My babies overheating!! Waterpump most likely? How difficult?

[longhornsqx4]

So this weekend was the first really hot weekend, and i went on a road trip, about 200 miles. The whole freakin trip, my temp gauge was about 2/3-3/4 up on the gauge.

It would stay there and never get hotter. It would get cooler when I got into slower traffic though, its perfectly fine when cruising @ 40mph and 2000rpm. But at 65mph and 2800 rpm, the temps rose up.

When I pulled over, you could hear the coolant bubbling in the radiator under the cap with your ear close.

I waited for it to cool, and checked the fluid level, which was fine. It took about a 300ml to top it off, but nothing significant.

I felt both upper and lower rad hoses and both were hot as sin (to me that meant thermostat IS openning? properly.)

IM no exactly rich so I love some insight on how to tell what the problem is.

Has anyone ever done a waterpump swap on these cars? I just looked at the manual, seems VERY tricky

[fueler]

could be anything as small as a radiator cap, to a tstat or water pump. you can rule out the fan clutch.

Do you have the 3.3 or 3.5 engine?

[longhornsqx4]

3.5L engine

Ill do just the thermostat today I guess and see where that leaves me

[keelhaul]

3.5L have dual thermostats and gear driven waterpump. hopefully its not the waterpump.

[longhornsqx4]

Well they only have one thermostat

The manual seems to show a water control valve aswell, but I dont know if that would be the problem or not.

I just went and priced everything in town, a thermostat was $40, and the waterpump was $180

Im sure there much cheaper online so depending on what help I get here, Ill decide what to buy

I did buy a new rad cap since it was only $11. Ill swap that when the cars cool again

[mda185]

My 2001 Pathfinder needed a new radiator at 80K miles. I bought my 01 used with 70K miles on it and noticed a faint smell of antifreeze while changing drive belts. I could not find the leak but decided to change the radiator and hoses as a precautionary measure. They were the original parts at 80K and it was doubtful that the anti-freeze had been changed every 2 years as it should be. Long story short, with new radiator, my engine temp gauge dropped from around the 5/8 point to a little under the mid point and the smell went away. I believe I read on this forum that the radiator passages tend to clog up with gunk over time and this looks like the case with my pathfinder. No problems since I changed radiator, hoses and anti freeze.

[longhornsqx4]

well the radiator could very well be the problem, I dont know

I just pulled the codes on my car though and got some 02 codes

P0140 O2 Sensor Circuit No Activity Detected (Bank 1 Sensor 2)

P0160 O2 Sensor Circuit No Activity Detected (Bank 2 Sensor 2)

Being as these are sensor 2 codes, and Ive never seen them before, I just cleared them. I didnt get the greatest gas mileage on this trip, but nothing crazy

[mda185]

Keep in mind that the radiator also has a transmission cooler built into it. If you are running high radiator temps, you are also cooking your transmission. That is one repair bill you don't want to face. That is why I replaced mine at the first sign of trouble. I don't post here a lot but I am a professional mechanic.

I don't recall you saying how many miles are on your QX4. Water pumps on these engines tend to last a long time if coolant is changed every 2 years. They are not easy to replace but they are one of the more durable designs out there. The radiator is the weak link in this design and most likely thing to fail after hoses. Don't let this problem go too long or you will be spending for a lot more than simple radiator replacement.

The O2 codes are not related to high engine temps. They indicate the oxygen sensors behind the catalytic converters are not putting out any voltage. O2 sensors start to go south around 70K miles and by 100K miles, most are shot. When they are shot, the engine will probably run richer and over time, this will clog your catalytic converters.

[longhornsqx4]

The car has 114k I believe

I dont know if the rad has even been changed or not, but it an OEM nissan/infiniti rad and its prtty beat asetically so Im thinking it may be the original

Like would this radiator be a good replacement? (cheapest I could find on ebay)

http://cgi.ebay.ca/ws/eBayISAP...49829

[Chuck Tribolet]

You gotta pull the rad to do the thermostat, so flush a lot of fresh water throughthe rad while it's out.

Nissan Coolant and Distilled Water to refill. There's vent (metal pipe with a rubber cap) up against the firewall top center that has to be open when yourefill to let the air out.

[longhornsqx4]

You dont have to pull the rad to do the thermostat, you just take off the hose, 3 10mm bolts on the drivers side, and the housing and thermostat come out, I read a DIY on it with pics. Pretty easy

I dont get what you mean by something having to be open to fill up the fluid though?? I just simply take off the rad cap and top it up when its cold, then if I check it a day later, itll still be full... so I believe i DONT have to have that valve open to fill?

[mda185]

I don't know anything about that brand of radiator. The price is about $50.00 less than I paid for a Nissin radiator. Note that is Nissin not Nissan. The two companies are not related AFAIK. The Nissin unit I bought is good quality and it went in with no problems. This is one part I like to buy locally so I can return it easily if there is a problem. That is probably why mine cost more. Had to pay a local parts store mark up even with the discount I get.

[longhornsqx4]

Well I dont have a deal, and a new oem radiator is $500

I did flush the coolant today, simply drained it, filled it back up 2-3 times with tap water and drained it again, then just let the hose run through it for a few minutes, then drained and filled back up with proper coolant

So I guess we will see what happens.

If it overheats again, I guess its safe to say my rad should be replaced?

[W O T]

You can find cheaper on ebay obviously, I would defientely try a flush with water a few times first though, and just see what it does. May clean out the clogs.Id much rather replace the rad than the water pump on these cars though, water pump is a bish!!

[Lars]

Another thought would be to clean your current radiator by running water through the fins from the back (engine) side. DO NOT use high pressure you'll just bend all the fins and f-it up worse. You want to do it from the back side because if you do it from the front you'll just push the dirt back into the rad even further. This will help clean some of the dirt out of the fins and increase cooling efficiency.

[Chuck Tribolet]

Your right, you can do the thermostat without pulling the rad. I pulled mine because it was already drained and disconnected, so it was a good timeto flush it.

When you empty the radiator, you need to pull the vent plug to refill. The fluidlevel dropped about a half inch when I pulled the plug. If you are just toppingup, that area probably already has fluid.

Chuck

[Chuck Tribolet]

I topped up the rad tonight. First I filled the rad, then I pulled the vent plug.The level in the rad dropped about a quarter inch.

Chuck