180 degree thermostat – Is it worth it?

Everything under the hood of that truck was designed to run at 195 F and not 160 F I don’t think that there are many of us here who’s smarter than a team of engineers.

Your PCM uses a logic system that enriches the mixture at lower coolant temps to aid in starting and warm-up driveability. It lengthens the injector on-time and basically acts like the chokes on a carb vehicle only better. If you put a lower temp thermostat into this not only will you set a code, if you continue to drive it like that where it cannot reach the operating temp it is engineered to reach you will constantly run rich. All that fuel isn’t getting burned and isn’t making you more power. What it is doing is going into your cats, which are extremely expensive, where it creates a fire inside the substrate and wrecks them. So you’d end up needing a grand or two in new cats, possibly new upstream O2 sensors as they can get damaged as well from this, and a stock temp thermostat to keep this from happening again. If pieces of the broken substrate migrate down the pipe a bit further, you could also have to replace the muffler that would be clogged up with broken catalyst.

Lower temp thermostats was an old trick on carbed cars that were souped up to reduce detonation if you used a most aggressive timing advance on your car. It is no longer applicable to todays vehicles and will actually harm them. But some of the old ideas that are now myths are still out there, for instance;

“If a battery is on concrete it will go dead.”

Not the case anymore. The reason this happened way back in the day was that early batteries were wooden cases with glass cells. Most people had a garage that was poorly vented and more of a shed than anything, and every morning dew would condense all over your battery. If it was on concrete, this would allow a small parasitic draw of just enough milliamps to kill a small 6-volt car or tractor battery. Putting the battery on something non-conductive like a block of wood stopped this, and thats where we get the myth from.

“If you take a battery cable off while a car is running it will test the alternator”

Do not ever do this to anything computer controlled. Maybe you have before and got away with it, but next time you might be in for a very expensive lesson. Before alternators, we had generators, which would put out a given amount of power based on the RPM they were run at. Cars didn’t have a lot of electrical needs then, and it was a way to see if your generator was still charging the battery. But now that it isn’t 1948 anymore we have alternators, which utilize a regulator to energize their field coil to control power generation as needed for our solid-state electronics and sensitive little circuit boards. If you unhook a battery cable on a running engine with an alternator, you will create an inductive spike generated from the collapse of the magnetic field in the field coil of the alternator. This inductive spike cannot go through the battery which acts as a capacitor to cushion the blow because you unhooked it, so it backfeeds into whatever path it can find. Seen a few PCM’s get smoked this way. The only way to test an alternator anymore is to have it measured for amperage output when the field coils are fully energized momentarily (referred to as “full-fielding).

Unfortunately so many of the old ways of doing things and outdated ideas of what can make a car better are still out there. You have to sift through it a bit to get to the facts of the matter. I’m glad you asked the question first before going ahead and installing the part. I’d hate for you to have that kind of expensive repairs over an eight dollar thermostat.

This topic is quite interesting, thanks! :cheer:

I kinda have this problem too, but on a completely different car, my 1990 Citroen BX 1.6

Some months ago I completely changed the coolant and cleaned the circuit as well since it was a completely “new” 23 years old car for me and wanted it as clean as possible.
I didn’t replace the thermostat for only one reason, and that is I didn’t know which thermostat was right to put in it.
Of course I checked citroen’s technical docs, and haynes too, but the first mentioned both thermostats (the 83C and the 88C one, about the same as 180F vs 195F), and the second only mentions 83C thermostats, but none of the two takes into consideration the A/C which is installed on my car.
It is a stock A/C, but it was a so rare accessory that it is almost never mentioned in technical information.

However, in a local forum of old citroen enthusiasts, a guy had a very similar problem with his 1.8 xantia , and found out that on that model, all of the A/C cars need the lower temp thermostat.

And this started me to wonder about having the same requirement even on my BX.

By the way, the xantia is a 1994 and has electronic fuel injection, whereas my BX still has ha nice carb 🙂 on it.

So, which thermostat do you think I should put in my BX?

Thank you in advance for any feedback 🙂

Live long and prosper (and stay dirty!)

10nico

i hope o do not bother you guys buy adding something too this thread.

people who have the supercharged version of my car and heavily modify it seem too love the 180 degree thermostat, and i think there is a reason for that… when people modify my version of the car with the L-67 or L-32 series two and three supercharged engines they like too do all sorts of things, bottom end swaps with the l-36 and L-26 bottom ends (note the L-26s powdered connecting rods are thinner and tend too be weaker so quite frequently reanforced connecting rods are also added.)the pistons in the N/A engines are not bowled as deep which means higher compression, so a bottom end swap gives you more punch… smaller supercharger pullies are very common making the supercharger spin faster increasing boost, or better yet they bin the supercharger and toss in a turbo! maybe even combocharge the system i have never heard of that but that would apply here especially, these two modifications do one thing, increase compression pressure…

when you increase compression pressure you increase the chances of spark knock, and when the engine reaches operational temperatures of 190-220 degrees that is what typically results, you have several choices now, increase your octane of fuel or run richer, or lower operational temperatures of the engine too keep the engine cooler so combustion temperatures stay down a little more, can you guess which one people are going too pick, you guessed it 160-180 degree thermostats… no one is going too want too pay out the back side for race gas, and in the end with high performance engines any way you can get more compression, more boost into the engine the better! running richer, running colder… but a lot of times i have noticed with the 3800 engine community they do it too allow the higher boost and compression without needing race juice…

as for me i am not running boost and stock compression, right now as i type this my mods are very limited too Hipo plug wires and a cold air intake, and so for me the 190-220 degree operational temperatures specified is what i will stay with! in fact i have noticed when i changed my T stat beacuse it was not working right when the engine warms up too those operational temps i feel like it runs better anyway…

the reason why this helped in your case is because you can adjust the ignition timing buy advancing or retarding it, buy reducing the temperature of the engine you can reduce the temperature inside of the combustion chambers, just like when people put 180 degree T stat too allow higher levels of boost without pinging you can advance ignition timing more without pinging as much this means the air fuel mixture combustion expansion can press down on the piston earlier…