I have a D16y8 with about 240k miles. She still runs strong but a few months ago had a blown head gasket. Replaced the head gasket and got some head work done at the machine shop and also did a timing belt, WP, tensioner and v belts and adjusted valve lash. Motor runs great but when I’m driving for 20-30 mins and idling my temp gauge breaks the half way mark and rises fast untill I give it gas. Makes me think I have a coolant flow issue. I replaced the thermostat with oem Honda therm when doing the timing job. Did a leak down test after the head gasket and passed and my timing is dead on accurate. Any ideas??? Please help.

 

You may not have burped the car fully (properly). An air bubble that sits near the temp sensor can cause the needle variances.

Also, since the head gasket blew and you did the HG job, did you test the block for flatness? I assume the machine shop work on the head was to resurface it to be flat. If not, head could also be warped and the HG job is a fail.

 

Thanks for the reply Tomcat but yes both the head and block are True. I used a mechanists straight edge on the block and the machine shop did the head. As far as he air pocket I burped the hoses and I used a spill proof funnel when I bled the cooling system. I’m really confused cause I feel followed all the steps correctly.

 

Nose of the car higher than the rear. Spill proof funnel is good. You idle the car until the fan kicks on twice bare minimum before closing radiator cap, turning off motor and filling reservoir to the max line. Will go down as the car cools.

The other bit that can cause overheating issues is a faulty radiator cap. Quite probable you need to replace it with a new one.

 

Thanks tomcat for the reply. I actually just flushed the hell out of the cooling system and so far no issues. So thanks for all your advice. Truly appreciate it.

 

Sounds like a faulty water pump.
revving it forces the water pump to flow better.

 

Rad Cap problem? ONLY if it's leaking.
definitely sounds like a water pump.

 

Its JULY, Its hot outside. does the cooling fan kick on? before you give it gas does the guage go into the red? Or does it go to the halfway mark and you say WHOOPS and give a bit of gas to move the coolant? Let it idle and see if the cooling fan turns on. Mine doesnt turn on until the needle is at 3/4 area of the guage

 

His issue was air in the system and was resolved.