Eventoday

HI Everyone,

First of I really appreciate this forum and it is such a big help.

I have an 87 maxima wagon, automatic with 71k miles.

I recently purchased it and have noticed when I am in stop and go traffic the temp gauge goes a bit past the middle ( between hot and middle). As soon as I start moving again for a period of time it goes back to normal (just a touch under the middle of the gauge) . Additionally I recently found out on a warm day if I run the A/C, the temp gauge stays normal ( just under the middle mark) regardless if I am in stop and go traffic. This is my first Nissan maybe this is normal but I am assuming not. Any ideas? Maybe the coolng fan doesn't work unless A/C is on?



Oh yeah I dont know if this ties in but as soon as I turn off the A/C the I get a sulfur smell out of the vents.

Thanks so much for any advice

Jake

vernk

when you turn on the A/C it turns on the cooling fan which is why it will stay the same..... do your cooling fans come on without the A/C when it gets warm? make sure your coolant is full and your fans come on when it's warm and not moving. As far as the smell clean out your heater box and fan and see if that helps.

vernk

be sure to check the coolant in the radiator and not just in the overflow cuz if you have a crack in the hose or if the seal on the cap is bad the overflow will stay full but coolant in the engine will be low.... the fan will cool the coolant in the radiator but not the engine if it's a little low and the pump isn't going fast enough to pump enough water when it's a little low. does the heater work when it is heating up?

gen1

1. pressure test the cooling system, it may be that the radiator cap is leaking or other leaks
2. when did you last replace the thermostat. If its sort of sticky, but not quite .., turning on the AC increases engine revs, which leads to the thermostat staying open more so than closed.

Eventoday

Thanks for the ideas.
Is there a way to pressure test the cap for someone who doesn't have the tools? Would soapy water around the cap work?
I don't know if/when the thermostat was changed. Maybe that will be my next step. If the thermostat was only half working could I tell by touching the upper hose?

gen1

Check the simple stuff first!

Radiator cap rubber seal should have NO visible cracks.

Symptom of temperature correct when continuously driving, trending higher in stop and go traffic suggests thermstat.

With only 71K miles I suspect that the thermostat has never been replaced.

That said I also suspect that the coolant may never have been replaced.

If/when replacing the thermostat do a full cooling system flush, that will give you much better idea of the condition of the entire cooling system.

Sulfur smell when the AC is turned off; check to see if there is a small coolant leak in the heater box. If so, this is a precursor of serious problem with the cooling system.

arsonist63086

these cars have 2 fans and 2 speeds . make sure both fans turn on at low speed at a bit below normal temp then full speed once the temp starts to creep up past normal . when the ac turns on the fans turn on full speed so it keeps the car cool. the sulfur smell might just be the heat build up is sucking in from the outside (fresh air is selected instead or recerculating )

Eventoday

Thanks!
I didn't know they had 2 fan speeds. I have never had a low speed fan come on.

I just tried swapping Rad fan relay 1 with Rad fan relay 2. I read somewhere #1 controls low speed. After swapping them , I still didnt get the low speed fan to come on and the high speed fans still operated (when I turn a/c on). Does that rule the relay out? Should my next guess be the fan switch??

Additionally I let the car sit and idle with the hood closed. The temp needle moved to about 3/4 mark.
I turned A/C and let the fan cool the engine back down to halfway mark. Then I opened the hood and let it idle. It stayed at the halfway mark without going up. Would that indicate that my temp problem is tied to the low speed fan not working?