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Air bubbles in radiator


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My 87 gl has air bubbles in the radiator. I let it bleed for over an hour so I know it's not airpockets. I have replaced lower rad hose, rad csl, driver side head gasket, throttle body gasket, thermo housing gasket. It's not loosing coolant. It's not over heating. It's not leaking any visible coolant. I put white paper under the car and the only that fell to the ground was oil. No coolant coming out of the exhaust. I originally thought head gasket but it has no symptoms besides the bubbles. It was shooting coolant out of some holes on the passenger head. On the top back corner. I put bolts in the holes so nothing is coming out. I'm at a loss of where to look for it. I'm thinking of putting in some coolant leak stuff to see if it fixes it. I figured before I try it I would ask others to see if they have some ideas

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Definetly do not add anything other than coolant, I would say because you plugged the holes with the bolts you are not getting complete circulation, I would be curious to know what exactly are they? And if you only changed the driver side head gasket why not the passenger side? My head gasket blew out on that side and was pushing exhaust gasses into the cooling system.

Just cruising across town will allow exhaust gasses into the system with out showing much of a temperature change because it can purge off into resivor.

Get on the highway with sustained 3,000 rpm if ya got a 5spd and you will see the temperature begin to rise. That would definetly indicate a blown head gasket.

And/or just maybe maaaybe you still have air bubbles if ya didn't jack the front up w aaay higher than the heater core while running the heat and giving if a couple grand for about 10 mins at the least...

Edited by Len Dawg
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Never ending stream of bubbles is coming from headgasket, or cracked head.  Headgasket leaks can start very very slow.  Will eventually get worse.

There is no other source of "air" that can pump it's way into the cooling system. 

I have had small amounts of air sucked back into the cooling system during cool down when there was a slightly loos hose clamp, or seeping radiator leak.  But these will not cause a never ending bubble supply.

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Why didn't you change both head gaskets at the same time if you suspected one already?

While I agree that most coolant stop leak additives are garbage that cause more trouble, these are generally acceptable for sealing tiny leaks that may occur after an engine overhaul or head job: https://www.amazon.com/Bars-Leaks-HDC-Radiator-Tablet/dp/B000KKND3Q/ref=asc_df_B000KKND3Q/?tag=hyprod-20&linkCode=df0&hvadid=312181776237&hvpos=1o1&hvnetw=g&hvrand=1759667204531667135&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9031106&hvtargid=pla-569057243725&psc=1

This stuff works best if coolant system is filled with water only for first few miles. Then drain system and add coolant mix.

The additive pellets are generally believed to be ground ginger.

Had a possum get into my garage a few yrs ago wreaking havoc :mad: and 3 packages of the stuff were eaten so it must be tasty ginger. Not the package,  just the pellets ;)

 

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I didnt take the other head off because we needed room in the garage. Also when I changed this one I had a million problems. I had to replace the intake manifold because a bolt got stuck in it. 2 head bolts somehow stripped the threads on the block. I was thinking of changing the other. Just wanted to see what others might think of it. I'll pull it in and change it out

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You’ve learnt a golden rule of the flat four. If replacing one head gasket, you always replace both. If there are issues on one side you can expect issues on the other side too. 

That bolt you’ve put in to stop the coolant coming out is a head bolt hole that has other smaller bolts drilled in the side of it. You’ve effectively plugged the head gasket leak with that little bolt.

If you’re pulling threads it could be several reasons as to why:

1) block severely overheated, resulting in the alloy being soft

2) dirty thread on a bolt used, damaging the thread, or that thread was cross threaded

3) over torqued bolts 

Cheers 

Bennie

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Rather than using a stop leak, try using pepper, as in salt and pepper pepper. If its only a small leak, pepper can seal it up enough to at least help diagnose the problem but apart from being either a head gasket problem or a cracked head/block, no other way air can be pumped into the system as previously stated.

 

You can buy a test kit from some parts store that from memory wasn't all that expensive and it will tell you if exhaust gasses are getting in to your cooling system.

 

Cheers,

 

Al

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I have found that getting the entire engine up to 150 to 190 degrees F makes a huge difference in successfully removing stuck bolts.  Either by running it, or by using a space heater and a heat gun, to get enough power.

 

Then carefully working the stuck ones loose / tight.  Gradually,  the sticking point moves further unscrewed.   It helps to learn the feel of the bolt turning vs twisting.  When they start to twist, that's when they snap.

 

The radiator stop leak stuff can temporarily fix a 13psi leak from the radiator to the air.  It won't survive the temperature and pressure involved with the combustion chamber.

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1 hour ago, DaveT said:

The radiator stop leak stuff can temporarily fix a 13psi leak from the radiator to the air.  It won't survive the temperature and pressure involved with the combustion chamber.

Agreed. Stopping combustion gasses is the job of the fire ring on the head gasket. Once that is compromised its all downhill.

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When I was taking the head bolts off they all looked fine. It was the one on the top front of the engine. When I went to put the head back on, one of the bolts started to tighten and need more force to move it. It all of the sudden got super easy. I pulled it off and the bolt now had the threads from the head on it. I used a helicoil to fix it.

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I have re sealed a handful of these engines. Had 1 head bolt strip during reassembly that was overheated badly.  I follow the directions in the fsm - oil the threads, 3 tourque steps, order. 

 

No coolant shouldbe leaking out of any of the tapped extra holes in the heads.  Many of those holes do intersect head bolt holes.  Head gasket probably leaking  into one of those.

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Ok this was my first time pulling the heads so I dont know what exactly stripped the threads. I put oil on the bolt threads and tightened them in 3 steps. I have been chasing leaks. Started with thermo gasket then throttle body then it started shooting out of the holes. I am going to take this head in to get it checked for warping and for cracks

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Yeah if anything nothing should be coming out those holes now we know which ones they are... I was thinking it was the elbow... I'd would suspect if it's coming out there the head is cracked/warped I spotted a light up the hole on the backside and seen that only it goes in and would bottom out. Could be deteriorated.  If you can getaway with patching the leak then put those bolts back in you very well could get away with it until you find another head or another decent motor..And that man if it works you got into the Top10 at 3 for the best Subaru MacGyver of all time!!:headbang:

That could very well be where air is getting sucked back in when it cools down. Keep us posted:popcorn:

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