View Full Version : Cooling system help/questions

04-26-2010, 12:00 PM
Alright so I installed a brand new Mishimoto radiator and Nismo thermostat along with a barely used water pump in my 240sx with KA24E.

I was trying to flush the system by disconnecting the top radiator hose from the radiator and having the water dump out into a bucket once the thermostat is open. The car warms up faster than usual but nothing is coming out of the hose. The water temp guage is sitting in the middle. The heater is full blast on hot as well. When I turn off the engine, a little bit of water flows out of the hose. I try this again with the heater off and it doesn't flow. Another try with the heater on and a little bit flows out. Seems like the thermostat is open.

I remove the Nismo thermostat and tested it and it opens up at around 140-150F, so its definitely working. I figured it would be the water pump since it is a used unit. To test that, I went ahead and installed the thermostat housing without the thermostat and basically did the above flush. Even with no thermostat, nothing flows out! However, when I remove the thermostat housing some water does come out.

I removed the water pump and it spins perfectly fine. A 1:1 ratio between the pulley and the fin things inside. There was no water leaking out of the hole on the water pump while it was installed and engine running. Also, a bunch of water came out of the area where the pump attaches to the timing cover. Kinda makes me think the water pump is actually fine.

Would you guys say the water pump is problem? Is there any other test I can do to figure out why no water is going out of the thermostat housing? My last question is, the upper radiator hose connects to the thermostat housing while the lower one connects to the intake manifold housing right?

Also, my cooling system was working properly before installing the above. Nissan OEM radiator, Nissan OEM thermostat, OEM Water pump.

04-26-2010, 01:29 PM
After reading the FSM and looking at my S14, I'm 100% sure that I have the radiator hoses connected to the wrong spots on the engine. I always thought the water would flow out of the thermostat into the radiator, but according to the FSM water flows to the thermostat, from the radiator, after it has opened up. I feel like a big ass idiot...

04-28-2010, 03:16 PM
UPDATE (not so good one):

I went ahead and installed the radiator hoses, correctly, and I'm still having the same problem! The coolant is not circulating. The water pump I installed spins perfectly and there is no leak from it with the engine running. I'm went ahead and bought an OEM Nissan water pump and going to install that today.

Has anyone received a faulty Mishimoto radiator before? If the coolant still doesn't flow, I'm going to install my old radiator and try again...

Cliff notes:
Installed Brand new Mishimoto Radiator, Nismo Thermostat, ISIS Radiator hoses, OEM Water Pump.
Tested thermostat: opens up at 140-150F
Had hoses installed wrong, installed correctly this time
Coolant isn't flowing or circulating.
Engine runs perfectly fine except for the coolant not flowing.
The coolant was flowing perfectly fine before I decided to upgrade to a Mishimoto unit

04-28-2010, 03:23 PM
Have you tried to reinstall the stock radiator to rule out the Mishimoto?

04-28-2010, 03:25 PM
Have you tried to reinstall the stock radiator to rule out the Mishimoto?

I actually gave it to my friend since his is leaking. Lucky enough, he hasn't installed it yet. I plan on installing the old radiator back if the new water pump doesn't solve the problem.

04-28-2010, 03:28 PM
^ Jerk! Oh well I still have the JB welded one for now. :D

04-28-2010, 03:39 PM
Don't you forget, that was my JB Weld you used! Where mah JB Weld CUHHHH?

I'll get back to this thread tomorrow night after installing the water pump.

04-28-2010, 04:02 PM
Take out the new radiator and dump water in one end and see if it comes out the other. This seems like a very strange problem, I mean the cooling system is pretty cut and dry and you've done all the major diagnosis.

04-29-2010, 09:00 AM
Stinky 180, I have never heard of something like this before with one of our radiators. Please keep me updated and let me know if there is anything I can help you with.

04-29-2010, 03:27 PM
^+1 for Mishimoto! If I didn't already have a Koyo I would pick one up.

04-29-2010, 03:41 PM
Sorry for the wait. I won't be able to work on my S13 until this weekend. But I can assure you, I will get back to this thread with updates.

04-29-2010, 04:29 PM
just makin sure, the fan belt is connected right?

04-29-2010, 04:54 PM
Yes, that is hard to miss.

05-04-2010, 11:10 PM
Update: FINALLY!

Alright so I went ahead and installed a Nissan OEM Water Pump purchased from frsport.com. The cooling system is finally circulating! Piece of crap aftermarket water pumps! I don't understand how the other one failed. It did not leak and the 'fins' spun perfectly fine with the pulley, it just doesn't make any sense. The only difference between the two is that the Nissan one has liquid gasket grooves and larger 'fins'.

Now I gotta re-wire my electrical fans before I can do a test drive.

So for those with cooling systems problems similar to mine; USE A NISSAN OEM WATER PUMP!!! You'll thank yourself later.

Thanks zilvia, enjuku racing, mishimoto, swapped, frsport!