Autozone vs. Napa thermostat

[doonze]

Ok, so I had purchased a Autozone $4.99 198* Thermostat a couple of months ago. That was when I bought the truck, and it had an overheating issue. So it worked ok I guess, didn't solve my problem because a clogged Radiator was my problem, but I didn't much care for the way it acted.

When it would first get to temp every day it would rise to R/M, then the thermostat would open, and it would fall to below the O. It would stay there, and if it was cool outside it would do the rise to R/M (because the stat was closing) thing again. You could tell the thermostat was having issues responding to temp changes. Pretty much the temp just moved all over the place.

So I was looking that the Napa site, and noticed they had a "premium" thermostat. 195*, and looked bulker then the "regular" one or the Autozone one I had. Online said it had better control then the cheaper ones. So i swung by today and picked one up. The "regular" ones are like $5.50, the "premium" are like $10.50. I was taking the radiator out for one last super flush anyway and thought I'd swap the stats while I was at it.

So I get the old one out and compare them. The new Napa stat is bulkier, and does appear most solidly built, but it has no weep hole. I get everything put back together and try the new stat out.

It was 90*+ out today, and I cranked on the AC and took it out on the hilly freeway here. I was doing a trial by fire. The 3 things that have always made this truck overheat are the AC, or hills, or the freeway in general. So I tried all 3 at once, just to see if I could get it to overheat.

Right off I noticed the Napa stat runs hotter then the AZ one I had, even though it's "rated" 3* lower. It ran at the TOP of the O, instead of down at the bottom of the O. And it did move up and down, from the top of O to the middle of R. So about 1/2 a letter movement. And that was all. Never went below that or above that, no matter what I did. So even though it ran a little hotter, it had much better control and kept things in a range I could live with.

So I'm just wondering if people have seen differences with different thermostats like that, or if anyone else has used this thermostat and how it ran for them. I'm a little concerned about it not having a weep hole, but that may be why to other stat kept moving the needle all around and this one keeps it almost still.

I have a small concern about it running "hotter" then it did, but then again it's staying pretty much still and if it goes no higher I would think it would be ok. Any opinions?

 

[techieman33]

Use a Ford thermostat. That's your best option.

 

[BrooklynBay]

They make a fail safe thermostat that is designed to fail in the open position. Maybe the more expensive one is like this? Could you take a side by side comparison picture of both thermostats?

 

[Maniak]

Ever since I got a bad thermostat I now check them before I install them. I throw them in a pot on the stove with a instant read thermometer (same one I use to check the a/c vent temps).

I then make sure it is fully opened by within 5 degrees of the thermostat.. the 195F I have in now is completly open before 200 which will keep the temp < 200 assuming the cooling system is up to snuff.

~Mark

 

[doonze]

They make a fail safe thermostat that is designed to fail in the open position. Maybe the more expensive one is like this? Could you take a side by side comparison picture of both thermostats?

Sorry man, it's in already, and I'm not pulling it out at the moment for a photo op! LOL But pretty much it's just beefier all around, everything looked heaver duty and tougher...Let's see if I can link from NAPA.

Ok, here is the one from Auto Zone I was using...

And here is the one from NAPA I just put in...

Neither is the "failsafe" type, I though that was overkill, I don't want it sticking open really either, I might not even notice a problem then.

But as you can see, the NAPA one is just beefier all around. Bigger spring with more windings to it, and heaver, bigger, longer middle core. Heaver Frame..... Not that all that means anything, but it's defiantly a different design. I'll keep an eye on it and post my findings about how well I like after I've broke it in. But I bet not having any bypass (weep hole) will make it better for in the winter. Currently I think the system was sometimes keeping the stat closed when it was cool outside, ran way down on N.

 

[Anime]

I tend to stick with Motorcraft stats, but have been through a few.

The wimpy Autozone stat I threw on as a quick replacement for a roadside repair for a stuck stat actually gave the best cooling, with the weak spring it never went over the middle of the gauge.

The Motorcraft stats I've used have varied slightly in performance, doing everything from a rock-solid middle-of-the-gauge-no-matter-what like the original stock stat, to a wide range of movement with/without A/C, hillclimbing, high RPM, etc. The original stat on the X made it around 7 years/150,000 miles. After that, I've only managed to get a few years out of the last two Motorcrafts. They all fail by slowly going closed and making the temp gauge creep up.

I stick with Motorcraft since they are 190 degree stats. The extra few degrees of a 195-198 stat don't seem worth any initial savings.

If I had to go aftermarket, I'd likely go with a Stant stat that had the lifetime warranty. Seems like a great deal to just pop into the parts store with your old stat and receipt and grab a new one. Unfortunately they only offer the 195-198 range in these as well.

Years ago, I bought a stat for an import vehicle from Napa that was manufactured by some aerospace company that apparently made parts for missiles, and thermostats. It was an awesome precision part for the money, and works flawlessly. If they made them in the right size and temp range for an Explorer, I'd probably use one of those at least once to see how it holds up to a Motorcraft stat.

 

[mgmgmg]

Ford thermostat Made in germany!!!! You cant go wrong Ive replaced 1 in each of my X's no problem.. " Made in germany you know they make great things"