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Coolant not flowing
Posted 04 December 2012 - 08:56 PM
Have a dilemma with my 98 OBW.
Car went to overheat yesterday on my son and he immediately pulled over and called me. When I got there the upper radiator hose was collapsed, I opened the radiator (no pressure, cool water) and the radiator hose immediately expanded. I put coolant in and got it back home with the heater going and the temperature didn't move past mid-point (15 miles).
The lower radiator hose is not getting hot (barely even warm, I'd call it cool). Scangauge is telling me the temp is getting up into the 205-210 range.
I took the thermostat out figuring it was malfunctioning and replaced it with an OEM stat from Subaru. Before putting in the new stat I tested both old and new and both opened in a pot of hot water.
Put new stat in, bled the system while on ramps. Have excellent heat, upper radiator hose gets hot, fans kick in, temperature still goes into the 205-210 range (I don't want it to get any higher so I run the heat full blast and get back to the garage).
I was thinking maybe the water pump is not working so I took off the sprocket cover on the right side and checked to make sure that the timing belt is turning the water pump which it is. The water pump is about 15k miles old and this problem only started yesterday, been running great since I did the headgaskets this past summer.
Any other thoughts on what to try before I rip the water pump out?
Posted 04 December 2012 - 09:44 PM
Posted 04 December 2012 - 09:59 PM
Top up the coolant and run the car (from cool) with the rad cap off. See if you're actually getting coolant circulation or not. Sounds like either poor/no flow, or a blockage somewhere.
I've done that as I was filling and bleeding, not visible flow. I considered blockage in the radiator but when filling it lows well and when squeezing the upper hose I get good movement in the right hand tank. Also the fact that it appeared as a problem all at once makes me think some kind of mechanical failure.
I'm thinking that before I pull the water pump I'm going to run it witout a tstat to see if I get flowing water.
Posted 04 December 2012 - 10:38 PM
If a bad HG, lets enough hot exhaust gas to enter the cooling system, it will form a hot bubble. The water pump is designed to pump coolant, but can't pump much coolant, when a bubble of exhaust gas is present.
A good test is to let the motor cool down, add coolant to the radiator, then start the motor, then look for air bubbles in the filled rad over flow tank, as the motor starts to warms up. If you see bubbles, then it is for certain that your HG has failed.
I have both a 98 and 99 OB Wagons. They have both blown head gaskets, so I have seen the HG over heating problem first hand.
Posted 04 December 2012 - 10:40 PM
Do you have heat (if not that is an air bubble possibly caused by a failed HG)
Assuming hoses are good and havent failed and the thermostat is not in backwards (hey we all do it once).
How many miles on this car and was the last time the water pump was changed. Subaru WP don't usually fail by falling apart but there is always one who has to show off
Lets drain the radiator. With the car running SLOWLY fill the radiator. If the thermostat is in the car, wait for the Tstat to open (surge of coolant). Then keep topping off. replace radiator cap and drive around block. Allow the car to cool off (make sure overflow is full). STart car with cap off and check level, repeat as needed (once).
Posted 04 December 2012 - 11:09 PM
The water pump is about 15-20k miles old but is an Advance Auto part.
Posted 04 December 2012 - 11:32 PM
EJ water pump failure is extremely rare though being an aftermarket that's a good call to consider it. if it's that bad due to the pump you could try to rig some system where you simply run the car with the hose disconnected, running into a bucket on the passengers side while pouring water into the radiator cap....probably not, but is there a way to test pump without removing?
water bypass hose, does that normally flow?
Posted 05 December 2012 - 12:21 AM
Posted 05 December 2012 - 11:08 AM
I wanted see if the water pump was spinning properly. I took the cam sprocket cover off and could see that the belt was spinning the water pump pulley.
I then took out the thermostat and while turning the crank with a wrench I looked up into the water pump and could see that internally the pump and impeller were spinning (not sure that it would spin as well under full load but can't really test for that).
So I put the thermostat housing on without the thermostat and set it up based on grossgary's suggestion (see photo, Rube Goldberg would be jealous).
I filled the radiator with water and as soon as it reached the top on the cap side it was coming out of the passenger side (where I had disconnected the return hose) so that leads me to conclude that the radiator isn't blocked.
I then ran the car while pouring water into the radiator, as expected the water came out of the return hose and into my bucket. The only concern I had is that it didn't flow out of the return continously, it would flow, then stop, then flow. I'm guessing this is fine because it did remove as much water as I put in.
Next I'm going to put it all back together without a thermostat and drive it to see how the temperature performs.
I'm back to where I started, not knowing what the problem is.
Any thoughts based on the latest observations?
Posted 05 December 2012 - 11:09 AM
Posted 05 December 2012 - 11:13 AM
water pump not turning ? or gauge is lying or air lock
The water pump is turning and water does get pumped out.
Scangauge is giving real numbers on the temp and the fans are kicking on also to confirm heat.
Did real good job of bleeding it (on ramps, filled through passenger side, etc) so I don't think it's airlock issue.
Posted 05 December 2012 - 01:25 PM
Have a dilemma with my 98 OBW.
Car went to overheat yesterday on my son and he immediately pulled over and called me. When I got there the upper radiator hose was collapsed, I opened the radiator (no pressure, cool water) and the radiator hose immediately expanded.
Sounds like a bad radiator to me. Since the hose was collapsed that means it was trying to move the water but couldn't for some reason most likely a bad radiator.
Posted 05 December 2012 - 01:54 PM
Posted 05 December 2012 - 03:08 PM
I'm thinking this has the symptoms of bad head gaskets, but try a new radiator cap first. The valve that opens to let coolant back in could be plugged up with some crud.
Posted 05 December 2012 - 05:35 PM
How can I test the radiator for blockage?
Again, since it happened suddenly after running fine for months makes me shy away from the air issue and to some degree the radiator blockage. I would think that radiator blockage would be a creeping issue over a period of time.
I checked for air bubbles in the coolant and there aren't any so I'm thinking the head gaskets are still good, I just did them at the beginning of the summer and this was the first and only time there has been any increased temperature.
I'm going to run it without the thermostat for a few days and re-assess. I appreciate everyone's input and look forward to more.
Posted 05 December 2012 - 06:59 PM
From the bimmer forum
One quick test you can do is to spray the outside with water while you're idling. If the temps drop, you have a poor efficiency radiator, weather it be from the inside or the outside (outside fins clogged up).
Posted 05 December 2012 - 08:25 PM
Sometimes it's pretty obvious...
P.S.: The garage I bought it off of couldn't figure out why it kept overheating...
Edited by the_bard, 05 December 2012 - 08:31 PM.
Remember to drain the radiator first. Just a friendly public service announcement.
Posted 06 December 2012 - 09:07 AM
Back on my old '97 OBW, all I had to do is remove the radiator, tip it upside down, and give it a mild shake. I would recommend draining it first . Got a mineral deposit the size of my thumb out of it, plus lots of little bits the size of hail I wouldn't want to be standing under.
Sometimes it's pretty obvious...
Excellent idea The_Bard!
I'll probably putz with it some more this weekend (when it's a little warmer), for now my son is driving it without the thermostat.
I've changed the engine, timing belt, etc on this car so many times that I have few bolts left holding the fans and radiator in, I can pop it all out in about 5 minutes.
Posted 06 December 2012 - 10:40 AM
Posted 06 December 2012 - 12:12 PM
to test radiator flow:
Remove radiator, remove fans.
Take the radiator to the bathtub. Stand it up on one end, and run hot water through it. The water will fall through any open tubes. Feel each one to make sure that all are getting hot to the touch. If it's even, then the radiator is flowing at least to some extent.
Honestly, it sounds like it could be as easy as a radiator cap issue.
Posted 06 December 2012 - 12:31 PM
So the collapsed hose probably doesn't have anything to do with your other problems.
Posted 06 December 2012 - 12:55 PM
You shouldn't run it much without a thermostat it could cause more damage
mikaleda, what damage can occur running without a thermostat? I've got a scangauge in the car with the water temperature being monitored so overheating won't be an issue. I ran it yesterday for about 80 miles and the temp never got above 185, in the colder night it actually stayed below 150.
Posted 06 December 2012 - 02:29 PM
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