Hey everyone...my first post...anyways, this is my second car and by far my favorite. Anyway, I am having a huge problem.

Yesterday...Thursday, I picked up my car from a garage down the street that specializes in radiators. I have 109000 miles on the car and I wanted to get the radiator flushed so I did and made sure I got it replaced with dexcool. Anyway, I drive off the lot and notice that the temp was slightly higher than normal and about 5 miles later it was at about 230 degrees. I called them up and he said it was normal and an air bubble had to pass through or something. So I forgot about it.

Since then I have driven to work or the gym, no more than 7 miles a trip...and at times my temp had risen to 255 or 260 degrees. So tonight, Im driving to my moms on the highway and all of a sudden a message read "Coolant hot" and soon there after "Stop Engine: Engine overheated" Panicking, I did with my sister and cat in the car we waited for the tow truck while seeing the steam pour out of my engine. My change engine oil message also appeared at the same time when yesterday it read 33% life left.

Under the car I saw two small puddles (like 6" in diameter under the front wheels) couldnt tell what it was but both were clear and smelled sweet. The tow truck came and brought it to the garage that was suppose to flush it but they wont open again until MONDAY! I also squeezed the hose above the radiator and there was nothing in it.

My questions are (please help)
1. Why did the change engine oil come on?
2. Is it normal for the engine to overheat before the air bubble leaves? How long does it normally take?
3. Could I have massivly damaged my engine? (when it said stop, I did immediately stop)
4. Could my thermostat have gone? If so, how can you tell..is there a check engine code that could pop up?
5. Could it be an error on their part?
Any more information is GREATLY appreciated, I dont want to get shafted by that garage.

1. Engine temp is one of the things factored in when oil life is calculated.

2. Possibly

3. The engine has a limp home (camel mode) feature that helps protect the engine. Apparently, you didn't get to that point. Hopefully, you are ok.

4. Sounds like the stat may be the problem. No codes will come up for stats. You could (and should whenever you change stats) put your stat in a pot of water with a temp probe, turn the heat on and check the temp that it opens up at.

5. I think so.

Thanks for info! I dont really understand your fouth answer about the stat.

1. Where is it and how do I get it out or test it?
2. And why would my stat just go the same time I got my radiator flushed?

I was searching online and I saw all these problems about leaking radiators and head gaskets going, but I hope that is not the problem.

3. Is it normal for the two small leaks I had when the engiine overheated?

Thanks again! I appreciate the help.

I have came across brand new thermostats that didn't open at the proper temp. Most recently, when I changed the rad in my eldorado, I also changed the stat. Started it up and the temp kept rising. I cut off the car before it went too far. Pulled the stat out and put it, along with the old stat, in some water. Heated it up on the stove and watched. The new stat opened out a substantial amount of time after the old one. Needless to say, I put the old back in and all was ok. The only reason I was changing it in the first place was just preventative maintenance since I was doing the radiator.

The stats location...look at your upper hose. See where the hose attaches near the water pump. When you remove those two small bolts holding what is called a water neck, the stat is there. I don't see why it would go out if you were just flushing the rad. But, no fluid in the upper hose...stat could have got stuck closed. I have heard about the air bubble, but have never experienced it.

About the two leaks, you would need to locate where they came from. Did they even have a tint of orange in them? Was it just water?

The two small leaks, it was night but when I stuck my finger in it it was clear, no noticable orange but it did smell sweet. There were 2, I could see it was leaking from somewhere under the engine but only being 17 I have not been exposed to cars too often lol.

Anyway, I think I am going to bring my car home and pull it apart tonight and check the thermostat. I dont know how long this freakin airbubble could last, but I dont think it is meant to ruin your engine. I am also not too sure if it is coolant because my DIC never said "Add more coolant"

Any ideas...or anything would be helpful. By the way, what temp should the stat open up at? Thanks again for your help!

There should be no air bubble. There is a purge line that runs from the water pump to the surge tank. It enters the surge tank at the top via a 3/8" line. If that line is clear it will purge any air in the system, and should do so almost immediately. If you remove that line at the surge tank there should be a coolant flow. If not, then the line is plugged and will not purge air.

Stat starts to open at 192-199*F.

Fully open at 219*F

I found out where one of the leaks was. I went to the car today, the garage doesnt open until Monday. I bought them oil and an oil filter since the oil that was in there is now ruined since I guess it got too hot that the oil bubbled. I am going to call them on Monday and tell them to change it since it should have not happened in the first place. The leak was antifreeze, I saw it leak from the black box where the coolant goes. It leaked out of the top of it, but through the tank itself, through an oem crack i think. Anyway, I followed it from the tank to the ground, its not leaking anymore and the hose above the radiator is still completely empty. Those people better fix any problems they caused and FOR FREE. Any suggestions?

The stats location...look at your upper hose. See where the hose attaches near the water pump. When you remove those two small bolts holding what is called a water neck, the stat is there. I don't see why it would go out if you were just flushing the rad. But, no fluid in the upper hose...stat could have got stuck closed. I have heard about the air bubble, but have never experienced it.

I'm pretty sure the thermostat on a Northstar engine is at the bottom radiator hose, not the upper hose.

Since you reached 255-260 degrees, I would have the head gaskets checked via a cylinder pressure test by another unbiased shop.

Bubba is right. The stat is under the water neck that the BOTTOM hose is connected to. Two small bolts to remove.

Most cars, at least the older ones, it would be the top hose. Northstars are an exception.

Head gaskets....wow sounds expensive. If they are gone because of that shop, the shop is goin down. What are the symptoms of a bad head gasket? I didnt drive that much with a temp that high, no more than a minute. Could that still kill them?

Symptoms are coolant useage and overheating. They will get worse with time. I would be very concerned any time my engine got to 255-260, but theoreticly the the engine goes into camel mode to prevent damage when the temps get to 250 or so, and yes, head gaskets are very expensive ($3000-$4000) as the entire drivetrain must be dropped out the bottom to do the rear head.

Haha, thats not a hard job- I could do that in my sleep :-D Yea, my car isnt worth that much...didnt even spend anything like that lol even though its in perfect condition the guy was rich and wanted to help a poor kid out. I dont know, that shop better fix ANY problems they caused and change my oil...or they are out of my town...After my car is fixed Ill tell you where it is....I dont want them to read this then sabotage my car!

I am wondering if you did get head gasket damage? My 96 DeVille overheated yesterday and I stopped as soon as it said "Engine Idle" "Coolant Hot", my husband is checking the thermostat now.

Great. Head gasket problem :-) It leaks, they did a die test. Wonderful. Any estimates?

Ok, here is the whole story as I called the shop. PLEASE TELL ME IF ANY OF THIS SOUNDS WRONG SO I CAN CONFRONT HIM. Anyway, they flushed it out. Used a regular garden hose. Filled it up with dexcool. And then it started to overheat when I started to drive it. He said it was probably sealed before and flushing it removed the seal. So I drove it unsealed. When it overheated the head gasket leaked. They did a die test and it came up positive. What am I going to do? He told me he will add sealer and drive it around and he is going to tell me how it works out. Do you think it is too late for sealer? What exactly is a head gasket and where can I see if it is really leaking? Thank you guys for the help.

By the way, if the coolant never got to the engine (as the temp NEVER dropped, it always rose) How would the sealer have gotton dispersed through the engine? Who is liable?

This is after the fact, I know, but unless you have pluggage in the system, you don't need to flush the system. If it has to be done, you only want to use distilled water. Hose water will introduce undesirables. Next time just drain and refill.

How did he do the leak test if coolant isn't getting to the engine? Make him show you it is leaking? Does the exhaust smell sweet, see steam coming out exhaust?

Im sitting in the car now, it has been reading 224 for the past 10 min while the car is off. He showed me some pump thing, he put it in the antifreeze hole and got air or somethin and it tested positive. Anyway, he gave me some more coolant and told me to keep adding it when the car has been off for hours (if its not full) in order to get the air out of the system. The reading flucuated between 217 and 244 within 5 min while i was driving between 30 and 40. He told me that the temp reader is flucuating because it reads the air and then the coolant which is obviously hotter. He basically said keep adding coolant until the air is out...which I hope is soon. Im a 17 year old kid lol I cant afford a new head gasket. What advice do you have? Thank you!!!!!

HOLY CRAP! I JUST CHECKED THE SYSTEM THROUGH THE WARMER AND UP BUTTONS...AND THESE WERE ALL NEW TODAY! LIKE I PICKED UP MY CAR TODAY AND HE PROBABLY DIDNT KNOW THAT THESE WERE IN MY HISTORY! (They wernt here before!!!) I cant find them online...ANY EXPLANATIONS? THANK YOU AGAIN GUYS!!

ir
2064
1740
1770
2129


ip
1552
2152
2064
2016
2750

pz
2470
2471
2472
2473
2476
2056
2152

Before today there were just pcm codes....only 2 a transmission circuit and a memory reset. WHAT THE HELL DO THESE MEAN? THANK YOU!!

You can find the OBD II codes here.
http://myweb.accessus.net/~090/dtcobd2.html

The sealant tabs will not help a bad head gasket. Sealant tabs are only to prevent niusance leaks from porous castings or minor gasket seepage other than head gaskets. The head gasket is a seal between the head and the block. You cannot see it. You have to have each cylinder presssurized with shop air to tell if it is bad. You need to have this done at another shop. This guy is not going to admit to a mistake that will cost him $3000 - $4000, if infact it is his fault.

Look at the surge tank. See that 3/8" line running into the top of it? It should be on the front side if it is like mine. That line runs across the top of the engine to the water pump. It is the purge line and it's job is to remove any air in the system and by routing it to the surge tank where it will be vented overboard throught the cap vent as pressure builds beyond 15 psi. With the engine running, loosen the clamp on the purge line and carefully twist it back and forth to remove it. Be careful not to crak the nipple it attaches to (I just had to fix mine). When you pull that line loose, there should be a steady flow of coolant from it. If there is, then the purge line is open and there is no air in the system. It is self purging if it is operating properly. If there is no flow, then the line is plugged and there may be air in the system, which could be the cause of your problem.

Ok, so when I pull that line out, the coolant will be hot I assume...where do I point it to and how can I stop the flow so it doesnt get all over the place? Thank you! By the way, what temp should the coolant be at when I take it off?

Do it as soon as you start the car so the coolant is cool. That way you won't burn yourself. Just momentarily pull it loose and point it toward the ground. As soon as you see flow either have an assistant shut the engine off or plug it back on right away so you don't drain the system or make a big mess. You just want to verify that there is flow. Then just rinse off any coolant that spilled on anything.

I looked for those trouble codes....I cant seem to find half of them!!!! Any help is appreciated. I am going to check the coolant now. If there is head gasket damage is there a way I can prove he did it? Thank you!

Proving it will be difficult. You can argue that he told you to continue to drive it to get the air out of the system. That alone proves he doesn't know much about the Northstar. He, on the other hand will argue that the head gaskets were damaged already and the sealant tabs that were in there where masking the problem til he flushed it. It is hard to tell when the problem (assuming it is a head gasket which hasen't been established yet) began. What you do have in your favor is that there was no problem (I assume?) til he worked on it. Why was it there in the first place?

Some updates.

My engine stayed cool (didnt go above 197) on my 10 min drive from work today, roughly a complete 10 minutes at 40 to 45 miles an hour. I did add coolant before I left work because I was told my him to add the rest if it could take it. The engine took half a bottle and I could have added more. I am happy it stayed cool. Next to deal with was the smoke. All I did was add 2 quarts of oil (since i am overdue for an oil change as i over heated my engine, im going tomorrow) and the smoke was gone! I stuck my nose over there for a min or two, besides getting a little queasy, I think I smellled some sweetness...like a heavy smoke but I am no expert. It was not like a lawn mower smell but it was more "dressed up" than it.

I am getting my oil changed tomorrow, hoping it will stay at 197 or below. Are there any signs I can look for that yell out "problem!" Were any of my codes important...why did they become history after a single day?

Everyone I thank you for your help and I look forward to more advice.

I got my oil changed. Seems better. BUT I noticed some weirdness in the coolant temperature. While driving, it does not like to go over 199 (I drive for 20 min or so, always above 40 below 50) But then I took my car to my friends, decided to park it and leave it on. I sat there listening to music and to my surprise it rose to 222 and stayed there for a minute then dropped till about 210. Then it went back to 222 and dropped again. When I drove away, it stayed between 200 and 210. Should I replace my thermostat?

Also I noticed, even when my engine was at 215, the fan was not on. I put the AC on and both went on, but when I turned it off, they both turned off. When should my fan turn on?

Thanks again guys, I know I can always come here for help, by the way does anyone know about my smoke problem or my check engine codeS?

Fans are always on when the A/C is on. Otherwise they turn on low speed at 224 and high speed at 229 I believe. They are operating normally.

Your tempuratures also sound about normal.

Do you think I can rule out a head gasket problem? I am pretty happy I hope- but I looked in the manual, it said the stat opens around 176...which would make my temps high. I just dont want to ruin my head gasket if it is infact in good shape. My exaust still smells though, like a dress up lawn mower...is that normal too?

Stat starts to open at 192-199*F.

Fully open at 219*F

You got 176 from the manual? Maybe my quote was for a Deville with a 4.9L. I will have to check into that.

Your temps aren't high. That is when it starts to open. The reason your temp was hovering around 200 while driving was because of the air flow trough the engine bay. When the car sits idling, the temp will raise.

I personally think your head gaskets are ok. I don't trust that the mechanic you used actually did a dye test as you had mentioned. Now would be an oppurtune time to test it yourself. Do a search on the forum for head gasket test.

I agree with Ranger and EldyFig - my '99 Deville nearly always, through four years of summer/winter, stop-n-go and go like hell on the Interstate, always hovered within four degrees of 197F on the display.

The ONLY time it got hotter (to a max of, I think, 218) was one summer day coming up I95 through North Carolina with an outside air temp of about 104, and I stopped for gas. As I got back on I95, the temp dropped back down to 199 for the rest of the trip.

Phathead, don't have a bird.. .There are a couple of possible explanations for your overheating episode. One, perhaps not enough coolant was added after the flush (and now you know to NEVER do a flush again, right?). Two, perhaps there was an air bubble or blockage that the flush caused. Or could just be phases of the moon....

My '99 cracked the nipple on the pressurized surge tank at about 75K miles, and a tiny bit of coolant leaked out, during operation of the car. Got the "Low Coolant" message one Saturday AM, found the leak... Dealer replaced tank and rad (it was under a GMPP) and no problems anymore.

Make sure that you add the tube or two of "Bar's Leak Golden Seal" to the lower hose one of these days. It will NOT cure HG failure or any of that sort of stuff, on the NS it is recommended just for minor nuisance leaks. DO NOT use any other "engine coolant sealer" under any circumstances - only the Golden Seal variety - they are available at any Walmart. And do NOT add it to the surge tank - add it to the lower hose. (Yeah, it makes a mess, but try to do it at someone else's house...lol)



Good luck and keep us informed.

Thanks guys, I will get that golden seal stuff next time I venture to the empire of the world- walmart...lol Anyway, that guy...never again haha. Is there a way to check the head gasket myself? I know you cant see it, and Im not planning on getting it fixed as it would cost more than the car...but I was just wonderin- just in case it is going I can get rid of it now. Thanks again guys, I appreciate all of the help- hopefully no more problems here!

Go to the top left of this page and click on Technical archives. There you can read up on how to check for a bad head gasket.