WhiteTrash87

I have been told that eliminating your t-stat will allow your engine to run cooler. It aint good for mud boggin and racing, but for a dd and weekend trail riding it will be fine and run cooler. I was wondering what everyone would have to say about this, I know there will be those who think it is a bad idea and those who will be out trying it on theirs!! Let me know what yall think!!

OverlandZJ

Eventually a rig without a thermostat will run at the same temp as one that has one in proper working order.

Just takes a few minutes longer to heat up and the thermostat wont be opening and closing.

Destro

Um, well if the thermostat didn't have a purpose, why did they put one in there?

Allows the engine to reach operating temps quicker and allows the regulation of engine temp. Want a cooler engine temp? Put in a lower rated thermostat.

OverlandZJ

A lower rated thermostat wont make an engine run cooler, just comes to the fully open position sooner than a higher rated thermo.

ol"blue

Bad idea. Running without a t-stat doesn't allow the coolant to remain in the engine long enough to draw excess heat away because it flows right through. While the t-stat is closed the coolant in the rad is being cooled down, and the coolant in the block is drawing heat from the engine. At the designed temp the t-stat opens allowing hot coolant to flow out until it cools sufficiently to close the t-stat, repeating the process over and over again.
Without the t-stat there's nothing to hold the coolant in the rad long enough for it to be cooled. It doesn't happen instantly. OK I'm done.

mike37

it only helps get the motor up to the proper operating temp
if you don't have one you may run to cold and the motor wont run properly

and on some systems can cause over heating from coolant passing to fast threw the system

5-90

Correct.

This is why race engines run restrictor plates if they don't run thermostats. The heat acceptance and heat rejection of the coolant follows a fixed rate (simple thermodynamics,) and if it's flowing too fast, it won't have enough time to accept heat from the engine or reject heat in the radiator.

If you decide to eliminate the thermostat, you'll need some way to restrict coolant flow - I've actually seen engines end up running hotter without a thermostat (for the reasons stated. That's how - and why - I found out about all of this.)

It's very rare that an engine runs happily without a thermostat - it something like 200-250 vehicles I've personally dealt with more than once, I've seen three. So, less than 1.5% - and I'd be willing to bet the actual statistic would be much lower (and this wasn't a decision made lightly - in all three cases, I'd ended up doing a total overhaul of the cooling system, including tearing the IP to bits and replacing the heater core! - before deciding that running with a thermostat was the culprit.)

BuckB91XJ

Running without a T-stat is just a bad idea all the way around. Could cause you to run too cold. Could cause you to overheat. Running too cold with a 4.0 will hurt your MPG. Jeep 4.0 run right at the brink of overheating when they are running right so, any modification to the cooling system is just asking for trouble. IMHO.

WhiteTrash87

wow, well here is my situation. I have replaced water pump,t-stat (180), and am still running hot and not getting good circulation. I pulled the t-stat out and now runs around 200. I also know of a guy that doesn't run one at all and has done so for years. No problems, and he has the 4.0L. So should I run a t-stat and just have the engine running hot all the time?? Heck of a boat I am in, aint it!! lol

BuckB91XJ

Hey, one thing I've learned is that no 2 Jeeps or 4.0 liters for that matter, run the same. If pulling the T-stat and running without it works good for you, Bro. I say go for it. How hot it is in the outside air in your loacal area plays a lot into this, too. So, what works for you and what works for me could be two totally different set ups.

98 JeepJeep

then you have other issues and taking the T-stat out is just a bandaid...and if your going off your stock guage/sender your guesing anyway.

Jesse James

X2.. who knows... maybe ur temp sensor is readin wrong.. I dont recommend runnin without the t-stat... sure its been done... but as someone else said... if you didnt need it then why'd they put it in?

Just my $.02

jd4x426

if your still running hot after all that try getting 2 row radiator much better of an idea in my opinion

WhiteTrash87

ok for the record, manufacturers put stuff on our vehicle and not all of it has to be on there. Sure they put it in , but doesn't mean you need it. As far as figureing out other issues, I am open to suggestions. Replacing the radiator with a 2 row, I don't have the funds. I did replace the radiator with a newer one that doesn't leak. I have removed the a/c system and condensor. So better airflow in. The lower t-stat didn't help. I have removed it and drove all evening and it ran between 200-210. Ran fine, no bubbling over of coolant, or running hot. So if any other suggestions, trust me, I am open for them!!

OverlandZJ

Were discussing an integral part of the cooling system, not a cig lighter.