97 3.1 Cooling system Issue........

I have a 97 3.1 Lumina that had a front end collision back in 01, and since then I haven't driven it. I recently crashed my Jimmy :( so I needed a vehicle, and embarked on a repair mission on the Lumina.

So, a long story short I replaced the smashed leaky radiator, and when refilling after repair I could could only fit 4 qts water into it, and heats up to around 180-200 (above normal temp), no heat comes out, and the water boils into the resoivor tank. Then, it sprung a leak from a small rubber hose underneath the air intake. That hose comes off of a metal hose that runs from the top of the water pump, across the block along the exhaust manifold heat shield, then underneath the throttle body (where it has 2 rubber hoses coming off, 1 of those leaking, going into the block) Is the cooling system clogged? What is the purpose of that hose, what is it? What are other possible diagnosis for this? Also, I did NOT replace the A/C condenser since the radiator support was smashed so bad it didnt fit. Suggestions anyone? Please help. Thanks...

It sounds like a few things; (1) you may have a bad thermostat, if its stuck in the closed position, it would cause your car to overheat; (2) not getting heat inside the car and the temp gauge is reading higher than normal suggests that an air pocket is trapped in your cooling system, and it needs to be bled. The small rubber hose coming off of the metal pipe is your throttle body coolant bypass hose. I think the purpose of that is to send a little heat to the throttle to prevent icing during cold weather (kind of like the old caburetor preheat hose). Not replacing the A/C condensor would not affect your cooling system. Hopefully, the bubbling in your reservoir is because of a stuck thermostat and not because of a blown head gasket.

The 3.1 engine requires a specific coolant bleed proceedure any time the cooling system is opened. Air gets trapped in the upper end of these engines, and that's what the two little brass valves (one on the t-stat housing, one on the transfer tube end near the water pump) are for. Failure to bleed the system will cause the symptoms you describe, and can lead to overheating and head gasket failure, so don't dirve the car until you bleed the system.

Thanks for the help so far...

When I replaced the rad I bought and tried to install a new thermostat as well, but I could not get a good angle on the bottom of the 2 screws to take the housing off (throttle body/exhaust heatshield in the way), and I didnt want to try to take the throttle body off, so i couldn't install it. The haynes manual picture makes it look easy (like the throttle body isnt jammed right above it).

Any suggestions on how to easily replace the thermostat?
Maybe it's just me but it's not nearly as easy as I've seen in other cars.

Also, the metal pipe I described that goes off the water pump, across the engine, and into the firewall (that has 2 rubber pipes going off it under the throttle body, one of them that sprung a leak) I think that that's the line to the heater core? Anyone know about that? Thanks for your help and time.....

I have something similar.

My engine will run about 45 minutes before it overheats due to lack of coolant.

The coolant dissappears, then it starts to overheat, the vapor bubbles into the plastic overflow tank.

1. I blew up the radiator water hose because the excess of pressure.
2. It blew the "low coolant" sensor out of the radiator.
3. It blew the radiator side reservoir because of the excessive pressure.

The overheating tents to find a path of least resistance to vent, blowiing the weakest links in the cooling system.

It appears this is caused by a leak in the intake manifold that drains the coolant.
I will have this gaskets replaced tomorrow.
Will post results.

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I have a 97 3.1 Lumina that had a front end collision back in 01, and since then I haven't driven it. I recently crashed my Jimmy :( so I needed a vehicle, and embarked on a repair mission on the Lumina.

So, a long story short I replaced the smashed leaky radiator, and when refilling after repair I could could only fit 4 qts water into it, and heats up to around 180-200 (above normal temp), no heat comes out, and the water boils into the resoivor tank. Then, it sprung a leak from a small rubber hose underneath the air intake. That hose comes off of a metal hose that runs from the top of the water pump, across the block along the exhaust manifold heat shield, then underneath the throttle body (where it has 2 rubber hoses coming off, 1 of those leaking, going into the block) Is the cooling system clogged? What is the purpose of that hose, what is it? What are other possible diagnosis for this? Also, I did NOT replace the A/C condenser since the radiator support was smashed so bad it didnt fit. Suggestions anyone? Please help. Thanks...

I have something similar.

My engine will run about 45 minutes before it overheats due to lack of coolant.

The coolant dissappears, then it starts to overheat, the vapor bubbles into the plastic overflow tank.

1. I blew up the radiator water hose because the excess of pressure.
2. It blew the "low coolant" sensor out of the radiator.
3. It blew the radiator side reservoir because of the excessive pressure.

The overheating tents to find a path of least resistance to vent, blowiing the weakest links in the cooling system.

It appears this is caused by a leak in the intake manifold that drains the coolant.
I will have this gaskets replaced tomorrow.
Will post results.

================================================== ===

Do you have any other drivability issues? Bubbling in the coolant reservior and excess pressure (compression escaping from the combustion chamber), unfortunately sounds like a blown head gasket. When your coolant disappears, does it puddle on the ground, or is nowhere to be seen? Check your oil dipstick and filler cap. If your oil is milky brown, you may have a head gasket problem.

Overheating due to lack of coolant shouldn't cause pressure that high.

Thanks for the help so far...

When I replaced the rad I bought and tried to install a new thermostat as well, but I could not get a good angle on the bottom of the 2 screws to take the housing off (throttle body/exhaust heatshield in the way), and I didnt want to try to take the throttle body off, so i couldn't install it. The haynes manual picture makes it look easy (like the throttle body isnt jammed right above it).

Any suggestions on how to easily replace the thermostat?
Maybe it's just me but it's not nearly as easy as I've seen in other cars.

Also, the metal pipe I described that goes off the water pump, across the engine, and into the firewall (that has 2 rubber pipes going off it under the throttle body, one of them that sprung a leak) I think that that's the line to the heater core? Anyone know about that? Thanks for your help and time.....

I'm having the same problem. I managed to get the entire cooling system out of my father in law's 99. Can get the damn thermostat though. Spent a few hours trying to get it off last night. I think you just gotta take the throttle body off.

Do you have any other drivability issues? Bubbling in the coolant reservior and excess pressure (compression escaping from the combustion chamber), unfortunately sounds like a blown head gasket. When your coolant disappears, does it puddle on the ground, or is nowhere to be seen? Check your oil dipstick and filler cap. If your oil is milky brown, you may have a head gasket problem.

Overheating due to lack of coolant shouldn't cause pressure that high.

================================================== ==
Hello Everybody:

Just to give closure to the case.

I forgot to mention that I had thrown away the thermostat some time back.

The oil was clean at the disptick and the oil cap. No signs of water or rust.

Had the car at the mechanic while the Hurricane was coming through
Florida.
When I got the car back I didn't had the chance to see the Intake gaskets. I only saw one of the head gaskets. Had signs of water leakage.

Since then I have drove the car for several days and the needle fluctuates between 1/4 and 3/8ths of the gauge.


Good luck to everyone else

Allan

FYI to all concerned:

At least the 3100 engines, if not the 3400, have unreliable intake gaskets which erode from any type of coolant you use, not just long-life.

This is a known issue with 3100 engines; confirmed by my mechanic and my brother in law's mechanic.

There are replacement intake gaskets made of a better-quality, reliable material but be forewarned this takes ~6 hours of labor to replace with a mechanic.

I still say from what Suke described, that the bleed proceedure wasn't done properly, causing steam to build up in the upper intake and now more problems have cropped up. The intake gaskets are suspect, but Suke gave no indication that there was a problem prior to the accident that led to the new radiator and t-stat, and refilling the cooling system, just my :2cents:

I still say from what Suke described, that the bleed proceedure wasn't done properly, causing steam to build up in the upper intake and now more problems have cropped up. The intake gaskets are suspect, but Suke gave no indication that there was a problem prior to the accident that led to the new radiator and t-stat, and refilling the cooling system, just my :2cents:

I'm not debating, I just wanted to give a heads-up on an alleged known-issue with these engines, that's all. I figured I'd put it in a somewhat-relevant thread than make a new one. :)

no offense taken, you make a good point bhame, and it's always good to present other known problems. Since it seems that the car has been run hot, then the intake gaskets SHOULD be checked at this point for sure. What I was getting at is that if the bleed proceedure isn't followed properly this time, no matter what they do, they'll be doing it again. I have always supported any and all suggestions on this forum as long as they aren't personal attacks, so don't worry if you thought you may have stepped on my toes, we're good. Every bit of info a person gets is helpful.

The 3.1 engine requires a specific coolant bleed proceedure any time the cooling system is opened...

I'm pretty stupid: can you describe for someone like me this specific procedure please?

The actual step by step proceedure is in most good repair manuals. I've posted this before, let me find it and I will post a link, as it's a lenghty proceedure.

The actual step by step proceedure is in most good repair manuals. I've posted this before, let me find it and I will post a link, as it's a lenghty proceedure.

I very much appreciate that, and I will do some more searching in here in the meantime.

OK, I've found the following links:
http://www.automotiveforums.com/vbulletin/showthread.php?t=429431&highlight=bleed+coolant
...not super-descriptive but informative...

http://www.automotiveforums.com/vbulletin/showthread.php?t=367854&highlight=bleed+coolant
...a little more description...

BTW, should the screws be replaced while the engine is running, or shut engine down first?

http://www.automotiveforums.com/vbulletin/showthread.php?t=289873&highlight=bleed+coolant
...a different-sounding (to me at least) method of bleeding...

http://www.automotiveforums.com/vbulletin/showthread.php?t=249185&highlight=bleed+coolant
...a third recommendation, from my ignorant perspective...

I found these under a search in the Lumina thread, "coolant bleed". I believe you that you've posted it - it's just that I'm unable to find it. :)

I'm still trying to find it too, it may have been over at the Grand Prix forums, I'll check there.

You'll want to close the screws while the engine is still running. The goal is to seal the system when it is void of air and the coolant is expanded; this allows the cooling system to draw in coolant from the resivoir when it cools down, rather than from the bleed screws (if you left them open).

I'm still trying to find it too, it may have been over at the Grand Prix forums, I'll check there.

No problem: I know how difficult it is to trace my own steps in forums that I've participated for a while too! I appreciate everyone's assistance in helping me understand this procedure better!

You'll want to close the screws while the engine is still running. The goal is to seal the system when it is void of air and the coolant is expanded; this allows the cooling system to draw in coolant from the resivoir when it cools down, rather than from the bleed screws (if you left them open).


Ahhh...that makes sense, yes!

So far I gather that I...
unscrew the two bleed screws
start the engine
wait until coolant is spewing from both bleed screws
screw the bleed screws back in
and that's it?

I assume I'm still missing something because that sounds too 'typical' compared to peoples' comments that the 3100's process differs from 'typical'.

I'm still trying to find it too, it may have been over at the Grand Prix forums, I'll check there.

Hey, I found this: http://www.automotiveforums.com/vbulletin/showthread.php?t=436768&highlight=bleed+coolant

Where you say:
"I know you said you bled the system, but these cars can be darn near impossible to bleed. Because of how quickly you're getting steam, it sounds as though you still have air in the system. Here is how I bleed these engines. Jack the front of the car up so that the radiator cap is higher than the engine. Leave the t-stat and housing off, and s-l-o-w-l-y fill through the radiator until coolant comes out the intake where the t-stat should be. Now install the t-stat and housing, and remove the small hose at the transfer tube where hooks to the engine (leaving the rubber hose hooked to the transfer tube). Crack the bleeder at the t-stat housing, and insert a small funnel into the hose on the transfer tube that you disconnected from the engine. Again, s-l-o-w-l-y add coolant through the transfer tube until it comes out the bleeder at the t-stat, then close the bleeder. Continue to add coolant until it comes out the pipe on the engine where the hose you're filling through attaches. Hold your thumb over the pipe, remove your funnel, and quickly re-attach the hose to the engine, doing your best to not let air in or too much coolant to escape. Finish filling the radiator, replace the cap, and fill the coolant reservoir. Start the engine an let it run until it gets warm, (set the heater to hot so coolant circulates through the heater core also). After the engine starts to warm up, crack the bleeder at the t-stat to see if any air/steam escapes. if not, you're done. If it does, keep working the bleeder until no more air escapes. Good Luck!"

Is THIS what you want me to read?

That's the one I was trying to find. I've used that proceedure on many 3.1's and 3.4's and have had excellent luck doing it that way.

That's the one I was trying to find. I've used that proceedure on many 3.1's and 3.4's and have had excellent luck doing it that way.

Well since I wasn't going to drain/refill I just did the bleed portion.
Where I park at our apartments is on quite a steep-incline as is so I didn't really need to jack up the car.

One thing I noticed is that the bleed valve by the water pump sprays coolant intermittently: and having nothing to do w/the T-Stat opening/shutting - I kept testing the pre/post temps w/an IR thermometer at the coolant housing and it took about 10-15min. before it got up to the upper 180°'s - but until then, for about 5-20 seconds each, the bleed valve by the water pump started spewing coolant. How can that be if the T-stat is shut. There was NO pressure in the hose to the T-Stat...I don't believe it was erroneously-opening/shutting.

Anyways, once the T-stat obviously opened and the coolant spewed, I rescrewed the valves as soon as the T-stat shut. I'll let everyone know if the temps spike again.

Does the T-stat valve (is it truly a valve, looks like a normal bolt to me) need ot be completely-removed? It was so far out I didn't dare unscrew it anymore: SOME coolant dribbled out: should it be spewing as much as the water pump valve did?

The t-stat valve should spew more than the water pump one. IF it is just trickling, your t-stat may not be opening all the way.

Urgent question: should coolant always be sitting idle by the T-Stat? i.e. - should I be able to open that 'valve', squeeze the hose and coolant pour out?

I just had my T-Stat replaced, my problems are worse than ever, and there is NO coolant in the hose from Rad to T-Stat until engine goes >185°F (or so), and even then the coolant comes through intermittently: spitting out the brass bolt pre-T-Stat.

Is my mechanic screwing me over? I've spent a huge amount of money in this.

The t-stat valve should spew more than the water pump one. IF it is just trickling, your t-stat may not be opening all the way.

I've had two non-mechanics tell me the typical way a cooling system works is that a water pump pulls cooled coolant from radiator, through engine, out thermostat and back into radiator.

If this is true, then I don't see why the T-Stat's bleed valve should spew more coolant than the water pump's bleed valve...wouldn't it be the exact opposite?