Syptoms of a bad thermostat?

[my dreamt dsm]

Am I missing something or over read it. but I'm guessing the thermostat is changed along with the water pump and so on.
http://www.dsmtuners.com/forums/frequently-answered-dsm-questions/239375-maintenance-schedule.html
If thermostat ever kicked your butt
Purpose of this thread is I'm trying to figure out if it's my thermostat.
When my car is cold say 70 degree mornings it is very sluggish. The car can barely pick up. Another issue is the fan is not turning on so I have to turn it on manually via fan knob.
I have suffer mileage issue (1/4 tank= @50 miles. Over a 3 months observation). Car does not pick up even when the car is warm. Example entering free way. Another symptom is when I turn on the ac or fan. The car drastically looses power. I understand a sight loss is normal but this is major loss. You can feel the big difference.
Feels like I have a major boost leak but I already check and no leaks anywhere. Log and everything seems fine? Is if the tstat or some sensor else where. No check engine light btw. Clueless!
Zero boost leaks, timing marks and logs are fine, tires are fine.
I'm getting my car ready for the 16g build but at this point it's pointless.
http://www.dsmtuners.com/forums/bolt-tech/412893-colder-thermostat-vs-gas-mileage.html
http://www.dsmtuners.com/forums/tuning-engine-management/395179-cooler-thermostat-opinions.html

 

[bryanwheat]

What do your temps look like when the car is warmed up? I'd assume something other than the thermostat causing your issue. How many psi did you leak test it to, and how long did it hold?

 

[my dreamt dsm]

What do your temps look like when the car is warmed up? I'd assume something other than the thermostat causing your issue. How many psi did you leak test it to, and how long did it hold?

Warmed up about 5 miles freeway driving. It'll hoover around the 186-192 degree mark. Boost tested to 17 psi and holds for bout 20-40 secs.
Weird thing is I thought it was boost leak, thought it was slipping clutch, bought new rad cap, flush all coolant, new plugs and wires- all this year and same thing. Last thing I remember was and notice- I can't remember the last time my fans came on themselves. Then I realize that's when my problems starting popping up.
My car use to pull like a champ. Now it's plague and only doing 15 sec a 1/4 with solid 14 sec mods

Oh and when I turn on the fan regardless a/c or not. IT FEELS AS IF I'M APPLYING/ TAPPING THE BRAKE. Yes that bad.

 

[russell3123]

The car is not picking up because youre running way to rich if 50miles=1/4 tank.Id check the front oxygen sensor. Also pull out youre oil dipstick and smell it, if it smells like gas change youre oil.

 

[camsmurdered2g]

The car is not picking up because youre running way to rich if 50miles=1/4 tank.Id check the front oxygen sensor. Also pull out youre oil dipstick and smell it, if it smells like gas change youre oil.

This sounds right and would explain the feeling of massive power loss. If you are running mega rich you won't be creating the same HP/TQ output, therefore any engine drag (lighting,fans,AC,etc) will feel WAY different. Although if you had a bad O2 it should be throwing a code. I am assuming you don't have an A/F ratio gauge?

 

[perks563]

You can check the thermostat real easy. Get your engine up to operating temps (you said it gets up to 186-192). Carefully grab your upper radiator hose and see if it is hot. If it is hot, then the thermostat is open. If it is cold, then the thermostat is closed. (there is a small chance I got those backwards, but I'm 99.9% sure that's correct)

Good luck!

 

[russell3123]

If youre car is not running over 192 at all , then youre thermostat is fine.

 

[Talondvr]

Just throwing it out there: Temp sensors. I'm not real sure bout the 2g's but these can cause problems on the 1g's. The one in the radiator will keep the fan from kicking on and the one in the thermostat housing can even make a car not start.

If its a failsafe T-stat and stuck open it wont warm up for a long time, if at all. I had one of those go out on me in 2 weeks.

 

[chellelouj22]

I don't know really about how to fix cars because my partner does that. I just want to share an experience of mine about the broken thermostat of our ride... The engine of our car just stopped working if I turned on the aircon of the car (I can hardly remember if its the other way around). Anyways, If the thermostat is broken, it might be because the engine can't support it well or there's a short circuit in the wirings of the car.. Hope this will help...

 

[LiquidX]

If you want to test the thermostat, pull it out and put it in a pot of boiling water. If it opens its fine. If it doesn't change its bad.

 

[my dreamt dsm]

The car is not picking up because youre running way to rich if 50miles=1/4 tank.Id check the front oxygen sensor. Also pull out youre oil dipstick and smell it, if it smells like gas change youre oil.

My logs of normal driving and 5rpm shifts actually shows good air/fuel readings. Normal driving around .7 volts and 5krpm shifts around .9volts. I don't do 5krpm shifts btw. I'm a 2.5k rpm shifter. Wide band is on a list of things to do w/ the build.

You can check the thermostat real easy. Get your engine up to operating temps (you said it gets up to 186-192). Carefully grab your upper radiator hose and see if it is hot. If it is hot, then the thermostat is open. If it is cold, then the thermostat is closed. (there is a small chance I got those backwards, but I'm 99.9% sure that's correct)

Good luck!

Thanks for the luck, I'll need it. Yea! Something like that. the thumb of rule is if the bottom one is cold then the stat is not opening. Everything seems fine! Normal op temp and everything.

If youre car is not running over 192 at all , then youre thermostat is fine.

I'm with you on this one!

Just throwing it out there: Temp sensors. I'm not real sure bout the 2g's but these can cause problems on the 1g's. The one in the radiator will keep the fan from kicking on and the one in the thermostat housing can even make a car not start.

If its a failsafe T-stat and stuck open it wont warm up for a long time, if at all. I had one of those go out on me in 2 weeks.

With my search I did come across something like that! My results are kind of contradicting each other. Stock t stats open at 180 I think. If my temps are reaching 192 and the stat is not opening. It mind as well be my stat. But if it does reach stat opening operations, why isn't my fan coming on?

If you want to test the thermostat, pull it out and put it in a pot of boiling water. If it opens its fine. If it doesn't change its bad.

Will see. I won't have time to tear into this 15 min job until sunday. Management position allows no time for a dsm. Until then keep ideas coming.

Thanks Everyone,
-Korrey

 

[Talondvr]

With my search I did come across something like that! My results are kind of contradicting each other. Stock t stats open at 180 I think. If my temps are reaching 192 and the stat is not opening. It mind as well be my stat. But if it does reach stat opening operations, why isn't my fan coming on?

All three of my thermostats have the Temp stamp on them. All three say different temps. Cant recall, 2 are at the garage and 1 is in the car.
The Fan not working could be due to the fan, wiring, or relay. If its on all the time it could be the Temp switch thing by the lower hose (1g anyway). Someone else know different?

 

[oreo4g63]

my. t stat is 170 and car never. gets to more than 190 Evan under boost what does the plugs look like and which ones do u have ?

 

[DSM1G90]

when I turn on the ac or fan. The car drastically looses power.

Welcome to the world of the power robbing AC compressors and 4 cylinder motors. They're not made for each other... You need a big 2.5L 4 cyl or a V6 for the compressor so you won't feel the power loss difference. 1998 - 13 yr old compressor: could be getting tired and they do get sluggish during operation.

Bet, your temp sensor is kaput, t-stat stuck open, radiator fan temp sensor kaput, or coolant level low.

my. t stat is 170

..and that's too cold for your system to run properly... needs 196* since the system's sensors, esp the ECU is manufactured to this factory temp setting, are manufactured to that temperature. Low temp coolant will cause the ECU to fire in more fuel to try to heat up the system to 196*.

 

[dondmon96]

Check your Coolant temp sensor. @32F 5.1-6.5ohms @66F 2.1-2.7ohm @104 0.9-1.3ohm @176 0.26-0.36ohm. If that's bad then the ecu would default the temp and cause it to run like turd, and give ya bad gas milage. The fans still work when you turn them on manually so the relay is most likely good.

If your thermostat is bad, it would either get really really hot, or would take forever to get to operating temp. You should be able to take the coolant cap off and with someone starting the car, watch the water level and if it lowers right off the bat then your thermostat is stuck open. It would overheat if it was stuck shut.

Sounds like the Coolant Temp. Sensor.

 

[my dreamt dsm]

Bet, your temp sensor is kaput, t-stat stuck open, radiator fan temp sensor kaput, or coolant level low.
.

I guess I'll be changing all 3 just to be sure! Will keep ya'll posted when the parts come in!

Check your Coolant temp sensor. @32F 5.1-6.5ohms @66F 2.1-2.7ohm @104 0.9-1.3ohm @176 0.26-0.36ohm. If that's bad then the ecu would default the temp and cause it to run like turd, and give ya bad gas milage. The fans still work when you turn them on manually so the relay is most likely good.

If your thermostat is bad, it would either get really really hot, or would take forever to get to operating temp. You should be able to take the coolant cap off and with someone starting the car, watch the water level and if it lowers right off the bat then your thermostat is stuck open. It would overheat if it was stuck shut.

Sounds like the Coolant Temp. Sensor.

Thanks for clearing that up for me. I wasn't sure if it was the relay also. Since you mention that I guess it still works.
When its cold in the morning around 70 degrees. I let it warm up for 2 minutes and start to drive. I do see the temp start to rise so I guess that's normal.

 

[DSM1G90]

I let it warm up for 2 minutes and start to drive. I do see the temp start to rise so I guess that's normal.

Just jump in and go ... motor heats up quicker under load and you're not wasting gas and diluting and dirtying the oil with that rich fuel mixture with letting it warm up for that 2 minutes.

 

[my dreamt dsm]

Just jump in and go ... motor heats up quicker under load and you're not wasting gas and diluting and dirtying the oil with that rich fuel mixture with letting it warm up for that 2 minutes.

It does heat up faster but remember that my problem is also when the car is to cold. It runs like crap. This problem is in my way at the moment. I can't wait till it's over!

 

[dondmon96]

So have you checked the resistance on the Coolant Temp. Sensor yet?

 

[my dreamt dsm]

I have yet to check the temp yet. I'm broke of that tool, forgot the name of it. I'll be sure to check at the local meet.