Two days ago my 2003 S40 over heated on me. Upper radiator hose was spitting coolant so I took it to a Big O tires because they were close. They replaced the hose and it was still over heating. The mechanic was convinced it was because there was air pockets stuck in the system and said letting it cool completely overnight should resolve it.

Unfortunately that did not fix my issue, I tried working working any air out it using the bleeder bolt on the lower hose and "burping" the hoses to no avail. Fan works fine at both speed and I removed the thermostat completely to confirm that it wasn't stuck closed. It will over heat within 1/2 mile of driving, but will cool from sitting just a few minutes. One weird thing is I have no heat when using the heater now. Barely warm air, and the heater worked great this past winter.

Any and all help is greatly appreciated.

 

water pump may be spinning on its shaft. pull off the timing belt cover to see if there's any signs of leakage. When was the timing belt last done? Does it look like the water pump has ever been replaced?

 

Thanks for the reply Mt. To answer your question, the timing belt and water belt were replaced 5 years/50k miles ago. I'll pull the timing belt cover and inspect again, when I pulled the thermostat I didn't notice a ton of coolant down bu the pump but I wasn't looking extremely hard.

 

yeah when you pop off the thermostat cover you should see the coolant level. When I did the temp sensor on my 2000 (its right under the thermostat) I lost a half cup of coolant just as a sense of the level in the block.

 

Yeah, I lost quite a bit when removing thermostat. Also was able to confirm coolant in the lower rad hose by checking the bleeder. I read online (not sure how accurate these "tests" can be) about if the head gasket is bad that if started cold and let idle for 1 minute it should not build pressure in the expansion tank. And if started from cold idle for one minute then rev to 3500rpms with tank cap off it will shoot a geyser of coolant if the head gasket is bad. My car "passed" both of these "tests" lol.

I don't have the tools necessary where I'm at to do any real tests. Just stumped on why I have no heater. Makes me think water pump, but failing after 50k miles seems unlikely.

Any other ideas out there or suggestions? Anything is appreciated, I'm grasping at straws at this point.

 

budget after market water pumps have been known to fail much more quickly than OEM. Based on the fact you noted no heat says to me there's no circulation = no pump action.

 

I haven't been able to inspect the pump visually yet but it's not leaking bad if it's leaking at all.

Is there a way to test the water pump without removing it? Take one side of rad hose off and start car cold and see if I get good flow into a bucket perhaps?

Thanks for all the replies, the help is appreciated.

 

Pulled timing belt covers off and it doesn't appear that the pump is leaking or has leaked. I took the small return tube off of the upper radiator hose that goes back to the expansion take and started the car to see if it would increase the spray/volume of coolant and it didn't change its the car running. Also let it warm up for 2-3 minutes and with the thermostat removed the upper rad hose began to warm up but the lower hose was still cold to the touch. I'm pretty confidant it's the water pump and not a head gasket. Hopefully atleast....

 

If the head gasket has blown you would probably see bubbling of the coolant liquid in the expansion tank with the cap off. (engine running at idle)
The air in the system will make for the highest point.
Have you noticed any obvious coolant loss from the expansion tank when the overheating has occurred whilst driving about?

 

I am losing coolant from that area when it overheats. Idling with cold car and cap off I get no bubbles or overflow. Also read that starting cold car and let idle for 60 seconds and then rev engine I should see coolant spew out of open expansion tank (if head gasket us blown) and my car didn't do that.

 

Blocked heater core?

 

I had just fixed a honda crv that was air bound after a radiator replace. It can cause over heating. Other than that, thermostat, water pump or blockage. Head gasket would cause bubbles.