Proactive Thermostat Change?

[tjkeno]

98 Chevy Malibu, 3.1 V-6

My apartment complex has very restrictive rules, and only allows quick checks of oil, coolant and other fluid levels,
and even tire pressures -- preferably not all at the same time. The only thing that can be added in the parking lot
is windshield washer fluid. This is spelled out very specifically in the lease.

Got a good deal on the car from a friend last November, but his maintenance was somewhat "irregular." The stat
has prolly been in for at least 7 or 8 years now -- it could possibly even be the original. Since I've had it, the coolant
has always stayed right on the mark with no top offs, the temp gauge has never gone above the halfway mark,
and the warmup time and the heater output was outstanding last winter.

I could drain enough coolant to get at and change the stat at a friend's house now, but I couldn't do that here even in
an emergency. With no access to even an unheated garage, I'd like to prevent a $150+ repair-shop bill come January.

So my questions are:

1. Should I change the stat this fall, even though there hasn't been any indication of a problem?

I'm also gonna get a coolant flush and fill soon. If you do think that replacing the stat is a reasonable precaution:

2. Should I replace the stat before or after the F&F? Do you get a better flush if the stat has been removed first?
.... If I do it after the flush, I'd lose some new coolant and have to replace it, but I can live with that.

And finally, considering the age and the way the current stat is performing:

3. Don't fix it if it ain't broke? How would you rate the risk of leaving the current stat in, and just getting the F&F?

Thoughts? Ideas? Suggestions?

Thanks

 

[eljefino]

My 2000 century 3100 the stat was fairly annoying to change. Not sure if yours is too. Of all the parts on a 14 year old car that could fail, IDK why you picked this one to change prematurely.

 

[Kruse]

The thermostat in that car is a little harder to change than your average car. It will have an exhaust crossover pipe in the way. While not impossible to change, there's no way you should try it in apartment complex parking lot. If you have absolutely no place to work on it, you just might leave it in. When you do find a place, I'd buy the thermostat from the dealer. There's now way I'd put a cheap, aftermarket thermostat in that application.
Slightly changing the subject, but I'd be more worried about the intake manifold gasket.

 

[tjkeno]

Originally Posted By: eljefino
My 2000 century 3100 the stat was fairly annoying to change. Not sure if yours is too. Of all the parts on a 14 year old car that could fail, IDK why you picked this one to change prematurely.


Thanks. I'm just guessing here -- you chose door #3.

It's at least 7 years old, and could possibly even be the 14-year-old original.

I can get a socket or a wrench on the bolts without having to remove the air filter housing.

If it were to happen right here in the parking lot tomorrow, I couldn't do the work on the premises.

If it were to fail in the winter and was still drivable, I don't have access to even an unheated garage.

It's warm now, and I can have a beer while doing it at my friend's place.

After Oct 15 here, all bets are off.

I'd like to try to prevent a $150+ repair-shop bill come January, possibly plus a tow with my luck.

A new stat is $8.39 and hopefully will take less than an hour. Or longer -- see beer reference above.

 

[demarpaint]

Changing it IMO is a good idea, as is checking belts hoses and other maint items related to the cooling system. If you do decide to change it spend the extra cash and get an OEM thermostat. I found over the years that some aftermarket thermostats were hit or miss at best. Opinions vary, I had the best luck buying my Ford thermostats from the dealer. JMO

 

[oilmaven]

I just changed out the original thermostat in my 1999 Mercury Villager. There wasn't any problem but I had the system flushed and decided to replace it as a preventative measure (how long can these last?). The local radiator shop that did the flush recommended an OEM thermostat...which cost almost five times what an aftermarket cost. The guy at the shop said that OEM thermostats would be more consistent and provide less variation before "responding" (which can cause the temp gauge to move during operation with an aftermarket thermostat). I wasn't sure whether he was feeding me a line of bull but went ahead and got the OEM unit. All is well after the replacement and I notice that the engine warms up quicker with the new 'stat.

 

[Turk]

Move.

 

[tnt31]

For your peace of mind I would do the T-Stat change. I would also just do a few drain and fills (with distilled water) then drain and add the fluid of your choice instead of paying a shop to do a flush and fill with unknown fluid. Check your hoses and belts while in there.

 

[edwardh1]

my moms 98 buick v6 has a very very slow warm up.
oem stats may have an air bleed hole in them, with a wiggle piece to keep it clear that the aftermarket ones do not have

 

[tjkeno]

Originally Posted By: Kruse

The thermostat in that car is a little harder to change than your average car. It will have an exhaust crossover pipe in the way. While not impossible to change, there's no way you should try it in apartment complex parking lot. If you have absolutely no place to work on it, you just might leave it in. When you do find a place, I'd buy the thermostat from the dealer. There's now way I'd put a cheap, aftermarket thermostat in that application.
Slightly changing the subject, but I'd be more worried about the intake manifold gasket.


Thanks for replying Kruse.

1. I can get a swivel socket on one bolt, and a C-wrench on the other. Looks like without removing the air filter housing.

2. My lease terms expressly prohibit working on cars in the parking lot.

3. Leaving it in is certainly an option, but I can do the work at a friend's place right after Labor Day.

4. Already have a Stant, stamped made in USA, which I will hot-water test before installing.

5. Car has, and has always had Dex-Cool. Either no gasket leaks on this one, or it has been replaced by a previous owner.

My main concern -- how risky is it to leave a 7- to 14-year-old stat in a car that has not been maintained all that well?

It seems to me that a stat must almost constantly open and close, at least partially, in response to driving conditions.

You run it for an hour, shut it down for 20 minutes, then run it for 10 minutes and shut it down for two hours.

So there are mechanical as well as thermal stresses, which must have at least some negative effect on the life expectancy.

I'm just try trying to weigh risk vs. (potential) repair expense. My cost and my time to replace the stat are minimal.

By Jove! I guess I just convinced myself to do it!

Now I just hope someone responds to the part about the stat being in or out for the flush and fill.

Edit. After reading the replies about OEM stats, I will gladly take that advice and return the Stant. Thank you all.

 

[The_Eric]

Originally Posted By: tjkeno


Now I just hope someone responds to the part about the stat being in or out for the flush and fill.

Edit. After reading the replies about OEM stats, I will gladly take that advice and return the Stant. Thank you all.


I say "Why not"? You're already there, so go for it. I also recommend that you take the time and separately flush the heater core too.

You've made a good choice on using an OE stat, as I agree with the others. I too have had better experiences with an OE.

Last thing is to take your time and bleed the cooling system. It's not real hard, but can be a bit tricky. It's very important you get it completely bled out. Once you've got enough air bled so that the stat opens, let it run for a while, then top off the coolant. Take it out and drive the car at higher RPM and load for a couple miles. Come back, let it cool off, then top the radiator off again as needed.

Also, a properly working radiator cap is a must on these cars, so do yourself a favor and pick one up while you're getting your thermostat.

 

[eljefino]

If you're going to do it I'm not going to stop you.

My century 3100's old stat always ran at 35% on the gauge. The new one was 50%.

The discussion of preemptive stat replacement has come up before here. There is never a consensus raised, except for avoiding cheap nasty parts.

My y2k 3100 needed an open end wrench and a prayer to get started on the bottom bolt. A stubby is also a good idea. Make sure you seat the o-ring gasket thingy right without pinching it or you'll get a leak: at least the bolts will come out easily the 2nd time, LOL.

 

[Chris142]

you do not have to remove the exhaust to get the housing out. the lower hole is slotted. stil a pain to change

 

[JHZR2]

If there is no indication of an issue (car too hot, too cold, too slow to get to temp, etc), Id leave it.

Any stat that gets changed should be first tested with a pot of water and thermometer on the stove.

 

[mechtech2]

Originally Posted By: eljefino
My 2000 century 3100 the stat was fairly annoying to change. Not sure if yours is too. Of all the parts on a 14 year old car that could fail, IDK why you picked this one to change prematurely.


Eljefino is right again.

 

[Kestas]

I never change thermostats unless I have a problem, which is rarely. And I drive high mileage cars.

Oilbabe's Volvo S40, on the other hand, needs a new thermostat every 50K.
It fails in the open position... a code is set by the computer... I replace the thermostat... problem goes away.

 

[bradepb]

Originally Posted By: mechtech2
Originally Posted By: eljefino
My 2000 century 3100 the stat was fairly annoying to change. Not sure if yours is too. Of all the parts on a 14 year old car that could fail, IDK why you picked this one to change prematurely.

Eljefino is right again.

Ditto, of all the things on a 98 that can fail just save your time and money till you need something,maybe drain and fill the coolant would be good though.

 

[zzyzzx]

I would not change out a perfectly good, working thermostat.

 

[TFB1]

Originally Posted By: zzyzzx
I would not change out a perfectly good, working thermostat.


Same here, don't really trust the aftermarket's... Can't remember last time I changed one that had failed...

To flush I remove a heater hose and probably the top radiator hose, never touch the stat...

 

[Virtuoso]

I used to change them as a precaution, but not anymore. Almost all the aftermarket (even OEM branded like Motorcraft) thermostat's have failed in amazing short order after installation.

Don't fix what ain't broke. It's not a piece that will leave you stranded.