Engine Overheats

My 98 Maxima engine overheats after driving in higher rpms in lower gears... it never used to go more than 1/4 of the guage before, but now it reaches 1/2 and sometimes even more than that... I also found traces of rust in my radiator.. does coolant with traces of rust overheat the engine??? if so how can I clean it?? what are the other possible reasons for engine over heating???
thanx a lot in advance
regards
Girish

Your coolant should be a 50/50 mixture of water and antifreeze. Over time the additives in the coolant break down, and must be replaced. These additives help cool the engine, lubricate the waterpump, and prevent corrosion. The 'antifreeze' in your coolant is very corrosive, and so is the water you put in their, which is why it is so important to change your coolant at the recommended time, and to make sure your coolant is always full, if you get air in your radiator, not only does it not cool your engine efficiently, but it increases the rate of corrosion. I would get the radiator flushed and replace the cap, they wear out over time as well... Good luck. :)

Two things....

1) Have your cooling system flushed and refilled correctly.
2) Check to see if your cooling fans are coming on.


As a side question.. Why are you driving around at slow speed with your revs up high? We have 190 hp V6 engines. Not 4 banger Hondas here. Shit the damn thing into the right gear.

thanx for the response NJMAXSELTD & mtrai760 actually, mtrai760, I bought coolant from Nissan dealer today but it is mentioned on the can NOT to add coolant.... looks like this is some different type.. its light blue in color, Holland made.. anyway I'll flush my radiator and see what happens... and what do u think of those radiator cleaning solutions available in the market.. STP and similar... r they worth trying???

NJMAXSELTD, checked my cooling fan... its working fine.. actually once it switches on it never gets a chance to switch off :) because of the engine temperature.. I drive in higher rpms when driving off a signal and on highways when I see someone coming close to my car from behind... I slam the pedal to the floor and it feels great when it goes to a lower gear and "flies"... there aint many cars of its class with the top speed Maxima has..
thanx for the response once again
regards
Girish

thanx for the response NJMAXSELTD & mtrai760 actually, mtrai760, I bought coolant from Nissan dealer today but it is mentioned on the can NOT to add WATER .... I mentioned coolant by mistake...
Thanx

Originally posted by girishraj
thanx for the response NJMAXSELTD & mtrai760 actually, mtrai760, I bought coolant from Nissan dealer today but it is mentioned on the can NOT to add WATER .... I mentioned coolant by mistake...
Thanx
Most coolants you buy over the counter is concentrated and needs to be mixed with water. Sounds like what you baught is the correct mixture and thats why it says not to add water.

If your fans work fine, check your thermostat, it may be stuck, and prevents the flow of cold water-refrigerant towards the engine, or replace it.
If you take it out, put it in hot water and at about 82 degrees Celsius (180° Fahrenheit), the thermostat should open, if it doesn't, replace it

Take off your radiator cap and look inside your radiator... If you see a bunch of brown build up, or it looks like someone took a dump in your radiator, then I would use a radiator flush. Otherwise, just make sure you drain everything out, and I would flush some extra coolant through to help clean it out. As for the coolant, it must already be mixed, which is why it says do not add water. The blue is just from the dye's they put in it, but I would try and use the same coolant from now on, since it is already mixed. Good luck. ;)

Thanx Ralmada/mtrai760/njmaxseltd...

Ralmada, My thermostat it working fine... it only switches on the fan when the engine is actually hot... its on for a loong time because of the high temp of the engine...thanx for the response

NJMAXSELTD.. ya may be the coolant I bought is already mixed with water and so they mentioned not to mix again... thanx for the response

mtrai760 thanx for the response..
I flushed my radiator today... but I'm still not satisfied.. he opened the radiator cap, connected a tap there, opened a hose which was connected on top of the radiator and started the engine... the tap water was passing through and coming out through the open end of the hose... there was some traces of rust initially but later was clear water... then he poured the coolant while still idling the engine and when the coolant started coming out from the hose he connected it back and told me its flushed.. is this the normal procedure?.. still my engine temp. is more.. and now when I start my engine, when cold, I hear some sound... sounds like a fan turning inside a bowl of water.. is it trapped air bubbles???.. if so how can I remove the bubbles?.. and what is the capacity of the radiator+can?? is it 8 lit ? that's what he told me...
regards
Girish

The cooling fans on your car are controlled by the engine coolant temperature sensor ( not by the thermostat), which appear to work fine (remember your fans has two speeds).
The thermostat is a different thing, that has nothing to do with your cooling fan.
The thermostat is a mechanical piece that goes in the water piping inlet,. Where the upper radiator hose connects to the engine, it is a valve with a spring and an small compartment sealed, but filled with a special element that expands with a certain high temperature, so the thermostat valve is closed in the mornings, when you start your car, helping the engine to get fast to its working temperature, by closing the entrance of refrigerant (yes, the engine for a while works without having the refrigerant circulating in its interior), as the temperature rises, the element in the thermostat expands, opening (mechanically) the valve and allowing the coolant to start passing to the interior of your engine, to maintain a certain temperature.

If valve of the thermostat is stuck or if opens at a higher temp or if it doesn’t open wide enough, the amount of coolant for your car would never be enough, and the high temp would appear, it wont matter if your fans work perfectly and in high all the time, as the cold refrigerant won’t get to your engine (the thermostat valve would be closed or not opened enough!)

Change it , or get a thermostat that opens at a lower temp.

If this doesn’t work, your water pump might be damaged.

The coolant capacity with reservoir is 8.5 liters (9 qt)

Some more data

Thermostat
Valve opening temp 82° C (180° F)
Valve lift 8.6 mm at 95° C (0.33 in at 203 °F)

That sound about right, most flush machines send fluid into the feed line and out the return into a bucket. I never use tap water, I've always used fresh coolant to flush it out, but we have a 200 gallon supply, so... I have a cool new machine now that sucks all the fluid and air out of the radiator first, and then uses the vacuum created to suck new fluid into the radiator. Takes about 10 minutes start to finish, and you don't get any air bubbles stuck anywhere. The sound you are getting I am not familiar with. I would open your radiator cap when your car is cool and check the level, since that doesn't sound normal. It does not seem normal that your car is still overheating, their must be something else causing this, like your thermostat. Ive seen in an extreme case a cracked cylinder head causing overheating, with no other symptoms, no water in oil or vice versa. Check and make sure the radiator is full first, did you get a new radiator cap?

Originally posted by girishraj
Thanx Ralmada/mtrai760/njmaxseltd...

Ralmada, My thermostat it working fine... it only switches on the fan when the engine is actually hot... its on for a loong time because of the high temp of the engine...thanx for the response

NJMAXSELTD.. ya may be the coolant I bought is already mixed with water and so they mentioned not to mix again... thanx for the response

mtrai760 thanx for the response..
I flushed my radiator today... but I'm still not satisfied.. he opened the radiator cap, connected a tap there, opened a hose which was connected on top of the radiator and started the engine... the tap water was passing through and coming out through the open end of the hose... there was some traces of rust initially but later was clear water... then he poured the coolant while still idling the engine and when the coolant started coming out from the hose he connected it back and told me its flushed.. is this the normal procedure?.. still my engine temp. is more.. and now when I start my engine, when cold, I hear some sound... sounds like a fan turning inside a bowl of water.. is it trapped air bubbles???.. if so how can I remove the bubbles?.. and what is the capacity of the radiator+can?? is it 8 lit ? that's what he told me...
regards
Girish

Thanx for the respnose RALMADA/mtrai760

Ralmada... thanx for the information... actually till now I thought the thermostat is connected directly or through a relay to the cooling fan for the radiator... and I'll surely have it checked ... now after u told this possibilty I too feel the same... it may be the thermostat.. do I have to take it to the garage to check it or can I do it myself and take it to garage if there is a problem??.. If u think I can do it myself please tell me where it is located and how I can check it...

mtrai760... now that sound has stopped.. actually it was there only the first day after I flushed my radiator.. anyway I checked the coolant level when the engine was cold and found that the level was little less.. I filled it with coolant...thanx a lot for the advice..
regards
Girish

hey guys,

I need help bad, i have a 98 maxima, i noticed that when the car is warmed up the temp gauge is at 1/2 way, i dont know if that is common, but my real problem is that my car starts to overheat when i am either idle or stopped in traffic. and u know that when u drive in da city that happens often, but when i am on da highway or driving decently fast the temp. gauge goes back to normal...i noticed that my radiator fans dont turn on either, so i checked the fuses and they look fine, i figure it could be the thermostat, if so where do i locate it

sal,

u shoulda made a separate thread, but since this is kinda relavent...

did you confirm that your fans work? you can bypass the relays & jump the terminals to the battery to see if they work... or you turn on your air conditioner or defrost-windshield mode to see if the fans turn on...

if they go on, then it may have to do w/ the coolant temp sensors... you can goto autozone for a free OBD II scan as well to see if any trouble codes were stored.

or you can try to find the ECT sensor & see if the plug-wire connection is corroded...just clean it off w/ a wire brush & some brakecleaner

http://www.troublecodes.net/Nissan/95ams96-00.shtml#95max

P0125 is the Engine coolant Temp Circuit...

vovw, how u found an anciend thread...

If needle doesnt rise, that is a problem itself.

What happens if/when your engine overheats?

Check/tighten belts first. Then fill up & bleed air bubbles out as FSM suggests.

Most common overheating causes in this order:
- loose belt,
- by low liquid level (system leaking),
- airbubbles (unproper fillup),
- thermostat (sticking),
- pump blade corrosion,
- and/or blocked radiator/system.

For thermostat check this page, your engine block system is very similar. Seek via 'Favorite Links' more infor for VQ http://www.cardomain.com/ride/748507/8