My 1995 Maxima started to overheat but in a strange way. The sequence is: (1) Start in the morning, drive it for 1/2 hour to 1 hour, temp gauge is fine at middle of the scale. (2) park for 1/2 hour. (3) Start again. The gauge goes all the way to Hot either right away [before I even turn the engine on] or within 5 minutes of driving. Other related, puzzling symptoms:
- (3) is intermittent, doesn't happen every time.
- No coolant loss that I can see.
- No smoke at all from the tailpipe.
- The car drives very well even when the needle shows Hot. I'm not driving it much in that mode, I let it cool down, then it's back to step (1).
- It has 74,000 miles, all the maintenance done on time.

Took it to the dealer, who said the thermostat is getting stuck and the radiator has coolant flow restrictions. I believe both were pure [maybe intelligent]guesses, since I don't know any procedure that will actually measure these before taking them apart. I let them replace both, since my extended warranty paid for it [glad I got the warranty].
You guessed it - barely a week later and the symptom is back. So I'm asking for your expert opinion:
(a) Head gasket or something else ?
(b) Can you explain the sequence of symptoms as it happens on my car? In particular why would it seem OK while driving then get very hot as it's parked ?
(c) What would you check to find the underlying problem ?

Regards
GS

 

It's not the head gaskets.

Here are some guesses without actually probing your car.

1. The radiator fan motor is bad.
2. The radiator fan temp switch is bad.
3. The temp gauge is faulty.

 

I would take the car back to the dealer and ask them to do something and tell them they are stupid. some mechanics in the dealer are really good but many are stupid trying to make money. consider they are certified and get all the tools and dealer-only machines. hopefully get one good mechanic to fix it. Or try a differnt dealer after trying some suggestions from the .org.

 

He has the extended warranty, so why not just keep bringing it back to the dealer until the problem is solved?

They'll try the easiest (and cheapest) solutions first before moving on to the expensive ones. All the easily replaced parts like thermostat, hoses, radiator fans, coolant temperature sensor, temperature sensor to turn on the fan, relays, etc etc, before moving on to the big items like the water pump and head gasket.

Its probably a clogged radiator or a faulty coolant temperature sensor.

 

Let the car sit for a couple days and check the dipstick for any milky-looking oil (coolant flowing back into engine).

First thing in the morning have someone else start the car and sniff the exhuast. Yes, that's right, get right down there. If there's any trace of coolant being burned it will smell sweet, kinda like coolant itself. I wouldn't sniff for long though....

Have them pressure test your cooling system.

Have them do a compression test on all six cylinders.

Replace the sending unit for the gauge.

Replace the gauge/dash cluster.

-RMB