EJ22 cooling issue after timing belt

[speders]

Hi, new poster here from Seattle.  I have a 1993 Legacy wagon 2.2L with the EJ22.  Yesterday I installed new timing belt pulleys (last year had a timing belt done due to a broken cam sensor issue, and didn't get pulleys replaced).  The lower right cogged pulley blew apart. Noticed a high pitched chirping noise near the water pump.   I replaced all the pulleys.  Got the belt back on following the instructions and videos I found.  Timing is great and runs like an absolute champ. Nice and quite and smooth running motor with full power.   BUT, now I have a cooling issue that was not present before the timing belt pulleys job.  When the car is hot, the temp jumps up to the hot mark.  Ok I thought, so I replaced the thermostat this morning and still no change. 

 

Now for the honesty part.  I noticed some (combustion gasses?) bubbling up in the coolant last year and not wanting to have to pay for a head gasket job, I used half a bottle of bars leak.  I know I know...but it has ran perfect all year until last week when the chirping noise came.  The bubbles stopped, coolant stayed full and ran at normal temp.

 

I'm stumped because after doing the pulleys and getting everything back together and replacing the thermostat, It now overheats.  I even filled up the radiator with the car at idle, facing uphill to ward off the air bubble issue? 

 

Some of my observations:. 

1.  Upper radiator hose gets very hot and pressureized. 

2.  Lower hose that goes to the thermostat stays cool and not under as much pressure. 

3.  When it was cool enough to crack the radiator cap open, I noticed the upper hose was suctioned tight (looked shrivled up like all the air was sucked out of it).  When I cracked the cap, I heard a loud swishing gust of air and pressure release. 

4.  When I squeeze both upper and lower hoses, it moves coolant at the cap so I don't think anything is clogged. 

 

What in the world would I have missed during this?  Water pump bearings felt great.  Smooth and tight and could hear that it was moving water when I spun it when I took the radiator off. 

 

Any ideas or things to try next?  Thanks for your help!  -Shawn

 

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[speders]

I'm guessing it's a plugged radiator for tap water and bars leak?  I understand there is some way to burp the air bubbles out as well?  I see there is a plug on the left side of the radiator, above the upper hose that loosens with a phillips.  I'm going to just replace the radiator as I'm not sure there is anything else to do.  I'll pick up a tock OEM thermostat too while I'm at it just to be safe.  Not sure if the new one was bad, but might as well be safe since I'm draining fluid anyway. 

I still dont understand how just draining it did this...unless it exposed and opened up something that got clogged in the draining process. 

[lmdew]

You can take the old radiator to radiator shop and they can check the flow.

 

Sounds like you have an air bubble in the coolant system.  Search Burping.  

 

You can put the Stat in a pan of water and heat it up and make sure it's opening at the correct temp.

 

It can be hard to move the air out of the coolant system if it's in there.  

 

Some, start the engine and fill as the engine is running.

I usually jack the car as high as possible in the front, back fill the engine with coolant and then start the engine and fill the coolant slowly the rest of the way.  With the heat on high, keep on filling the system as it heats up.  Once the coolant starts to come up in the radiator, put the cap on and let it come to temp.  Shut it down and let it cool.  The system will draw coolant in from the overflow bottle.

 

You may have  bad radiator cap if it's not allowing the coolant to be sucked in.

[idosubaru]

1.  air bubble - always an air bubble if the overheating is 100% associated with having the coolant system recently opened up.

2.  i've ran a garden hose through a radiator to see if it's clogged.  having another rad to compare to is helpful but if it's bad enough you'll notice a notably low flow rate out the other side

3.  rad cap good suggestion

4.  the head gaskets on that engine are insanely easy to replace, they're awesome for doing head gaskets on if that's what it ends up being.

[MilesFox]

Replacing the radiator is a good idea. One could be had at napa for about 125-175 bucks. IT is good insurance along with the timing belt, not as if it were a shotgun approach to troubleshoot.

 

Replacing the water pump would have been a good idea for all the labor involved with the timing belt. Perhaps you could go back in and do that along with the radiator, since you will be draining coolant.

 

Use only an oem type thermostat with the little jangly ball and the fattie brass thermocouple.

 

It would be possible to re-torque the heads as the bolts are exposed; six of them on each side. Be sure to find a proper procedure and torque values.

 

Likely you have an air pocket in the cooling system. One way to tell and if the coolant is low is the heater goes lukewarm and cold before the coolant is low enough to overheat.

 

It's possible the water pump is inefficient. Perhaps the pulley is dragging on the belt, or the impeller is worn. You did mention squeaky sounds near the water pump before the timing belt job. If you smell burning rubber at anytime, this is your culprit.

 

To burp the air pocket, you must ensure the thermostat is open. There is a vent cap on the side opposite of the radiator fill cap to let air out of the ratiator tank as you add. Often times it is more successful to add coolant to the vent hole. If you had disconnected the hoses or drained the coolant, it is best to fill the block via the upper radiator hose. What happens is the coolant comes out while adding, while the air pocket is behind it in the engine. once the radiator tops off, it backs into the air pocket, and the air pocket pushes the coolant back out, although the air pocket itself does not come with it. This is why the vent hole works for filling coolant.

Edited April 8, 2014 by MilesFox

[Fairtax4me]

Air in the system. When the system is hot its pressurized and pushes some coolant out into the overflow. As it cools it draws a vacuum, and is supposed to pull IN coolant FROM the overflow bottle. But air just stretches and doesn't pull the coolant back in. Without coolant to support it the upper hose will suck flat.

Have to fill the block first through the upper hose, then fill the radiator. System should take about 1.5 gallons or a bit more. If you don't fill the block first it'll only take about half that. Leaving the block almost completely empty.

 

Remove the upper hose from the radiator and pour coolant into the engine through the hose. Put the hose back on the radiator, open the bleeder screw in the top of the radiator, and fill until coolant starts pouring out of it.

[speders]

Thank you so much for the responses everyone.  It was indeed an airlock issue.  Earlier today, I ended up filling the block up from the upper radiator hose and then topping it off through the bleeder hole.  Everything came back to life right away.  The lower hose finally showed some life with some warmth, heater started to work etc. After it ran for a while at temp, I turned on the heater to full and then cracked the bleeder screw lightly to bleed out any remaining air...some bubbles came out before a solid flow of coolant.  All seems ok now.  A few long test drives and no issues.  Thanks again everyone.  I learne a lot today!

[mikec03]

Congratulations on fixing the problem.  I think that really quite safe to fill  to fill the coolant via the radiator spout, but I like the assurance of filling the block through the upper hose.