I just changed my head gasket and timing belt. And when my car starts thw temp starts at halfway. After about 5 min it starts to rise. I shut it off cuz i didnt want to overheat it. Not sure whats wrong, it was working fine, car hasnt been driven in about 2 months.
-Upper radiator hose gets hot, lower doesnt.
- also what i found weird was, when filling it with coolant, i loosened the bleeder screw, and when i topped it off with coolant, no coolant squirted out the bleeder... any one know what can cause this?

 

If youre gauge starts at half when the car is completely cold thats an issue.

And if the lower hose isnt getting hot the thermostat obviously isnt openning, if youre sure its full of coolant, just wait longer

Top off the radiator from cold before doing anything else, also put the heater in the car to full hot to make sure youre filling/circulating the heater core aswell

 

When i put the keyin the ignition, and turn it to the point where the dash lights turn on, the temp gauge automatically goes to halfway... does that mean it doesnt work?

Yes its topped off, should i drain it and refill... and what about the bleeder screw? When the radiator is full, coolant is suppose to come out of the bleeder... but it didnt do it in my case..

 

Are you sure the system is full?
When was the thermostat last changed?

Sounds like your gauge or sensors are failing if the gauge reads half way like that. If your fan doesnt work you can do a resistance check on the sensor which should be on the back of the block. Check either a chiltons, haynes or Honda service manual for the value.

 

Well the thing is, i did a mini swap like 3 months ago, and the car ran, the fan came on and everything, but my camshaft snapped, so i put the stock head back on( stock ecu and everything stock)
It was working before... car hasnt been driven since then.

 

So when the car is completely cold and you go to crank it up, the temp gauge shoots up halfway. Sounds like the temp sending unit that controls that gauge is faulty.

 

The small one on the side of the head right? Ill change it, see if anything changes.

 

The engine has to be running in order for coolant to come out of the bleeder screw.

The sensor for the gage is indeed the small one with on cable attached to it. If you want to check the sensor the easy way, disconnect the cable and turn on the ignition. If the gauge doesn't rises, the sensor is faulty.
If it still rises, there's a bad connecting in your wiring loom.

Also, it takes about 15 min for your engine to heat up and for the thermostat to open. If there is no heat in the car with the heater full open (and of course no air pockets in the system), the engine has not yet reached operating temperature

 

not necessarily true. you can bleed the engine coolant without having to start up the engine. open the bleeder valve when filling up (assuming you start fresh with no coolant) and once the bleeder valve starts to pour, you're done. (for those of you that think you need to warm it up because only then the thermostat will allow more coolant in, there is a tiny hole at the top of the thermostat. this tiny hole is enough for coolant to flow through)

I have done it this way and the "other" (engine start, warm, etc) way. Driven 300+ miles after i bled the system like this and had no problem. The "other" way is much more time consuming.


also OP, sounds like the temp gauge is faulty. but double check the sensor (under distributor, single wire) and see if you see anything abnormal.
My guess would be the sensor or the gauge. my previous car had a broken sensor that wasnt visible until i removed the sensor and found that it was broken in half.

 

 

Ok. Mine doesn't if its not runnig. Thanks

 

Well it turns out that small piece where the upper radiator hose, well underneath the bleeder screw where that tiny hole is, it was plugged with dirt or debris or something, i poked it with a needle and it cleared up. I was able to bleed my coolant now. But the temp reading is whacky. It starts high then after 10 min goes to below half. I switched the temp cool sensor with one off my z6 head... and now the temp gauge starts at nearly h... but thefan does come on, so im not tripping about that anymore.... now i have this oil leak problem that leaked away my 25$ of oil...