Blocked radiator?

[New92]

While getting on the highway, heading into work, my temp gauge pegged and I started smoking. Got to a gas station and cooled the car down. Ended up feeding about a gallon into it. I had to let it sit yesterday then had time to check it out today. It leaking along the bottom pass side. I was hoping it was the drain cock but that appears to be dry so Im thinking its the core itself. 20 years old so no surprise there. What has me puzzled though is the fact that when I started to bleed out any excess air and top it off, the coolant began to expand right at the moment the car hit norm operating temp. Meanwhile the return hose was still cool like it was full of uncirculated fresh tap water. Can the core become so blocked up that it will crack the hot side? And if so what sort of damage do I need to be concerned about with a closed deck? BTW while trying to bleed the air this morning the fans never came on. They were running full steam though during the initial coolant loss.

Thanks for any input guys.

Ben

[Legacy777]

You may have a bad thermostat that is stuck and an air pocket in the cooling system.

Have you altered any of the cooling system hoses/routing?

How did you bleed the air out of the cooling system when initially refilling the cooling system?

[New92]

Hey Josh. Well I have a completely unmolested cooling system. Only mod is a WRX aux tank as mine had turned to wax and crumbled. I topped it off at the aux tank, burped it by squeezing hoses etc, startedit up and continued to burp while toping off. After it appeared full I let it wharm up to idle temp (still no fans and return side still cold). Then I reved it up to about 2k and held it while topping off as it settled. All told it took about 5 or so mins before the return heated up and the fans kicked on. Before the coolant appeared to flow through and the fans popped on, the leak opened up under the drain. Since Ive had the car it has always taken a long time to hit idle temp and for the revs to drop. This of course is worse in winter. It has a new water pump and temp sensor.

[Legacy777]

It sounds like you may want to replace the thermostat. I only recommend getting one from Subaru since the aftermarket ones are different.

[New92]

Hey thanks. Yeah Id read your posts on that before and will follow your advice thank you. I got the tank off and it looks like it ultimately failed at the return end tank. Big crack running down from the top to about mid tank on the street side. Also the rotating cuff on the drain was split (though I dont think that would have caused a leak). Its odd though. There was a steady leak from the bottom yet I didnt see any coolant coming from the drain or the end tank. Well now Ill be getting the new thermostat, upgrading to the all aluminum mishimoto radiator and doing a thorough flush of the system to be safe. The flush is gonna suck since I dont have a hose connection at my apt complex. Any other recommendations while Im at it?

[Legacy777]

It sounds like you've got the majority of it covered.

When you put the thermostat it, orient the jiggle valve on the thermostat so it's at the top. Like this:

http://www.main.experiencetherave.com/s ... P_5005.JPG

Yeah, without a hose, flushing is going to be kind of tough. Can you bum a spot to do the flush where there's a hose? If not, just drain as much coolant out as you can, get some buckets or old milk jugs filled with water and just let it cycle through. Depending on how bad things look, you could let the water circulate with the engine running. It depends on how big a mess you wan to make too

[New92]

Lol! Thanks again Josh. Your advice is appreciated as always. My new radiator shipped today and Ill be grabbing the thermostat tomorrow. I guess Im stuck with using the jugs as I wont really be able to move it till its filled and I dont want to flush any gunk into the new rad or thermostat. Ill just run it and keep filling from the reservoir tank and let the water drain. I already pulled the old tank and removed the fluid so it should pretty much be just water at this point. Ugh!

[New92]

Sorry it took so long to get this updated. I got the new radiator in with out a hitch. The new unit is a dual core all aluminum design that is a bit thicker than factory. As a result the fan shroud has maybe a quarter inch clearance at the power steering pulley and belt. So far there has been no rubbing. But everything fit perfectly in the factory mounts. I had initially switched sides with the rubber inserts at the bottom which caused the radiator to sit at an angle but that took only a moment to fix. The new thermostat does indeed make a difference in achieving normal idle temperatures. Its quicker by maybe a min or two. And now my fans hardly come on at all. Especially with the nights getting cooler. So this unit is awesome. Ill be doing another flush, hopefully with a hose, just to be certain that all is clean and clear. Thanks again for all the input guys.

Ben

[Legacy777]

Ben,

Glad to hear everything went well!

[New92]

UPDATE:

Well as it turns out, I had not in fact replaced the coolant temp sensor. I had replaced the sender to the temp gauge! So I went ahead and pulled the two pin sensor. Boy was that thing dogged. It had a fair amount of corrosion and was deeply discolored. I expected the discoloring but not the corrosion. I had to pull a return line from the drivers side valve case to the intake to get access and I used a swivel joint on the socket to allow use of a wrench with extension (I was being lazy and didnt want to take off anything else). Ive not had a lot of time to drive it yet but it does seem to be running better. The rich over fueled smell I was getting previously has been significantly reduced so hopefully I wont have a problem with my emissions now (I had failed at idle by just a smidge).

[Legacy777]

Well that's good to hear the new temp sensor has helped. A bad temp sensor can really create a lot of problems with these cars and how they run.