Engine Cooling issues '99 2.5L

[evanejp1980]

Hello,

I have a '99 outback with the 2.5L DOHC 5-speed. I'm having issues with cooling. The car has never over-heated, but the guage will get to the hot mark while driving, and if I run the heater on full it will drop a bit, but still seems to run hot, according to the guage. I recently replaced the hoses and thermostat at 170 degrees. I bought this car a little while ago, and when we took the old thermostat out it had a few drill holes in it, so I assume the original owner drilled it as a band-aid for cooling. It takes forever to warm up, and when it does it gradually goes right to the hot mark. I don't think it's over-heating, because it cools off almost to cold within 10 minutes, when it's 25 degrees outside.

The car has almost 140k, and I'm certain the water pump is original. Will replacing it help with the cooling issue? I've had several subarus, and my fiance has a '99 impreza outback with the 2.2L, and her temp guage never moves, and the heater gets hot much quicker.

[eggroller]

Our 1999 2.5l Outbacks have a problematic headgasket. I highly suggest taking the time to read through this sticky thread in the Problems/Maintenance forum:

Head Gasket Issues

[porcupine73]

Also you should be running a Subaru OEM thermostat; the aftermarkets are just not as good. A soob also likes to trap air pockets in the system if when refilled with coolant, the cooalnt is simply poured quickly in the rad filler neck with the vehicle level on the ground.

[evanejp1980]

I went with an aftermarket thermostat from O'Reilly's 170 degrees. I've had issues with them before. I will try a factory one! Got any suggestions on where to look?

Also, I knew about the air pocket thing, is there anyway to bleed to check?

[porcupine73]

You can get the Subaru OEM thermostat from one place: a Subaru dealer. you can get them for much less than a typical dealer walkin by buying from Subaru dealers who sell parts online. There are dozens, i.e. www.subarupartsforyou.com www.subarugenuineparts.com www.subaru-parts-dealer.com www.subaruparts.com www.1stsubaruparts.com etc etc

Also make sure to get/order the gasket as well.

[evanejp1980]

Thanks for your time on this...

FYI, what kind of mixture do you use? 50/50? I think there's mostly antifreeze in it now...Does it really make much difference if I use mostly antifreeze?

How do you eliminate or check to see if you have these airpockets.

[xcgates]

I don't have documentation in my room right now, but I believe that you want 50/50 unless you will be in truely cold conditions.

[Rob_D]

Originally posted by evanejp1980

FYI, what kind of mixture do you use? 50/50? I think there's mostly antifreeze in it now...Does it really make much difference if I use mostly antifreeze?

The higher the concentration of coolant the lower its cooling properties.

Water has a higher cooling effect than the ethylene glycol but we have to add it for its anti-corrosion and anti-freeze properties.

Here in Australia I use a little over 30% coolant but if you need better antifreeze then you would have to go higher.

Rob

[evanejp1980]

Thanks Guys! Awesome replys.

We have extremes on both ends. It will be 10 degrees F tonight and in 6 months it will be around 105 degrees, so you can see my issues...

[Rob_D]

I suggest you read this:

http://www.peakantifreeze.com/tech/tech_c.html

If you are using an ethylene glycol coolant (read the bottle to find out) then going over two thirds coolant reduces the anti-freeze properties and well as the cooling.

And look here:

http://www.engineeringtoolbox.com/et...col-d_146.html

40% ethylene glycol will protect your engine down to -13 Fahrenheit.

50% down to -36 F

Rob