Temperature Oddity

[Kiqman]

When I first start my 89 k5 with tbi in the morning the auto choke kicks in and the truck then gradually idles down as it should as it warms. Problem is the temp rises to about 240 on the gauge as I'm driving before it drops back down to 210 where it stays for the most part. During this "start out" time it doesn't want to idle at a light, stutters as you start from a stop, and acts like there's water in the gas. I have flex-a-lite fans but they don't even phase the temp for those first few minutes when the temp is climbing. I'm worried that getting the engine this hot every day, even if just for a few seconds, will ruin my heads or engine, etc. I'm wondering if I should switch my 180 degree thermo to a 160 degree unit? It can't be good for my engine to get that hot before returning to a normal temp!?! After the day's innitial warm-up the engine runs like a top. I should mention my 5.7tbi has HP heads, headers, cam. Spent a lot and I'm worried I'm doing damage daily!

 

[Jagged]

Mine used to run kind of hot, I removed the defunct AC compressor and condenser, and installed a 160* thermostat... even out wheeling all day it doesn't even touch anything close to 200*

 

[RootBreaker]

I'm wondering if I should switch my 180 degree thermo to a 160 degree unit?

Err if your thermo is a 180 and you are puking up at 240... then something is definitely wrong.. (cpt obvious kickin in...)

my jimmy was going high... and turned out to be my radiator gunked up and waterpump bad.... replaced both... also replaced the thermo for safe measures.... now she sits nice and low....

remember one thing... I believe computer controlled vehicles.. need certain temp to run at peak... so going lower temp may not be good or adviseable...

 

[Jagged]

radiator gunked up

heh, forgot about that... had gunk in the radiator, and had to flush the block out, there was a lot of buildup around the knock sensor.

 

[Kiqman]

Temp Continued

Radiator, thermo, hoses, h20 pump all replaced new with engine rebuild 3 years ago. Cooling system works fine after innitial overheat. A local guy here says he thinks I got a bad 180 degree thermo that sticks until 240 - then stays open for the day. Guess I'll try a new 180 thermo first to see if it is in fact "sticking". Any idea how long a vehicle has to be close to the red before you're doing damage? When I start out for the day it's near the red but only for 1-2 minutes - then perfect all day long.

 

[Jagged]

you didn't put that thermostat in upside down did ya?

 

[dyeager535]

Probably a sticking thermostat. Repeatable problem, not consistent during operation pretty much leads away from anything that works the same regardless of time spent "sitting", like the water pump and radiator.

Aren't doing yourself any favors with the 180* stat, but if thats what you like, stick with it.

Delco's are supposed to be fairly good "off the shelf" compared to most anything else off the shelf, short of the Robertshaws that are generally highly recommended as well.

3 years for an aftermarket thermostat can be considered good anymore, when probably 25% anymore seem to be bad before install.

 

[Kiqman]

Upside down

I didn't install it so that's possible. I didn't know you could install a thermo upside down? How do you tell which side is up?

 

[RootBreaker]

you didn't put that thermostat in upside down did ya?

you looking at my truck again??? I did that.... once....

spring part goes down into the engine....

 

[Kiqman]

Aren't doing yourself any favors with the 180* stat, but if thats what you like, stick with it.

Isn't the 180* the stock stat? Are you saying I should be running a different stat temp? If so which one...looks like the only alternative is the 160 but some folks are telling me that could screw with my computer controlled tbi?

 

[Jagged]

you looking at my truck again??? I did that.... once....

No, but I think we might both be related to some guy named Murphy

 

[dyeager535]

195* is almost universally what GM used in every application.

It would be stock for yours.

Lower temp thermostats in most cases are used as an attempt to band-aid an inadequate or improperly working cooling system.

 

[RootBreaker]

195* is almost universally what GM used in every application.

It would be stock for yours.

Lower temp thermostats in most cases are used as an attempt to band-aid an inadequate or imporperly working cooling system.

exactly.... when I was a younger lad.. I band aided EVERYTHING!!! or used duct tape

however now.. do it right or dont do it at all

 

[Jagged]

F4 tape works wonders, I used it a lot in my job in the AF, and also to repair leaky radiator hoses... wrap it good with F4 tape, then zip-tie the ends and it's good to go.

 

[mudslinger99]

I had to replace the thermostat in mine 3 or 4 times because they were bad right off the shelf... I finally went to a different parts store then I got the 1st few from... Turns out the the parts store got a bad batch... Just something to keep in mind...

You should keep the factory themostat... A lot of people use to do that on non-computer motors with varied results.. But as was stated it is not reccomended for yours.. If you type in ''thermostat'' in to the search you can find alot of info...

 

[Wes Harden]

thermo and tbi

Yes if your truck is running GM programing in the puter it realy is disigned for a 195 degree thremo. but if your truck has been modified and you have no cat.
you'll be fine, it'll run a tad rich, so fuel economy will suffer.
As for up or down on stat they're noramly marked "this side to radiator" or "This side up" <- also radiator. One question thou is the truck realy getting that hot ? have you popped the hood and started it to see if the engine temp truly that hot.
But if that stat is 3 years old I would change just because. In my old non-puter cars/trucks I change from a 180 winter to 160 summer stat. other wise newstat every 2 years.