Ok well I recently I installed a low mileage b20b into my sedan. Its a bone stock automatic.
I got everything put together, new radiator, cap, hoses, fresh coolant and its all been bled.
Radiator fan stays on all the time, condensor fan dont work.
We aint using the a/c at all.
It has no leaks whatsoever.

But it has been encountering a problem to where itll heat up after an hour or so of driving.
Once we put the heater on, it will cool back down and the temp will stay down after shutting the heater off for about 20-30mins or so b4 heating up again.
Any ideas on what it may be? I was told the guage sensor, but if the heater is cooling it down would it even be that?
All help is appreciated. Thanks

 

Ok so today i was revving it with the cap open and i didnt get any bubbles. I guess that will rule out headgasket. Coolant stayed at a constant flow.

 

No insight what so ever? Could it be a water pump that is failing? Its not leaking.

 

does it run fine other wise?

if no it could be running lean this will make the car run hotter.

when you turn the temp selector to hot it opens the valve and flows coolant through the heater core giving it a rush of cold coolant that it had to heat up.

did you replace the water pump? it could be bad and not be leaking.

you went to all the trouble of doing the swap first thing you should have done was the timing belt and water pump.

 

Ya it runs amazing. Its really healthy.
Ya that was what someon told me, water pump.
And I know, i was just in such a rush that I needed the car running asap for my babys momma lol.
But now im kicking myself in the *** for it.
I threw the cooling pressure tester on it, and revving the car will move the pressure needle up a pound or so. I mean it never loses the pressure. Is that normal?

 

How lean does it have to be? Not being a dick but I've never seen a problem with this issue before.

Water pumps will just go out and leak if it was bad in the first place. It would not take that much time to cause the motor to overheat with a bad water pump.

 

Yea its a mystery for me. I cant seem to figure it out. I mean I had a few tell me it could just be a failing pump that hasnt gone completely bad yet. But im not sure. Ive also been told headgasket, but there is not really any air in the cooling system when i revv it with the cap open. Coolant stays steady.

 

Can you smell coolant burning? Do you have any CEL?

 

Hows the thermostat? Kind of a stretch but possible. They make this really cool stuff for checking for combustion gasses in the cooling system. Its a clear cylinder with a cone on one end that goes in the rad cap opening. You put this in the rad and fill the cylinder half full, then put the squeeze ball on top and it when you squeeze and release it pulls air from the rad through the liquid. If the liquid changes colour you have combustion gas in the coolant, head gasket. You can also run the engine say 1500 RPM and either use a laser thermometer to see temps of upper and lower rad hoses for heat drop accross the rad, or CAREFULLY touch each one to see if theres a noticeable differance.

 

There is no check engine light, and no smell of coolant.

And that combustion leak detector test I tried friday and it passed.
I need to stop by acura and pick up a thermostat.
I can feel that its circulating to the bottom hose, but don't hurt to have a new one.

 

why is the fan on all the time? is it hard wired?
also, when does it begin to overheat? while cruising? or at idle?
are you sure pressure never dropped though? how much pressure did you place? and for how long?
you can try running it without the t-stat. if problem ceases, you've found the issue. no need to replace parts until you've verified.
and yes, pressure will increase as you rev, since the pump is moving faster.
a pump can fail without leaking. the blades corrode, causing a lower than expected flow rate. or the pump becomes separated from the gear. the latter causing an unmistakable noise, so don't think it's your issue

 

I believe its because I never connected the thermo fan switch. The one on the motor was broken. And I'll give the no thermostat a try. It heats up at random times. Most of the times when going up hills. for example today I was driving for about an hour and 20 mins and right when I got close to home the heat got slightly hot. I put the heater on and it didn't move. Drove more with the heater still on and the temp was going up and down. Heater was still blowing hot air.

 

is the switch hooked up?

 

The wires are good but its not connected.

 

the 91 teg fan should only run if it is grounded on the yel/grn wire. located ether at the rad fan swithch and/or the connector on the drivers side firewall next to the injector resistor box.


if the car Has/Had AC then it a little more complex but its still the same color wire for the rad fan.

 

But I dont see how a constant running fan will contribute to overheating. Im not worried about the fan cuz its working.

 

if any thing the car should run cold with the fan always on.

also does it smoke at all when warm?

you might have a bad ECT if it thinks the car is running cooler then normal it will run rich and you will get black smoke when at op temp. and if it thinks the car is running hotter it will lean out the fuel. this might not throw a code if the ECT is sending a normal value to the ECU so let say the ECT say to the ECU the coolant temp is 80 degrees but in fact the car is at op temp. no cel might be showen as the ECU belives it's running cold but still in the normal rang same as if the ECU belives the car is running at 230 Degrees when at op temp it's still with in the rang but will lean out the fuel.

pull the plugs and post pix if you can.

here is a chart for reading the plugs.
http://www.vtcoa.com/forums/attachme...plugchart1.jpg

 

You mentioned that the car will not heat up until about an hour or so of driving, and then it will begin to overheat. The thermostat may be at fault. It sounds as if the thermostat is stuck open upon driving, and then closes after a while, which is strange considering it should do the opposite. Its worth dropping a couple bucks to see if that fixes the problem, and if it doesnt, you know you have a nice new thermostat. Hope I helped.

 

Well itll get to operating temp within 5-10 mins, and drive normal and stay at that temperature. Then after about an hour or so, the normal temp will start to rise over the half way point. Sorry if that was confusing.

And ok ill test the ect or replace it and see if that helps any.

 

just pull the t-stat and see if the problem goes away. if it does, replace with oem. it's one of the more common issues. start there

 

Agree on the thermostat. could be that it is not opening all the way so you have a restriction.
Also, do you have any new bodywork on the front of the car? May be restricting airflow.

 

Verified today it was the water pump. Thermostat has been out for a day and it still overheating but I do hear a squeal coming from the water pump. Thanks everyone I appreciate it.