regarding temp gauge

I read (by accident) that your temp gauge should read approx 192 new, and no less then 180 used.

To my knowledge noones ever changed mine, and it runs at normal temperature around 155.

What should I do?

Verify that you have a 195° F thermostat installed. If so, I suspect that the gauge is bad.

How far it is on the gauge?

1/4 1/2?

It should read between 1/4 to 1/2 but just slightly closer to half.

How far it is on the gauge?

1/4 1/2?

It should read between 1/4 to 1/2 but just slightly closer to half.


http://groups.msn.com/_Secure/0TAANAyMXXHKqBPY*Ryy0xaGusbL!A0SR0kpC5Ll4FLee*qeXj UM*xgTsMUgPQGCc3QPxtQo7T1FAvpXw5fwg9vKpQMaZUUnbaXG 1sgeOySojk4qevVLV*Q/IMAG0080.jpg?dc=4675507507395494474

upload your pic to your gallery and link the pic from there.

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Edited by moderator so the pic will show up.

You can just copy the link in and have it work.

You have to put the x tags around it.

your thermostat is stuck open.

Change your thermostat.

your thermostat is stuck open.

Change your thermostat.


doubtful man, my car heats right up, and blows hot air.
Gonna get a trouble code test done before I replace it.

doubtful man, my car heats right up, and blows hot air.
Gonna get a trouble code test done before I replace it.

Listen bro, I don't sit here and spout advice just out of the blue.

Heater output has NO BEARING ON THE ENGINE TEMPERATURE.

Replace the thermostat, trust me, I had the same problem.

Listen bro, I don't sit here and spout advice just out of the blue.

Heater output has NO BEARING ON THE ENGINE TEMPERATURE.

Replace the thermostat, trust me, I had the same problem.

I'm not doubting you, I've just been told that it wouldnt even get up to 155 if it was open. That's not true? And doesnt the heater blow heat from the heater core? Wouldnt it be cooler air in icey temps like now if it were stuck open?

A factory set new one (192 degree) is cheap enough.......only $12.99 at NAPA. Is it a quick replacement?

Amen, amen, amen. I got a $1.00 that says the thermostat is stuck open or someone put a 160° f thermostat in it.

I think it might just depend on how far it was stuck open as to how hot the engine would run. Replace the Themostat and you'll be good to go.

Amen, amen, amen. I got a $1.00 that says the thermostat is stuck open or someone put a 160° f thermostat in it.
how can I be sure that it's not a 160degree one?

I'm not doubting you, I've just been told that it wouldnt even get up to 155 if it was open. That's not true? And doesnt the heater blow heat from the heater core? Wouldnt it be cooler air in icey temps like now if it were stuck open?

A factory set new one (192 degree) is cheap enough.......only $12.99 at NAPA. Is it a quick replacement?

Shouldn't be hard.

Remember to replace the stat housing gasket as well. It is a rubber ring you will need to also buy.

Oh, and while you are doing that, buy a replacement rad cap as a preventative measure.

Once you remove the thermostat from the housing, the temperature rating should be stamped on the bottom of the unit. Trying to determine the temperature rating without removing it from the housing is simply guessing.

Replacing the themostat is simple enough, usually only two bolts, a gasket scrapper and some gasket sealer. But this is usually a good time for flush and antifreeze.

Shouldn't be hard.

Remember to replace the stat housing gasket as well. It is a rubber ring you will need to also buy.

Oh, and while you are doing that, buy a replacement rad cap as a preventative measure.


Did you have hot air still blowing when you had to replace yours? And how can I be sure it's not just the gauge or sending unit? Will a simple computer test at Autozone tell me anything?

This has been discussed in previous posts.

The failure rate of sending units is almost nil.

Replace the thermostat and the thermostat housing rubber gasket (get the proper gasket, not the gasket maker stuff), and swap it out.

I did have heat but remember, even at 140-155, that is pretty damn well hot for air temperature.

If you want to pay for the test, they can check what the actual computer coolant temperature sensor is sending to the computer.

Like BlazerLT says, the heater temp has virtually nothing to do with the engine temp. I have seen it both ways. It depends on a multitude of factors as to whether your heater is blowing hot or cold. (outside air temp, level of antifreeze, condition of the actual heater core, how far stuck open it is etc.) The simplest and least expensive way is to replace the thermostat with a 195° F. You'll spend more time and money trying to get the gauge checked than if you R&R the thermostat. I would think that cost wise, the Thermostat R&R should only run about $15 - $25.

If I remeber right, you can have an engine diagnostic check done that will probably run you $60-$80 just for the hook-up, that might tell you what the computer says the engine is running at.

If you replace the thermostat and you still have the low gauge reading, at least you know that the engine is running at the recommended temp and you can ignore the gauge at that point or get the gauge fixed if you prefer.

This has been discussed in previous posts.

The failure rate of sending units is almost nil.

Replace the thermostat and the thermostat housing rubber gasket (get the proper gasket, not the gasket maker stuff), and swap it out.

I did have heat but remember, even at 140-155, that is pretty damn well hot for air temperature.

If you want to pay for the test, they can check what the actual computer coolant temperature sensor is sending to the computer.

I did see your other posts where you suggested it. I never heard if they replied confirming it was that or not.

So you're saying it's pretty common for the thermostat to go on a Blazer of 1998 and 103k miles?

Can you give me the details of what happened when you did it? Did gas mileage suck? Did it change? Did the temp gauge change from then on etc?
thanks again

I did see your other posts where you suggested it. I never heard if they replied confirming it was that or not.

So you're saying it's pretty common for the thermostat to go on a Blazer of 1998 and 103k miles?

Can you give me the details of what happened when you did it? Did gas mileage suck? Did it change? Did the temp gauge change from then on etc?
thanks again

Yes, it is common, and is more common when people don't properly service their cooling system.

Ever done a cooling system and heater core reverse flush and fresh fill? Ever replaced the rad cap?

Yes, gas mileage DID suck. The engine was not getting up to temperature so the computer was staying in open loop and constantly throwing in more fuel trying to warm the engine up.

When the stat was put in, everything went right back to normal as you wil see when you do it.

I suggest you flush your system as well as doing the stat change. With old coolant, it will stick open again.

Yes, it is common, and is more common when people don't properly service their cooling system.

Ever done a cooling system and heater core reverse flush and fresh fill? Ever replaced the rad cap?

Yes, gas mileage DID suck. The engine was not getting up to temperature so the computer was staying in open loop and constantly throwing in more fuel trying to warm the engine up.

When the stat was put in, everything went right back to normal as you wil see when you do it.

I suggest you flush your system as well as doing the stat change. With old coolant, it will stick open again.

sound's like it's worth doing then. one thing though. check out this previous post.

http://www.automotiveforums.com/vbulletin/showthread.php?t=319304&highlight=thermostat

In it, you're quote say's you think the temp gauge picture looks acurate. It's exactly where mine is now all the time. Why did you say it looks right?

sound's like it's worth doing then. one thing though. check out this previous post.

http://www.automotiveforums.com/vbulletin/showthread.php?t=319304&highlight=thermostat

In it, you're quote say's you think the temp gauge picture looks acurate. It's exactly where mine is now all the time. Why did you say it looks right?

What temperature is it outside when it reaches this level?

Also, will the temperature climb and then the stat will pop open and drop?

All operative stats will have the engine teamp rising to 210 and then drop down after it has popped open.

What temperature is it outside when it reaches this level?

Also, will the temperature climb and then pop open and drop?


Thought I said that. Temp's have been below freezing lately. Snow etc. But I just bought the truck so I don't know if its different then when its warm out.

Havent noticed it warm and drop down really. Just heats to that point and stays around there

Yea, that is a sign of a partially open stat.

A working stat will build heat up to the 1/2 mark or just slightly above and then pop open and drop to between 1/2 and 1/4.

Oh and by the way, WHEN you R&R the Stat, it may physically appear to be stuck open and then it may not look stuck open. The proof is in the engine temp after the new one is installed. Replace this stat and you'll see!

Yea, that is a sign of a partially open stat.

A working stat will build heat up to the 1/2 mark or just slightly above and then pop open and drop to between 1/2 and 1/4.


Oh. The post looks like the temp gauge is where it's supposed to be. Several others are replying on it saying thats where theirs are as well.

If I do replace it, they told me that the thermostat they have in stock is a 192 degree one, and it comes with a rubber gasket (o-ring style).

A - Is the 192 one good enough?

B - Is there more then one gasket? i.e. - a flat one as well?

192° should be plenty good enough. The gasket is the rubber "O" ring type. Don't forget the new Rad Cap and new Antifreeze.

Yea, a flush should be done.

Replacing the stat will only be a patch that will come back and happen again.

Yea, a flush should be done.

Replacing the stat will only be a patch that will come back and happen again.


Ok, check it out.

I replaced the thermostat. I drained the radiator, but there was no feasable way for me to see, not even throught the wheel wells, to drain the block.

Therefore, I didnt do the complete flush. I'll consider bringing it in to have it done. Anyone know what a flush costs?

I couldnt even FIND the drain plug on the passenger side. All I could see was the starter. As I said before, its below freezing, and I was trying to do it all while laying in a puddle of water. So, needless to say, I gave up on the flush.

Since replacing the thermostat, the temp gauge reads exactly where you said.
One click to the left of halfway.
I will keep an eye on it, and the level, as well as my "new" gas mileage. What should I be expecting to get for mileage now?
Also, when the engine is revved up, I seem to hear gurgling under the dash that wasnt there before. Like maybe the heater core is filling up. How long should this last before it stops the gurgling?
thanks
Josh

This is good, you have replaced your faulty stat and are now getting proper temperature.

Also, you will want to reset the computer by pulling the negative terminal off of the battery overnight so the computer can relearn the fuel curve faster with the engine getting up to proper temp.

I also told you to get a new rad cap installed. Did you do that.

Tomorrow morning, go out and fill the rad up and fill the overflow resevoir to the proper levels. You have air in your system that you have to get rid of.

Again, the new CAP will help this. And don't get an AC Delco cap.

I'm not doubting you, I've just been told that it wouldnt even get up to 155 if it was open. That's not true? And doesnt the heater blow heat from the heater core? Wouldnt it be cooler air in icey temps like now if it were stuck open?

A factory set new one (192 degree) is cheap enough.......only $12.99 at NAPA. Is it a quick replacement?


I'm having the same problem w/ my '97. I just bought this truck and haven't spent much time under the hood yet. Is there anything else that has to come off before I get to the thermostat?

didnt get a new cap yet, as I didnt have the money with me last night. I'll get a new one. Any specific kind?
also, how do I get rid of the air in the system?
Thanks
Josh

I does my heart good to see someone take our advice, solve a problem, and then come backand tell us. Keep an eye on your coolant level in the radiator for a few days. You do this by removing the brand new Rad cap that you just bought every morning when the engine is cold. The radiator should be full to the very top. If it is not, carefully add a little more coolant to top it off.

Like Blazer LT said, the NEW cap should do this for you IF YOU BOUGHT THE CLOSED SYSTEM TYPE. If your new cap has a pressure release lever on it, you will have to manually fill it. Hopefully you bought the closed system cap and restored the system to original.

I does my heart good to see someone take our advice, solve a problem, and then come backand tell us. Keep an eye on your coolant level in the radiator for a few days. You do this by removing the brand new Rad cap that you just bought every morning when the engine is cold. The radiator should be full to the very top. If it is not, carefully add a little more coolant to top it off.

Like Blazer LT said, the NEW cap should do this for you IF YOU BOUGHT THE CLOSED SYSTEM TYPE. If your new cap has a pressure release lever on it, you will have to manually fill it. Hopefully you bought the closed system cap and restored the system to original.

I'm having the same problem w/ my '97. I just bought this truck and haven't spent much time under the hood yet. Is there anything else that has to come off before I get to the thermostat?

Hey man, just FYI since it's fresh in my mind right now. I don't know if theres a simpler way of doing this, but I had to pop the plastic air intake tube off (easy only one twist screw securing it) and the bracket for the throttle body cables (also easy, only two cuts securing it).

You'll need a deep well 1/2 inch socket and extention to remove the two bolts securing the housing for the thermostat.

How's your fluid level this morning?

How's your fluid level this morning?


I added some. Probaby 20oz max. Probably less. Still heard the gurgle for a while. Not sure if it stopped yet. I plan on getting the system flushed and refilled soon anyway.
I will be replacing the cap today as well.....the current one was a little bit gunky.

That was all air in your system, and if you keep doing the Check/Add every morning for a few days your gurgling should stop. Get the new cap and remember not to buy the AC-Delco cap. Get a STANT cap.

That was all air in your system, and if you keep doing the Check/Add every morning for a few days your gurgling should stop. Get the new cap and remember not to buy the AC-Delco cap. Get a STANT cap.


Will do. Thanks for the assistance. What should I be expecting for gas mileage now? Keep in mind I havent done the plugs and wires yet. I'm getting the STANT cap today by the way.
Also, you guys really reccommend I do the flush right? It's gonna run me close to $90 to get it done.

I really can't say regarding milage, other than it should improve. Maybe BlazerLT would know.

As far as a power flush is concerned, keep an eye on your new antifreeze, if it stays clear and clean then I would leave it alone. If you are still having trouble, or if the coolant starts looking muddy or dirty then I would take it in for a through reverse power flush.

I really can't say regarding milage, other than it should improve. Maybe BlazerLT would know.

As far as a power flush is concerned, keep an eye on your new antifreeze, if it stays clear and clean then I would leave it alone. If you are still having trouble, or if the coolant starts looking muddy or dirty then I would take it in for a through reverse power flush.


did you read that I didnt flush the system? I had only drained it from the radiator

Thanks JoshBarber for the input. I'm gonna takle this today if I can get a sitter.

My original advice still holds. If you're antifreeze is still clear and clean, AND your not having any more trouble leave it alone. If you are having trouble or the anifreeze is muddy,cloudy, or dirty then go for the flush.

Did you add Green or Orange Antifreeze? What color was the original that you drained out?

My original advice still holds. If you're antifreeze is still clear and clean, AND your not having any more trouble leave it alone. If you are having trouble or the anifreeze is muddy,cloudy, or dirty then go for the flush.

Did you add Green or Orange Antifreeze? What color was the original that you drained out?

I had it done this morning. The original was the Orange. Thats what they refilled with. Should be good to go.

So, was the thermostat stuck open or was it a lower temp stat?

You said the temp gauge was "reading about where we said" so I assume the temperature is hotter than it was before.

How bad was the system when they did the flush, did they comment on it?

Yip, you should be ok with the new cap.

It will take some time to work the air out of the system.

With the new cap, it will really purge the system quickly.

Just go for a good 50 mile run with it.

also, reset the computer by pulling the negative terminal for an hour to reset the comp so it can relearn the fuel curve with the engine getting up to proper temperature.

So, was the thermostat stuck open or was it a lower temp stat?

You said the temp gauge was "reading about where we said" so I assume the temperature is hotter than it was before.

How bad was the system when they did the flush, did they comment on it?


It was the thermostat.
Yes, the temp was reading around 155 before, and since the thermostat replacement, is now approx. 206degrees.
no. no comments on the flush, although they did say "no problems".
still have air to remove from the system. putting the new cap on as soon as it cools down.

Yip, you should be ok with the new cap.

It will take some time to work the air out of the system.

With the new cap, it will really purge the system quickly.

Just go for a good 50 mile run with it.

also, reset the computer by pulling the negative terminal for an hour to reset the comp so it can relearn the fuel curve with the engine getting up to proper temperature.


I did remove the neg. battery cable this morning....after the new thermostat, but before the flush, for about 15-20 minutes. That should be adequate, right?

Should be.

The thermostat was the problem, but was it stuck open or was it a lower temp?

The thermostat was the problem, but was it stuck open or was it a lower temp?

can't tell for sure. there wasnt a stamp on it.

Should be.


got an additional question for LT. or anyone else really.
While underneath with the plastic cover off to drain the radiatior, I noticed small trace spots of oil, that ran down the hose of the oil cooler. It wasnt a lot, but still would like to know where you think it'd be oozing from. Any common causes?
Top of the cooler?

got an additional question for LT. or anyone else really.
While underneath with the plastic cover off to drain the radiatior, I noticed small trace spots of oil, that ran down the hose of the oil cooler. It wasnt a lot, but still would like to know where you think it'd be oozing from. Any common causes?
Top of the cooler?


just did a search.....should've beforehand.
It appears from a previous post, that this is "weeping" is a pretty common occurance, and is to be accepted as "ok" providing theres no excessive leakage....correct?

yea, mine have been sweating oil for over 5 years with no problem.