Quote:
Originally Posted by svxcentric
Hey everyone. I'm looking for some help on troubleshooting a coolant system issue on my 97 SVX.
Symptopms:
I can travel as long as I like at highway speeds with stable coolant temperatures. As soon as I come off the highway or if I get stuck in stop and go traffic, the coolant temperature rises, sometimes just before the red line, and then drops back down again. It will do this 4 or 5 times and then will stablilze again.
I can delay or prevent the onset of these temperature changes by keeping the revs below 2000 rpm when crusing on the highway. This limits me to speeds around 60-65 mph
Actions taken:
At first I thought I might have a bad thermostat and I replaced that. The new thermostat had no effect. Since It was time for timing belt service anyway I had that done which of course included a new water pump. All parts were genuine Subaru, Again, no effect on the temperature changes. I also replaced the radiator cap. Again, same result.
I thought that maybe the system had not been purged of air properly so I bought a Lisle No-Spill funnel kit. I filled the funnel over halfway and also made sure there was coolant in the overflow. The heat was on - "Econ" with max temp and the fan on low. I was able to see that there were bubbles in the system coming up through the funnel and let the system purge for 25 mins at idle once the car came up to operating temperature. During that time I monitored the temperature remotely via a bluetooth OBD adapter and my Android tablet running the Torque app. The temperature never rose above 209 F and the fans operated as expected.
Results:
What I noticed is that even after 25 mins at idle, I still had small bubbles coming up every 5 seconds or so, three or four at a time. From my experience the system should have been completely purged of air by that point so I have to conclude that I have a leak in the system somewhere. The problem is that on visual inspection of all the hoses and the radiator, I can not see any leaks. No wet spots, nothing.
Likewise I would expect that if I had a leak in the heater core I would smell antifreeze in the cabin or see a leak. Neither of those things are the case.
By the way, the head gaskets are fine, at least for the time being. The car does not perform in any way like one with a head gasket leak would. There's plenty of power and there are no signs of coolant in the oil or any visible smoke in the exhaust.
So I'm left scratching my head about where to look next. I know I should have the radiator pressure tested, but as I've spent quite a bit on the car of late I want to eliminate stupid stuff like maybe loose hose connections or maybe some SVX quirk I don't know about before sending it to the shop again.
Has anyone had this issue or can anyone point me in the direction of a likely source of a coolant system leak so small that would let in air but not let coolant out at any significant rate?
Jim
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Its unfortunate but the likely hood is the headgasket is leaking, it doesn't leak water into the oil or water through to be burned, at least not yet, this appears to be a mild case that may run that way for 10k or more miles without affecting anything else.
What is most likely happening at this time is exhaust gases are slowly seeping into the water passages and those are causing the bubbles.
Your symptoms (getting hot after slowing down from highway speeds) are very consistent with our cars when they blow the headgasket.