[overdalimit]

OK, heres another overheating post.... I have read hundreds of posts and reply concerning this issue on my 04' but noothing has worked so I'm posting exactly what mine is doing in hopes that SOMEBODY can help!

Ok, I had my truck idling in the driveway one afternoon and came out of the house and it was running hot.... Hot as in the needle was at the 3/4 mark before all the way hot.

So, I take off in an attempt to cool it down with more airflow through the radiator. and it cools down rather quickly and I don't hear the radiator fan increase speede so I suspect the clutch is bad.... So i go to Nissan and buy the clutch, and the thermostat and replace them both. Runs good, no problems.... sitting still after about 5 mins and we're back hot again...OK..... so now I go and replace the radiator cap, and overflow cap and extensively attempt to bleed the system thinking that I may have air in the system.... ......ok.... running and after 10 mins we're hot but drive it and the temps come down after turning on the heater. (i forgot to say that I had the gheater on while refilling the system). so, heres what has taken place in short order:

New radiator (not from this but it was cracked last year) so iI replaced it.
Replaced fan clutch last week and bought another one yesterday.
Replaced thermostat twice
Replaced water pump.
Replaced radiator cap
Replaced overflow cap
Dealer did the condenser fan recall and it's coming on perfectly.
Re-Bleed the system several times including jacking the front end up

I removed the radiator yesterday thinking maybe it was clogged and took it to the shop and it's flowing perfectly.

Now, lastnight I turned the heater on and removed the line from the heater core going back to the engine and it's barely tricking out of that line.... Now, i'm thinking it should be pouring out of this line... especially after the engine is warmed and the thermo is open... RIGHT????? The line before the heater valve is hot and the one after the heater valve is hot so It's flowing..... but why isnt it pouring out of the heater core return?

Also, I'm thinking that If the heater valve was bad and the heater is not on then the core isn't even in the circulation of coolant so why is my truck running hot? Even single thing in the coolant cycle has been replaced...

Now, I am getting the friggin water on the floor with the A/C on and I know that is the drain hose situation and I"ll get to that later. I do notice that the water soaked carpet is hot but I think thats from the fact that the exhaust is under the passenger side floorboard and I have checked for the presence of coolant, thinking that maybe my heater core is bad and allowing air into the system but that's ok too...

Funny thing is, I have a 04' Infiniti QX56 which has the exact same system and engine and I have changed the thermo and radiator in it and have had no problems! but I notice that I don't hear my thermostatic fan like I use to in the titan as I hear in the QX56, but I changed it twice in the Titan thinking that I had a bad one.... but same issue.... I don't see any woobling or anything.

I'm a mechanic and STUMPED fellas! Please Help!

 

[NBhunter80]

I hate to say this, but any signs of possible head gasket failure? Oil in coolant, coolant in oil, exhaust in coolant, low compression etc?

 

[overdalimit]

Well, I haven't done any tests of that nature but from my past e=xperiences a head gasket failure either mixed the oil and water or caused the engine to overheat regardless of sitting at idle or rolling... I'm getting ready to pressure test the system now....

 

[CVTitan05]

This is kinda off topic, but I remember at one point my truck kept burning coolant (in the winter) and it was just disappearing, It went through like 1/2 gallon, now it hasn't burned any since.

 

[overdalimit]

I'm sitting here thinking...... Ok, this afternoon I jacked the front end up and rebleed the system.... I let the thing sit and idle for over 30 mins and the temperature never past the normal mark... oooooook, check this out, the condenser fan never came on and that's probably because it's was cool outside and raining and the ambient temperature must not have warranted the fan coming on, BUT it never ran hot.....

Now, evertime my truck runs hot that darn fan is running........ I'm wondering if my condenser fan is spinning backwards and couteracting the other fan because they are pulling in opposite directions and hindering the flow, which makes sense because if you start driving the truck then the temps come back down and thats because the air rushing past is stronger than what that cond. fan can overcome........Now, Nissan did replace my fan and install a harness a few weeks ago when I brought it in to have the bcm programmed...... I wonder if the friggin thing is spinning backwards!

Good thing is, I have an Infiniti QX56 outside and I'll start it tomorrow, turn the a/c on and notice the direction of the fan and verify that with the Titan.... GOD! I hope that's it..


MAKE SENSE?????????????????

 

[Walrus]

Nice job on the diagnostics so far.
If checking the fan doesn't do it, get a remote reading thermometer and read the temps all over the radiator.
They should be consistent.
One of the last guys with a thread like this changed everything before he found out his radiator was plugged.

 

[smiller51283]

I would also make sure that the fluid is mixed and not just straight coolant.

 

[overdalimit]

Changed fluid again to 50/50 mix....fan is spining correctly.. no a/c and it doesn't overheat....turn it on and it overheats.... this is frustrating!

 

[overdalimit]

UPDATE: Ok, I pull out the ole trusty radiator pressure tester today and pressure the system up and see that the top hose going into the reservoir tank is leaking and the top hose on the radiator going into the engineis leaking. Soooo, now i'm excitied and thinking that I just have a pressure lose problem. So, I remove the squeeze clamps and install two screw clamps on the upper radiator hose and one on the overflow tank hose and repressure the system and it holds for over 30 mins without a drop in pressure. I drive the truck for quite a few miles to the house with no problems (never had any driving anyway, just when sitting still). Now, I turn the a/c on just let the truck sit in the driveway idling.... 5 mins.....8 mins....10 mins.... 12 mins... Dogone, it's overheating again! WTH!!!!!! condenser fan is running and the clutch fan is turning and I can feel the heat from coming from the fan!..

Now i'm ticked cause my truck just started this crap oneday out of the blue!.. So I get the keys to the Infiniti QX56 and start it and notice the cooling fans operation and all that good stuff. I climb under the Titan with a flashlight and look for any other leaks or signs of a possible problem. I walk over to the QX56 and inspect the fan shroud and notice that on the Passenger side of the shroud is three rubber flaps which are held on by two plastic clips a piece..... Now I walk over to the Titan and inspect that shroud.... They're GONE! the rubber pieces are not there.... the holes are there but the plastic pieces are nowhere to be found.... HUH! they must have fallen off somewhere. So, I go over to Nissan Parts, NISMO and Nissan Accessories - Courtesyparts.com and look at the diagram to see if I can get the name of those three rubber flaps and they don't show a seperate listing for them.... SOOOOOOOOO is this hindering my cooling?

Tonight after the truck started overheating I turned the heater on and the temperature came down faster than a parachuter jumping from a plane without a parachute... but one thing is weird.... when I raise the rpms in the Infiniti the clutch fan sounds like it is raising 15 kinds of hell.... but when I increase the rpms in the Titan the symphony isn't doing much.... sooooooo are these missing flaps my problem??????????

I hate to keep bothering you guys but I'm just trying to save a trip to the STEALERSHIP in hopes that someone has had this problem... and actually solved it!

 

[bestatchess]

The plastic jug reservoir cap is vented. I was trying to pull a vacuum on it with an Air Lift today and couldn't get a decent vacuum until I put some plastic wrap over the reservoir mouth and then put the cap back on. After I did that, I collapsed the upper and lower radiator hoses with the Air Lift. The manual says to replace the cap with an unvented cap prior to vacuum testing. I don't think missing the flaps should make it over heat at idle. I have a CSF aluminum radiator and just bypassed the tranny cooler in the radiator with a Hayden cooler per bills' thread and everything is real cool after extensive idling in the driveway. I am missing all the foam seals around the radiator shroud cuz they were crumbling so I ripped them out and threw them away and haven't replaced them yet.

 

[smiller51283]

Tonight after the truck started overheating I turned the heater on and the temperature came down faster than a parachuter jumping from a plane without a parachute... but one thing is weird.... when I raise the rpms in the Infiniti the clutch fan sounds like it is raising 15 kinds of hell.... but when I increase the rpms in the Titan the symphony isn't doing much.... sooooooo are these missing flaps my problem??????????

I hate to keep bothering you guys but I'm just trying to save a trip to the STEALERSHIP in hopes that someone has had this problem... and actually solved it!

I know when I first start my truck the fan is very loud for a minute and the more RPM the louder it got. But after the minute the clutch kicks in and does not make the fan spin so much. Even in my 97 Hardbody the fan was only loud when you first started it. Maybe something is wrong with the fan clutch...

And the reason for the flaps is so that when on the freeway the air going throught the grill can do all the work instead of the fan. And when you're at slow speeds they shut and the fan can suck air from the entire surface of the rad. instead of just in front of the fan. I would not think it would cause any problems. And if it did it would be during stop and go traffic on a really hot day.

 

[BAKOTITAN]

hey brotha i know i dont know alot about the titans . but man for like the past month i have been having the same problem as you i switched my radiator like 3 times . and come to find out the reason i was overheating .
all the time was because i had the wrong radiator cap on . i had one with a spring .. and i went and got a oem one from nissan and problem fixed .. no more overheating after sitting their for 3-5 mins. with ac on.

 

[overdalimit]

Well, new fan shroud with the flaps and still overheating.... took the radiate back to the shop and they ran pressure through it and it wasn't stopped up...... I have replaced everything.... it was running normal then the pressure shot up then back down then back up and it stayed there.... im baffled! And disgusted..... but even when it runs hot the clutch fan doesn't increase speed! But my QX56 does........... this is the second fan clutch! Im sick of this...

 

[HRTKD]

Bad temperature sensor?

 

[overdalimit]

Changed the temp sensor too.... I have replaced everything.... Did the pressure test the other day and it held as well.... No evidence of any water leakage anywhere..... I have never had anything like this before... BUt I guess i'll take it to the dealer tomorrow..... One thing though, I still can't figure out why the fan doesn't spin like it used to after the temps get warm.... I have replaced the fan clutch twice though! with Brand new Nissan OEM parts.....

 

[nyc2005armada]

Overdalimit, you stated that you replaced the radiator last year, and I can tell you from experience, I was going thru the same thing you are going thru now, after it being in the dealer for a week, they changed the thermostat, the fan clutch, pressure tested the water pump, changed the radiator cap, and reservoir cap, and it still overheated, finally they found the problem was the radiator, it passed pressure and flow test, the problem was that one core was at one temp and the other was higher, the radiator was changed, and I have not had any overheating issues at all, including today where the temp felt like it was 115* in stop and go traffic and the needle stayed below the middle with the AC on full blast.

 

[Quartz]

Now, lastnight I turned the heater on and removed the line from the heater core going back to the engine and it's barely tricking out of that line.... Now, i'm thinking it should be pouring out of this line... especially after the engine is warmed and the thermo is open... RIGHT????? The line before the heater valve is hot and the one after the heater valve is hot so It's flowing..... but why isnt it pouring out of the heater core return?

I'm surprised no one has suggested this so far but it sounds to me like you need a new water pump.

 

[NBhunter80]

He said in the op that he had already replaced the water pump. But based on his statement it seems like he might have a blockage somewhere, or the water pump isn't working properly.

 

[Shane06fl]

Silly question but have taken a digital temp of the radiator/hoses in and out of the block? You may have a f***** up gauge. Temp sensor is only part of the temp reading system. What exactly is overheating on the gauge? Where is the needle point, on what line of the 3?

Next step is a blockage in the block itself.

 

[Quartz]

He said in the op that he had already replaced the water pump. But based on his statement it seems like he might have a blockage somewhere, or the water pump isn't working properly.

I read that but I'm not convinced that the new water pump is working properly. He obviously has circulation problems.