http://www.geocities.com/dsmgrrrl/FAQs/leakdown.htm

 

Mechanic called today and asked for another day with the car. He said they replicated the overheating but have NO clue what is causing it.

Whooopie!

 

He has no clue. Fluids tested clean and now they can't replicate the problem. They told me to drive it around and bring it in when it's overheating.

 

Did the mechanic do a compression test or a leak down test?

It is puzzling to me that the mechanic wants you to drive the car until the engine overheats when he has already replicated the overheating problem. You might consider taking your Civic to another mechanic.

 

He did an extended compression test under load and checked the fluids/tested them for coolant/exhaust. Everything came out fine. I'm stumped.

 

Are you still having the overheating problem? If so, maybe it would be helpful to briefly summarize what has been tested or replaced up to this point.

 

No problem, I replaced the following:

Thermostat
Coolant temperature sensor
Radiator
Water pump (12,000 miles ago)

Car still randomly overheats. It even overheated with the mechanic there at 2 separate places and neither could figure out why.

The car is losing coolant, but we cannot identify where. There are no leaks to be seen and testing of the fluids indicates that the head gasket is ok (along with the aforementioned compression test).

 

Is it possible that there is a problem with the new water pump?

 

Is there anyway to tell other than taking the whole thing apart and trying a new one?

 

Car hasn't overheated since the last time (3 weeks ago). Yesterday I opened up the radiator to check the fluid level. I hadn't driven the car for 2 full days. As I opened the cap it basically exploded coolant and air out in a moderately sized splat. The fluid was as topped off as it could and the reservoir was all the way to the top as well.

What the F*ck?