After Engine "Rebuild", Bubbles In Overflow Res.

[NuclearBacon]

Ok, 1997 Impreza 2.2l Outback. Heres what was just done

 

-New OEM Headgaskets

-New waterpump

-New OEM thermostat

-New Upper and Lower Rad hoses

-New Intake manifold gaskets

-New OEM Rear Main seal

-New clutch/pressure plate/flywheel/throw out bearing/pilot bearing

-New coolant

-New rad cap (not OEM, Stant 13psi)

 

 

I hear theres an air bleeding procedure, yet i couldnt find it in any of my searches. Why are there bubbles in the overflow tank?? i did some searches that said

 

1) blown headgaskets (replaced)

2) Bad rad Cap (replaced)

3) bad water pump (replaced)

4) Bad thermostat (replaced)

 

?????????????????????????????????

 

I have heat.

 

Could there be a clog somewhere? the car gets warm when not moving, but then cools down. Electric fans are coming on.... I guess it could be the rad cap... not being an OEM...

 

Clogged radiator??

 

I havent tested the coolant for exhaust gases. there is no black sludge or anything in the overflow to "say" that its headgaskets.

 

The car had a "headgasket problem" before when my friend bought it. he drove it all over town before getting weary of the problems showing up, bought the parts, and we took it apart.

 

any ideas?

[idosubaru]

since i want your other car i want to help you with this one. call me if you have EJ questions.

 

that engine can be hard to bleed the coolant in. that year/model should/might have a bleeder screw on the top left side of the radiator. large plastic screw, just unthread it until coolant starts coming out. then tighten once no more air.

 

i would bet it's just needing a good burp.

 

if not then a clogged radiator.

 

or worse a cracked block.

 

an EJ22 doesn't blow head gaskets for no reason - so we can guess with almost 100% confidence that the engine was overheated, which caused the headgaskets to blow. so that suggests there was a pre-existing condition and it was significantly overheated.

[NuclearBacon]

there isnt any type of "bleeder screw" or anything to bleed the air out of the coolant system.

 

Would (tomorrow morning after the car has cooled completly) leaving the rad cap off, and starting the car for a little bit allow the air to escape?

 

How do you bleed the air out? is there a way to test for a clogged radiator besides buying a new one? (ran my IR thermometer around the radiator fins and saw no cool spots to indicate a leak)

 

Also!!! went for a drive with a OBDII diagnostic scanner in my hand... watched the temp after coming to a stop and saw it get hot just once... then we moved not even 30 feet. and it was back to 196.

 

how do i burp the system!!!!?!?!?!?!?!?!?!

[Fairtax4me]

Park the car on a incline facing uphill with the driver side higher than passenger. (or whatever side the radiator cap is on)

Open the radiator cap and let the engine run until the thermostat opens. It will puke coolant out for a minute or so through the cap opening, but it should stop and go back down. Once it begins to recede add fresh coolant to the radiator, also fill the reservoir to the "full" line. Cap off the radiator, let the car idle until the fans cycle once or twice then cut it off and let it cool a few hours until it's near ambient temp.

 

Repeat the process once more and monitor coolant flow through the radiator. If you see lots of large bubbles after the second attempt to bleed do a combustion gas test a.k.a. a block test.

[OB99W]

Ok, 1997 Impreza 2.2l Outback. Heres what was just done

 

-New OEM Headgaskets

[...]

The car had a "headgasket problem" before when my friend bought it. he drove it all over town before getting weary of the problems showing up, bought the parts, and we took it apart.

 

any ideas?

I don't see anything that indicates whether the heads were resurfaced or at least checked for flatness. If there was overheating previously, things might have gotten warped so that new gaskets alone aren't enough.

 

By all means "burp" the system, but if that doesn't resolve the problem, it will definitely be time to check for exhaust gases in the coolant.

[idosubaru]

if the temps are coming back down quickly then i'd suspect your radiator. IR temp guns don't test radiators very well. they probably do if it's really bad, but probably hard to detect minor internal issues which is what it sounds like you have. but of course who wants to "guess" with a $100 radiator. radiatorbarn.com, the partsbin.com should give a good price for one.

[NuclearBacon]

Excellent ideas everyone thank you. So The bubbles also show up after the car is turned off ... dont know if that tells anything either... but i checked for flatness and the heads seemed ok before putting the head gaskets on.... but that definitly could be something, since i did it more out of novelty, since i thought you basically couldnt warp a subaru head. ....

 

probably wrong on that one i'm going to try to inclined burping method, since the engine was completly taken apart and basically all the coolant was removed, also the radiator could be clogged as the previous owner did pour magic goop inside...

 

All good stuff! the "overheating" problem is very hit and miss... we messed with the car last night for over 25 minutes (in 90+ degree heat in the sun) before we could finally get it to reproduce the symptoms, and after 30 feet... not even.. like 10 feet LITERALLY... the temp dropped over 20 degrees!!! in a second basically!!!!!! thats just crazy to me...

 

i'll keep you posted

Edited July 23, 2010 by NuclearBacon

[idosubaru]

the bubbles are not encouraging - that is typical EJ exhaust signs. but, of course we don't want to jump to conclusions.

 

does the a/c work - if it does and it overheats quicker with the a/c on or it doesn't overheat when it's cold outside (like drive it at night), then that's probably a good sign the radiator is the cause. still doesn't explain the bubbles.

[SuBrat84]

New radiator, "flush" the coolant system with a garden hose on low with the car running and the heater on full blast.. hose in the top.. just let it run out the bottom. Shouldn't take more than a minute or two until nice clean water is coming out the bottom.. don't want to overheat your car. Fill with car running and heater on full blast as directed, allowing t-stat to open, etc. If you have bubbles with a new radiator and properly filled coolant system you have exhaust gas sneaking past the headgasket. My 98 legacy did the heat up cool down thing like you describe but it was because I had an air bubble in the coolant system.. I never looked if the overflow bubbled.

[NuclearBacon]

Would there be bubbles showing up in the coolant overflow AFTER the car has been turned off?????

 

Car off.

Pop hood.

Open Hood.

See Bubbles.

 

I would think the engine would need the car running in order to create exhaust gas bubbles? yes?

[idosubaru]

I would think the engine would need the car running in order to create exhaust gas bubbles? yes?

the EJ25's do it all the time when their head gaskets blow. that's classic EJ25 headgasket sign - bubbles after the car is shut off, seen it tons of times and folks on here see it all the time.

 

but yours might just be superheating and boiling or something locally in spots due to a bad radiator too?

[Fairtax4me]

Bubbles might indicate boiling coolant, either due to low system pressure or excessive heat. Boiling after stopping the engine is usually caused by a bad radiator cap.

[OB99W]

A 50/50 mix of ethylene glycol and water as coolant, pressurized to 13 lbs, shouldn't boil until at least 250 degrees F. As long as the water pump is properly circulating the coolant and the radiator and fans are doing their jobs, there shouldn't be any boiling if the engine is staying well below 250 F. So, going back to an earlier post in this thread...

 

Also!!! went for a drive with a OBDII diagnostic scanner in my hand... watched the temp after coming to a stop and saw it get hot just once... then we moved not even 30 feet. and it was back to 196.

... just how hot did it get before going back to 196?

 

Keep in mind that all engines have hot spots that are significantly warmer than the block's average. If coolant isn't moving fast enough past those points, it can boil even if the system pressure and coolant mix are okay. When the engine is shut down after being run for a while, those hot spots can cause instantaneous boiling for a short time if system pressure isn't holding or the cooling was marginal due to clogs, etc.

 

If you can borrow a pressure tester, check the cap for holding the rated 13 pounds, and the system for a pound or 2 more (15 pounds max, there's no need to overly stress things).

 

If you have reason to believe that the previously used "magic goop" has clogged the radiator, either have it flow tested or (as already suggested) replace it.

 

A few other questions to help home in on the problem:

1) What temp does the engine have to hit before bubbles show up?

2) How much does the coolant level rise in the reservoir from when the engine is cold to when its hot?

3) Are both fans running at high speed?

4) When the coolant temp spikes, does running the heater on high bring it down, and if so, how fast?

5) After the engine is hot and it's shut off and cools, does the coolant level in the reservoir go back down? (In other words, is it getting pulled back into the system as it should?)