[Hunter_t1d]

I have a 2010 that I bought this past spring It is way more rusty underneath than I realized. This summer I noticed that the coolant was a little low and refilled it, I had made sure it was good when I got it. I refilled it and kept an eye on it and didn't notice it dropping. This fall when we got cold weather I went to test the antifreeze mix and it was a little low again I filled it and checked it the next day and found antifreeze blown around underneath. This is the first time I had seen any sign of a leak but with the previous warmer weather and lower concentration of antifreeze it might have just dried before I seen it.

At this point it is leaving small puddles when parked very long and it is going through about 20oz every week and a half to two weeks. I put UV dye in the tank and let it leak through and all of it that I found is on the underside mostly behind the oil pan. I haven't been able to find anything that says there is something in that area that is known to fail.

I can't find any around the water pump so I don't believe that it is the problem. I've crawled underneath it with it off, running cold, and after driving it for a while and can't find anything actively spraying or dripping. I checked the oil and it didn't appear to have antifreeze or water in it (haven't had it tested).

I have read in a post or two on here that it could be the start of the head gasket going. I don't know what to do next and because of other issues I don't want to take it to a shop and start blindly throwing money at it. I was thinking a compression test or having oil sent to be tested but i don't know which is better.

 

[adc]

You have to find out where the leak is. Its that simple. Find a subaru specialist. Heads did not fail as often in 2009/2010. But there is almost a 50% chance. Earlier it was a 90% chance.

Welcome and keep us posted.

 

[aleekat]

Do a coolant pressure test first. Might just be a hose. Most auto part stores have a "loan-a-tool" program for a pressure tester.

 

[DragonSubie7]

A couple of things -
When it gets cold, coolant level will drop everywhere, all the time, in every vehicle.

It may be that you have a heater core leak, based on your report, and I think that most likely.

You can eliminate this as a cause by rerouting thehose so it doesn't go through the heater core to see if that eliminates the coolant loss. Unfortunately, a heater core failure is a royal PITA to fix.
Good luck.

 

[donkpow]

You say it's on the back side of the engine? Or firewall? Heater hoses back there. It's premature to take action based on the assumption that the head gaskets are leaking. How many miles on the car? What does the coolant look like? Does it look like the previous owner used Subaru coolant? Did you do a drain and flush when you got the car? Does it look like the previous owner replaced hoses? There are a lot of questions in my mind given this situation.

 

[Hunter_t1d]

@donkpow I can't find coolant anywhere other than underneath by from the oil pan and back. It has 95,000 miles. I did not flush the coolant when I got the car. I don't think hoses have been replaced.

 

[donkpow]

The throttle body uses engine coolant. There are two hoses up there. Are you sure your leak is not on top of the block?

 

[Blotto]

The throttle body uses engine coolant. There are two hoses up there. Are you sure your leak is not on top of the block?

I have found coolant pooling on the top of my block, would it likely be from the throttle body or a gasket?

 

[bman400]

@Blotto, Welcome to the forum from DFW, TX. Please update your forum profile with details of your vehicle: Your forum "Public Profile" - how to fill this...

Also please start a separate thread with more details, it pictures?

Thank you,
bman.

 

[donkpow]

If that's the source of the leak, it is more likely to be dripping from the hose ends. Sometimes you can tighten a clamp, Sometimes the hose needs replaced. Here's a picture from the service manual. Coolant hoses marked in red.