I have a dilema. Not even the dealer is sure of the problem.


I have changed the Thermostat, Radiator cap (5 times), Fan Clutch.

Thermostat was tested before installing. Alike with the cap.


Problem:

Upon filling the radiator and bleeding the system and going on the highway the fluid is pushed into the radiator reservoir and if driven substantially far you will see bubbles going into the reserve tank. It acts as there is air in the system. after the car has cooled the water is not drawn back into the radiator thus leaving air in the cooling system.

Once you get out of the highway and hit city streets at say 30mph the temperature will rise. Dramatically.

But if you are at a standstill you can free rev the car to 1500 RPM and the temperature will drop.


Some mechanics at the dealership contest that its an air pocket. Others say headgasket, and some say water pump????

Temperature at idle when system clear of air and full of coolant: 177 - 183
Temp @ Highway speeds : 190-199
Temp @ City 30mph (after highway speeds) 199-230 (already on it's way to overheating)
Temp @ Red light with engine revved to 1,500 after highway speeds: 190.

I'm baffled by the situation.

Ran a flush with a water hose to remove air, also added a flush additive to remove sediments, reflushed the car..

No water is mixing with Oil or Burning in the exhaust.

Leak down test has not been performed.
No water leaks anywhere.


Any input??


?????????????????????????????

 

Sounds like there is a pressure imbalance in your system but not sure what would cause that. Water pump perhaps??

 

When did the problem start, right after you flushed your system? If so, I would guess an air bubble. Did you properly burp the radiator?

http://www.infinitihelp.com/diy/gsed..._procedure.htm

 

Problem started after a long trip to Okeechobee, FL. When i got to the destination the temperature spiked up. I filled the radiator with coolant and drove back to Miami and the car did not overheat again.

a Week later after coming out of the highway i noticed the temp spiking again, pulled over noticed the overflow tank bubbling. Refilled the radiator and then diagnosed the problem. Found the fan clutch to be faulty.

So I replaced the fan clutch and thermostat just to be safe.

Flushed the system as I found some sediments in the old thermostat.

Bleed the system for about 5 hours. Problem happens on a daily basis now.

Took it to South Motors Infiniti here in Miami, FL they said either failed head gasket or air in system. Mechanic used a spill proof funnel as such http://www.drivewerks.com/catalog/sh...CAT591_pg2.htm

Purged all of the air from the system.

when I got back home the temperature was begining to spike, all of the coolant was pushed out into the resevoir tank, and air was in the radiator again.

I called them back, Mechanic is not sure its a head gasket leak as when we performed the bleeding process he stated that if it were a head gasket leak air would continue to excavate into the radiator regardless of highway speeds or idle and idle @ 2000 rpm for over 30 minutes.

The car does have 160k miles.

What has been replaced:

Radiator
Thermostat
Radiator Cap (5 times)


What has not been replaced:

Water Pump
head gaskets
Hoses


No leaks have been detected.

One observation we noticed.

With the funnel and revving the car in bursts to 3k rpm and back down to idle air bubbles in the form of foam (very small about the size of grain of salt would arise).

seriously baffled by the situation.

 

Ok, so did a quick Water Pump test.


I removed the top hose leading to the radiator. Then plugged the radiator inlet and poured water into the radiator while the car was running (yes difficult as only 2 hands)

But here is the outcome of the car at 188degree's and the water flow from the block to the radiator.


When you rev it, it slightly pushes more water. Nothing like a water hose with pressure.

Is this normal? Or does the pump need to move more water?

 

Any takers???

 

update


Had South motors infiniti change the water pump, seems the pump was ok no broken fins, no sediments....


Drove the car home noticed the heater blowing cold... (they didnt bleed the system throughly)

Got home and went to bleed the system, the moment i go to remove the screw ""SNAP""

FUUUUUUUUUUU

Heater hose tee snaps.

Upon further investigation, the plastic is corroded on the side that meets toward the engine seems as if perhaps the heat from the headers caused the plastic to prematurely deteriorate.


pic of tee is attached.

 

wow, why isn't that made of metal?

 

Will be in 5 hours....

 

Was that cracked before...and letting air into the system?

I was wondering if the water pump had a small leak that was bleeding air in slow enough at idle to not cause issues but with higher pressure and higher RPMs the pump pushes more so it became more noticeable.

 

To be honest, I inspected the car so much that I did not notice any leaks including in the heater/bleeder area.

I personally believe after seeing one of the O-Rings for the water pump that more than likely the pump was creating some type of air suction at higher rpm's. The engine does have a bit over 160,000 miles. The pump itself looks to be in great condition. I'll post pics later on but it seems as if Nissan designed the pump to never have issues. They have a built in oil lubrication/cooling passage so that the pump doesn't burn itself to bits. It's a 1 to 1 design so whenever the timing chain moves it, the fins move at the same pace no clutch or slippage at all.

Yet 1 o-ring had life the other looked squished.

The only reason why I found the Tee to be corroded was due to the fact that the dealer was unable to open the bleeder. The screw was stripped and the mechanic was lazy. No big deal. I JB welded the plastic bleeder screw with a good dab, and inserted a #2 phillips screw driver into the head creating a mold after 2 minutes i removed the screw driver and allowed it to harden about 1 hour later WAM BAM :SNAP: FUUUUUUUUUUUUUU


So I went to Ace Hardware in the morning and devised a tee similar to the Motordyne throttle body water heater block. Just instead of blocking the water from entering I used 2 brass 1/2 fittings teflon taped them and tightly sealed them to a galvanized steel 3 way Tee. on the top side i fitted the Tee with a terminating cap. Now, I do not have to worry about stripping the plastic bleeder which is a special order from the dealer no auto parts nor salvage yard has. and best part it is not plastic. I had to shorten the hose from the radiator pipe to the heater block by about 2 inches which is fine. No kinks in the hose provide for a stock fitment. As for appearence... ehh, some Matte black will handle it just fine when I get a moment.





Yet I've beat on the car these past few days at no issues. No overboiling at all. What I did notice is that the dealership may have drained my synthetic oil and replaced it with conventional oil. More than likely they had to drain it to access the pump. Not too happy about that but pleased to have an engine not overheating. I will change the oil in the weekend. (engine has not seen conventional oil since 40k miles when I bought the car).

Another observation I noticed small drops of oil mixed in the radiator. As if were a early sign of a cracked headgasket. My best bet is that since the pump is relatively close to the oil passage some small amount of oil found itself in the internal water passage. The spots are very tiny you would seriously have to pay attention. Since I've had nothing but nightmares bleeding the system I will allow for it to stay as it's so tiny that it wouldnt create any blockages. (size of grain of salt) very tiny spots.

 

funny i caught your post. i've been going through the same thing for the last month. My scenario is the same, (2003 sedan a/t). I've changed my thermostat 3 times now and barely got my car back today. Every time my mechanic changes my thermostat, I enjoy a week of driving before I catch the needle jumping up. I haven't bled the car's system yet but based what your input, i may have to consider other options. =(

 

Is the water visibly leaking somewhere? If so yay, at least you know its not too bad. Now, if its coming out of the exhaust, mixing with the engine oil, or mixing with the transmission due to a radiator cooler leak that can lead to new engine, or transmission rather quickly. I lost a transmission like that before.

If its overboiling into the radiator overflow then your ****ed like me... either headgasket, warped head, or cracked block. I have yet to rip my engine apart as I've been working 36 hours straight. I just got out going home to get rest and start the process. Hopefully it was just wear and tear on the headgaskets and not a sever problem with my car nor your car.

 

ps, by 230 the temp needle starts to move, at 250 your heads ae warped. By the time you notice the needle 75%up its passsed the 242.00 part and well on its way to kabooom status

 

the thing about getting the thermostat changed, the mechanic lets the car run for about 1-2 hrs and its ok. Its only when i started driving, and driving it for a couple of days does the needle start to move. I haven't driven the car aggressively either. Good luck with your car, i'm going to keep an eye on your updates. Thanks