Life span of the MM-180T

[CRUZTAKER]

My thermostat has failed.

I'm looking for opinions on life spans.

I put mine in 27k miles back. Is that good?

[David Morton]

My thermostat has failed.

I'm looking for opinions on life spans.

I put mine in 27k miles back. Is that good?Nope. It ain't good.

Aftermarket huh? Yeah, I've been trying to talk sense to folks about this thermostat business but it's like talking to a pill-head. If he's already doing it, he's not hearing you until he's obviously being hurt by it.

195 degrees is the factory thermostat setting for almost all manufacturers and there's a good reason why. Metal wears at different rates depending upon its' temperature and 195* fahrenheit is optimal. At 180* the wear rate is more than doubled and at 160* it's ten times that at 195*.

So your thermostat is 195* from the factory because they want the parts to wear as slowly as possible, but guess what? The engineers designed the whole cooling system, fuel system, oiling system, engine block and head design, with the intention that the cooling system was going to be running at...

...195 degrees fahrenheit.

So some guys are getting a better run (they say) running a 180 or 160 degree t-stat, everybody wants one so a few companies answer the call pounding out poor quality thermostats that are mostly running hotter than they can stand because your engine still runs pretty hot, remember the radiator isn't big enough to keep that thing down at 180 all the time, it's only big enough (by design) to keep the engine at 195*, and the 180* t-stats wear out at 27,000 miles and "nobody knows why"?

I know why. I went to the factory schools and when it comes to reliability, trust me, the factory knows what makes their cars last. They don't want to spend one dime more on warranty costs than they absolutely can't avoid. If you want a thermostat that will last, get a Motorcraft 195 degree thermostat. Keep the coolant fresh by doing a drain and fill every year, fall if you're a yank, spring if you're a reb. Fresh coolant not only keeps the t-stat from leaking out the parafin expansion pill but it keeps the water pump seal lubricated. Do good, regular coolant service, never use those acid based flushes, just drain and fill two gallons every year, and you'll get 50,000 on the t-stat at least and probably 100,000 on the water pump. Since the t-stat is so critical, I change mine at 50,000 just to be on the safe side.

Cheap insurance.

[DEFYANT]

Whoa! Thats a very good response! Thanks Dave.

In addition to what you posted, I beleive the reason for a hotter running engine also has to do with emissions. A hotter fire burns more completly thereby being cleaner and meeting the feds strict guildlines.

As far as the temps go, I have run the data logger for several hard runs and rarely does the temps spike. When they do, they drop to 180* very quickly. This also helps to keep the trans temps down.

Just my .02

[mpearce]

Whoa! Thats a very good response! Thanks Dave.

No kidding! This site amazes me on a daily basis. I love learning new things like this. Thank you for that response.

-Mat

[David Morton]

Whoa! Thats a very good response! Thanks Dave.

In addition to what you posted, I beleive the reason for a hotter running engine also has to do with emissions. A hotter fire burns more completly thereby being cleaner and meeting the feds strict guildlines.

As far as the temps go, I have run the data logger for several hard runs and rarely does the temps spike. When they do, they drop to 180* very quickly. This also helps to keep the trans temps down.

Just my .02Sounds good but here's the factory-source straight dope on combustion temps.

The only emissions concern with combustion temps is that when they get too high, oxides of nitrogen are formed, NO for short. We cool off those temps all the time by using EGR, exhaust gas recirculation, basically putting dead air with no oxygen in it into the intake stream. Cooling system temps have a negligible effect on emissions, unless there's a hot spot in the head causing pre-ignition and that's a horse of a different color. Too cold is not a problem as far as emissions is concerned. Matter of fact it's great once the PCM sees 150 degrees or so from the ECT (engine coolant temperature) sensor.

No doubt, when the engine is back down to idle your temps go right back to 180, but how often is the engine at idle? Most of the time that 180 t-stat is running hot, and besides, the parts are wearing out faster when your are at idle. Why cause more engine wear just to get .2 seconds at the track if your not a professional drag racer?

But if you want to, hey, more power to ya'! You're the one paying for the new bearings, rings and valve guides.

[DEFYANT]

I just went and looked at some saved data logged runs. My temps are actually at 188* while cruising and spike to about 198*-199* then back to around 188*.

[David Morton]

Not too bad I guess. Maaybe 180 isn't so bad but those factory instructors are sure fanatical about aftermarket stuff like that and I can't see any bad motive that might be pushing them to fudge things their way. I tend to give them the benefit of the doubt. After all it's like I said, THEY are the ones paying for warranty repairs.

For more clarification, as I recall the optimal temp for the metal wear curve gets lowest at 195* (I'm sure of that number) and stays pretty level up to about 215* where it starts to go back up. Around 275 or so it's back to where it was at 160.

[jobrien8]

Sounds good but here's the factory-source straight dope on combustion temps.

The only emissions concern with combustion temps is that when they get too high, oxides of nitrogen are formed, NO for short. We cool off those temps all the time by using EGR, exhaust gas recirculation, basically putting dead air with no oxygen in it into the intake stream. Cooling system temps have a negligible effect on emissions, unless there's a hot spot in the head causing pre-ignition and that's a horse of a different color. Too cold is not a problem as far as emissions is concerned. Matter of fact it's great once the PCM sees 150 degrees or so from the ECT (engine coolant temperature) sensor.

No doubt, when the engine is back down to idle your temps go right back to 180, but how often is the engine at idle? Most of the time that 180 t-stat is running hot, and besides, the parts are wearing out faster when your are at idle. Why cause more engine wear just to get .2 seconds at the track if your not a professional drag racer?

But if you want to, hey, more power to ya'! You're the one paying for the new bearings, rings and valve guides.


The other effect when the combustion temperature gets colder is that the CO (carbon monoxide) levels are increased. So maintaining temperatures not only in the combustion chamber, but also in the block do have an effect on emissions.
The colder you run an engine, the more fuel you use as it runs in open loop, instead of closed loop. Temperature (air/fluid) is a factor that is used for the fuel tables. For emission certification of an engine, temperatures must be maintained to properly test an engine.

[RF Overlord]

So your thermostat is 195* from the factory because they want the parts to wear as slowly as possible, but guess what? David, when I changed my thermostat to 180° back in December of '02, I saved the factory one, and it says 188° on it. Also, the FSM states that the 4V thermostat opening temp is 183° to 190°, while the 2V is 192° to 199°.

I guess an 8° difference probably doesn't add a lot of power, but I can't see it hurting the longevity of the motor THAT much, either...

[metroplex]

Generally speaking the t-stats start to open at 3-5* above the rated temperature. All of my motorcraft 180F tstats start opening at 183-185F (verified using a hot water bath and thermometer in a chem lab). They're fully open at about 20F above the rated temperature (200F).

My 2000 Crown Vic came with a 192F t-stat from the factory. It starts to open at 195F and is fully open at 212F. That does not mean water is boiling at this point due to a max of 15-16 psi for the cooling system. Under pressure, water does not boil at 212F, in addition, the solute (ethylene glycol based anti-freeze) raises the boiling point further.

The first thing I noticed switching BACK to a 192F t-stat (from the Motorcraft 180) on the Crown Vic was the engine runs much hotter and the exhaust also runs hotter. The cats should be running more efficiently now but the rotten egg smell also rears its head. The 2003 E-250 with 20k miles does the same exact thing. I'm not surprised if running too hot is exactly what causes factory cats to fail so prematurely.

Running a 180F t-stat will not cause your engine to fail early and in fact, if anything, will allow it to run longer. The Ford Lightning uses a 180F tstat from the factory (5.4L SOHC V8). If Ford was concerned about the engine falling apart within 3 years / 36k, they'd be slapping hotter t-stats right away.

[Smokie]

Barry in a word, NO. A thermostat should work properly far more than 2 years.

When I changed my OEM 188 degree rated thermostat for the 180 degree rated aftermarket thermostat, I kept my OEM thermostat.

If I should have the misfortune of having the 180 stat fail, I probably will reinstall the OEM one I kept.

My temperature gauge is not capable of measuring the difference between 188 and 180, my temp. needle rest in the exact same spot as it did the day I bought the car.

[metroplex]

Thermostats should last a fairly long time, but the spring starts to wear out eventually.

[FordNut]

I went with a 170....

[SergntMac]

My thermostat has failed. I'm looking for opinions on life spans. I put mine in 27k miles back. Is that good? I never consider a "life span" for t/stats, but I change mine every 20K anyway.

The rationale for the 180 stat is that it works in conjunction with colder spark plugs, and is to cool the combustion process just a bit. This allows better tweaking of the SCT tune, and helps control detonation. I've had SCT tunes with, and without the T/stat and Denso IT 20 pulgs installed, and there can be a difference, when the tuner knows what he's doing.

When we first started tweaking the MM, it was by chip only, and initial tunes were imported from the MarK VIII. As MMs moved around the country into tuner's hands, the tunes became more refined and tailored to the MM specifically. Many of you are driving on tunes tweaked on my N/A Marauder by JW, and much of the tranny tuning has been refined on Zack's and my supercharged MM. The SCT files for a supercharged Marauder originated on my KB-1x over the summer of 2002, and this is where the rationale originated.

You do not have to add T/stat and colder plugs, it's merely an option in tuning that works.

[Marauderjack]

Well Mac.....

What's your take on reduced engine life running a colder (180*) thermostat??

I don't see it with only 8* difference but I've been wrong before!!

Marauderjack

[CRUZTAKER]

Thanks to all.;)

I run that 180 stat from day one back when most of us got our tunes from Dennis. Remember the Diablo days.....
Apparently my tune took advantage of it.

That tune is long since gone and Lidio does my tuning exclusively now via SCT software.

The Dealer is replacing it under extended warranty. The dealer also added that IF...I say IF, the is a FORD MOTORSPORT part number for a 180 stat, they will gladly order that rather than the OEM 188 stat.

And yes, OEM is 188.

I wonder if it really matters anymore?

[Petrograde]

I've been running mine for the last 25K miles,... no problems yet,... yet. :P

[DEFYANT]

*snip* reduced engine life running a colder (180*) thermostat??

I am no certified machanic. I know the basics. I have been around trained machanics and read the magazines in the Mustang and 4x4 circles since 1990. I have never heard such a claim as stated above.

Just my .02 FWIW :o

[TripleTransAm]

I am no certified machanic. I know the basics. I have been around trained machanics and read the magazines in the Mustang and 4x4 circles since 1990. I have never heard such a claim as stated above.

Just my .02 FWIW :o


I've heard similar claims but mostly when comparing T-stats in the 195F range with those in the 160F range... but between 188F and 180F, I wonder if 8 degrees would make such a difference? Anyway, in the case of 160F, the claims were along the lines of increased engine wear due to the engine operating with tolerances outside the intended operating range, since things expand when heated. Also in the case of 160F, the engine might actually drop out of closed-loop operation now and again, or otherwise run richer than it would need to because the PCM is probably programmed to do so when the engine is still considered 'cold'.

And yes, I tend to agree that this particular T-stat we're discussing failed kind of early. I'm used to getting at least 60000 miles out of my T-stats (the original one in my WS6 is still working fine at 56000 miles, so far). How did it fail? Did it get gunked up or just quit t-stat'ing?

[CRUZTAKER]

Did it get gunked up or just quit t-stat'ing?

Gunk?

Gunk in my Marauder?

Why I outta...:fishslap:

Thanks Man.;)

[TripleTransAm]

Gunk?

Gunk in my Marauder?

Why I outta...:fishslap:

Thanks Man.;)


You'd be surprised... while it never happened to me (yet... shhh, my car might hear...) all it takes is mixing coolant types by mistake and voilà, sludge in the coolant system. I know of one guy who's had to have his coolant system flushed once a year or he no longer gets heat. All because of ONE incident of mixing.

And even in the cases of not mixing, some of the recent revolutionary long-life coolants have been abandoned after long-term results were less than satisfactory.