Overheating on idle

Posted by: oface

Overheating on idle - 12/06/05 02:06 PM

Have a 02 Xterra SE S/C with 60k miles. No Aux. fan. I'm seeing the temperature skyrocket on Idle, but cool down to normal while cruising.

The A/C also goes warm on Idle when the temp increases.

The fan is belt driven and turning on Idle, but I can't tell how fast. I'm thinking the fan clutch is not engaging at is supposed? Could it be the cooling system obstruction also?

Any ideas?
Posted by: XOC

Re: Overheating on idle - 12/06/05 04:20 PM

check your coolant level.

check to see if your radiator has any blockage.

check your thermostat.

check your water pump.
Posted by: Anonymous

Re: Overheating on idle - 12/06/05 05:48 PM

Overheating at idle sounds like your T-stat is stuck. I'd r&r that just to be sure.

Oh, yeah, like Admin said, check your coolant level. Check the pressure cap, too. That's always a cheap fix.

Get the vehicle up to ot and feel the cores of the radiator. They should be evenly warm/hot. If you've got cold spots then you've got a clog.

Man, I hope it's not the pump. When you start to overheat, turn the heater on full blast. If that cools it down, then the pump should be ok. If the pump's bad, then it's time to do the timing belt, also.

My money's on a clogged radiator, or stuck T-stat. Check this site out for radiators: radiatorbarn
Posted by: Southernx7

Re: Overheating on idle - 12/06/05 08:39 PM

my bet is the fan clutch.
Posted by: Anonymous

Re: Overheating on idle - 13/06/05 06:06 AM

Probably the fan/clutch.

I believe the problem is independent of the idle, though. It is probably heating up when you're stopped and working fine when you're moving.
Posted by: Anonymous

Re: Overheating on idle - 13/06/05 08:52 AM

Mine always gets a little warm idling in traffic too. If you're sitting, shift into neutral and kick it up to 1500-2000 rpms and watch the temp guage come back down. Just needs more airflow through the radiator than the fan can give it at idle.
Posted by: Aero Steve

Re: Overheating on idle - 13/06/05 12:59 PM

The first thing to try is cleaning between the AC condenser and radiator. An amazing amount of crud can get trapped in there. Unbolt the top of the radiator and tilt it toward the engine to get access in there and clean it out with a garden hose.

Do you have skid plates or are you stock? I never had cooling problems until I added a Calmini bumper and full skids. Now I can't run the AC idling for very long without the temp gauge climbing. With no AC it seems to do fine regardless of outside air temp.
Posted by: silverxglider

Re: Overheating on idle - 13/06/05 03:59 PM

Check your coolant level and take a look at the hoses while the engine is running. FWIW, when the same thing happened in my Trooper, the cause was a pinhole in very short, small hose. There was no sign of a leak until coolant was flowing through it under pressure though.
Posted by: spillboy

Re: Overheating on idle - 14/06/05 02:41 PM

Oh the irony! Same thing happened to me today. I have an '01 manual wih A/C. Today the heat index was 103, tommorrow 106. I went to a local shop and was told the A/C cancels out to relieve stress on the engine. Then I blasted full heat on the floor to bring the gauge down. Am going to the dealership in the morning. local shop told tales of Nissan owners running into headgasket problems, but I am praying I will only have to pay for a radiator due to blockage. Any idea what causes this? Any prevention? If not, any idea how for headgasket? Thanks for the URL for the radiator barn.
Posted by: Anonymous

Re: Overheating on idle - 15/06/05 08:46 AM

Hah, that full heat on the floor is fun (but it's dry heat) laugh . Just before I switched my rad. I had to do that. Ended up having to do a 2 1/2 hour run across the city, on the Friday before Memorial Day, in rush hour. Thought my shoes were going to catch on fire.

I put my new 3 core in the next day. $173 shipped from radiatorbarn. It was on my doorstep in less than 48 hours (dealer wanted $425 for their single core). It fits like a glove and holds an extra 1/2 gallon of coolant.

I'm running an '01 S/C cc 5 sp. Had problems w/cooling for the last year. That new rad. solved my problems. Can't get it to overheat. Been running it in the heat, 75 - 80 mph, w/the a/c on and the guage doesn't move from slightly below center. I do have the condenser fan, thou.
Posted by: TJ

Re: Overheating on idle - 15/06/05 03:53 PM

All good advice.

I had a stuck T-stat that did the exact thing on a jeep a few years back....I walked away from it leaving it idling while spotting some one (Paragon)...and the radiator blew up.

I'd check the T-stat first, as blowing up the radiator is sudden, and worse than some of the other items, and a cheap fix if done before hand.

Posted by: oface

Re: Overheating on idle - 21/06/05 05:46 AM

If it was a struck T-Stat then why would it go up and down? If it were Stuck, it would be stuck in one place. You can easily see it go up and down. It just goes up more rapidly on Idle, probably because it's not getting enough air flow.

It probably the fan clutch. With a clog, it would probably overheat while cruising, as the wind would not be able to sufficiently cool.
Posted by: TJ

Re: Overheating on idle - 21/06/05 07:29 AM

The temp goes up and down as the idle speed, radiator losses, and air flow vary...

That's what mine did...I was typicaly OK when moving, and the temp would tend to rise more and more during idle over the course of several weeks..but never all up...just a tendancy.

I think its that it gets stuck a bit at a time, and not all the way one way or the other either.
Posted by: Anonymous

Re: Overheating on idle - 21/06/05 07:36 AM

If it is stuck open, then the coolant is flowing freely. It's not being held in the radiator to cool, so it overheats when you're sitting still.

When my truck was overheating the temp would climb while cruising (anything over 50mph). The temp would also go up if I ran the a/c at idle. My radiator was clogged.

I'm just saying t-stat because it's a cheap fix. I'd change the t-stat and rad. cap, about $25 in parts, and see where you're at. But my money's on the radiator. Check those cores for cool spots. The radiator in my truck was a single core pos.

Let the truck idle and listen for the clutch fan to cycle. You should hear it "roaring" when it engages.

If I had it to do over I'd change the radiator at the 1st sign of any type of overheating. Overheating is what blows the head gaskets. A 3 core radiator is the 1st mod I'd consider. If you run the heater too much, to compensate for overheating, you're going to blow the heater core (ask me how I know smile ) and you don't want to go there. I think I'd rather pull the heads.