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I guess it's time to strike fear into the heart of the op. Here are photos of a badly corroded water pump and a new pump. The corroded pump was no doubt run in an engine that didn't have any antifreeze in it.
Is there a crack in the radiator tank just above the last "c" in word calsoniC?
Wow, it really does look like that, good eye. I never noticed before. I'll check that out tomorrow too but it did pass a pressure test at least when cold.
Ended up not having time to work on it today but definitely will flush with water first and see what happens, it needs it anyway.
Did you do the higher rpm test to check water pump efficiency?
When it comes to coolant, instead of assuming the previous owner must have changed it right, you can bank on the fact that he messed up (tap water ... you name it) or some shop put a dexcool clone in it.
Since you get only a 10F difference between hot and cold on the radiator, change the radiator (I assume the fans were on right?).
FWIW I changed the water pump on my Maxima at 155k because I was in there doing some other work and it was flawless. That may not be the case for you as the cooling system seems to have been abused.
I did the flush and food color tests and it's all very interesting.
I drained the radiator and pulled off the bottom hose to see if I could find any junk or anything in there, all perfectly clean. Coolant comes out clear green and seems fine.
Filled with flush and water and let it warm up. It seemed different as soon as I started it, can actually see obvious flow throught the radiator and it overflows when I just barely crack the throttle, before it wasn't nearly as responsive to opening throttle.
Most importantly of all, there is now a 20* - 30*+ temp drop across the hot to cold hoses which seems much better.
At this point did the food color test and it was just immediately carried away in the coolant flow from right to left.
I have no idea how just draining the fluid did this but it seems like a night and day difference.
So I took it to test drive and seemed to do much better than before, drove miles and miles uphill, hot outside before it started reading hot again. There seems to be an improvement.
When I got back with it still reading above normal temp, I measured the hoses again and they were actually COOLER than when it wasn't too hot(according to gauge). Top hose was only 160* and normally stays at 170* when hot and idling.
So yeah, maybe it's never been overheating?
The gauge sure seems to make sense though because when I go faster, it gots hotter, When I run the heat it gets cooler, when I go uphill it gets hotter, downhill cooler, etc. I don't know how that could be wrong.
I really really want to use an OBDII scanner and live read the temps but the autoparts store won't rent a live scan tool and they are just too pricey to use once unfortunately. Is there any other reliable way I could measure coolant temp to make sense of this?
Oh also, that isn't a crack in the radiator, just a molding line that happened to be wet.
Did you use the chemical coolant system cleaner I linked a few posts back?
If you didn't, I'd do that and flush with water then drain it and add the proper amount of AF and then top it with distilled water.
I'm convinced an idiot put something in the coolant reservoir that shouldn't have been there. Hopefully, all it did was change the characteristics of the solution.
Coolant capacity in 4th gens is just under 7 quarts. So a gallon each of quality antifreeze and a gallon of distilled water. 3.5 of each.
The water pump appears for function properly.
It seems that tge car overheats when the engine is working hard, and not so much when it's not.
So I'm making a call that you have a partially blocked radiator. Please add the flush chemical which KP suggests. It might fix your problem, or help it overheat less.
It is possible that a previous owner poured a stop leak product into the cooling system. Question:
is the heater blasting nice hot air, or not so much?
I would say that you probably need a new radiator.
Might as well replace the upper and lower radiator hoses while you are in there anyway.
Last edited by JvG; 07-10-2018 at 10:11 PM.
Reason: Additional comment added.
The water pump appears for function properly.
It seems that tge car overheats when the engine is working hard, and not so much when it's not.
So I'm making a call that you have a partially blocked radiator. Please add the flush chemical which KP suggests. It might fix your problem, or help it overheat less.
It is possible that a previous owner poured a stop leak product into the cooling system. Question:
is the heater blasting nice hot air, or not so much?
I would say that you probably need a new radiator.
Might as well replace the upper and lower radiator hoses while you are in there anyway.
I did actually use the Preston flush with distilled water to refill today and tried to drive and run that though the system well.
The heater works fine and never fails to blow toasty hot.
Sounds good and I'll put in a new radiator and hoses and flush it all out well again and see what happens.
Now I agree with time to think radiator as a partial contributor. I'm a cheap bastid. LOL
Could the thermostat open somewhat and yet still be restrictive from corrosion from whatever was in there?
As far as Radiators go.... eBay has a CoolerMaster ALL aluminum for around $117. I don't know anything about them, but all aluminum is definitely a plus.
Mishimoto has a NICE all aluminum radiator made specifically for M/T Maximas.
Find the right part number and shop for lowest delivered price on Google if that's what you want.
JvG recommends one that he used in his Maxima, looks like a very decent choice as well! Probably priced the best of the three I list.
Your current radiator looks original, and had served for 20 years. It's unlikely that you will keep the car that long. The Mishimoto radiatior would be over kill . I bought a Koyorad radiator a few years ago. Some where on this forum there was some kind of group deal. I called the pkace, mentioned the deal, and got the discount. I paid 106 dollars.
I would not buy the cheapest one you could find. That would be 40 to 50 bucks.
I suppose that 100 dollars or so would be decent quality.
Kp, the thermostat seems to function. Mine is still original.
KP,
Thermostat is possible, but most members don't report their failure much. But they do have radiator issues now. They are 20 years old.
If I have to guess about which part to replace in a system with several possiblities, I usually choose the most likely one. Also the part which will increase reliability in in case the real cause is something else.
The radiator is simple to replace. Sometimes the the thermostat us more difficult. Frankly, I don't know where the stat os on our cars, because mine has never needed service. It has at least 100k on it, possibly 200k .
Your ebay radiator choices is helpful. Seems most are 40 to 50 bucks. I noticed that the last one, around 100 bucks, seems sturdier than the cheaper ones.
Pull the thermostat and if you're still overheating it's either the pump or radiator...Does it overheat while driving at a constant 50-70 mph (frwy)no stopping? If it's overheating on open highway again either Water pump the Radiator! Check your oil for water as well Head gaskets that are leaking/blown tend to elevate water temps!
I just got the new radiator in and was surprised to see that it is twice as thick as the old one! Which of these is the stock size? Otherwise the new radiator is identical to the old one and looks good, fit perfectly.
I got it bled and just left to test drive and another coil failed so I have to resolve that first.
But I can tell the heater feels hotter, before was hot but now is painfully hot so hopefully that's good.
All seems to be good and temp is rock solid at just under halfway on the gauge, tried to drive a lot today and test it on hills, blasting a/c, etc.
Well I checked out what Autozone had because there I get an easy lifetime warranty and they actually had the same (strange?) brand as the current radiator. I decided to get that since the old one has held up will, at least physically and everything. But I didn't realize until I was installing it that the new one was twice as big.
While it is a good thing, it bothers me also that the new radiator is bigger. It seems to me that the additional cooling capacity colud potentially be masking another issue? At least there would be no way to tell for now.
Plat, the temperature is controlled by the thermostat. Once the coolant temperature is past a certain point, it opens , then the pump sends coolant through the stat, then to the radiator.
Sounds like your new radiator is better than the old one. So it has more cooling capability than tge old one. This is a good thing.
Time will tell if this repair worked. Keep on stressing the cooling system till you trust it.
Please report back regarding your results.
I'd say that you have most likely solved your problem.
I would like to say everything is good since I have had no overheating issues and pretty much stressed it as much as I can.
But, the expansion tank has gone totally empty twice now. Once before I did the final bleed and added the antifreeze and now again after. This is empty when the car is hot, so it should be expanded and full I would think.
I have previously filled it to MAX with the engine hot after bleeding. The first time it went empty I thought maybe I had left some air in there that it sucked up and filled those spaces, but for the final bleed I made SURE there was no air at all left.
I don't understand how this could happen because I have just checked and eliminated leaks, rad cap, headgasket, radiator, everything else. I can feel the system holding pressure after it is shut off. There is no water leaking out.
I guess it must be the new radiator because that is the only thing that changed. But I just can't believe how that much water could disappear so fast without a drop visible leaking.
I had the same thing happen to me.
I thought for sure that I bled out all the air, and the expansion tank still emptied about three times before finally settling down.
So add still more coolant until it's thirst stops.
I had no idea but glad to hear it's probably fine.
Yes actually today I pulled up some long, steep grades on the freeway at 100* outside with a/c on and it never flinched. I'm very happy that it seems totally good.
On a side note, what's your thought on reverse osmosis water in the radiator? When I saw the tank empty tonight I rushed out looking for distilled to add before it cooled and sucked up a bunch of air, but only found this weird stuff that says "distilled/reverse osmosis" and ingredients only water. Compared to a similar product that lists some minerals as ingredients as well. I figure this has no added minerals.
So unable to find real distilled, I put that reverse osmosis stuff in the tank. Do you think that was a mistake?
I already have a full gallon of pure antifreeze in it so it should be 50/50 once the other half is full of just water.
I was thinking the same but reading about it, seems like I can't get a straight answer online about whether reverse osmosis really has low enough mineral levels, etc. I've just always heard distilled only was important.
Thanks so much for all your help, I've learned a lot here too.
Funny but that's where I went and couldn't believe it, the shelves were bare. Nothing but mineralized stuff left at Walgreens and another place, and just one bottle of the reverse osmosis stuff left at CVS. Maybe everyone is redoing their radiators about now?
It has been pushing 100* or over every day straight for what seems like weeks now near LA.
07-09-2018, 08:25 PM
