[twinsig]

2000 v6 crew cab w/250k
My coolant temp is Always low in winter months, always. Heater blows warm air, sometimes its almost hot, maybe.
I changed the thermostat/flushed like 2 yrs ago which did not help.
Right now with temps in Bama well below the Anchorage AK temp, the guage is mostly bottomed-out,,, Cold. Last year during several long distance trips it would take 2-3 HOURS before the temp "normalized" in the center of the gauge.
During summer the gauge indicates normal as well.
Anyone experience this problem?
The engine is designed to run at a certain temp and if lower will affect operation & mileage, right?

 

[Cusser]

What temperature thermostat do you use? I got significantly better heat (and did not run hot in Arizona summers) with my 1988 Mazda truck when I use the 195F Stant thermostat.

Also very important is to flush ALL the air out of the cooling system; sometimes one has to jack up the front of the truck while running with radiator cap off to accomplish this. There should also be coolant bleeder screw(s).

 

[twinsig]

Not sure

It's the stock/oem t-stat. Don't know what the exact temp range. And that was 2 yrs ago, but its so freaking cold this week the gauge will hardly move off Cold.

 

[phatB]

try sticking a piece of cardboard in front of your radiator to block the air flow. a common thing many people do in cold climates during winter.

 

[Cusser]

It's the stock/oem t-stat. Don't know what the exact temp range. And that was 2 yrs ago, but its so freaking cold this week the gauge will hardly move off Cold.

Looks like 180F is stock thermostat temperature for Frontiers (with a 170F available) so you want the 180F. Purge out all the air, need to try that.

I've also heard of folks blocking off half their radiator for winter, but I'd read more about that before trying.


Running at too-low a temperature also causes more engine wear, so you need to get that right. Doubt your coolant temperature sender is the issue since heater doesn't get hot (feel connections at the firewall).

 

[twinsig]

yeah, 10-4 on the engine wear!
thanks

 

[Nissan4Life]

Could be that your coolant temp gauge sensor is toast. Nissan uses 2 temp senors a 2 prong unit for the ECU, a 1 prong unit for the gauge.

 

[twinsig]

Maybe, but the gauge works properly in warm seasons. Stays right in the center/normal range. I appreciate that info though..

 

[phatB]

Like i said, this is very normal in cold climates, happens to millions of cars. used to happen to me with multiple cars, i lived in Alaska for 30 years and saw down to -40, everyone who has this issue just sticks a big piece of cardboard in front of their radiator during the cold snaps when its below zero. i wouldnt bother changing out the t-stat.

 

[The other Sean]

Not being familiar with 1st gens, does the truck have a mechanical fan?

My only two thoughts are a stuck or partially stuck open thermostat or a fan clutch that is stuck and the fan is always turning at full speed.

 

[GotToGo]

Considering your location, I wouldn't hesitate to run a 195 tstat. It'll be fine in summer too.

The cardboard trick does work. They even used to sell a "radiator blanket" that did the same thing.

 

[LittleBull]

Like i said, this is very normal in cold climates, happens to millions of cars. used to happen to me with multiple cars, i lived in Alaska for 30 years and saw down to -40, everyone who has this issue just sticks a big piece of cardboard in front of their radiator during the cold snaps when its below zero. i wouldnt bother changing out the t-stat.

I don't understand why this would work.

I thought the purpose of the thermostat was to block coolant flow to the radiator until
the engine reached operating temperature. Seems he SHOULD he be checking the thermostat if
he's running cold?

 

[GMK14]

It stops the airflow through the rad so the coolant isn't cooling down as much. It really helps getting your heater to blow hot air much quicker when its cold. You can buy winter fronts everywhere it gets cold enough, cardboard is the cheap choice.

Sounds like an air bubble to me. I'd start by parking on hill, add a bit of coolant and see how it works. Could it just be warming up to normal operating temps in the summer because the ambient temp is a lot warmer? Maybe check the radiator hose's/water pump to make sure there in good shape to.

 

[09eq]

If coolant is full (should overfill tank a little to make sure) and no air bubble (that should work its way out pretty quickly anyway), I think you have bad stat. At 20 below mine puts out good heat. Also, as mentioned, don't trust gauge to be accurate.

 

[Mathster]

just a thought here from when my gen1 X blew a radiator hose.

the temp sending unit is downstream of the thermostat. if the themostat isnt opening properlly, it will read cold. can you get a temperature reading of the engine?
I think the heater core inlet is upstream of the thermostat, but you may be having multiple failures.

 

[Skibane]

My vote is for the thermostat being stuck open.

Typically, when this happens, the temperature gauge shows a sharp drop in temperature when you get out on the highway, because driving fast forces a lot more cold air through the radiator (and the stuck thermostat isn't preventing that cold coolant in the radiator from being pumped into the engine, like it should).

Then, when driving slow, the temperature gauge shows warmer, because there's less cold air being forced through the radiator.

 

[GotToGo]

Dang, I thought you said you were in Alaska but I see that you said Bama. Sorry.

So what you're describing sounds like a stuck open thermostat. Did you put it in upside-down?

 

[finallygotatruck]

Dang, I thought you said you were in Alaska but I see that you said Bama. Sorry.

So what you're describing sounds like a stuck open thermostat. Did you put it in upside-down?

Which was my guess... Or theres a large air pocket. fill that overflow tank overfull, take it for a ride and see if it drops any. It might take a couple of trys to get it to stop taking fluid.

Air pocket would have sensor in cold air.

 

[twinsig]

It stops the airflow through the rad so the coolant isn't cooling down as much. It really helps getting your heater to blow hot air much quicker when its cold. You can buy winter fronts everywhere it gets cold enough, cardboard is the cheap choice.

Sounds like an air bubble to me. I'd start by parking on hill, add a bit of coolant and see how it works. Could it just be warming up to normal operating temps in the summer because the ambient temp is a lot warmer? Maybe check the radiator hose's/water pump to make sure there in good shape to.

Funny you mention that, timing belt w/water pump is on the to-do list, soon, along with the weeping coolant on the intake? issue....Maybe this is sucking in small amounts of air?

If coolant is full (should overfill tank a little to make sure) and no air bubble (that should work its way out pretty quickly anyway), I think you have bad stat. At 20 below mine puts out good heat. Also, as mentioned, don't trust gauge to be accurate.

Agree, and I did just that, maybe a short lived china-stat. Its getting changed during the maint as well.

Fan clutch seems fine.
I installed the cardboard leaving most of the center/clutch area and lower section open to airflow. Drove a few miles and its a good bit warmer, around 25% increase.

This arctic breeze sucks, 15 by morning in Bama. Come On with some Global Warming please!

ALL good info, I appreciate your time and the help.

I'll be back for the maintenance effort. Not looking forward to it but $500-$600 once is way better than $500 a month!

[Derail Alert]
By the way, at 250k what about the injectors?
Buy new $$$, Or have mine tested & cleaned?
I spent $117 at RCEngineeringInc on my BMW K1200 (4cyl, 80k). Two were weeping, none at max flow, two were down on flow by about 12-15%. Turn around at RC is 24 hours from arrival.

 

[smj999smj]

Funny you mention that, timing belt w/water pump is on the to-do list, soon, along with the weeping coolant on the intake? issue....Maybe this is sucking in small amounts of air?



Agree, and I did just that, maybe a short lived china-stat. Its getting changed during the maint as well.

Fan clutch seems fine.
I installed the cardboard leaving most of the center/clutch area and lower section open to airflow. Drove a few miles and its a good bit warmer, around 25% increase.

This arctic breeze sucks, 15 by morning in Bama. Come On with some Global Warming please!

ALL good info, I appreciate your time and the help.

I'll be back for the maintenance effort. Not looking forward to it but $500-$600 once is way better than $500 a month!

[Derail Alert]
By the way, at 250k what about the injectors?
Buy new $$$, Or have mine tested & cleaned?
I spent $117 at RCEngineeringInc on my BMW K1200 (4cyl, 80k). Two were weeping, none at max flow, two were down on flow by about 12-15%. Turn around at RC is 24 hours from arrival.

If there is nothing wrong with the injectors as far as misfiring or failing an ohm-check, usually a professional-type, injection service (the type were they disable the fuel system and run the engine on chemical supplied by a pressurized cylinder) is all that is needed. When I got my 2003 SVE, I had a bad #5 injector and the truck had almost 200,000 miles on it. I went ahead and got a set of Autoline remanufactured fuel injectors and a new pressure regulator (since I was there) and installed them. They weren't that expensive. I got them from Advance Auto Parts, ordering them online and using a discount code and it qualified for free shipping. I was able to just bring the cores back to the local store to get my core charge back. My thinking was: if one is bad @ 200,000 miles, how far behind are the other five? I got better things to do that R&R my supercharger every few months!