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First post ... I've been coming here for a while but usually am able to find the answers to my problem by following other people's posts. This time I'm coming up blank. I've found topics similar but none with my particular issue... so here it goes.

The car is a 96 Civic LX. I've been having some temperature problems with it for a while. The scenario is usually the car doing well for example on a 40 mile trip to work... no temperature spike, reaches destination fine. I might park it the whole day (or drive it back inmediately) and then maybe halfway back the temperature starts to rise... never to a point of reaching top temp and staying there, it rises then on it's own levels down... then rises again then back down and so on until I get home.

On one of those episodes the Mrs was the one driving and the radiator plastic top cracked... she didn't notice, ended up blowing the gasket. I had the radiator and engine fixed, hoping maybe that would take care of the problem... it didn't. Continues the exact same way and it's driving me crazy. On some longer trips I've noticed that for example when the car is climbing a hill temp starts rising... as soon as I'm over the hill it starts going back down. Not sure if it's the inclination factor or the engine working harder when going uphill.

What has been done or tested:
-replacing the cap
-replacing the thermostat
-removed the thermostat
-repairing and cleaning the original radiator
-replacing the radiator
-tested the engine for leaks with pressure
-always on fan (in case it was the fan not coming on when it should)

My next shot was trying a 1.3 lbs cap to see if maybe the 1.1 it currently has is not up to the task.

So there it is... any suggestion or any Civic wizard out there that can point out anything else I'm missing I'd greatly appreciate it.

Thanks

 
Rep Power: 314

A few things come to mind.
Failed temperature sensor
Air in the coolant system
Failed head gasket.

 
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I did read another post in which they mentioned how to purge the air out of the system... was thinking of trying that too...

The temperature sensor, do you mean the one that's right underneath the distributor? I think that one isn't too expensive so it's worth a shot replacing it

 
Rep Power: 314

It usually isn't the temperature sensor. It's more likely air in the system. Do that first because it's free if you have some coolant lying around. Do not increase the coolant system pressure because if you have a car that is older or has a lot of kms on it you will blow a hole somewhere in the system.

 
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Got it... I'll try that over the weekend... hopefully It's air.

I was thinking after I replied to the last message that I doubt it's the sensor because the water does start to dry up in the reservoir so there does seem to be an actual temp problem, and not just a false read on the sensor.

Thanks!

 
Rep Power: 314

The level in the reservoir is dropping? How long has it been doing that? Start by bleeding the air out. If it persists you need to look into other stuff. How did you check for leaks? Were there any? Has the water pump been checked?

 
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To be quite honest the leak check and pump testing was done at a shop... I don't have much equipment or tools to do any of that myself. But I do know that the system wasn't bled after the radiator was replaced.

 
Rep Power: 314

^ Bingo. Guaranteed air in the line.. You MUST bleed the air out after opening the system pretty much anywhere other than the rad cap.

 
Rep Power: 188

Let us know the outcome