My b18 is idling just under 2000 rpm's. It is also overheating.

My problem began when I noticed that I was leaking coolant from throttle body. I just recently purchased the car, and failed to realize that the previous owner bipassed the throttle body. I simply capped that valve. I filled up my coolant resevoir, and let the car run. It will heat up to almost redline within 15 minutes. Later on I realized that my radiator was about half filled, and it never pulled any coolant from the resevoir.

I'm on my way over to burp the car now, but any help would be greatly appreciated.

 

without coolant in the system the computer cannot get an accurate temperature reading and the engine will idle high as you've said. You've ran it for a long time without coolant and it's possible that the engine has suffered damage from overheating. Get the coolant filled, even if just with plain water for now. If the cooling system will not stay filled and there are no external leaks then you have an internal leak, probably from a blown headgasket or cracked head.

 

I apologize if I didn't state the problem clearly. I has had antifreeze in it and I can not find any leaks. My top hose is getting hot, and my lower hose is staying completely cool. I'm not sure if coolant is cycling properly.

The engine is running great, Unless I rev it up. After I let off the gas, it dips down to about 800 rpms and back up to 2000, until it slowly steadies off and remains at idle

 

Well that helps alot, your lower hose should get warm and not stay cool. That is evidence that your coolant is not circulating through the radiator and causing your overheating problems. First thing to check would be the thermostat, it may be stuck closed. You can remove it, suspend it in a pot of water on the stove and as the water gets near boiling it should start to open up. If it doesn't you've found your problem.

 

thermostat is located where the lower hose connects near the intake manifold

 

I appreciate the help. I'll test it tomorrow afternoon. Could this explain the idling problems also?

 

yes this could be causing your idle problem, the computer adjusts the idle speed based on the engine coolant temperature among other things.

 

I tested my thermostat, it's perfectly functional. I ran the car without the thermostat. It took longer to heat up (as expected). The top hose got hot again, and the bottom remained completely cool.

I immediately thought about the possibility that my radiator may be clogged. I removed the radiator cap. Since I had the bottom hose disconnected because of the thermostat, I blew into the hose. As I blew steadily, coolant blew out of the radiator cap as expected. Prior to this, the radiator was a bit low because of removing the thermostat housing. When I allowed the car to run without the thermostat, the radiator didn't pull any coolant out of the resevoir.

As a side note, when closely observing the top radiator hose, I noticed an obvious non uniform heat distribution. The upper half of the hose was much hotter. This leads me to believe there is no flow of coolant. I am no expert mechanic by any means, but I do have an intermediate understanding of fluid mechanics and heat transfer. I believe if coolant were present, the hose would have a uniform heat distribution. If there were no fluid, the head would simply be heating the air in the hose. Obviously hot air will rise and heat the upper portion of the hose more than the bottom.

I may be analyzing this way too much, but please any help would be great.

My thoughts are possibly the pump? Or possibly even some internal problems (I pray not)

 

Hmmm I recently put a new intake manifold on and my gsr is doing the same thing with the idle issues. And I bypassed the coolant lines on the stock throttle body, now after I'm reading all of this I'm thinking I shouldn't have done that Hahahaha ????????????????? Wtf

 

If you remove the coolant lines from the throttle body then the FITV is Never going to function correctly and you will always have a fast idle.

as for the uper hose getting hot and the lower hose staying cool with No thermostat installed i would say your warer pump is Crap.

also if you can get a cooling system pressure tester it will help you find any leaks in the cooling system.

if the Pump is crap and has lost the fins on the inside you will want to get a new timing belt at the same time. in that case get a timing belt and pump from a GSR.

 

The radiator will pull coolant from the reservoir as the coolant cools to ambient temperature if the radiator cap is sealing and functioning correctly. Sounds like there is either a blockage of some type (could even be an air pocket) or your water pump is not doing its job. If you suspect an air pocket you can squeeze the upper radiator hose by hand repeatedly to try and blow any bubbles out of there and into the radiator neck where they can escape. To find out if your radiator is clogged unplug the radiator fans and remove them. With the fans out of the way you should be able to feel around the radiator and the heat should feel uniform near the hot side (bottom) and gradually cooler as you get to the other end (top) but there shouldn't be any cold spots. This check might not work in your case since it seems that the coolant is not even moving through the system. It is possible your water pump isn't functioning, though that problem is rare... sometimes the fins on a water pump can errode away. Did you notice any corrosion inside the system when you removed the thermostat?

here's some videos that might give you some guidance/ideas

http://youtu.be/zUpXgAJ1gjU

http://youtu.be/evpaTW2WJ5Y

 

Might want to recheck your Flow chart for the cooling system.

honda uses a centrifugal water pump that pulls coolant from the center of the pump and pushes it out the side.

this pulls coolant from the tube on the back of the motor and pushes it into the block then the head. the head has 3 outlets for the coolant #1 passes through the intake and into the thermostat housing on the Pellet/Pump side of the thermostat, #2 goes from the head to the Heater core and #3 is the Upper radiator hose.

Most all imports work this way so the top of the radiator should be hotter the the bottom

*on car's where the radiator flows side to side the hose that come from the head is the hotter side. unless the thermostat is mounted in the block or intake.*

*(the above is a GENERAL rule for all cars.)

When the thermostat opend the cooling system fallows the path with the least resistance. as the radiator hoses are the largest it should flow throught the radiator but if the pump is unable to push the water into the head there will be no flow at all.


OP does your heater in the car work?? if the answer is NO then most likely your pump is the fault.

if it is working your not getting enuff flow in the radiator and will need a new one

 

yep, my mistake