[christliche]

I have a '98 Forester, automatic. 160k miles. Overheated after I bought it, replaced thermostat, radiator cap, new coolant.

Seemed fine, but started to notice that after driving a while, or even on freeway 30 min+ at 75 MPH + the temp gauge is normal, but when I exit freeway the temp gauge quickly goes up. Not to the red line of overheating, but more than "half way" on the gauge. Then It goes back down.

This evening it happened and I parked it when I got home. Motor off, but batter on; temp gauge went back to normal, radiator fans on.

The timing belt/water pump aren't even 10k miles old. I am wondering if the radiator needs to have air burped out? I did this already, but perhaps did not go about it properly. Seems like water/coolant isn't getting moved quick enough, although when radiator cap is off, you can see the water pump spinning the fluid just fine...could the radiator have a clog or need cleaning?

If anyone has any other ideas, please share. As far as head gaskets go, I am not sure that is the issue. I almost want to say the previous owner had them done, but I need find their number and ask for sure.

THANKS!

 

[gk26]

I had the same issue with a Tacoma and it was either a cracked head, or head gaskets.

An easy was to test is to go to Napa Auto parts and buy a block tester kit. It is test tube of sorts that you put the whole where the radiator cap would go. If the blue fluid turns yellow, you have exhaust gas in your cooling system, which is bad. This is a test that can be performed by those not having mechanical skills.

NAPA AUTO PARTS

Part Number: BK 7001006
Product Line: Balkamp
Attributes:
Manufacturer : Test Tools Inc.
Product Application : Test For Cracked Blocks, Leaky Gaskets, & Cracked Or Warped Heads
Contents : Aspirator Bulb w/ Valve, Large Engine Adapter & Leak Test Fluid

 

[SkidPlate]

I have a '98 Forester, automatic. 160k miles. Overheated after I bought it, replaced thermostat, radiator cap, new coolant.

Seemed fine, but started to notice that after driving a while, or even on freeway 30 min+ at 75 MPH + the temp gauge is normal, but when I exit freeway the temp gauge quickly goes up. Not to the red line of overheating, but more than "half way" on the gauge. Then It goes back down.

This evening it happened and I parked it when I got home. Motor off, but batter on; temp gauge went back to normal, radiator fans on.

The timing belt/water pump aren't even 10k miles old. I am wondering if the radiator needs to have air burped out? I did this already, but perhaps did not go about it properly. Seems like water/coolant isn't getting moved quick enough, although when radiator cap is off, you can see the water pump spinning the fluid just fine...could the radiator have a clog or need cleaning?

If anyone has any other ideas, please share. As far as head gaskets go, I am not sure that is the issue. I almost want to say the previous owner had them done, but I need find their number and ask for sure.

THANKS!

I am not familiar with the vehicle, but I think that you have a fan problem. In a Honda, I had a similar problem and it was a thermostatic switch in the coolant that was supposed tor turn on the electric fan when the coolant got too hot. (Maybe your car has a mechanical fan.) If it does have a mechanical fan, some of those have a thermostatic fluid that acts like a clutch.

Anyway, on the freeway, your speed pushes cooling air through the radiator. Going slower moves less air and a fan can be required. I'd look for that type of cause.

 

[zi0matrlx]

98 Foresters should have electronic dual fans, if they're anything like 2000's. Look underneath your radiator and make sure both your fans are connected. Someone might have replaced the radiator/did a timing belt job and forgot to re-plug them. With the car running, AC button on, blower running, look under the hood to make sure both fans are running. If they aren't running, check the appropriate fuse/relays for the fans.

Fuses/relays faulty? Replace them.
Fuses/relays okay? Maybe replace fan(s)

 

[twowings]

I am not familiar with the vehicle, but I think that you have a fan problem. In a Honda, I had a similar problem and it was a thermostatic switch in the coolant that was supposed tor turn on the electric fan when the coolant got too hot. (Maybe your car has a mechanical fan.) If it does have a mechanical fan, some of those have a thermostatic fluid that acts like a clutch.

Anyway, on the freeway, your speed pushes cooling air through the radiator. Going slower moves less air and a fan can be required. I'd look for that type of cause.

Agreed....the symptoms described by the OP are common with a failing fan clutch or failure of the auxillary cooling fan...

 

[adc]

He said his radiator fans were on

 

[jstawgn]

Fan on does not mean it running properly. Its very common on older car that the ground or wire connection got corroded and cause the fan to run slow. Or even the motor are getting bad. Try connecting the fans directly to the battery if it runs any faster.