Woodsman1001

I bought a 4th generation Nissan Maxima and have been trying to repair it back to par. One problem I can't figure out is why the engine is overheating. I have changed the radiator cap, the antifreeze, and the thermostat but the engine continues to overheat. Whenever I start driving it runs just fine in reaches temperature. Normally on cooler days everything is fine and it doesn't overheat only whenever it's hot outside and I'm doing a lot of stopping and starting will it overheat. Usually from the time that I start driving to the time that it starts overheating is about 30 to 45 minutes. Could this be a problem with the transmission overheating or is it something wrong with the cooling system? PS I did flush the system quite well just to cover all my bases.

Turbobink

iTrader: (2)

Let's start with you explaining what it is you're calling 'overheating".

Based on what you've explained I'm assuming that you're simply seeing your temperature indicator gauge climb into the ranger where you feel the engine is running too hot.

You haven't experienced a true overheat, correct?

Woodsman1001

I have had it overheat on me. Driving down the road and the temperature gauge starts to climb. I was thinking at first that it was normal. That was when I first got the car. I came to a stop at a stop sign and steam started pouring from the hood. I pulled off the road and got the hood open, the steam was coming from the antifreeze Reservoir. The reservoir was only half full at the start of the drive but had filled and was overflowing. I let the engine cool and toped the antifreeze off before I started driving again. I wanted to test it to see if it would happen again a few days ago after I changed all the things listed but got the same result. I have been driving it still and when I see the temperature gauge start going up I turn the heater on and the temperature gauge drops. I can drive as long and far as I want while the heater is on.

Tarzan

Is your water pump failed? I heard of vanes rusting off.
So you may have perfectly good antifreeze and thermostat, no bubbles, but overheat.
Do you get any heat from the heater before thermostat opens? If not, pump is the suspect.

Woodsman1001

I have been told the water pump is good from a friend that is a technician for Ford. It might still be the problem not sure and I'm a little afraid of the price tag on a new one. The heater works great, it takes the car about 5-8 minutes to heat up but the heater is working in 2-3 minutes. It works a little to well once the thermostat opens up.

PH98I30

Did you put in an OEM thermostat? These water pumps are hard to tell if they are bad. They are a different looking animal. Do you have any cracks in your plastic radiator tanks? Make sure you don't blow the head gasket.... your gambling here when you are running hot.

Tarzan

When thermostat opens, you should feel rapid increase in radiator temperature if the pump is working properly. If your rad is still lukewarm, but it starts boiling, the pump is not working. Do the fans turn on when hot?

Woodsman1001

yes the fans kick on. They wait tell the car is at temperature then come on. If I'm parked and the engine cools they will shut off and come back on when needed. The hose that leaves the engine and goes to radiator will be lukewarm then it will heat up fast. It takes about 5-8 mins to get to that point from start up on a cold engine.

JvG

Two possiblities I'm thinking of

1. After opening the cooling system, air in the hoses needs to be removed so that the engine will not overheat.

The car needs to be run while the front of the car is on ramps or jack stands. Blip the trottle from time to time. This process might take 30 minuites

2. The radiator might have a leak. Either between the core and the plastic tanks, or in the core it's self. Another member had this problem. There was a leak in the core, and a stain right below it.

Since you mentioned low coolant levels, I'd say that the radiator could be the cause.

JvG

I forgot to mention that the radiator cap should be removed in order to bleed air from the cooling system while the front of the car is elevated.

jholley

iTrader: (13)

Have you ever felt coolant flowing thru the lower RAD hose that connects to the thermostat? That hose will not get as hot as the upper hose but feeling warm coolant coming from the RAD thru that lower hose is the easiest way to clarify if the thermostat is opening and allowing coolant to flow thru the RAD.