Chevy & GMC Vans

the temp. gage in my 1992 astro is reading odd when i start the van up in the morning the temp. is about 60-70 degress but the gage reads 150 degrees then i drive to the store and turn the van off but before i turn it off the temp. gage says about the same or a little over then i go in the store 10 min. later i come back out and start the van and the gage reads totallly diff. it reads cold then i go home shut it off for a while then restart it the gage reads 195degrees so do you all think this is the temp. sensor for the gage? also the engine never overheats and runs great.

Try not to get confused with the actual temp guage, and the temperature coolant sensor. is your guages analog or digital. i know my digital guages can show some funky things sometimes. However it is the nature of the beast.

it is analog gauge it is the sensor for the gauge i am talkng about okay here is the issue i really need help with this please i replace the temp. sender unit for the gauge the gauge is still doing the same thing every morning when i start the engine the temp. outside might be 50 degrees and the gauge says it is 150 degrees and this is the van sitting over night. it will automatically say that temp. the gauge never starts off on cold.

Did you put thread sealant on the threads for the gage sender? If you did, it is probably affecting the ground path for the gage. Don't use thread sealant on sending units, the fine threads on the sensors are there so you don't have to use the thread sealant.(this also applies to teflon tape sealant)

no sealant was used

since it's running ok, I'd suspect the gage. Bad coolant temp sensors tend to make the engine run like crud.

i think the one you are talking about is the computer one which is by the thermostat housing i am talking about the one in the drivers side head between cyl. 3 and 5

hmm interesting. My '89 only has the one temp sensor in the thermostat housing, and the sensor between 3 and 5 on the drivers side is the knock sensor... go figure

[edit] nope, that's not right, my '89 does have a separate temp sending unit for the gage. the knock sensor is in the block down below. learn something new every day on this site.

where is the gauge cluster grounds and does the temp. gauge have a seperat one? i did change out the sender unit for the temp. gauge with a new one and i am still have the same problem and i tested the gauge it reads cold when the sensor wire is diconnected and reads hot when it is grounded so the gauge is good the temp. sender unit must not be getting a good grounded.

i meant to say that when i tested the gauge it reads cold diconnected and does not change when grouded. also my gas gauge is not working right it has always not worked right the needle bounces arould now when i have a full tank the guage reads half then start moving aroud. how do i fix this?

most likely need a new sending unit in the gas tank. the fortunate thing is you can buy a separate sender for the gage for a '92. first search I would recommend is http://www.rockauto.com
Now, getting it out is a bit of a chore. Basically the same process as replacing a fuel pump.
You will have to drop the gas tank. But actually it's quite a fun experience the first time. after that not so much. done 3 now...

Bryan,
While I just replaced the fuel pump on the LT,all the places I searched on the web stated it was highly recommended to replace the wire harness inside the tank because it is a common failure with these vans.The wire harness is very cheap to buy.I tried to remember if there was a ground on the harness outside of the tank by the connector to the van and couldn't mostly because I was focused on the fuel lines and really didn't pay much attension to it.Surely buy the sending unit,wire harness,and I would replace the strainer while I was in there.Drop the tank and clean it,then put on the strainer and wire harness inside the tank.Then put in some gas and see if it cures the problem with out putting on the sending unit checking it while the tank is still out.Return the sending unit if it does or then put in the sending unit if it doesn't.Could save you some money if the inside wire harness fixes it.