What is normal coolant temp

eppoh · Jun 2nd, 2004, 02:01 PM

Trying to track down the reason for my poor fule mileage on 94 pickup w/2.4

I noticed the coolant temp runs at about 1/4 to 1/3rd scale all the time. This includes 70mph on the highway with AC running or driving around town - Outside temp 90-94 F.

What is normal? I'm thinking it may be running rich because it thinks it is a cold engine and needs fuel enrichment.

KA24Ewoog · Jun 2nd, 2004, 02:14 PM

Quote:

Originally Posted by eppoh

Trying to track down the reason for my poor fule mileage on 94 pickup w/2.4

I noticed the coolant temp runs at about 1/4 to 1/3rd scale all the time. This includes 70mph on the highway with AC running or driving around town - Outside temp 90-94 F.

What is normal? I'm thinking it may be running rich because it thinks it is a cold engine and needs fuel enrichment.

Mine runs in the same range, KA24E 2WD 1995.....I'm sure mine needs a thermostat, because last winter I froze my ass off...took the heater a while to get toasty. Just haven't got around to it this year.

I adjusted my timing a while back and I have gotten 30-40 more miles per tank of gas than I did before....but I was tracing down a 'pinging' problem.
The timing adjustment fixed that.
Wish I could help you with your fuel problem but I'm not sure what's up with yours.

KA24Ewoog · Jun 2nd, 2004, 02:15 PM

aaronford · Jun 2nd, 2004, 02:34 PM

Mine runs in that range, too. Unless I am pulling a trailer, then she climbs a bit. As far as fuel economy goes, 2WD>4WD Reg Cab>King Cab Light Foot>Heavy Foot My problem is the latter. A good sythetic oil (read Mobil1) and a good set of plugs (read Bosch Platinum) will really help out. My truck was also very picky about its air filter. More than 3K miles and it would be notably slower. Replace the filter and it would pick right back up. I went with a K&N and have never had the problem since. I have heard that synthetic in the gearboxes and differentials makes a big difference. I wouldn't know as mine has had the slippery stuff in there since 5K miles.

BTW, Great Job on the signature. Both my grandfathers put it on the line to defeat that way of thinking. I would hate for us to lose the lesson.

jadcock · Jun 2nd, 2004, 02:36 PM

Quote:

Originally Posted by eppoh

Trying to track down the reason for my poor fule mileage on 94 pickup w/2.4

I noticed the coolant temp runs at about 1/4 to 1/3rd scale all the time. This includes 70mph on the highway with AC running or driving around town - Outside temp 90-94 F.

What is normal? I'm thinking it may be running rich because it thinks it is a cold engine and needs fuel enrichment.

I don't know what the Nissan gauge really indicates (temperature-wise). Mine normally runs right at the 3:00 position. Sometimes, when idling in traffic, it'll creep up to just a hair above 3:00, but once I get going, the fan will pull lots of air through the radiator and the gauge will fall back down to around 3:30 or even 4:00. When starting it after a hot soak, the gauge will register as high as 2:00, but quickly falls back to operating temperature as the coolant circulates.

Again, I don't know what all that means in terms of actual coolant temperature. I'd say yours is close to normal. Maybe your gauge is off a bit. Or maybe your thermostat is stuck open, or is incorrect for your application. A new thermostat (get one from Nissan) would likely rule out any problem with the cooling system, and maybe indicate to you that the gauge might be a little off.

By the way, what is your "poor mileage"? Is your truck 4x2 or 4x4?

arc · Jun 2nd, 2004, 02:59 PM

I've been wondering about that, too. I have a '97 2wd and it rarely gets above the 1/4 mark. I replaced the thermostat with a genuine Nissan part (what a pain in the backside that was) and it made zero difference.

The one oddity on my truck is that the previous owner replaced the coolant with the orange stuff. Don't know if that makes any difference or if it would affect anything.

aaronford · Jun 2nd, 2004, 04:16 PM

Been running Havoline Dexcool (orange/red) since 20K (I am at 100K) I have been very happy with it. Not sure if it makes a difference. I might be able to tell ya more at 200K.

jadcock · Jun 2nd, 2004, 04:17 PM

Quote:

Originally Posted by arc

I've been wondering about that, too. I have a '97 2wd and it rarely gets above the 1/4 mark. I replaced the thermostat with a genuine Nissan part (what a pain in the backside that was) and it made zero difference.

The one oddity on my truck is that the previous owner replaced the coolant with the orange stuff. Don't know if that makes any difference or if it would affect anything.

The temperature gauges on the '97 models must just be calibrated that way.

The orange coolant will have no effect on your cooling capacity. It's still an ethylene glycol-based coolant and has exactly the same cooling capacity as the green coolant, given the proper mixture (50/50). The advantage of the orange coolant (usually marketed as DEX-COOL) is the dramatically decreased change intervals (from 2/24,000 miles to 5/150,000 miles) due to organic corrosion inhibitors (vs. the silicated inhibitors in the green coolant). The green coolant needs to be changed every 2 years/24,000 miles to be an effective corrosion inhibitor, since the silicates have been depleted by this time. However, the DEX-COOL has no advantage when added to a system which previously was filled with green because all the internal surfaces are already coated with the silicates, so the change interval would be the same. The DEX-COOL does have one slight advantage over standard green coolant -- in that it doesn't have the tendency to "gel" in areas of low flow (like a heater core) like the green coolant does. I wouldn't switch coolants based on that slight advantage, but I thought I'd point it out.

arc · Jun 2nd, 2004, 05:28 PM

Quote:

Originally Posted by jadcock

The orange coolant will have no effect on your cooling capacity.

Thanks, jadcock.

I didn't think it would make a difference; just thought I would mention it. I did find another difference when I had to buy some to top off after I changed my thermostat. It's a lot more expensive than the green stuff.

97HB · Jun 2nd, 2004, 06:38 PM

maybe I'm at the dumb end of the spectrum....here in Texas if we can keep a car or truck temp guage below the 1/2 mark, we are smitten geniouses...

jadcock · Jun 2nd, 2004, 07:24 PM

Quote:

Originally Posted by arc

It's a lot more expensive than the green stuff.

Yes it is -- and it's great stuff. When you're looking at used vehicles, you can really be assured of no internal corrosion if the vehicle is equipped with DEX-COOL -- it's good, practically, for the life of the vehicle, although it does have the 5 year/150,000 mile change interval. With the green stuff, you're good for 2 years (maybe 3). I think some manufacturers recommend the first coolant change interval as far out as 50,000 miles, but usually recommend changes every two years after the first change. But who actually changes their coolant? In the past, with iron blocks and iron heads, it wasn't that much of a problem. With the current crop of aluminum/iron and full aluminum engines, cooling system maintenance should be as important to the owner as the oiling system, but it's usually not. The result, sometimes, is failed head gaskets and other cooling system failures.

One of the first things I do when buying a used vehicle is to change the coolant, regardless of the type of coolant it has. It assures me that I have a proper cooling system mixture, because that DOES have an affect on cooling capacity. Too much coolant will lower the heat transfer and freeze/boilover protection. The recommended 50/50 ratio is important to maintain.

aaronford · Jun 2nd, 2004, 08:20 PM

I recall that the factory fill in my 95 was a orange color. Any idea on the brand Nissan used?

jadcock · Jun 3rd, 2004, 07:34 AM

Quote:

Originally Posted by aaronford

I recall that the factory fill in my 95 was a orange color. Any idea on the brand Nissan used?

Interesting. If it was, I have no idea what brand it was. Probably Havoline or Prestone. But my '95 is green, and Nissans to this day, if I recall correctly from the Titan I drove, are filled with green coolant. Any original owners out there with orange/red/pink coolant in their Nissans?

aaronford · Jun 3rd, 2004, 03:20 PM

Was bought in AZ, if that helps. Also came with no undercoating, so its alot lighter around 2000-2200 lbs empty. Me + stereo + all my stuff weighs in at 2500 and I ain't little.