HOW TO CHECK FOR BAD THERMOSTAT

[@smartdummy5751]

If upper radiator hose is hot, your thermostat is at the lower radiator hose and since thermostat is fully shut or not open enough, coolant can't flow to the radiator to cool down and supply the engine with fresh coolant via the upper radiator hose. If your lower radiator hose is hot and your upper is cold than you have a thermostat at the upper radiator hose and coolant flows from your bottom radiator hose to top radiator hose. hot upper = coolant flow bottom to top. hot lower = coolant flow top to bottom. Also sometimes the thermostat stays fully open or more than needed. This affects your engine's thermodynamics and power management among other things. It's better than a stuck closed thermostat but you should still correct a stuck open thermostat ASAP. In This case, both your hoses will be relatively cold even after driving for sometime or one hose will be colder than normal.

[@WorkingwithBobby]

This is knowledge that will save a lot of people a headache! Thanks for sharing!✊🏾✊🏾

[@mack606]

Man thank you now I know I bought a bullshit defect thermostat and I appreciate you getting straight to business my brother

[@WorkingwithBobby]

Yes sir! I'm glad I helped you in some way! Good job getting it done.✊🏾✊🏾

[@Raul-ys5vm]

Firestone told me I needed a new radiator..Gotta second opinion, discovered it was my thermostat! 👍

[@NaliHawraz-n5y]

I have corolla the upper hose is getting hot but the bottom one which is connected to the thermostat is cold. Do you think it is stuck closed or what thank you

[@WorkingwithBobby]

It could be. Hot coolant will only flow through it if the thermostat is open.

[@StationRussification]

Beware some vehicles have the t/stats @ the bottom hoses connection & they R installed backwards.

[@WorkingwithBobby]

Yes sir, I've experienced that before and it's not fun when you gotta tear it back down to correct your mistake.

[@poker345611]

I just replaced the thermostat in my 2011 ford escape 2.5 l because it was taking a long time to warm up in 40°f weather. The thermostat is connected to the bottom radiator hose and the bottom hose is cool and the top is hot. I figure that i have to wait for warmer weather to see if the engine temp goes above normal operating temp. I don't really want to remove it and test it in boiling water.

[@WorkingwithBobby]

@poker345611 it's tough to get the engine up to operating temperature in colder weather. I normally force it by holding the engine to 2500 or 3000 rpm for a period of time while monitoring coolant level and temp. That sometimes forces the thermostat to open even when it's cold out.

[@orboakin8074]

God bless you for this sir. i am fixing up my first car, Pontiac g3 2010, and the fan ia not working and i think the thermostat is to blame. Respect from Nigeria.

[@WorkingwithBobby]

@orboakin8074 blessings to you and your family as well. That's great! Don't give up and keep wrenching on it. Normally, the thermostat not working properly would either have your car overheating(stuck closed) or running too cool(stuck open). You may have 2 separate issues causing a similar symptom. You should have a coolant temp sensor somewhere on the engine that relays coolant temperature to the ECM. Then the ECM will ground the cooling fan relay to operate the electric fans on high or low speed setting. I hope this helps.✊🏾✊🏾

[@grose350Zed]

@@WorkingwithBobbyjust replaced my coolant temp sensor. my temp still keeps rising and fans won't kick on both upper and lower hoses are hot, my obd reader said it was a thermostat but another reader that was more advance then mine said it was the sensor, i don't want to go and buy a thermostat and that not be the problem and thoughts, ive already checked the relays

[@WorkingwithBobby]

@gavinrose5662 you seem to be losing signal somewhere. The ecu has preset parameters programmed into it to tell components what to do based on the inputs it gets from the sensors. You need to check the fan relay control side of the electric fans circuit. You could have a driver circuit issue, and ecu ground internal circuit failure or simply a bad fan control relay.

[@erickbonilla4023]

My cAr water pump 😢work for a few minutes after that Air is star blowing out from the coolant top and thermostat alway hit up

[@ivand5527]

Is that a Nissan Sentra? Looks like the same motor I had, was 1.6L

[@WorkingwithBobby]

Yes and it is and I think it did have the 1.6 in it. It has that stupidly expensive valve cover I had to put on it.

[@brooklyn7941]

I have a 04 Honda accord ex 2.4 the top hose gets warm the bottom is cool room temperature that's the thermostat ?

[@WorkingwithBobby]

Maybe, check for coolant leaks, air trapped in coolant system, etc. If all of these are OK, the thermostat could stick open causing the engine to take an extremely long time to reach operating temperature.

[@brooklyn7941]

@@WorkingwithBobbyok so I figured out the problem , it's the radiator Becuase when I went to go top it off it's leaking out the sides on the top part of the radiator

[@WorkingwithBobby]

@@brooklyn7941 good job! Those radiator tanks can be a major leak point sometimes.

[@brooklyn7941]

@@WorkingwithBobby yeah the aluminum teeth where it meets the plastic part it's leaking out

[@WorkingwithBobby]

@brooklyn7941 it seems like Honda and Nissan cars will have you replacing the radiator as least once!

[@Dude_Ness]

seems accurate, can confirm this is true,

[@WorkingwithBobby]

It has not.ally worked for me unless I had a blockage in the radiator.

[@Dude_Ness]

@@WorkingwithBobby it could totally be that too, that makes perfect sense

[@Dude_Ness]

@@WorkingwithBobby is your coolant the right color, consistency and smell?

[@WorkingwithBobby]

@dudeness6848 I can't say that I have smelled coolant to confirm it's right. I normally just drain, repair and add the required coolant and water mix for whatever I'm working on.

[@jaredreck882]

Thanks for sharing

[@WorkingwithBobby]

No problem, I hope it helped you.✊🏾✊🏾

[@buzzsawanthony544]

Thanks i was just trying to figure out if my thermostat was bad..

[@jasonpollock1731]

Thank you.

[@WorkingwithBobby]

No problem! I'm glad I could help.✊🏾✊🏾

[@robl.1053]

Cheap enough part better to change it but sometimes it is a pain in the butt to remove

[@WorkingwithBobby]

Yeah man, the only benefit to it for me is I've done a few before when I worked at the dealership. I'd rather replace it than the engine after it's cooked.

[@bestmandodad3850]

Stuck open?

[@WorkingwithBobby]

If it is stuck open, normal engine operating temperature will be almost impossible to reach. It would be flowing coolant through the radiator all the time which will make it tough to warm up properly. Hope this helps.✊🏾✊🏾

[@malkitsinghsekhon4958]

When it will not flow from reservoir tank ?

[@dannyc5389]

heres what you do: start car, place hand on hose that has thermostat running to the rad, if after about 10 minutes hose suddenly turns from cold to hot instantly then the thermostat is good. If the hose heats up just gradually then thermostat is stuck open. If the hose never heats up then thermostat is stuck closed.

[@WorkingwithBobby]

@@dannyc5389 I couldn't have said it better. Thanks for sharing your wisdom.✊🏾✊🏾

[@weirdgamerincxpected2882]

Never had to check it that way. If temp isnt normal its time to go start checking things. When theres only been coolant in it theres slim to no chance of blockage anywhere. So it'll obviously be the themostat they do get worn out

[@WorkingwithBobby]

What way do you check it? If you don't mind me asking, I am all ears to different ways and methods to diagnosing and repair. . .

[@georgerivera9220]

I use as pyrometer to check.

[@WorkingwithBobby]

I'm lazy dude. Either I feel the hoses or use an infra-red thermometer.

[@Dilloz12]

Your just trying to rip the customer off for kfc money

[@WorkingwithBobby]

That wouldn't be too smart since I AM the customer. 😆😆