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180 degree thermostat – Is it worth it?

Home Forums Stay Dirty Lounge Engine Modifications 180 degree thermostat – Is it worth it?

This topic contains 10 replies, has 7 voices, and was last updated by Mike Garcia Mike Garcia 3 months, 1 week ago.

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    Topic
  • #542792
    Rob Hriczko
    Rob Hriczko
    Participant

    I have an 04 Dodge Ram with the 5.7L Hemi. Im interested in swapping out the thermostat to a 180 degree but Ive heard mixed opinions. Some say that, and this was the impression I was under, swapping would be counter productive. The engine would try to compensate and bring the engine up to temp by increasing the fuel ratio and making it run rich. This would obviously decrease fuel economy and performance. On the other hand some say its good for the engine and increases their performance.

    Can anyone point me in the right direction?

    Thanks,
    Rob

Viewing 10 replies - 1 through 10 (of 10 total)
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  • #542824
    Bill
    Bill
    Participant

    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.

    #542850
    Rob Hriczko
    Rob Hriczko
    Participant

    Thats what I always have thought as well and mainly why I haven’t installed a 180 degree thermostat. Just for the sake of discussion though, others have made the point that cooler temps would be better for the engine, fluids, internal and external parts, performance, etc. They said the only reason manufacturers run the engine at the temp they do is to meet EPA standards.

    Ive always been an advocate of leaving it alone as well but these are good points. Im hoping someone can shed some light here.

    #549504
    Nick Warner
    Nick Warner
    Participant

    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.

    #550408
    dan
    dan
    Moderator

    [quote=”nickwarner” post=75260]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.[/quote]

    my thoughts exactly, additionally at lower temperatures parts clearances are greater, most engines are designed too run a temp from 190-220 degrees beacuse as engines get warmed up the parts like the pistons, main bearings, rod bearings, lifters (if your cars engine is OHV) cam, all the metal parts warm up and expand, the oil reaches a higher temp and flows a certian way, you decrease the temperature which your engine runs, this effects all of this including air fuel ratio… the cooler the engine the richer the mix, this fouls plugs screws up cats… people talk so highly about low temp stats 160-180 personally i think not so highly about them, ill stick too the stock temp stat.

    #554759
    Michele Pensotti
    Michele Pensotti
    Participant

    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

    #555889
    dan
    dan
    Moderator

    personally i think air conditioning if that is what you mean buy A/C should have no effect on what thermostat you use, beacuse the A/C system and cooling system are not nessisarily directly linked, though the A/C system can effect the cooling system… that is beacuse the Condensor is right in front of the radiator… and if the Condenser is clogged with debris so air cant flow through… then when you turn on your AC it will get hot and as a result heat up your radiator too, causing coolant temps to go UP!

    otherwise the only thing a A/C system will do is put more load on the engine when in operation, i think you should be fine with specifications of that temperature as most engines run at that temp!

    #558149
    dan
    dan
    Moderator

    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…

    #560059
    Tyler Killgore
    Tyler Killgore
    Participant

    I know this thread is old, but I’ll throw my 2 cents in on it anyhow. I threw a 170-ish degree t-stat on a 90 pontiac, and it did not like it. It threw codes left and right, was unhappy constantly and just ran like crap. I put the factory spec 192, and it was happy. On the other side is my 73 F250. I (being foolish) put quite a bit of advance (both mechanical and vacuum) and it wanted to start pinging. I threw a 160 degree t-stat in there and it now loves it. The 390 is happy constantly, no more hicuups or angry pinging. Also helped fuel economy a bit. Just depends on the application

    #560398
    dan
    dan
    Moderator

    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…

    #963137
    Mike Garcia
    Mike Garcia
    Participant

    Yeah right. I see dumb engineers on a yearly basis. Disregard this guy and look at all the recalls that are posted every year from crappy Engineers! Engineers back in the day did math on paper, now a days it’s done on the computers and them engineers can’t find the whole in their Ass without them.If they don’t check their work then the computer can only do so much. Always question the modern Engineer

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