[Noah P]

Ive got a 2002 cadillac deville base im gonna try to give as much detail as possible here.
First of all car only gas 106000 miles... been driving it for about 6 months with absolutely no problems furthest i would go was about 60 miles and nothing would go wrong the car ran like a champ then about 3 months ago the cars temp gauge went one bar over normal operating temperature with no heat good thing i was only about 6 miles from home i drove carefully and got home i checked it everything seemed normal drove it the next day about 20 miles gauge went one bar over but went right back down and nothing happened for a while after that then about 2 months later running the ac the car would start to get hot again so id turn on the heat and no heat would come out but it didnt get as hot this kept happening and i checked the coolant reservoir and it was a little low so i filled it up the car was fine for about 2 weeks then the problems started happening again.. i check the coolant its a little low and i notice leaking on my driveway kind of under the passanger side of the car it is orange so it is the dexcool and smells like antifreeze so i know its coolant well i just check it often now and keep it filled to halfway now the problems are worse i was driving about 50 miles from home then the car heats up quick all of a sudden i stopped anout 15 mins for it to cool off then i turned around it heats up again this time the gauge is all the way up and i gwt a message saying "engine hot ac off idle engine" so i stop again qbout 30 mins and im out in the boonies late at night with no money or no extra coolant or anything i had no choice but to drive home so i coasted home about 30 miles an hour 50 miles idling the engine. (There is no heat i have the heat blasting but its cold air) Get home and i check the coolant the next morning theres some coolant in the tank but its low i fill it up, go for a drive everything is normal heat is working its at operating temp and i get home in one peice. Next day comes, coolant reservoir is filled to half way i drive the car about 20-30 minutes heat blasting then the heat starts blowing cold air and the gauge goes up 3 bars past half. I let it cool down, drive back home and same thing happens i drove carefully. I check the coolant and the tank is filled almost full like it spit all the coolant into the tank it was halfway before i left. Now this same thing happens everytime i drive (overheats, no heat cold air, come home, and tank is almost full) i let the car idle in my driveway about 30 minutes it got up to operatint temp but heat never kicked in. I have to be driving to get heat but it takes forever and the heat isnt as hot as it should be. I dont see coolant leaking on my driveway anymore which i found wierd but i check the tank like 3 times a day and its either just under half full or almost all the way full.

Im sorry if this is very long i just want to give as much detail as possible i need help thank you

 

[Submariner409]

Perform a cylinder block exhaust gas test. Rent the test kit from any parts store.

Check the purge line for steady flow.

Check the surge tank cap for good seal.

Coolant expands greatly as the engine heats up. Correct cold (ambient) level is about half full, expanding to about 3/4 full, warmed up.

No heat means the heater core is airbound, due to low coolant - caused by coolant loss for some reason.

Coolant leaks, no purge flow, failing head gaskets due to cylinder block head bolt hole thread failure - leading to exhaust gas leaking into the cooling system, blowing off coolant.

Is the water pump drive system in good condition?

Many threads on the subject here, in Seville, and in Engines; Northstar.

 

[basscatt]

typically -
when you loose heat - there is air trapped in the cooling system -
the result is that the water pump can not move air - and the temp gauge goes up -

once the trapped air is purged out -
the water pump is able to move the coolant -
the heat resumes and the engine cools back down -

-------------------

check the PURGE LINE for a constant - gentle - coolant flow -
if not - the HOLLOW BOLT is clogged -

----------------

if the PURGE LINE does have a good flow of coolant -
it is time for a BLOCK TEST -

----------------

for more information - google: Cadillac Northstar PURGE LINE - HOLLOW BOLT - BLOCK TEST -
these have been discussed millions of times -

 

[RON93]

That was my first and only symptom of a bad head gasket, no heat. Do the block test first before you go crazy trying to find the cause. It is simple, cheap and takes all of two minutes to get your most important diagnosis out of the way.

 

[Noah P]

I will definitely get a test kit first and try then i will try to check the purge line after that is the test doesnt show a head gasket leak if the gasket is blown im screwed cause im only 16 and i have some knowledge on fixing cars but not enough to replace a head gasket on a northstar.

 

[Submariner409]

...... and you don't simply replace the head gaskets. You disassemble the top end - heads and all - and machine the 20 cylinder block head bolt holes to accept either threaded inserts or one-piece studs.

www.huhnsolutions.com

www.northstarperformance.com

All best done with the powertrain out of the car, on the floor.

Study the stickies on the subject in the Engines; Northstar thread. You're looking at over $1200 DIY or over $2400 local shop inserts, $3500 studs.

 

[Noah P]

Yes i am awars of all the work needed to go into this but worst case scenario i know this might not sound good but would blue devil be a good temporary fix if the gasket is blown. Its kinda funny cause im sitting on the side of the road right now cars running hot

 

[basscatt]

Yes i am awars of all the work needed to go into this but worst case scenario i know this might not sound good but would blue devil be a good temporary fix if the gasket is blown. Its kinda funny cause im sitting on the side of the road right now cars running hot

===========================
BEFORE dumping ANY crap in the cooling system
CHECK THE PURGE LINE - DO IT NOW - IT TAKES 2 MINUTES and it just mite FIX your problem -

there is absolutely NO temporary "fix" for failed head gaskets -
in fact - MOST of the "mechanic-in-a-can" products WILL cause MORE problems -

 

[Enterprise 4Cam]

Sure is hard for the 'non-mechanics' to wrap their 'head' around Northstars and 'head' gaskets.

No pour-in 'fix-it-all' is likely to work...at all...because the gasket is NOT the problem. The gasket is the 'symptom'.

The head bolts 'let loose', and, they also are 'not' the problem. Symptom.

The threads,,,in the block,,,ARE THE Problem, the great majority of the time.

There is no 'pour in' or 'pour on' fix for that. None.

 

[Submariner409]

Noah, before you go dumping in some goop please comply with posts 2 and 3. Discount the most common causes of Northstar overheating before condemning the head gasket bolt threads.

 

[Noah P]

Pulled the purge line and faced it into the tank it was idling that whole time said it was upto operating temp but nothing was coming out at all i tried to pull the rest of it appart but it wouldnt come of im gonna stick a wire coat hanger in there and see if its jammed up for now ill let you guys know

 

[Noah P]

Oh yeah and i have engine code P1258 could this have anything to do with it?

 

[bjc789]

Go to the purge line source by the throttle body and take the rubber hose off there. The fitting that gets plugged is right there.

Clean that orifice out by using a twist drill bit by hand and keeping the ‘stuff’ coming out toward you not back into the engine. Do not enlarge the orifice, it’s metered properly to do its job.

Or you can remove the fitting, but it will have to be resealed after cleaning it.

It’s amazing how that little purge line keeps all things working smoothly, and makes it so woefull when it’s plugged.

Oh yes, please post the definitions with the codes....

 

[ironeaglejrc]

I know with with my 2000 DeVille i had a coolant leak after chaging the thermostat and water pump. My leak was coming from the gaskets on water coolant crossover manifold on the side of the engine where the water pump is connectd to. Have some pics that I will post when I find them.

 

[RON93]

Oh yeah and i have engine code P1258 could this have anything to do with it?

P1258 means the operating coolant temp at some point got over 268*F and the car went into protection mode.

 

[Submariner409]

The Deville has a long purge line - clean the hollow bolt/nipple, the entire line itself, and the surge tank nipple. If the purge line itself will not clean out use a single correctly sized length of reinforced rubber fuel line from any parts store. New screw band clamps.

Once you get the cooling system working correctly the P 1258 will go to History and then self-clear after a while. It says the engine went into Camel Mode due to overheat.

Pictures and purge line - here you go. Click to enlarge, use the side < > to scroll.

 

[Submariner409]

More work for you - if the water pump drive belt tensioner pulley has never been changed, do it yesterday. When (not if) that pulley seizes you are in big bucks repair country.

The safety shroud comes off with two 10mm nuts and a 10mm bolt. Lever the pulley arm to relieve tension, remove the pulley center bolt. If the belt looks good, don't mess with it.

 

[basscatt]

Pulled the purge line and faced it into the tank it was idling that whole time said it was upto operating temp but nothing was coming out at all i tried to pull the rest of it appart but it wouldnt come of im gonna stick a wire coat hanger in there and see if its jammed up for now ill let you guys know

=============================
there should be a constant - gentle - flow of coolant from the PURGE LINE whenever the engine is running - regardless of engine temperature -

remember - the PURGE LINE is the ONLY way to get trapped air out of the cooling system -
and an air-lock WILL cause overheating -

oh ya - I TOLD YOU SO -

 

[Noah P]

=============================
there should be a constant - gentle - flow of coolant from the PURGE LINE whenever the engine is running - regardless of engine temperature -

remember - the PURGE LINE is the ONLY way to get trapped air out of the cooling system -
and an air-lock WILL cause overheating -

oh ya - I TOLD YOU SO -

Thank you so much i took the whole purge line assembly out and cleaned it out with a wire and blasted it with water. Hooked it upto the car it was idling there was a very steady stream coming from the line i drove kt about 15 miles no mishaps only thing is that the heat was kinda on and off or the hot air was very weak i think ive gotta flush out the heater core i didnt use the heat though while driving cause i feel like if its clogged it will cause overheating?

 

[Ranger]

If your purge line was clogged, you had air in the system. Now that you have cleaned it out, just give it a couple of days to purge the air and keep an eye on the coolant level during that time. No need to flush the heater core.