sprinter10

Engine overheats and heater blows cold air

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Hi I am Mark Gilmore and I am new to this forum, and being a caddilac owner. I puchased a 2000 STS with with 118,000 miles 32valve 4.6L northstar engine.

I am 16 years old and am driving it with my parents under my permit tring to get all the bugs worked our for when I get my license in less then a month.

It has a few problems I have been working on and fixing but nothing major until I finally took it out on the highway the other day.

After cruising for about 10 miles the water temp jumped up to 3/4 and I got nervouse watching it. It then dropped straight back down to 1/2 way.

5 miles later it began to tick up at an increasing rate where I funally pulled over and it went into the red. I had the heat on full blast in side the car and noticed it wasn't very hot. After a little bit of idling it it went down a little and then stopped. I shut it off for a little checked the watter and it was about an inch below the line where it is suposed to be filled to. I put 2 water bottles of water in it then started it back up. Then the temp started to drop and it fell straight to half way. I had heat blowing again inside the car. I was driving it really easy trying to keep it in overdrive with a lot of long hills. The water temp just ticked up above half way and I noticed the heat that I had on full in the car was no longer as hot and was starting to blow cooler again and then it continued to climb untill I pulled over at 3/4. I let it run on the side of the road until it got it back out of its system. Both electronic fans were running when I pulled over and popped the hood. After pulling over one last time I finally made it to my destination that was 40 minutes away. The water level was then another inch below the fill level so I filled the tank up. On our way home I drove it really easy not going over 55 maby hot 60 once and only twice the water temp climed close to 3/4 and dropped back down to half way never had to pull over. When I pulled over the first coupld times there was steem and wetness around the cap on the colant container and damp in a few areas. So I am guessing thats where I was loosing a little bit of water.

I am thinking it could be a thermostat because it seemed like the water just stopped circulating causing the hot water to stop going to the heater core but am not shure. I know i want to flush the system out and get out any sludge that could possibly be clogging up the radiator. The car sat for around 6 months before I bought it and it just started getting cold so That day might have been the first day turning on the heat. Maby could have loosed something up triggering this?

There was no raise in oil level to lead me to belive it would be a head gasket. And I was not able to run any codes yet.

I am going to later today hopefully when I get to my dads.

The fluid never went empy always was more then half ful when I owned it and ran it for just over 300 miles now so I don't think it is an air pocket but I am not ruling anything out.

Thank you in advance for your help I am looking forward to being part of this forum and helping out with some of my experiences.

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When the engine is cool, take the coolant tank off and put your nose in there in smell it. Do you smell exhaust fumes?


Pre-1995 - DTC codes OBD1  >> http://z-cut.de/US/dtcobd1.html

1996 and newer - DTC codes OBD2 >> http://carprogrammer.com/Z28/PCM/OBD2/On-BoardDiagnosticTroubleCodes(OBD-II).mht

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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If you just purchased this car, I'd take it back and get a refund. You have potential serious issues. I say potential, because it could be as simple as the tube that removes the air from the system might be plugged. BUT, You have to ask yourself how air is getting into the system! And this COULD mean a headgasket leak. That is why BBF told you to smell the tank. If it smells like exhaust gases, your hosed.

Dump this problem back on the seller as quickly as possible before any warranty runs out.


Never underestimate the amount of a persons greed.

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Engine coolant should be running through your heater core at all times. If the HVAC system is otherwise in good order a lack of heat would seem to indicate poor coolant circulation. Have you checked the purge hose at the overflow tank? How about the water pump belt? I like your idea about a bad thermostat.


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There is no means of avoiding the final collapse of a boom brought about by credit expansion. The alternative is only whether the crisis should come sooner as the result of a voluntary abandonment of further credit expansion, or later as a final and total catastrophe of the currency system involved. - Ludwig von Mises

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Good suggestion Warren

What made me have this member check the coolant for exhaust smell was his description of his overheating, that it did not seem too hot and because it settled down a couple of times. I was thinking lets eliminate combustion by products

But you are correct, if they heater controls are working correct, cold air when it was overheating would indicate low coolant or AIR in the system not purging out

As Warren noted check the purge line, do a search here for purge line and follow the directions as to how to check it


Pre-1995 - DTC codes OBD1  >> http://z-cut.de/US/dtcobd1.html

1996 and newer - DTC codes OBD2 >> http://carprogrammer.com/Z28/PCM/OBD2/On-BoardDiagnosticTroubleCodes(OBD-II).mht

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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He has all the classic head gasket symptoms, I'm sorry to say (using coolant, overheating on a hill climb, cold air from the heater). I'd follow JohnnyG's advice if you can, but unfortunately most used cars are sold "as is".

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A good radiator should should be able to do a test, have them write up a brief diagnosis (head gasket breach) so you can go back to the seller and say SHOVE IT

How much did you pay?

Next time you buy a Northstar come here before hand and we will tell you how to be safe


Pre-1995 - DTC codes OBD1  >> http://z-cut.de/US/dtcobd1.html

1996 and newer - DTC codes OBD2 >> http://carprogrammer.com/Z28/PCM/OBD2/On-BoardDiagnosticTroubleCodes(OBD-II).mht

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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I picked up this car for $1,000 and all I have in it is a $240 coil pack it is in really nice shape with everything working nicely. The engine does not smoke at all. I just picked ip and changed the thermostat. Picked up a few gallons of dexcool. I don't think I smelt any exhasust smell in the tank but I might be missing it. I took out the air filter and the air box hose with the filter to get to the thermostat easily. I did not get a chance to check the old one in a pot of water yet and I don't have a temperature gauge to do it with. The antifreeze did not have oil in it or stick out in any way. I forgot to mention that the guy that sold it to us did a leakdown test on all of the cylinders and the engine to check for bad rings and it all came up good. He was selling it to us and working on it as a favor. It wasn't his it was his father inlaws that he was selling. Would that check for a head gasket issue? Or is the headgasket more of something when it gets hot? I did just run the codes on the engine and came up with this.

No ABS

No AMP

No DDM

No Dim

IPC U1016 History

No IPM

IRC U1016 History

MSM B1820 History

MSM B1845 History

MSM B1860 History

MSM B1875 History

PCM P0650 Current

No RFA

RIM U1255 History

Rss C0592 History

RSS C0594 Current

Rss V1016 History

No SDM

TTM V1016 History

VTD B1009 History

VTD B2734 History

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I guess the car also just had the trans fluid replaced because the computer read 99%

17.4 mpg avg hasn't been on highway the last tank of gas. I didn't know it had all those options to show on the computer.

I forgot to add that the inside of the lines for the radiator fluid had this really gummy orange crust that I was able to scrape off with my finger nails and it was like puddy in my hands. I baught this radiator/cooling system flush stuff that sais to be mized with water and then to drive the car 4 to 6 hours and then drain it out flush again with water run it for 15 minutes drain then fill with dexcool. Is it possible for that puddy crap to be clogging up the heater core? I know there is a leak somewhere because there was orange dexcool on some of the frame and other parts when I took the skid plate off I will track it down when I have it running with the watter and stuff to try and find it before I put the dexcool in it so I don't have to drain it again to replace a hose. Is there normally any pressure in the coolant tank? When we opend it when it was running hot on the side of the road and a couple other times both when it was running and when it was not it never made a release or sucking sound. Could the cap be bad not letting it build propper pressure and making the engine run hot? I noticed with this car there is no radiator cap like some other cars I worked on.

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P0650 Malfunction Indicator Lamp (MIL) Control Circuit

RETURN THIS CAR FOR A REFUND IMMEDIATELY.

This car was sold to you with the "Check Engine" light disabled, and it will be ON which will be detected by any qualified inspection facility, which means that you will not be able to get the car registered.


CTS-V_Dashboard.jpg
-- Click Here for CaddyInfo page on "How To" Read Your OBD Codes
-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data
-- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC
Yes, I was Jims_97_ETC before I changed cars.

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It sounds to me like you have a leak someplace if you are seeing coolant and not having pressure

You should have the cooling system pressurized to see if it holds pressure and have the cap checked to see if it holds rated pressure


Pre-1995 - DTC codes OBD1  >> http://z-cut.de/US/dtcobd1.html

1996 and newer - DTC codes OBD2 >> http://carprogrammer.com/Z28/PCM/OBD2/On-BoardDiagnosticTroubleCodes(OBD-II).mht

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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Is it possible to get the check engine like re enabled? and then fix whatever is sending it off? The inspection is good for a nother year. How can I get the cap tested for preshure? It can't be a bad leak anywhere because the fluid never dropped that far even when it was running it is a slow leak I just have to find where.

Edited by sprinter10

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By the way thank you for helping me out and can fix whatever it is or give the car back or whatever now rather then wait till the inspection is up next year to find this out.

I looked up the other current code and I think it said something like cruis control. I know 2 weeks ago the cruise control worked fine but yesterday I dried setting it while driving and did not look at whitch buttons I had to press just thought I reamembered how and pressed the button and moved the lever up down hit the button a couple more times and it never came on. Could it be a fuze or something?

Edited by sprinter10

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We know what is setting it off, the codes you are getting are setting it off.

I am not sure what they did to disable it, maybe there is a bulb that they snipped or removed not sure

Your biggest problem is the overheating, get the cooling system pressure tested and repair the leaks


Pre-1995 - DTC codes OBD1  >> http://z-cut.de/US/dtcobd1.html

1996 and newer - DTC codes OBD2 >> http://carprogrammer.com/Z28/PCM/OBD2/On-BoardDiagnosticTroubleCodes(OBD-II).mht

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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How is the best way to preshurize the cooling system? Can I then Just spray soapy water all around looking for a buble like checking a leak in a tire?

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This is copied from a site on Northstar headgasket diagnostics, it states that your car can pass tests and still have a blown gasket. It maybe fine with the engine cold but as it heats up, things expand and what didn't leak cold is leaking now.

Here are the most common signs of head gasket failure on a Northstar:

- Overheating

- High pressure build-up in the coolant surge (fill) tank, that remains when the engine cools off

- Heavy white smoke from the tail pipes (condensation & water vapor is completely normal for any car)

- Coolant smell from the exhaust

- Engine temperature spikes during acceleration or climbing steep grades

- Coolant in the oil (this will turn the oil a milky white or light brown)

- Sudden severe oil leak coming from rear main seal area

The best test there is, make sure you have adequate coolant, and get the car on the highway and do a few quick acceleration runs. Get the car quickly up to 70 MPH (120km/h) and slow back down to around 30 MPH (50km/h). Only do this where it is legal! Repeat this process, monitoring coolant temperature. If you have the guage, the temperature should never normally run past the 5/8 mark. If you have the digital read-out, the temp should never hit the 240 degree F mark. If the temp keeps climbing to the point where it tells you "A/C off for engine protection" or "Engine hot - idle engine", or your guage passes the 3/4 mark, pull over immediately, let the car idle for a minute and shut it off. Let it cool down a bit, top off your coolant and make your way back home. At this point, keep your foot out of the gas as much as possible. Your head gaskets are blown / head bolts pulled.

Many repair shops are capable of diagnosing a bad head gasket but not all of them know how to deal with the Northstar. Did you know a Northstar can pass all the usual pressure tests, and still have a bad head gasket? This is due to the troublesome head bolts. This is why we recommend the method above for determining the state of your gaskets.

So what to do now? Well, for starters, DON'T use any type of quick-fix in a bottle. I'm sure you've read about miracle sealants that are designed for the Northstar and a bunch of other stuff on the market. All this will do is clog up the coolant passages. The guy who does your head gaskets won't appreciate the mess that will need to be cleaned out once he tears your engine down, and you won't like replacing your radiator and heater core. Of course it is never a bad idea replacing your water pump, checking the belt and tensioner, cooling fan operation (they do fail sometimes) and if in doubt, a new radiator. But a lot of the time, nothing but the head gaskets will need to be done.

If you have coolant in your oil, stop driving, period. Don't run the car at all. This can severely damage your engine. If you must move the car, make sure the oil is at the proper level and not too high.

If you are seeing moderate to heavy white smoke, don't try to start the car again- get to where you need to go and shut the car off. Especially if you have a 2000 or newer model- the engines are not as strong and have been snapping/bending connecting rods when coolant gets in the cyinders.

If you are getting exhaust gasses in the coolant (pressure in the plastic coolant tank), it is OK to drive the car providing you can keep your speed down to about 50MPH (80km/h) and you keep checking/topping off your coolant. No more sudden acceleration or passing, and stay away from long hills. Just don't overheat the engine. Regardless of what the owner's manual says, it's not OK to continue to drive without coolant- these cars have a limp-mode but it is not very effective. If you have overheated your engine, the oil-life-monitor will return to 0%. You should change your oil after overheating the engine

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All I can say is best of luck to you, if it were me I would be looking for a refund but it depended on the car and how much I really liked it. I wish you the best of luck, It seems to me this is becoming a larger problem


GM FAN FOREVER

Nice, clean, luxury= fine automobile

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There is no smoke no smell of radiator fluid in exhaust no preshure in the collant tank no raised level in oil. No oil in the rad fluid. I am checking the oil soon to check for water/rad fluid. All we have is that it overheats that is equivelent. There has to be a lot of things that can make a car overheat. The nasty orange crusted crap in the cooling system clogging something. Bad thermostate. I found a water leak this morning so I know where the water was going. I am in the processs of running the car to flush out everything

then I will get a new radiator car because this one isn't sealing at all. I ran the car for about 30 minutes and took that purge hose off that is suposed to get rid of teh air in teh system that hooks to the top of the plastic tank and rad fluid was comming out as a steady stream. Then after filling up 3 coffe cans of water to try to lower the level down with the cap off the tank because I over filled it slightly it started pulsating a lot and the watter was hotter seemed like it was boiling inside the motor/thermostate housing. The temp on the gauge was at 1/2 way.

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Many of the things that you describe do not happen with a Northstar,

You WONT always get oil in the coolant, coolant in the oil, you wont always see STEAM out of the exhaust

You will SUPERHEAT the coolant because exhaust gases are causing the coolant to boil

You said coolant flows out of the air purge line, good.

How bad is the leak at the radiator? Is that is what is causing no pressure in your cooling system?

A bad stat that is stuck closed or not opening could be a problem, replace it, if you have not already done so


Pre-1995 - DTC codes OBD1  >> http://z-cut.de/US/dtcobd1.html

1996 and newer - DTC codes OBD2 >> http://carprogrammer.com/Z28/PCM/OBD2/On-BoardDiagnosticTroubleCodes(OBD-II).mht

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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There is no smoke no smell of radiator fluid in exhaust no preshure in the collant tank no raised level in oil. No oil in the rad fluid. I am checking the oil soon to check for water/rad fluid. All we have is that it overheats that is equivelent. There has to be a lot of things that can make a car overheat. The nasty orange crusted crap in the cooling system clogging something. Bad thermostate. I found a water leak this morning so I know where the water was going. I am in the processs of running the car to flush out everything

then I will get a new radiator car because this one isn't sealing at all. I ran the car for about 30 minutes and took that purge hose off that is suposed to get rid of teh air in teh system that hooks to the top of the plastic tank and rad fluid was comming out as a steady stream. Then after filling up 3 coffe cans of water to try to lower the level down with the cap off the tank because I over filled it slightly it started pulsating a lot and the watter was hotter seemed like it was boiling inside the motor/thermostate housing. The temp on the gauge was at 1/2 way.

Sprinter, I like your calm rational approach to this problem and the fact you are not allowing yourself to be panicked/stampeded into a possibly false diagnosis. There's every reason to hope you'll come out of this smelling like something other than antifreeze. Keep up the good work.

Regards,

Warren


Posted Image

There is no means of avoiding the final collapse of a boom brought about by credit expansion. The alternative is only whether the crisis should come sooner as the result of a voluntary abandonment of further credit expansion, or later as a final and total catastrophe of the currency system involved. - Ludwig von Mises

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Take it to a radiator repair shop and have it tested for a leak, that should not cost you a arm and leg. You can do the repairs yourself once they locate it to save money. You say that the car got hot the second time but the resevior was about an inch low a inch shouldn't cause the engine to get very hot. Check your water pump belt it maybe bad causing slippage and poor circulation. Get your car warmed up and run it while parked at different rpm's and see if you can find where the leak is. Check the overflow tube see if it is blowing out there which could indicate a bad resivior cap.That would be a relatively cheap fix.

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Ok found leak is now from the coolant cap witch I do not like. We called up one place and they said there computer read a 18lb cap was recomended. a 15 is what is on there

and they didn/'t have teh 18 in stock but can order it. We stopped by a nother place and they said a 15 lb is what is recomeneded we bought it and I just flushed the cleaner out of it and am running it on pure water for the last time before filling with dexcool. My dad is on his way picking up a tester for the old cap and a tester to check how much psi is being produced when the engine is running. Thank you guys for all of your help. I really like this car and will give it every chance I can to not say its over until it is over.

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Old cap lasted 8 minutes of just ideling before it started pushing out water. New cap now running 17 + minutes reved it to 2,000 Held it around 1,800 for 30 seconds nothing bone dry. Might take the risk and take it up the the racing banquet tonight riding in style in my cadillac and see how it goes on the highway. Ill bring a gallon of cold water with me.

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Buy an AC Delco cap. According to the FSM for 94 the cap is 15 psi

It is not necessary to see how much pressure the system generates, you want to see how much pressure the cooling system HOLDS, maybe you are saying the same thing

The cap is the reason why it was not holding pressure.

If your radiator is leaking, the new cap will make it worse.


Pre-1995 - DTC codes OBD1  >> http://z-cut.de/US/dtcobd1.html

1996 and newer - DTC codes OBD2 >> http://carprogrammer.com/Z28/PCM/OBD2/On-BoardDiagnosticTroubleCodes(OBD-II).mht

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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If the engine is warming up and the heater is blowing cold air, either the temperature control doors in the A/C are stuck or your heater hoses are clogged. If the heater hoses are clogged, the bypass is likely clogged too. the flush should fix both problems.

And, yes, use only an AC/Delco 15 psi radiator cap recommended for your car. There are several types of systems with different radiator caps out there and the differences can cause problems if you have the wrong one.


CTS-V_Dashboard.jpg
-- Click Here for CaddyInfo page on "How To" Read Your OBD Codes
-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data
-- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC
Yes, I was Jims_97_ETC before I changed cars.

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