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Subaru overheating only in cold temps and at interstate speeds?


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I have a 2001 Subaru outback limited edition with the 2.5 liter engine and it just recently overheated. I was about 3hrs into a 6hr drive traveling at interstate speeds and the outside air temperature was 15 degrees F.

 

I am baffled, because this exact same thing happened to me last year while I was traveling to the same place, almost at the same spot on the interstate, and the outside air temp was roughly the same. The car doesn't overheat during the summer and I have driven comparable distances.

 

So far I have had several mechanics run compression tests on it, and the mechanics have said that it doesn't appear to be a headgasket problem; the thermostat has been checked and appears fine, and the radiator was replaced when I had the 100,000 mile maintenance done to it.

 

Any suggestions would be appreciated!

 

Thanks,

Justin

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Firstly please state your year and model of car you are dealing with. oops. I see 2001 .

 

Secondly, a compression test on certain motors will never show a failed headgasket, since they blow exhaust portion of the gasket, not compression portion.

 

More info needed.

 

When was the last service for water pump, coolant, etc.

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What thermostat do you have installed. If it is not a genuine Subaru thermostat that may be your problem. Aftermarket thermostats are sometimes shorter and do not correctly sense the temperature of the resulting mixture of coolant returning from the heater core/throttle bypass and the coolant entering from the radiator, and thus end up staying closed or not opening enough under these conditions.

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Lets go for weirdness.

 

Was it a true overheat or a gauge overheat?

Was the overflow tank full or empty?

How old is the radiator cap (if old replace).

 

If a car gets near some military micorwave antenaas or other telecommunication systems, if powerful enough and on the right frequency, can do goofy things to cars.

 

I am wondering if it is that since sampe bat place same bat time same bat channel or it can be just a combination of the perfect storm.

 

Was it snowing outside?

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Thanks for the responses guys!

 

The last time I had my coolant changed was January of 2010 when I had the the radiator replaced and the 100,000 mile service done.

 

I do have an after market thermostat installed.

 

Not sure if it was a true overheat, but the gauge climbed into the red, but I did not lose any coolant either if that helps.

 

It was not snowing at the time.

 

Not sure about the radiator cap, but maybe it was replace last year when the radiator was replaced.

 

Please elaborate on the clogged bypass or heater core?

 

All insights are appreciated!

 

Justin

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Thanks for the responses guys!

 

The last time I had my coolant changed was January of 2010 when I had the the radiator replaced and the 100,000 mile service done.

 

100k is around when the head gaskets tend to go.

 

 

I do have an after market thermostat installed.

You need to replace it with an OE Subaru t-stat. Anything else simply doesn't work and tends to overheat the engine. If you compare the aftermarket and OE t-stats you'll notice a huge different.

 

Not sure if it was a true overheat, but the gauge climbed into the red, but I did not lose any coolant either if that helps.

When did you check the coolant?

 

Not sure about the radiator cap, but maybe it was replace last year when the radiator was replaced.

Sincerely doubt it was replaced.

 

All insights are appreciated!

 

Justin

 

Find a mechanic who specialized in Asian cars and know Subaru well. Have them check the coolant for exhaust gases using the chemical test. If I had to put money on it I would bet your head gaskets are going. Sorry. :/

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i have a 2000 subaru outback, have to say i love it, 2.5i engine, but when i was driving it to work and stopped i noticed steam coming from the engine, when i poped the hood and noticed it was the engine but just underneath, it was anit-freeze. now it seems like the heat shield gasket (correct me if im wrong) on the front of the engine where the belts and pullies are seems to be the main leaking points. any ideas? also got to the oil pan looks very very dirty under there. need some ideas to see if i need to pull the engine or not.

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Thanks for the responses guys!

 

The last time I had my coolant changed was January of 2010 when I had the the radiator replaced and the 100,000 mile service done.

 

I do have an after market thermostat installed.

 

Not sure if it was a true overheat, but the gauge climbed into the red, but I did not lose any coolant either if that helps.

 

It was not snowing at the time.

 

Not sure about the radiator cap, but maybe it was replace last year when the radiator was replaced.

 

Please elaborate on the clogged bypass or heater core?

 

All insights are appreciated!

 

Justin

 

Pretty simple. The thermostat is on the inlet side of the engine, so large amounts of cold coolant In the radiator will cause the thermostat to close, thus blocking the flow of coolant, and causing the coolant in the block to boil.

 

There is a bypass system in place to prevent this. It runs from the engine block to the heater core, then back to the water pump through the bypass pipe. (its the hose that sticks out the side of the thermostat housing of the water pump) The coolant is still warm enough to keep the thermostat open and keep coolant flowing through the block.

 

Change out that aftermarket thermostat ASAP. They are known to cause problems in these because they are not the correct design.

Edited by Fairtax4me
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Thanks for the responses guys!

 

The last time I had my coolant changed was January of 2010 when I had the the radiator replaced and the 100,000 mile service done.

 

I do have an after market thermostat installed.

 

Not sure if it was a true overheat, but the gauge climbed into the red, but I did not lose any coolant either if that helps.

 

It was not snowing at the time.

 

Not sure about the radiator cap, but maybe it was replace last year when the radiator was replaced.

 

Please elaborate on the clogged bypass or heater core?

 

All insights are appreciated!

 

Justin

 

 

Subaru Thermostats ONLY. Aftermarkets do not flow properly as they have smaller openings and a shorter stroke of the valve. replace the cap, this should solve your problem.

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i have a 2000 subaru outback, have to say i love it, 2.5i engine, but when i was driving it to work and stopped i noticed steam coming from the engine, when i poped the hood and noticed it was the engine but just underneath, it was anit-freeze. now it seems like the heat shield gasket (correct me if im wrong) on the front of the engine where the belts and pullies are seems to be the main leaking points. any ideas? also got to the oil pan looks very very dirty under there. need some ideas to see if i need to pull the engine or not.

 

Ok names are all wrong here but I bet I know your issue.

 

How many miles and when the timing belt was serviced (it was serviced wasn't it) did they replace the water pump? It sounds like you need a water pump and oil seals.

 

How many miles on the car?

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Ok names are all wrong here but I bet I know your issue.

 

How many miles and when the timing belt was serviced (it was serviced wasn't it) did they replace the water pump? It sounds like you need a water pump and oil seals.

 

How many miles on the car?

 

The timing belt was changed. I apologize for the wrong names. The water pump was replaced. It has 169xxx miles on it. I just bought it from a dealer. It looks like it is leaking from the front and passenger side seals and right by the oil filter as is there is a crack in the motor

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Do you mean as if there is a crack?

 

1st step with any leak is to clean the engine, wash it down. This hopefully will help you find it. If it looks like it is coming from under the timing belt cover the only thing there to leak coolant is the water pump. If it doesnt check your hoses and around the manifold near the middle. The Idle Air Controller is there and that has coolant in it.

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The diagram helped. Looks like the pump and the jackets. And the heads.. ..

 

 

I bet it is the waterpump, as the heads rarely leak in that spot. The "jacket" is built into the heads. It is the cavity that the coolant flows through.

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I bet it is the waterpump, as the heads rarely leak in that spot. The "jacket" is built into the heads. It is the cavity that the coolant flows through.

 

I'm thinking so. Been reading that the late 90's and early2000's had that problem. May be dumb to ask. But are they easy to replace? Or should I take it into a shop?

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