Air in nissan Frontier cooling system

[Chadwilliam1]

I converted my truck from an electric fan to a clutch fan to increase gas mileage. Well I had the bad idea of putting the new temp sensor in the radiator hose. Well it didn't seal and I lost some coolant. I then fixed it by putting it where it belongs in the radiator fins. Well I got air in the lines. I did the normal opened the cap and let the bubbles come out but that didn't solve it. So I bought a no spill radiator funnel. Put that on filled it up about a 1/4 of the way opened the bleeder bolts and revved the engine. Watched bubbles come out. Well I did this until bubbles stopped coming out. Took the truck for a test drive got about 8 miles and it started to over heat. So I just did it again and this time I didnt open the bleeder bolt.

Its an 03 frontier v6 N/a. Most of the time I am driving it is running a little bit cold in stop and go traffic.Then I get on the highway and that is usually when the over heating starts. It is very sporadic but once it over heats its hard to get it to cool down. Is there a trick to getting the air out that I don't know? I am leaving for work in a bit and if it over heats on the way I will put the clutch fan back in for the time being. I want to make sure the fan is not the issue.

BTW the fan swap I did has been done by many people with no overheating issues but its possible I made an error installing it.

 

[mrsilv04]

Have you checked the owner's manual for any advice?

I've had vehicles where the procedure for burping the cooling system is detailed in the owner's manual... and that has been the *only* way to do it.

 

[Towncivilian]

Try opening the air relief plug.

 

[440Magnum]

Originally Posted By: Chadwilliam1
I converted my truck from an electric fan to a clutch fan to increase gas mileage.


I assume you typed that backwards and actually put the electric fan IN.

What size fan did you use? Is it comparable in CFM and differential pressure ratings to ones that other owners have used successfully? Its pretty easy to undersize an electric fan, and the fan is actually needed at highway speeds a lot more than people realize. Ram-air is NOT always sufficient, especially since the engine is working harder at highways speeds than it is in stop-and-go traffic.

 

[oggb]

Originally Posted By: 440Magnum
Originally Posted By: Chadwilliam1
I converted my truck from an electric fan to a clutch fan to increase gas mileage.


I assume you typed that backwards and actually put the electric fan IN.

What size fan did you use? Is it comparable in CFM and differential pressure ratings to ones that other owners have used successfully? Its pretty easy to undersize an electric fan, and the fan is actually needed at highway speeds a lot more than people realize. Ram-air is NOT always sufficient, especially since the engine is working harder at highways speeds than it is in stop-and-go traffic.



+1, unless others have had success with this same size/style fan I'd question the size of the fan.

If it's not the size of the fan I'd check/replace your thermostat just to make certain and keep attempting to bleed air out of the system. Doesn't take much to cause these problems.

 

[Rand]

what fan is it? IS the sensor adjustable maybe its set to high?

I refitted my 2002 ranger with an aftermarket e-fan

also make sure you put it in the fins at the hottest part of the radiator.(usually by the inlet-hose)

mine was adjustable from 180 to 225F
but there was some heat loss at the sensor so I ended up having it kick on around 190F.

how did you determine it overheated is there a light or gauge?

if gauge where was it at on the gauge?

I'm also not convinced there is air causing your problem.

 

[Chadwilliam1]

I picked up the same dual fan that all the other frontier owners use. it is off a 1990 maxima. I asked on another forum about CfM ratings.
I adjusted the fan to come on at the lowest setting 165.


the reason I think its air is because it is completely random when it starts to overheat. Also it tends to do it on the highway, when my rpms are about 2000. when I am on the highway the speed of the truck should be cooling the truck, correct?


also the truck runs a little cooler in city, and the thermostat is about 4,000 miles old and its OEM.

 

[mechanicx]

Usually you only open the bleeders while filling the coolant with engine off, then close the bleeder when you get a steady stream. It's important to run the heater temperature and fan on high when purging the air with engine runing to make sure all the air is purged out of the heater core.

 

[Chadwilliam1]

well I will leave early for work tomorrow, it will be about 100 degrees hopefully it runs cooler.

I put the heater on but fan off. I would blame the fan but it is a proven set up for my truck. when i bleed it today I kept the bleeder closed and I finally got the bubbles to stop.

 

[440Magnum]

Originally Posted By: Chadwilliam1
when I am on the highway the speed of the truck should be cooling the truck, correct?


Not necessarily. See my previous post. Sometimes ram-air flow is NOT enough to keep the engine cool on cars and trucks with even slightly aerodynamically constrained grilles, even more in hot weather and with AC on. Fans can still be necessary at highway speeds. A truck like a mid-70s Chevy with a flat plank of a grille running headlamp-to-headlamp probably has enough ram air flow alone. But even my 60s muscle car has proven to me that it NEEDS a fan at highway speeds, and its grille is probably more comparable to your Nissan's.

 

[Chadwilliam1]

its slowly started to overheat today, I am going to try to bleed it one more time in the morning. if no air comes out I will put the clutch fan in and see how that goes. I need to eliminate a variable.

 

[SOHCman]

You have confirmed the fans are coming on as programmed right? You
Might rig a led light to glow in the cab when the fan is running so you know it's at least spinning the fans when it is over heating.

Also, I don't know what solder or splicing is involved with this swap, but it is entirely possible a couple wires were crossed and the fan is spinning backwards. It has been done before!

that would probably allow a slow overheat.

 

[MarkM66]

I've had electric fans on a wide variety of vehicles, and non of them needed to be on at highway speed.

 

[Chadwilliam1]

I made sure the fans were pulling air through the radiator( blowing on the engine). I think I figured it out. I was talking to my father in law and he suggested parking up hill and doing it. Well my driveway is a slight incline towards the house and I pulled down it so the nose of my truck would be near the garage where my tools are well this morning I did it the opposite way so the nose of the truck is facing uphill. I just tried to bleed the system and I got a lot of air out of it. So hopefully this cures the problem.

I am going for a test drive in a few minutes to see if this helps.

 

[Chadwilliam1]

just got back from a 20 min test drive and the needle never moved. I learned I at least need to be on level ground to bleed my radiator. thanks for everybodys help!

 

[accent2012]

Who would have thought that geography was the cause of your problem lol.

 

[mechanicx]

This points out the usefulness of vehicles having the high and near engine mounted surge tank/pressurized reservoir. The radiator and fill level needs to be higher than the engine level to keep air out of coolant in the engine.

Your truck doesn't have that but as found the truck needs to be at elast level to maintain radiator fill height.

 

[SOHCman]

You might even jack the front end up next time to gain as much height as possible. Another thing is to pour slowly to allow the air to escape. I poured too fast changing coolant on the vibe yesterday, and had to squeeze the hoses for an hour to get the air out.

 

[Chris142]

Those VW Vanagons needed the rear jacked up 6ft to get those to bleed. I'm not joking.