So I have a few issues I'm trying to resolve as cheap as possible. Instead of breaking them up into 2 posts I assumed one would be best in case they are connected in some way.

/info - Car has approx 115,000 miles, has had a new a/c system put in a year ago and new pressure side power steering hose a few months ago. Also just replaced fans to try and solve the cooling issue.

Since I got the car I noticed at low speed / idle speed it would have a small almost hesitation when you hit the gas. Like starting off from a stop it would jerk around a little then go and be fine. It also sometimes would shudder on its own but it wasn't that noticeable. At the same time, the headlights would flicker a little at idle speed. Since then I replaced the battery and I think the flickering is gone however the idle issue has gotten much worse. At the exact same time, I noticed if you left it to sit at idle with the air on after 10 min it would overheat. as long as you were moving it was fine. I had the codes read even though no engine light just to see if any old codes were there. It came back with a misfire code saying possible coil pack, bad plugs. later that week I walked out to crank it up and it would not run. It cranked up, idle went all over the place sputtered and stalled out. I did this back to back half a dozen times and then it cranked right up no issues ran fine. Ran fine for a week or so with exception to the shudder sometimes. I ran fuel cleaner through the system and it seemed to do nothing. At this same time, I realize I can smell antifreeze so I'm assuming its from overheating. No signs of it anywhere though.

Got back to Tampa check everything and see it has a bad fan. I replaced the fans assuming that would be the fix for overheating. while there I Pressure tested it just to make sure and happened to find a super small pin hole in the radiator. I got some of the radiator sealer to try but not sure if it worked because it's still overheating except now even worse than ever before. So I ran the car at idle with the cap off to make sure all the air was out of the cooling system. I monitored it and kept it full. Some air came out but not much. After about 15 min I noticed a lot of tiny bubbles coming up which never stopped. So I just let the car keep running about 20-25 min it overheated and fast. It was like someone just flipped a switch and boom volcano. Both fans were running and working and at this time. The water was moving and heating up so I assumed the thermostat was working.

Few details about my cooling system I'm trying to also resolve.
1. the fluid will expand and flow into the overflow however it doesn't flow back once it's cooled. It leaves the void inside the radiator. Could this be because of the small hole not allowing a vacuum? or could it be a bad return valve/cap?
2. After I installed the new fans they now run all the time. As soon as you crank up the car even when cold they kick on and do not go off. I noticed the new fans seem to have larger motors could this be an issue? what would cause brand new fans to run all the time when the old ones didn't (one was still working like normal before I changed them)
3. Could the overheating be causing the idle issue since the throttle body is cooled by the radiator?
4. Are there any ways to figure out where the cause of the engine overheating is coming from without replacing the radiator? just wanting to make sure that's the problem.

I do have a really bad vibration when stopped with the engine in gear and foot on the break.
1. bad motor mounts?
2. anything to maybe do with the idle and overheating issue?

and just wondering if anyone knows of good online repair manuals? most I can find only sell you a limited subscription. If I'm gonna pay $30 might as well get a book I can have forever. But maybe there's something else out there you can recomend

 

Wow, sorry for the issues. This sounds complicated. I think it is four separate issues, maybe they are related. Here are my best armchair guesses:
1. Headlight flicker, intermittent sputtering: could be your battery ground cable. I would recommend pulling the battery tray out and checking where the cable bolts to the transmission. Remove the cable from the tranny and take a die grinder with a wire wheel to the cable end and the transmission housing where it bolts, clean up the bolt too (a wire brush will work, it will just take more elbow grease . If it is dirty that is probably the culprit. If the battery ground is fine, then check the rest of your negative battery cable. Besides an alternator failure this is the most common issue for a headlight flicker. I had this exact issue (intermittent sputtering and lights flickering) and did all kinds of things. When I finally found the battery ground issue I wanted to kick myself for not checking it first. Now I'm ready to blame that on any 7th gen maxima headlight flicker/engine hiccup issue....though I realize there could be other reasons. This could cause a vibration at idle with your foot on the brake...but I'm uncertain (see point 3 below).
2. Overheating: Are you sure it's overheating, or is the sender or sensor bad? If the sender or sensor is bad perhaps it's causing the fans to come on. If it is for sure overheating and you have tiny bubbles coming up once it is warm it sounds like you have something introducing air into your cooling system. Usually this is a blown head gasket (cracked head or block could do this too). Having not seen how many bubbles are being produced I hate to cry wolf and be wrong. Maybe it is something else. If a head gasket is blown, that would also cause the overheating. There is a test you can do to check for combustion gas in the coolant. Lisle makes a test kit "75500", I think you can get them from your local parts store (advance, autozone, etc) for around $40. Maybe less if you find a online coupon. That would be a way to rule out the head gasket leak.
3. Why are your fans always on, I'm not sure. Maybe someone else can comment on that, I can't think of a reason they would always be on, even when the engine is cold. Unless the sender or sensor or relay has an issue. Just guessing there. OR maybe a bad ground would cause them to act weird.
4. Vibration: possibly related to point 1. Otherwise if you don't have a misfire (should have a check engine light if you have a misfire) then it could be motor mounts. I'd fix issue number 1 first to make sure that isn't causing this.

 

http://www.nicoclub.com/FSM/

Link to the Factory Service Manual

 

Thanks, I am going to check the relays first. that's what a few people told me to for the fans. Because they worked fine before (minus the bad one) and now they don't. The difference is these fans seem to have a larger motor so maybe the extra load caused relay issues. I'll know in a moment.

I filled the radiator back up and let it idle again this time doing it the correct way by turning on the heater full blast and letting it idle. it seemed to be ok for a while then fluid level started dropping pretty rapidly. looking around with a flashlight I was able to find a large puddle of fluid at the bottom under the radiator. Seems to be coming from the radiator itself near the lower hose so I'm pretty sure it's just a run of the mill bad luck. radiator cap was also shot. the low-pressure side of the cap was bad. So that explains water not filling the radiator when it cooled. Now just need to troubleshoot the fans.

So, in the end, it was a bad fan, bad radiator, and bad radiator cap... so far. I'm going to change the thermostat just because at this point. I wish I could get to the temp monitor cause id change it also but I hear its a *****.

 

That's great! I'm glad you found the problem and that it's not too bad!

 

does anyone know where the relay diagram is on this car or know which relays are for the fans? I have the fsm but can't find the chapter that shows the relays for the fans.

Also anyone in or near Tampa that would like to help me change this radiator? I don't have a lift or shop here and live in an HOA. So I'm stuck paying to have it changed or finding a place to do it myself. I found a radiator on amazon looks ok lifetime warranty for like $65. It will get me by I'm not racing it or anything. Dealer says $900 to change this thing and I know its not that much. So anyone around town hit me up. I'll buy you a 12 back of the expensive stuff lol.

 

You can get a cheaper radiator on Ebay for like 40 to 50 $$.....over 1k sold with life time warranty so they are good, save a few bucks. Put the blue antifreeze for Asian cars only also......The radiator is a lot of work and that's actually a good price compared to other dealerships quotes I've heard for like $1500......do it yourself, not that hard but will take a whole day. If you got a misfire code that could be the reason you have sputtering and shut off at times. Might as well change the Transmission fluid also since you most likely cooked it with the over heating problem since the fluid runs into the radiator and that Tampa heat don't help either......when you remove the hose look if it looks cooked brown.......get the NS2 fluid from beeline auto parts, you will need 5 bottles, drain and fill it only ......cheapest you will find it most likely anywhere.

 

I did it once and that was enough! I do know a local mechanic in Winter Garden that has done a few 7th gens and only charged around $3-400 radiator included. Mike the Mechanic in Winter Garden! To me, it is worth it! Granted it is 70-90 miles from you but I know he has done it and does a good job. If mine ever gets another nail thru it, I will gladly take it to him! Radiators scrape the heck out of my hands!

 

I sent you a message.

 

Cleaning MAF (carefully) is a good start for jerking or lack of power.

 

unfortunately, the leak is too big to drive it far. I've got most everything on order will just work on changing it here. I am going to change as much of the cooling system as I possibly can since from what I can see you have to pretty much take all the same steps as the radiator for the water pump and the lower hose looks like a *****. So going to replace the radiator, water pump, thermostat, lower hose, cap.

That leads me to my next question and is sort of mentioned in a reply above. Adding a transmission cooler. I thought this car came with its own independent cooler but from what I've found online everything talks about adding one. Is it worth the extra $30? I'm going to have everything apart figured might as well.

For those of you who have added one what size did you go with? I see they have several different sizes.

thanks for the other advice. I will go ahead and change the fluid. Its got 120k miles so I'm sure it needs it anyways.

 

Is changing a radiator in these cars actually that difficult what makes it such a big job to do?

 

Well, to try it is to gain experience! There is a billboard I pass on the way to work that says words to the effect that "Even experts were once beginners!"

Taking off the front bumper is the easiest part of the job. The shroud and fans are tedious and the lower hose, just difficult. Of course the trans cooler connections need to be removed as well. For people with a lot of patience, time, and small hands, not as bad. I did see a video where a guy was able to do it without all the steps i mentioned and just sort of "ripped it out" but i saw that only after i spent an entire day and a bit of the next cutting my knuckles to shreds!

If you try it I would certainly like to hear of your experience and possible pointers for the future folks trying this!