'99 Legacy Temp Gauge Bounce

[WesleySands]

Good afternoon, I will first and foremost apologise for this super lengthy post, but I was trying to cover everything I'd done up to this point.

 

My 1999 Subaru Legacy Brighton with 231,xxx miles has developed an interesting habit of, while driving, the temp gauge will spike, stay pegged at hot, then drop down to its 'normal' position, then just as quickly bounce back up, stay there, then drop again.* Sometimes it will return to its 'normal operating temp' sometimes not.* It has done this under all sorts of driving, foot on gas, foot off, dropping revs and so forth.*

 

Now, this all started after I had to put a new battery in the car.* I didn't realise that just by removing the battery terminals the ECU resets.* I turned the car on and away I drove.* The temp gauge was bouncing and my rpms would stay up even with my foot on the clutch.* Once I realised what I had done, I reset the ECU and did the follow up correctly this time.* After that, the throttle behaved correctly, but on occasion the temp gauge would spike and return to normal.*

 

A few nights ago my power steering/alt. belt snapped, I had one in the car, so I replaced it.* After it snapped, I began to have a coolant leak, there was no definitive place to source it, as it looked like it was spraying over the inside of the car on the passenger side.* I replaced the coolant elbow hose, yet it's still leaking/spraying.* I found a few drops on the radiator itself, so I've begun to wonder if when the belt snapped, a piece was chopped up by the fan and struck the radiator core, so as it leaks under pressure, it hits the fan and sprays over the front of the engine. That's my theory anyway.

 

So today I'm driving, the gauge starts to climb and hits the H mark.* I pull over to put coolant in the car, but the overflow tank is full from where I'd topped it off last time and there is very little steam from the radiator.* I also had to put oil in the car as the oil light was coming on as the rpms dropped, the engine also sounded like it needed oil.*

 

So, I'm thinking the coolant is circulating poorly, the tube on top is hot, not burning, but hot, yet the radiator cap is cool, (which doesn't make sense).* I'm wondering if I should reset the ECU again, and potentially replace the thermostat and the radiator cap.* I know eventually I'll need to get a new radiator but at $316 from a dealership not including tax that's a touch steep.*

 

In an unrelated note, or potentially related note, after I put the oil in the car, I laid down a thick smokescreen of blue smoke, it then stopped and behaved normally, I've never had any indication I was burning oil before this. I'm more than a little perplexed, and thought that I'd bring it up to you guys before I did anything else.

 

I apologise again for the lengthy post, I've had the car for 2 years, and haven't had any coolant problems before. I thank you for any insight you guys might have. Thanks again, and I apologise for the super long post.

[WesleySands]

Well, my friends, my son and I did a great deal of testing, and burping of the system, we've discovered that our Scooby doesn't need a radiator cap, or a thermostat...it needs a new radiator. When it's full and the system is correct, it leaks like a sieve out the bottom....sigh...

[Brighton96]

I was gonna say, I have a few OEM temp gauges lying around, I'd be up to sending you one, but it sounds like you figured it out. As far as the blue smoke, it sounds like it was overfilled a little bit. I've seen inexperienced mechanics put 5qts in a subaru that takes 4.3qts, and I've seen them smoke even when the motor is low mileage. They will still burn oil when you do that, regardless of how many miles are on it or regardless of the condition of the rings. So in short, it doesn't sound like a big deal.

[WesleySands]

It's usually not the gauges fault, I would have thought either sensor or t-stat. But it seems it was air super heating, and then liquid being a diff. temp. Thank you for the offer of the gauges however. I had to have overfilled it then because I didn't realise the diff. blinks and then steady burn before. Thanks again