I'm ashamed to admit that I have neglected the coolant in my car and have been doing nothing more than topping off the reservoir for the year that I've owned it. After noticing that my temp gauge has been going higher than usual lately, causing the A/C to stop working, I decided to replace the thermostat and flush/refill the cooling system. The stuff that came out was just oxidized fluid. Fearing the worse, I went ahead and replaced the thermostat, flushed the system untill clear water came out of the upper radiator hose, then refilled it with a 50/50 coolant mixture along with some Prestone treatment. I went for a drive and the temperature is still running high, getting too close to the H. Thinking that the new thermostat might be defective, I removed it and went for a drive again. This time the temperature gauge was not going that high but still more than usual (about 3/4 towards the high reading and going up and down). I'm afraid that the damage is already done and that the radiator is somewhat plugged preventing it from working as efficiient as it should, but I'm not sure about that. On the other hand, I'm hoping that running the car like that for a couple of days will clear up any obstruction. Any advice is appreciated.

 

Under what condition is the temperature getting that high? Have you already checked to make sure your fans are operating properly?

 

Under normal city/highway driving conditions. (My driving pattern has not changed, by the way; I don't drive hard). I have checked the fans and they work as they have been. As soon as the temperature start getting too high the AC fan kicks in. I went for a short drive at lunch time and the needle did not go beyond what used to be the usual mark (aligning with that little white dot by the base of the needle). I'm crossing my fingers but I prefer to be sure that something else is not messed up.
Edit: Should I assume that at least my water pump is not ruined?

 

did you let all the air bubble vent out as you added your new coolant mix? It takes a bit of time idling for the car to remove all the air bubble out of the system. The only way I know is to let the car idle and slowly add the coolant...the premature heating is possibly a result of that...

 

have u done a hot flush? if not get the car to regular operating temp. BE SURE U HAVE A PRESSURE RELEASE RADIATOR CAP! if u dont plan on goin to the hospital for burns. once u have released the pressure then drain the fluid. u may have created mud in the cooling system. also like humaras said make sure u release the air from the cooling system.

 

what is the pressure that the system should be running in the 5th gens? If he ends up buying a pressure release cap that allows too much pressure to build up, he could cause something to rupture, or am I mistaken in my assumptions?

 

I didn't use that method for letting the air bubbles out. Last night, however, I jacked up the front of the car, removed the radiator cap and jammed a funnel to minimize spillage. Then I ran the car at about 1700 rpm's with the heater at the highest temp setting (no A/C running) for 30 minutes. It was bubbling the whole time (not sure for how much longer I should've let it run). Today, the car is still running too close to the high mark.

What's a "hot flush"? Is it just draining the fluid right after the car is brought to regular operating temp? I've never heard that term and a search for that brought me back to this very same thread. I don't have a pressure release cap. I'm planning on doing the whole process all over again this weekend.

 

The car should be on a level surface when you fill up the radiator. Have you replace your radiator cap? If it is not holding pressure, that could be causing your issue as well. Much cheaper to replace than the radiator itself.

 

Thanks, I'll keep that in mind because the front of the car was slightly raised when I first filled the radiator. I haven't replaced the cap so I'll try that as well. But if the cap doesn't hold pressure, wouldn't that also cause the radiator to dump excesive amount of coolant in the reservoir, overflowing it?

 

When you bleed air, it helps to have the radiator raised.

 

I know. From what I've read, it has to do with the heater core being above the filler neck on our cars.

 

It can, but it will not always do so. The pressure caps function is to raise the boiling point of your coolant. When it starts to boil, it cavitates, causing a loss of efficiency for your water pump. You could just end up getting some air out of the system from the coolant boiling.

I have not had the problem with any Maxima, but in the past, I did have a problem getting all the air out of the system on my 240sx. That car, the air had a tendancy to get trapped in the water pump housing. I have had the engine out of my Maxima twice now, and never had any problem bleeding it afterwards, but I do jack the front end up several times to help coax any air bubbles to the surface.

 

Push comes to shove, yank the radiator out and take it to a local radiator shop and have them check the flow, that will answer a lot of questions for you right there.

 

That sounds like a blown head gasket, allowing cylinder gases to be pushed into the cooling system upon combustion. That could also explain why it's constantly overheating.

 

I would fully agree if I had any other symptoms, such as white smoke, loss of power, loss of coolant, etc. From the amount of oxidized sediment in the old thermostat, I'm still inclined to believe that I have junk in my radiator and it is restricting the flow. I'll take a picture of that this evening and post it.

 

I had a 4 cylinder overheat once and it warped the head enough to cause the same condition. No other symptoms. Ended up having to have the head decked and that fixed the problem. I'd keep checking the simple stuff before considering any engine teardown though.

 

Got it. I went ahead and purchased a new cap. We'll see how it does on my way home. Still planning on re-doing the flush this weekend and will find out about any radiator shop in my area to test the radiator. I replaced the thermostat and did the coolant flush because the gauge was going higher than usual, about 3/4 of the way. I don't know if that is really considered overheating and therefore cause the head gasket condition.

 

Below are pictures of the condition of the old thermostat.
This is what leads me to believe that the radiator has been compromised with lots of that oxidized junk restricting the efficient flow of coolant.
I put in a new cap and, it could be my imagination, but the condition improved slighty. The gauge is still getting close to the highest mark, though.

 

I am going to throw it out to the guys here on the forum, but I have done a radiator flush a few times, 4th generation was easy-- had that car 12 years...did it every other year...still runs beautifully. I have a 2004 pathfinder with the same 3.5 as the 2003 maxima...I know someone mentioned about burns. Okay, take it from me *emergency room visit during superbowl sunday-- long story from a radiator flush* on my pathfinder...it was so hard to bleed the air out...but after flushing it...I just let it run, run...run...according to the manual...there is a valve in the back (depends on the positioning) of the 3.5 engine placement...and that lets the air out...took me literally 2 hrs...unless anyone have any suggestions on how to quickly bleed the air out.
The method I use is turn the car on...heat on, recirculation button pushed...and I slowly add the coolant...and let it boilout air...

 

After seeing those pictures, I would not be suprised if your radiator is not flowing properly. I would still try to find a place to flow check it before ordering a new one.

 

When my radiator was bad, after I did a flush, and refilled with some nice green anti-freeze, days later, the antifreeze in the overflow had a brownish tint. Might be an indicator. Now, with my new radiator, coolant is the same green color since replacement.

 

That has been my feeling. I called a couple of places today and the price they charge for just testing it doesn't sound too "apetizing"; I would prefer to just buy a new one from the Group deals. I've spent almost all day replacing end links and all struts and shocks. Tomorrow I'll tackle the radiator again, this time will try purging the air out using the air release plug.

 

After seeing your pictures, you didn't have oxidation, you have strut up corrosion going in your coolant system. That will have an effect on your radiator. I've been running a Koyo radiator from the group buy for the last few years with zero issues, first running 10lbs of boost, and now with a VQ35, they are good replacement radiators.

 

Air bleeding procedure using the air plug, along with more burping after that, did not produce any positive results. I'm replacing the radiator tonight and will take it from there. On a positive note, the car handles great after replacing suspension components. Clunking noise on passenger side is gone. Alignment is next.

 

Does the fan start/stop spinning with the temperature higher than usually? If so , check the coolant temp sensor.

 

Both fans run when the temperature runs higher than usual. At first, only the radiator fan starts when the car reaches normal operating temp and then starts to go higher. As the temp keeps climbing up the AC fan kicks in and they both stay running. Today I replaced the radiator and went for a test drive but the temperature started going higher than usual again. I pulled a code P0110 (IAC sensor malfunction) and I realized that I did not plug back in that sensor before I took the car for a drive. I plugged it in, bled the air out using the air plug on the engine block until coolant came out of there, topped off the radiator and reservoir with coolant and drove the car again. In less than a mile the temp started going high again. Came back home and this time pulled a code P0217, Engine over temp. Other than that, the car is running fine with no other symptoms at all. I'm out of ideas. Any advice?

 

the overflow tank is supposed to go down if air is in the system (hence the bleeding) so you don't have to leave the cap open in order to bleed air. foolproof way is just to pour slowly using a funnel.

 

I actually did that when I installed the new radiator; poured the coolant really slow. I guess doing the air bleeding through the air plug was redundant. The car is still running a high temperature. Any ideas?

 

Download the FSM. LC is the Lubrication and Cooling section. Start going down the troubleshooting list.

 

Try this: when the temp starts climbing, rev the engine. See if the needle plops back down. If it does, your problem may be due to insufficient flow.

With the correct anti-freeze/water mixture, a new radiator, new thermostat, operable fans, unblocked airflow, and air fully bled out of the cooling system, might be pointing to your water pump; it may have corroded out and be "finless".

How often have you needed to do this? To my knowledge, coolant shouldn't need to be topped off unless you have a leak somewhere.

 

I agree. It looks like everything is indicating a shot water pump. I'll see if I can tackle that job.
I didn't have to top off the coolant in the reservoir all the time; probably in one or two ocasion for the past year, just to bring it to the max line.

Edit: If anyone has replaced a water pump using the steps outlined in the FSM but has any additional tips/comments please chime in. They look prettty straight forward but just in case there is some advise from someone who's been there, done that. I thinking about attempting that task over the weekend.

 

I was reading the Fluids and Lubricants section and saw that someone formed a coolant leak after using one of those Prestone treatments, and they concluded that the treatment probably loosened whatever gunk that blocked the leak.

Sorry didn't know why I wanted to post that little tid-bit of info But hope you've found the source of your problem!

 

Thanks for the info. I have no coolant leak at all. I'm almost sure my problem is the water pump. I'm making that assertion based on the parts that I have replaced so far and the car symptoms. I followed every procedure to a "t" and the engine is still getting too hot. It definitely looks as if there is no force displacing the hot coolant out of the engine block and into the radiator. I may have a "finless" water pump as a result of the corrosion, as ridinwitha35 suggested above.

 

I worked today on the source of my overheating problem. Being over patient, it took me around 6 hours. Below are pictures of the old and the new Water Pumps. I guess no need to say which is which.

 

Holy Cr@p!

This so called neglect, how much did you finally land up spending on parts? How much time in total?

I just showed these pics to my wife! Couple weekends ago she was on my case asking me why I was draining out all the coolant and putting fresh coolant in there. (I do this once a year)... I'm bookmarking this thread just to show my peeps what happens when u neglect your ride!

Sorry about this and I am glad you have a fully functional ride again! Just out of curiosity how many miles on your max?

& Another piece of advice... if yours is auto ... I hope you have been doing your trans drain+fills?

Cheers!

 

All I can say is DANG!

1) Can't believe the fins were that bad
2) Can't believe I was right...that hasn't happened since 8th grade.

 

Holy hell......the pump impeller is cadmium plated (by the look of the new one) steel. Corroded the cad plate and then the steel to nothing. How old was the coolant, or did it even have antifreeze in it? This certainly explains the iron oxide in the system (the obvious red color residue in the pic of your thermostat and housing). The Maxi cooling system doesn't have a lot of iron/steel parts other than some bungs/plugs, the block heater (if equipped), various hose connectors, and the pump impeller. I also wonder if the pump impeller had previously been FODed?

 

Damn...

 

Big time neglect!!!... I got the car a year ago and paid attention to almost everything except for the cooling system. Who knows for how long before that it has been neglected.
I ended up spending about $260 between thermostat, radiator and water pump. I would say it took me about 10 hours replacing all that. At least I have brand spanking new cooling system components for a while.
Feel free to use this as an example of neglect, guys.
Car has 156k miles and, yes, I have been doing my trans drain+fill

 

A lot of people do not realize that, while most call it anti-freeze, your radiator coolant provides a few different functions. First, the combination does not boil as low of a temperature as plain water does. Second, it is more effective at transfering heat than plain water. Third, it provides lubrication to your water pump. Fourth, it provides corrosion protection. All of those capabilities diminish as your coolant ages.

This is not directed at you Nelsito65, just general info for anyone in the thread.