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Coolant overflowing from rad with engine off and cold


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highmfer
Novice

Dec 19, 2015, 9:47 AM

Post #1 of 16 (954 views)
Coolant overflowing from rad with engine off and cold Sign In

Year 2003
Make Pontiac
Model Montana
Engine size 3.4
Mileage/Kilometers 225 000km

To start at the beginning: started losing cabin heat, intermittent heat(cool on idle, warm while driving) Water pump and t-stat were replaced with new parts. System was filled and bled.(bleeding done three times to ensure straight coolant flow from bleeders). Van does not overheat, take to long to reach op temp, blow white smoke from tail pipe, no oil in coolant or vise-versa. Fans come on and work properly. but still no cabin heat.
Now the really puzzling part: when i removed the rad cap to check level of coolant, coolant poured out of the filler. Engine was COLD and NOT running. Front end was jacked up so rad was highest point. I then squeezed the lower rad hose to look for bubbles, none. I squeezed the hose until level in rad was low enough to see top of rad fins, waited a sec and the level began to rise again to the point it overflowed again. At this time the overflow reservoir was empty, so it wasn't refilling from that. I'm really stumped here, any help would be appreciated!



Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

Dec 19, 2015, 10:11 AM

Post #2 of 16 (951 views)
Re: Coolant overflowing from rad with engine off and cold Sign In

The symptom is air still in or being pushed in as vapor from failed gaskets - any that carry combustion pressures or exhaust.
You've done what most would to bleed it out but some just will NOT without a vacuum fill by machine or even more extremes than you've already done.
? By cold do you mean overnight cold or just cold to the touch some time after run?
Squeeze hose trick is usually evidence of air but might be stuck where it will not purge on its own like that.
I believe this engine is known for upper intake gasket issues/failures doesn't mean yours just yet. Look for evidence, pressure test system as well for starters.
A clue is from stone cold (many hours) you can feel pressure in say the upper hose build or watch it with a pressure pump gauge build pressure much earlier than the time heat alone would have expanded coolant. If so that's damning for combustion pressures getting into cooling system.
If you want to try again and bleeding air out you can purposely buy correct temp rated thermostats that leak a very small bit of air past them - then coolant too of insignificant amount either by a notch in the t-stat or some can have what I call a "Jiggle Valve" just for this. It's real slow - know that. The idea is letting just the smallest leak past the thermostat when shut tight.
Heater fluctuations are usually air but can be clogging or other reason. If engine warmed up and changes to cold from OK it's usually hot air or vapor despite being hot doesn't transfer the heat, liquids do.
IDK - If you have exact same issue before and after water pump and thermostat it wasn't that alone so would proceed to check for gasket leakage visible and under pressure,


T



highmfer
Novice

Dec 19, 2015, 10:35 AM

Post #3 of 16 (946 views)
Re: Coolant overflowing from rad with engine off and cold Sign In

Cold as in sat over night. Vehicle was not running either. No pressure in any hoses when stone cold, system builds pressure as it heats up(not overly fast IMO).
When the cabin dial for heat/cold is changed from hot to cold there is a noticeable difference in sound and temp of air coming from vents. The problem is definitely worse after water pump and t-stat replacement. Before it had intermittent heat, now its cold all the time. The t-stat used has the little "Jiggle Valve". I'll try to track down a pressure tester to confirm system pressure build and make sure its holding.


kev2
Veteran
kev2 profile image

Dec 19, 2015, 10:58 AM

Post #4 of 16 (940 views)
Re: Coolant overflowing from rad with engine off and cold Sign In

have you had this vehicle long- has it heated well for you past years. The past performance would need to be known but.... There is a TSB 00-01-38-011B for low heat at lower eng speeds...also a TSB #03-01-38-013A for lower air flow at vents with full heat....
Is there an auxiliary rear heater? they create exponential bleeding issues.
As tom suggested be sure to use AC Delco t'stat - yes a simple part BUT aftermarket is problematic with it. Might want to recheck the gasket issue, test strips will test antifreeze to help ID exhaust in coolant- Try NAPA for them


Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

Dec 19, 2015, 11:05 AM

Post #5 of 16 (938 views)
Re: Coolant overflowing from rad with engine off and cold Sign In

OK - there wouldn't be pressure and shouldn't when cold as everything shrinks, coolant or air. Take a common party balloon and put in in your freezer see what happens. Same in reverse. Small air becomes large air pocket when superheated especially in area that might be exposed to up to full exhaust heat temps.
Looked for pics of thermostat with "Jiggle Pin" is the name they use most in a hunt for pics. May or may not have anything with a feature for the exact application or very hard to find as most don't know what the heck it's there for?
There's also (too hard a hunt IMO a valved one that doesn't allow liquid thru just air/vapor - never noticed one if one had that so can't expound. Action was like a swimming snorkel idea. Thermostat no matter what has to be correct for the engine - no changes for that and fit as OE. Since this is worse since the pump and thermostat change it could also be if used too much gasket sealer. Many thermostats come with a tiny pie slice wedge cut out for letting air thru as well get covered in gook and defeat it. These items must face highest spot on side mounted thermostats.
You can rule this out by getting it vacuum filled or keep trying. It's a very REAL issue on several engine designs and cooling systems. By rights they should purge out last tid bits and many do, some just wont.
I'll try some pics which are tricky here. Some show, some disappear in time and IDK why!
Thermostats with Jiggle pins............





^^^^
Hope that one shows with tiny pie slice hole

Hope those show for you to get the concept and why it's done and has been for decades if only to speed up easier engine refilling.
Again, rule it out as by the time you are sure gaskets, heads and intake both in question and do not have to show coolant in oil or vs versa or smoke out exhaust for evidence.
Good luck and high hopes it's easy as just this,


T



highmfer
Novice

Dec 19, 2015, 11:27 AM

Post #6 of 16 (933 views)
Re: Coolant overflowing from rad with engine off and cold Sign In

I've owned the vehicle about 3-4yrs(since 99000km now at 225000km) no issues with heat or air flow until recent. Roughly 3 weeks ago started to get intermittent heat, cool when idle, warm when driving(b4 3 weeks ago would be hot air) Now the air is ice cold(about +1C outside temp). With dial set to cold, air is noticeably colder, and I can hear the switch in HVAC doors opening and closing.
"Is there an auxiliary rear heater? they create exponential bleeding issues." yes there is the dual climate control. Two separate controls for front and rear(I'm assuming that's what you were referring to?
I'm going to run the pressure test, take those results and figure a parts list. I will replace the T-stat to an AC Delco(because I know it isn't ATM). And try the test strips(good call, completely forgot these thing existedCrazy)

Big shout out to this forum and its users! First post for me, 15 views later and two replies with great advice.
Thanks Tom Greenleaf & kev2


highmfer
Novice

Dec 19, 2015, 11:34 AM

Post #7 of 16 (932 views)
Re: Coolant overflowing from rad with engine off and cold Sign In

Thanks again guys! I have a day in the car port trouble shooting some more. The aftermarket T-stat had the notch, but I'm seriously debating if I even put it to the top.
Once the list is complete, I'll get back and post my findings. Fingers crossed!


Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

Dec 19, 2015, 11:50 AM

Post #8 of 16 (931 views)
Re: Coolant overflowing from rad with engine off and cold Sign In

I didn't see Kev2's suggestions and wasn't thinking of rear HVAC on my mind either just adds to bleeding out time and involvement.


OK - you saw the notch. That I find quite common or some bitchy ones make a flaw on purpose.


Whole bull is just plain filling a system even easy ones takes time and cycles of warmed up and cooled off and shops/techs aren't going to usually spend all that time or some do and work on something else OR end it all and vacuum fill now.


Let's not go there but how are you testing A/C making vent temps colder than I'm guessing ambient temps of cold air if close to 1C as you said it really shouldn't be blowing colder as that now brings on another concern. If it can do that the evaporator is colder than that and would frost up, ice up so isn't controlled not to do that.


That could make this an entirely different problem to deal with! A/C if shut down shouldn't interfere with heat request by itself,


T



Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Dec 19, 2015, 12:30 PM

Post #9 of 16 (927 views)
Re: Coolant overflowing from rad with engine off and cold Sign In

You have all the classic signs of a blown head gasket. This engine is very notorious for this problem.



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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



kev2
Veteran
kev2 profile image

Dec 19, 2015, 12:43 PM

Post #10 of 16 (924 views)
Re: Coolant overflowing from rad with engine off and cold Sign In

a bleeding trick -- raise the front end want rad high point, with the thermostat use a hard asprin to prop it open when starting fill have rear heat on/


better yet check your PM for a idea...


Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

Dec 19, 2015, 1:12 PM

Post #11 of 16 (917 views)
Re: Coolant overflowing from rad with engine off and cold Sign In

Interesting idea Kev and would work. Agree HT that this smacks of a head gasket just really want to rule out something causing air or removal thereof.
Yes - Have hoisted front/radiator w caps so high please don't watch! This isn't for just anyone to even do vs getting it vacuum filled now if available for just that. I had (past tense) use of that not owned and may not as retired and have enough stuff around now.
It's me, I hate to blame a larger job without seriously knowing it needs it as sure as I can be,


Tom



highmfer
Novice

Dec 19, 2015, 2:07 PM

Post #12 of 16 (912 views)
Re: Coolant overflowing from rad with engine off and cold Sign In

I agree with you guys abut the HG, was most defiantly my first thought. But I really don't want to jump to the conclusion of its not the actual problem. it seems weird that there is no temp fluctuation on my scan tool(no overheating) it doesn't seem to show any classic signs of HG leaking. Or maybe I'm being overly optimisticSmile

Looks like tomorrow is gonna be my day to rip and tear. That helpful PM was very useful kev2, and worth a try. I will post back with any findings as I hate reading through a thread only to find it abandoned and unanswered.

Thanks again to all who have chimed in!


Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Dec 19, 2015, 2:43 PM

Post #13 of 16 (910 views)
Re: Coolant overflowing from rad with engine off and cold Sign In

Here's a trick for you to try to check for head gaskets.

Find a stretchy latex glove and put it tightly around the radiator cap with a rubber band. A balloon will work too if it will fit over the radiator filler. Now run the engine until it gets to operating temp and see if the glove inflates with air. The air would be from combustion gases getting into the cooling system



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



(This post was edited by Hammer Time on Dec 19, 2015, 2:45 PM)


highmfer
Novice

Dec 20, 2015, 9:04 PM

Post #14 of 16 (890 views)
Re: Coolant overflowing from rad with engine off and cold Sign In

Ok...so today I installed the AC Delco T-stat and sorted out that. I refilled the system after a quick water flush, basically just the rad. Filled until the level remained to the filler neck with out dropping or bubbling. Also side note, I opened both bleeders while filling and left them open until coolant came out.
Started the vehicle, got it to op temp, bled the system....bled the system....fans cycled. Checked the bleeders one last time, both straight coolant.
ATM I'm cooling it down and will go back to check it all agian.
Also used(b4 system was drained) the paper test strips for exhaust gas, they were neg.(didn't change colour) I can not borrow a pressure tester until tomorrow.

So my finding are: still no front heat, but the rear blows HOT air. So baring any major pressure drops in the test tomorrow, I'm thinking it may not be HG? Maybe the heater core is hooped? what do y'all think? Crazy


Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

Dec 21, 2015, 2:57 AM

Post #15 of 16 (883 views)
Re: Coolant overflowing from rad with engine off and cold Sign In

Feel the hoses when running the front heater core both in and discharge. If both warm that is a good sign. If discharge cold it's either just hot air going thru or probably clogged. Flush that backwards and forwards and note debris if any then you are back to making sure cooling system is really filled again. Why not flush whole system not just radiator anyway?


T



highmfer
Novice

Dec 21, 2015, 1:12 PM

Post #16 of 16 (869 views)
Re: Coolant overflowing from rad with engine off and cold Sign In

I did the flush b4 I installed the T-stat, so it was a little more than the rad. I didn't do a full front to back flush of the system. Rear heater core hoses are hot(expected) front ones are not as hot(more warm) but both very close in temp.
Also did the pressure test today with a universal kit(hand pump and gauge w/ rad cap adapter) system held 13 psi for over a min. LOL, think i might just buy a space heater to plug into my inverterCrazy
Thank to all the tips, tricks and advice from everyone. Will post up any head way I make with this POS...I mean vehicle.

Cheers,

M.S.






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