? Or if ut doesn't over heat?+

[ntrenn]

Renaldo - yep old trick to see if the tstat is working properly. I've also cooked them on the stove in a pan of water with a candy thermometer.
It's possible that the tstat that went in the car was the wrong type. There are a lot of aftermarket parts that are just enough different to cause issues.....bypass holes a little smaller.....different spring rates....

[jerrymadd]

Good day everyone,

It's been awhile since I posted about my issue.

Still have the same problem. Just drove the car on short trips, about 3 miles, before it starts to over heat. That's basically how I drove it all summer.

Someone suggested that it could be the heater valve for the following reasons (which I failed to mention in this post):
-- there is water coming in on the floor of the driver's side
-- no heat
-- coolant is now leaking from somewhere. It's not the hoses because I checked.
-- I bought the Steel Seal but never tried it. What would happen if I tried it now, with the coolant leaking...even if it's possible that it's not the head gasket. Remember that it doesn't have the symptoms of a blown head gasket: no white smoke, no coolant in the oil...

I really don't know what to do now. I'm a high school English teacher, and school started again. It's tough without a car. I procrastinated all summer because I didn't use the car as much; I used public transportation. However, it's really difficult to start teaching at 7:30 am without the convenience of a car.

Any advice or words of encouragement would be greatly appreciated.

Thank you.

Kind regards,

jerry

[jeremy1980]

I wouldn't use anything other than what GM recommends on these engines, particularly with the cooling system, so I'd vote no on the "Steal Seal". If you want to try a stop leak, the only thing I would use is the GM seal tabs they make for our engines. It's an aluminum engine and Dexcool coolant, so any of the other stuff out there I wouldn't trust. But the others can chime in if they know better than me or have tried it with success.

The seal tabs are only five or ten bucks, and you can buy them at the dealership. I wouldn't put any of the parts store stop leaks in a Northstar engine. GM seal tabs are organic, ginger root if I remember right. You can crush them up if you like and they go in one of the radiator hoses, can't remember whether it's the upper or lower hose. I haven't used it in my car, but others swear by it, and if I was having any leaking that's what I'd put in.

Have you replaced the radiator cap yet or had the "sniff test" done by you or your mechanic?

I wouldn't rule out the head gasket unless you've done some test for it. I had one with a bad head gasket/pulled head bolts, and I didn't notice white smoke, smell, or coolant in oil either. Easiest and cheapest thing to do is the sniff test and replace that cap. Then rule out other areas as mentioned by others.

[ntrenn]

OK...so 4.0, overheats with a wild temperature needle, right?
From the FSM
1. Refill with -34F coolant concentration (50/50 or better)
2. Start the engine
3. Place heater in any mode but max and the temperature on the highest
4. Allow engine to run until the lower hose to the water pump is hot
5. Turn engine off.
6. Allow to cool to ambient temperature and top off at the overflow tank.

So...on the 4.0 it's fill and run.

For overheating:
1. Diagnostic system check
2. Check level and concentration of coolant, inspect for leaks.
3. Run engine at 1200 rpm until normal temp and check with scan tool (yep got one in my back pocket)
4. Verify engine cooling fan operation. They should
5. Inspect for air flow blockages at the condensor/radiator
6. Inspect drive belt system for proper operation (failed tensioners can look fine but don't put tension on the belt sufficient to turn the pump)
7. Inspect for kinked system hoses
8. Check Thermostat operation
9. Remove thermostat and operate engine
10. Remove surge tank cap and check for stream of bubbles in the surge tank
11. If still overheating, flush cooling system to remove blockage
12. Change water pump.

With a 12 year old car, you probably have a bad water pump drive system (belt and tensioner), but I've had:
- Bad water pump (3800 and 3.5)
- Split radiator side tank (3800)
- Bad belt tensioner (3.5)
- Bad surge tank (3.5)
- Bad cap (3.5, 4.0, 98, lots of cars)

For the water on the floor - if it's not coolant, it's either the sunroof drain or the evaporator drain. Search for fish lips and you'll find how to fix the evap drain - take a rain coat.
For the sunroof drain - I just put a cork in my bad one - driver side front.
No heat - evap overrun with water causes this ask me how I know...
Still losing coolant - how much? quart a day?

And...where do you live? Maybe we have some help fairly close by. PM me your phone number - maybe we can talk through it....

Can't recall a bad tstat ever...

[jerrymadd]

I live in Queens, New York City. I don't know if you're anywhere in that area. If you are, I could have it towed to you. Any help would be great. I'm trying to stay away from buying a new car...it's been too difficult saving money...and this car has used up so many of my resources.

I still don't know why coolant is now leaking from the engine area. It's not leaking from any of the hoses...I checked. It appears as if it's coming from somewhere around or within the engine. It wasn't doing that before, it was just overheating. Now there is a leak somewhere. Someone suggested that since I was driving it locally, a lot of pressure might have built up and caused the coolant spew out from somewhere difficult to assess.

[roara]

What about a cracked expansion tank? Can you feel underneath and check for "wet" ?
Also I find looking in the engine area after dark with a flashlight is easier to spot things than fighting reflections in the daylight.