Hey guys, just got my d16y8 swapped with a less mileage motor. After getting it back... Couple days later its overheating and I have a weird noise from what sounds to be the waterpump. Anyway that could be unrelated. But my car ONLY overheats when a/c temp **** is on cold and driving. At idle it will not overheat at all. All new belts, thermostat, hoses, radiator, fan switch, and ect sensor. Whats my next step. I've also flushed the system multiple times.

 

More important than flushing is bleeding the cooling system.

 

Yes ive done that A LOT

 

Please give details.

Does the radiator fan run when engine gets hot?

 

Details on bleeding? I jack the front end, remove cap, install bleeder funnel add fluid, start engine and rev engine constant around 2500 rpm until the radiator fan kicks on (yes it kicks on, but not until the temp is at like 190-200F, seems late to me with a 170f thermostat) then just let it go until air is gone.

 

Its also making a strange noise from driver side pump area. Can the timing belt be overtightened?

 

Yes

Follow the tensioning procedure in the service manual.

 

The heater hose valve also must be wide open during the entire bleed procedure.

 

Yes sorry i forgot to mention that, heater full hot while bleeding no air on though. Ill try loosening the timing belt. If the belt was too tight would it cause overheating?

 

So got head gasket changed. Also water pump and thermostat again.... Still overheating. Shop said they cannot figure it out... Im at a loss?!

 

Besides the dash gauge. why do you think the car is over heating?

 

My scan tool is telling me its running between 183-226, obviously thats sharing the same info as the ecu but its a new sensor.

 

226 F is without question in the "start to worry bout warping the block and head" overheat range, assuming temp sensor is working.

 

I would check temps on the radiator with an infrared thermometer. You can also check temps by touching the upper and lower radiator hoses with your hands. Upper should be warm, not boiling hot. The lower hose should be much cooler, not cold.

Do you have boiling water in the overflow tank?

Did you change the radiator cap?

 

No boiling in the overflow. I tried to change the cap but the radiator is not oem so the cap i bought didn't fit. Although the cap and radiator are new.. Someone told me the knock sensor caused their overheat issue... This possible?

 

I don't know about the knock sensor. Maybe a voltage issue if they get power from the same place.

Doesn't sound like you're really overheating.

 

Zero possibility.

Stop driving the car until you solve the problem, though the damage may already be done (226 F).

 

Ok so took a infrared thermometer to the car, at idle it will not overheat, but top radiator hose is reading 160-180, bottom radiator hose is about the same but started out lower by about 20 degrees, thermostat housing reads approximately 160-170, top of radiator was reading 130-170 across the top, while my scanner is reading 180-209, new developments though.... Threw a p0505 code, which I replaced the iacv when i did the swap, idle is super low when a/c kicks on, then comes up to about 800, when i turn a/c off it kicks up to about 1200 rpm... So im not sure if this is all coincidence or if its all connected somehow. I know the iacv has coolant lines so i guess it would make sense, except its new and i bleed the **** out of the system after the motor swap.

 

Iacv has coolent lines to heat it so it could work in cold weather. It has no other purpose than this.

 

Good to know thanks!

 

So took my car to a honda specialty shop to have them diagnose the issue, the first day they had it, "we dont see anything wrong, it maybe your radiator not cooling the coolant down" so i go and replace the radiator. Still overheats, brought it back the next day, "yeah we think your head is warped or cracked, because its only overheating when a/c is on, oh and we pulled the spark plugs and your number two cylinder has a small puddle of coolant on top of the piston"

Wtf. So it passes the block test, doesnt overheat with the heat on but it does ONLY with the a/c on. Im ****** so confused. If the head was cracked wouldn't it overheat ALL the time?

 

Bump

 

Bump

 

I think you have a bad fan switch. It should come on and run continously if it cannot get the temp down to 195° and when the fan is on is the temp still rising?

 

Maybe you have a inaccurate ect. If you can replace it as you are only relying on scan tool which is getting input from ect. Secondly if there is no boiling in overflow tank then you are not overheating assuming that the overflow tank is properly connected and radiator cap is working good.