Hey, setup is a stock boosted b18c. New 1/2 double core rad, 12" slimfan, thermostat. Rad on angle, but surrounded with some ducting to direct airflow.

What happens is.. basically, it happens ALL the time.. City, highway etc. Im just driving normally.. below 3k, not going into boost or anything.

I have an autometer gauge, and normally its around 190-195.. It goes up to about 210 then comes back down, i can watch as the thermostat opens up. (sender is in location of stock dash unit). Then for some reason, it dosent come back down, just slowly goes up. Fan is ON, (on ign.) and i even put the heat on full, and its NOT hot out at all.. very cool still here. It goes up, and up.. to 240-250.

Now, i would think if it was a insufficent cooling issuie (ie. rad plugged/too small etc) then it would be a bit more predictable, and just get hot after some hard runs, or really hot days etc..

A few times ive done some spiritied driving on the freeway, and suprisingly enough, it dosent get hot.. but as soon as i drive like my grandman.. up it goes.

Is it possible that my thermostat is getting stuck closed once it goes though a few dozen cycles? And when i do spirited driving im assuming the water pump is putting the coolant under a bit more pressure helping it 'pop' open.

So what do you say guys, replace the thermostat? I was considering cutting some holes in the bumper to get more flow to the rad

Thanks!

Other then this small problem, car runs amazing after it was tuned, blast to drive!

 

I would replace the thermostat and make sure you have a air bubble free cooling system, I wouldn't bother cutting holes in the front end, honda designed the car to have enough air flow through it.

 

Yup thanks man.. Ive bled it 3x, properly that is too.

I will do the thermostat asap!

 

yep its pointing thermostat.

also, when you refill your block with coolant, you fill up the block first (use a funnel on the upper radiator hose on the front of the block), then your radiator. if u fill up only the radiator, your block will still be empty.

 

Change your radiator to a aftermarket aluminum one or you will blow your Head gasket after a while. Trust me i had to learn it the hard way.