: Northstar overheating-Repair



gino9
01-13-14, 06:57 PM
Hello
My northstar on seville 2001 start overheating.....and burned oil.....
Decision,,Yes I will keep car so have to be repair.
I order head bolts repair kit and head gasket full set from CCC(thank you CCC)
I left car in garage to repair and......
One Head gasket burned,the heads overheat(bend) and need new pistons rings.
Pls any advise on it??
I Should surface on block engine or heads?(heads on ready done)
What make pistons ring I should choose?
Need new Thermostat...

Engine done 71000 miles....

97EldoCoupe
01-13-14, 07:09 PM
Hastings. Did you email us today? We received a pricing request
-

-Jake

Ranger
01-13-14, 09:04 PM
One Head gasket burned,the heads overheat(bend) and need new pistons rings.
Are you SURE? That's pretty rare.

97EldoCoupe
01-13-14, 10:24 PM
Ranger is right, warped heads are very rare to see with a Northstar. If the engine has been severely overheated, check the ring lands for cracks. Pre-ignition has been known to do some damage.

gino9
01-14-14, 05:08 AM
Yes,I email to northstar perfomance

And yes warped head.

I seen some pistons ring on rockauto DNJ and SEALED POWER or from NP

maeng9981
01-14-14, 08:31 AM
FWIW, my engine parts were alright (except a chain tensioner) after being overheated up to 300 degrees. I checked the heads for warping and any other additional damages, but there were none. After the stud repair (and the tensioner of course), the car is running fine with no issues after 8 months and 10,000 miles.

gino9
01-18-14, 04:37 AM
Hello
When you do this job is ok to do grinding,polishing surface engine block?on side where gasket??

Submariner409
01-18-14, 08:53 AM
Do not surface the block or heads. Thorough cleaning with gasket remover only. DO NOT use any form of abrasive pad, sandpaper, or Scotchbrite. Any of those, and Scotchbrite in particular, is death to an engine.

If you feel the need, have an engine repair shop check the heads for surface flatness. Any warpage is head replacement - you do not resurface these heads due to combustion chamber quench area restrictions.

Contact 97EldoCoupe concerning block surface preparation. www.northstarperformance.com

Ranger
01-18-14, 09:57 AM
scotchbrite in particular, is death to an engine.
amen brother!

97EldoCoupe
01-18-14, 07:18 PM
As per the GM Service Manual. They say it clearly. Use nothing with a sharp edge- a wooden or plastic gasket scraper is fine. Surface feel is important, surface appearance is not. You should not feel any gasket material left on the surfaces at all.

Any corrosion spots can be smoothed out with a very, very fine grit sandpaper or surface conditioning disc, but any dust created by this process MUST be removed and not allowed to get into the cylinders or oil passages. If the surfaces is corroded; that corrosion is actually aluminum oxide, a very hard substance (think sandpaper).....you don't want those particals in your cylinders or oil system.

Any low spots, score marks or scratches will create a potential leakpoint. Be especially careful when removing the alignment pins/collars.

As Submariner409 and Ranger said; avoid scotchbrite at all costs.

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Surface corrosion is sometimes present around cyl #1 because of water and salt (depending on where you live) being splashed up from the RF wheel. But usually not deep enough in to affect sealing of the head gasket.

Heads can be resurfaced if need be, by VERY little. I believe the limit is .003". Blocks...if you resurface the block you need to run a thicker head gasket to make up for the difference because of what Submariner409 said: you mess with that quench area there will be problems. I suppose you could get away with a bit, but it will play with your C.R. and in that case use the 2004 pistons (GM upgrade). GM upgraded the pistons to reduce cold carbon knock...went from flat top pistons with no valve reliefs (2000-2003) to domed pistons to allow for more room for carbon to build up without slapping the head. Fortunately, the way most of us drive our Cadillacs, carbon won't get a chance to build up :)

gino9
02-27-14, 12:44 PM
Ok,tommorow big day..collect car from garage...
Before collect car from garage what I should check?

gino9
03-01-14, 08:29 AM
Hi
When vehicle idling Is

189714

When acclerate back to 90c
Pls help

Submariner409
03-01-14, 09:25 AM
Read the sticky posts ^^^ just above this for information on the cooling fan operation, cooling system operation, and gauge indications.

Your engine may simply have trapped air in the cooling system - proper coolant level, cold, is halfway up in the surge tank. Check the level and add some 50/50 coolant if necessary.

Search for tips on how to test and clean the coolant purge line and bolt/nipple. Google "cadillac forums northstar coolant purge line cleaning" and/or go through the pages of Cadillac Tech Tips.

gino9
03-01-14, 06:26 PM
Ok what I found upper radiator hose is not hot enough but when accelerate is very hot.Maybe water pump?

Ranger
03-01-14, 08:46 PM
Why does everyone want to blame the poor WP all the time. IF THE WP SPINS, IT'S FINE. Sounds like you may have air in the system. Is the purge line clear?

maeng9981
03-02-14, 12:23 AM
If your purge line is clear and you have enough coolant, check your cooling fans for proper operation.

04GrandAmGT
03-03-14, 01:59 PM
Why does everyone want to blame the poor WP all the time. IF THE WP SPINS, IT'S FINE.

for some reason when i read that it made me chuckle, like the WP has feelings, but Ranger is right check the purge line, Thermostats are pretty much bullet proof on these engines, but they can go from time to time doubtfull but can, make sure yat idle your purge line has a steady stream of coolant coming through.

gino9
03-03-14, 02:41 PM
Ok
How can I check cooling fan?

Is new Thermostat(old gone)
My engine was rebulid,new seals,gasket,head stud,piston rings etc.

04GrandAmGT
03-03-14, 03:15 PM
Ranger or Submariner, i forget which one has a nice diagram of the temp gauge and when the fans are supposed to kick in, if you guys could post it, that would be peachy.

MoistCabbage
03-03-14, 03:40 PM
It's in subs albums.

Low speed at 224 (or when any A/C function is set).
High speed at 236.

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Courtesy of Submariner 409:

http://i1130.photobucket.com/albums/m538/moistcabbage/CADE910B-E8F1-4161-B585-34AE4D2BEA32_zpstfvcletu.jpg (http://s1130.photobucket.com/user/moistcabbage/media/CADE910B-E8F1-4161-B585-34AE4D2BEA32_zpstfvcletu.jpg.html)

gino9
03-03-14, 03:44 PM
I seen diagram.
How You know when cooling fan is on speed 2?

MoistCabbage
03-03-14, 03:49 PM
It'll sound different than low speed operation.

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I have to backtrack a little. If you're testing fan operation, the car is still together and running. Correct? There's no way somebody diagnosed warped heads without removing them.

Back to your question. If the car is overheating at idle, low speed fan operation is all it would take to keep it cool. if the fans run, your problem is not cooling fan related.

Ranger
03-03-14, 04:03 PM
The cooling fans run anytime the A/C is on, so turn on the A/C (or defroster if it's below 1.6C). The fans should come on.

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I seen diagram.
How You know when cooling fan is on speed 2?
There is no speed 2. I believe the fan speeds are infinite. Somewhat like a dimmer switch.

Submariner409
03-03-14, 05:00 PM
Fans run in SLOW or FAST - 2 speeds.

SLOW at 224 degrees, FAST at 236 degrees.

Here's the 2000-2004 fan electrical circuit - SLOW speed is fans relay-set to series operation, FAST is parallel.

Sound alone will tell you when fans shift to FAST - they move a LOT of air. It's all just above this thread in the fan operation sticky.

gino9
03-04-14, 10:19 AM
Today I will check purge line...
Now some picture on my engine


190745



190753



190753

gino9
03-09-14, 04:38 PM
hi
Today I tested again engine..
Without A/C temperature go to 206F and back to 12 clock and again 206F and back to 12 clock(nice)
With A/C temperature go slowly to 236F and stay there,when accelerate go back to 12 clock and again.....
When driving always 12 clock.
When disconnect purge line looks OK.
Mechanic put in to cooling system GREEN antifreezer.
Not sure yet but maybe really small leak from radiator.

Ranger
03-09-14, 09:15 PM
When disconnect purge line looks OK.
Looks mean nothing. Does it flow coolant at idle?


Mechanic put in to cooling system GREEN antifreezer.
Was it low? If so, how low?

gino9
03-10-14, 05:19 AM
RANGER my engine was rebulid after HG failure.Now I would like be sure everthing is Ok.
Yes is flow on purge line...His put green antifreezer.
I'm not sure about temperature when idle.Should be like that what I wrote above?
Thx

MoistCabbage
03-10-14, 05:31 AM
The color of the antifreeze is irrelevant.

How did you check the purge line flow?

Was the coolant level low?

Before the HGs were repaired, did you use any stop leak products?

The repair did inure inserting or studding the block, correct?

Ranger
03-10-14, 10:09 AM
RANGER my engine was rebulid after HG failure.Now I would like be sure everthing is Ok.
Yes is flow on purge line...His put green antifreezer.
I'm not sure about temperature when idle.Should be like that what I wrote above?
Thx
No. Running the A/C should have no effect on the temperature gauge. Mine never leaves 12:00 A/C on or A/C off. 236 is too high. The fact that it goes down when you accelerate leads me to think that there is air in the system.

04GrandAmGT
03-10-14, 10:20 AM
No. Running the A/C should have no effect on the temperature gauge. Mine never leaves 12:00 A/C on or A/C off. 236 is too high. The fact that it goes down when you accelerate leads me to think that there is air in the system.

possible HG failure again? could have been improper hg job done... you never know.

Ranger
03-10-14, 10:26 AM
Good point Evrett. Was the HG job done? Where all 20 bolt holes drilled, retapped and inserted or studded?

gino9
03-10-14, 05:44 PM
192538

Purge line...I disconnect hose from bolt (when engine over 12 oclock)and coolant flow with high pressure.After coolant pee..
All 20 bolt holes was drilled.HG job done,all gasket seals,thermostat,piston ring...Not sure yet how good:bighead:
I didn't check yet nipple from surge tank,Maybe there is blocked.What I found,manifold intake take air.

MoistCabbage
03-10-14, 05:59 PM
NEVER open a cooling system when hot. The correct way to check the purge line is to disconnect it (when cold) from the surge tank nipple, not from the bolt/nipple near the water pump cover. Yes, you can also check the tank nipple for blockage.

As Evrett,Ranger and I have asked, were the proper inserts or studs used? They didn't use Helicoils, did they?

gino9
03-10-14, 06:06 PM
Head Bolts are from CCC

http://i777.photobucket.com/albums/yy56/gino9_2010/Screenshot_2014-03-04-15-14-10.png (http://s777.photobucket.com/user/gino9_2010/media/Screenshot_2014-03-04-15-14-10.png.html)http://i777.photobucket.com/albums/yy56/gino9_2010/Screenshot_2014-03-04-15-14-29.png (http://s777.photobucket.com/user/gino9_2010/media/Screenshot_2014-03-04-15-14-29.png.html)http://i777.photobucket.com/albums/yy56/gino9_2010/Screenshot_2014-03-04-15-13-17.png (http://s777.photobucket.com/user/gino9_2010/media/Screenshot_2014-03-04-15-13-17.png.html)http://i777.photobucket.com/albums/yy56/gino9_2010/Screenshot_2014-03-04-15-13-34.png (http://s777.photobucket.com/user/gino9_2010/media/Screenshot_2014-03-04-15-13-34.png.html)http://i777.photobucket.com/albums/yy56/gino9_2010/Screenshot_2014-03-04-15-13-25.png (http://s777.photobucket.com/user/gino9_2010/media/Screenshot_2014-03-04-15-13-25.png.html)http://i777.photobucket.com/albums/yy56/gino9_2010/Screenshot_2014-03-04-08-24-24.png (http://s777.photobucket.com/user/gino9_2010/media/Screenshot_2014-03-04-08-24-24.png.html)http://i777.photobucket.com/albums/yy56/gino9_2010/Screenshot_2014-03-04-08-23-58.png (http://s777.photobucket.com/user/gino9_2010/media/Screenshot_2014-03-04-08-23-58.png.html)http://i777.photobucket.com/albums/yy56/gino9_2010/Screenshot_2014-03-04-08-23-39.png (http://s777.photobucket.com/user/gino9_2010/media/Screenshot_2014-03-04-08-23-39.png.html)http://i777.photobucket.com/albums/yy56/gino9_2010/Screenshot_2014-03-04-08-24-13.png (http://s777.photobucket.com/user/gino9_2010/media/Screenshot_2014-03-04-08-24-13.png.html)http://i777.photobucket.com/albums/yy56/gino9_2010/Screenshot_2014-03-04-08-24-50.jpg (http://s777.photobucket.com/user/gino9_2010/media/Screenshot_2014-03-04-08-24-50.jpg.html)


Head bolts are from CCC

http://i777.photobucket.com/albums/yy56/gino9_2010/Screenshot_2014-03-04-08-24-35.jpg (http://s777.photobucket.com/user/gino9_2010/media/Screenshot_2014-03-04-08-24-35.jpg.html)

Ranger
03-10-14, 08:42 PM
OK, questions answered and it seems to have been done correctly.

04GrandAmGT
03-11-14, 10:58 AM
where alignment dowels reinstalled, ccc doesnt have self aligning studs in the upper 4 corners, could have torqued head down not 100% straight would cause instant hg failure again. by the looks of the last picture there was no alignment dowels installed.

PS - Drilling and tapping with no cylinder protection not recomended but should be fine because from the looks of it they had it completely apart and were ready to wash it, though by the looks of pic 18/23 looks like there are still alum shavings when they reinstalled the pistons, HOPEFULLY they cleaned those out because those could cause serious cylinder damage! but seems like the HG job was done correctly.

97EldoCoupe
03-11-14, 02:54 PM
Gino9-

Never drill/tap an engine block freehand. There is a reason I sell a fixture plate with my kits, the slightest alignment issues shift the stresses in the block. Take it from someone who has experience, doesn't matter what kind of a threading tap you have- bottoming, taper, spiral flute, etc.... you will NEVER thread a hole completely straight without using a guide of some sort. Anyone who wants to argue this point; come to my shop and we will do some experimenting on this.

I hope all goes well and that you can get that overheating issue sorted out.

Wishing you the best.

-Jake

gino9
03-11-14, 03:44 PM
Before the HGs were repaired, did you use any stop leak products?

Not me 'but previous owner.

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Gino9-

Never drill/tap an engine block freehand. There is a reason I sell a fixture plate with my kits, the slightest alignment issues shift the stresses in the block. Take it from someone who has experience, doesn't matter what kind of a threading tap you have- bottoming, taper, spiral flute, etc.... you will NEVER thread a hole completely straight without using a guide of some sort. Anyone who wants to argue this point; come to my shop and we will do some experimenting on this.

I hope all goes well and that you can get that overheating issue sorted out.

Wishing you the best.

-Jake

They used own alignment,so didn't drilled freehand.

So..what next if job was made correctly?

Radiator?
I will go check block surge tank now

I forgot,they give me 6 months warranty to check everything is ok.

04GrandAmGT
03-11-14, 03:56 PM
get a cooling system flush done maybe rad has limited flow from stop leak style products.

gino9
03-11-14, 05:21 PM
I think before about this but before HG failure was OK.I will do it....OMG

97EldoCoupe
03-11-14, 05:50 PM
Stop leak usually doesn't clog radiators first -

this is where I have to agree with the usual "check purge line" idea, it is imperative to cooling system operation that the system be free of air.

Have you done the exhaust gas test after the new build? I hope it is something minor. Nobody wants to do this job over-

gino9
03-15-14, 10:56 AM
Today I did exhaust gas test.....is ok.Blue colour....what now?
I found the manifold intake(top right corner) take air and idle is rough.Looks like manifold intake gasket not in correct place or......

Submariner409
03-15-14, 07:02 PM
Here are your intake manifold "gaskets" - 8 formed silicone seals. If you can see any part of one you have problems.

sts 03
03-25-14, 09:32 PM
ccc studs come with spring loaded dowel pins ,did you use them on the top bank corners?

gino9
03-27-14, 07:14 PM
ccc studs come with spring loaded dowel pins ,did you use them on the top bank corners?
don't know,car was in garage

Last time I warm up engine,turn off and checked by touch the radiator.For me bottom radiator was cold.Warm place was top left where hose is IN.
So I think there is problem.I will flush the system first.
What you think?

Submariner409
03-27-14, 07:29 PM
You'll never get any good idea of radiator "warmth" by letting the car sit and idle. It has to be driven for 10+ miles and the ambient temperature has to be high enough to allow the engine to heat to the point that the thermostat is fully open and coolant is circulating. You can actually, in cool//cold weather, cool the entire engine system with the heater core only - the thermostat would never open under low load conditions, so no radiator flow. You need to check inlet/outlet temps with an IR gun, and the inlet will be at least 188 degrees (thermostat opening point) - outlet temp will depend on ambient temperature.

The thermostat regulates flow through the radiator - very little flow under low power/low temperature conditions.

EDIT: A crossflow radiator core should be fairly - fairly - even in temp from top to bottom, definitely cooler on the outlet (driver's) side.

gino9
03-29-14, 03:34 PM
Ok thx submarine409
I flush system,and warmth engine and still the same.Again I check radiator and is warm (left and right Side)
All hoses are hot.
So what next:suspense: Could be failure New thermostat or cap from surge tank???Why when idle getting overheat but when even touch accelerator is ok(Back to 12aclock)Tested on gas in engine is OK,not change colour:yup:

Or something wrong with tensioner on water pump?
OMG I love northtstar engine:)

Ranger
03-29-14, 08:30 PM
Why when idle getting overheat but when even touch accelerator is ok
That sounds suspiciously like loose belt tension.

gino9
03-31-14, 11:35 AM
You think tennsoner from water pump?
How I can check that?

Also they replaced cap from surge tank and on label said 16 psi,I think sholud be 18psi or sholud work?

Ranger
03-31-14, 11:48 AM
16 or 18 psi will work. That is simply the relief pressure. You should never be that high anyway.

Look on the backside of the tensioner. There is a square hole. Put the drive lug from a 1/4" drive breaker bar in there and use the bar as a handle to pull on it and check the tension. It should be rather tight.

97EldoCoupe
04-02-14, 12:54 AM
Gino9, this may have been asked before, what brand thermostat do you have in there? To me it sounds like you don't have enough flow at idle- exactly what Ranger said. If it's not the w/p belt tension, it may be turbulence caused in the housing due to an incorrect t-stat. AC-Delco is what I always use, never had an issue with those.

If you run it on the highway, temp stays completely normal?

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If the temp reaches 236 and the cooling fans are commanded on "high speed", I fail to see how that is a problem. They're designed to kick in at that temperature. Mind you, that should only occur on a hot day, after some high speed (spirited) driving, then sitting idle at a red light, with the A/C on as you stated. Then the fans should drop the temp almost instantly back down to a reasonable temp. GM set that a bit high in my opinion.

Normal temp at cruise speed should be 192-198 degrees F. (+/-, thermostats are not all the same). It is the thermostat's job is to regulate this. Thermostats are cheap; and easy to change. I would change it just to be sure.

gino9
05-10-14, 05:22 AM
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[/COLOR]Hi
I used Motorad but replaced now for AC delco,also replaced surge tank cap for ACdelco 18psi.
Before that I flushed system and that little helped.
I tested temperature on pipe by thermometer gun.When engine overheat on before thermostat pipe show 90c on intake pipe to radiator 40c.water go out by surge tank cap.When accelerator was fine and thermostat open....
Now I waiting for intake coupling manifold becouse was damage and make my idle rough.Ordered on rockauto.
How you test temperature sensor?

Submariner409
05-10-14, 10:34 AM
90 C (195 F) is not overheating - that is exactly the desired normal engine temperature.

40 C (104 F) is low - very low.

The ECT (Engine Coolant Temperature) sensor is a variable resistor which changes value as the coolant heats and cools. If you suspect that it is bad, change it. Very difficult. The wiring or connector may also be faulty.

More pictures and diagrams in my albums - click my username, open the profile. Left column - 2 albums 6 pages of Northstar parts and service info.

gino9
05-10-14, 10:59 AM
On dash show over 195F overheating,water go out from surge tank cap but on thermostat is 195F(check by thermometr laser gun)but after thermostat(intake radiator pipe) is very low temperature.

Submariner409
05-10-14, 11:06 AM
Is your thermostat installed correctly - with the spring and copper tube pointed toward the water pump side ?

Click on a thumbnail to enlarge - use your browser <- to back out............

gino9
05-17-14, 02:25 PM
Hello
Today I fit new intake coupling for manifold and test engine with new surge tank cap and thermostat.
Wow engine run long all fans on in correct time and NO overheating.but engine check lights on.
I turn off engine to cool down.
After 2h Top up water in cooling system and start engine.I check codes a lot codes in history....when I cleared codes angine stall...off.
Now engine stall,Turn on and engine off.
Check codes and find one PCM P1599
Engine stall and detected.Smell little fuel but before that when changed intake coupling I removed fuel rack and intake manifold.
So why now engine stall,before when trst engine was perfect....

MoistCabbage
05-17-14, 02:42 PM
Recheck all of the intake ducting and clamps, as well as the resonator.

If you smell fuel, check around the injectors and fuel rail quick connectors.

gino9
05-17-14, 03:32 PM
Ok after 10 min engine ON nearly stall but back to normal rev.Drive OK after drive engine idle(little rough) 20 min and thanx god not overheat......I turn OFF engine and turn ON again but with engine check lights ON.
Current code is PCM P0102 I think is detected MAF sensor.
History code is PCM P1599 engine stall and detected.....not sure.
Also I used glue to repair intake coupling(big pipe before Throttle)not sure how to call that.

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Haha sorry
Air Flow Sensor was disconnected.....

MoistCabbage
05-17-14, 03:53 PM
Hmm, the engine should run fine with the MAF unplugged.

The large rubber tubes are intake ducting. Not sure that any glue would hold it and stay air tight. Grab a replacement from a salvage yard.

Ranger
05-17-14, 05:11 PM
Also I used glue to repair intake coupling(big pipe before Throttle)not sure how to call that.
:tisk: You need to replace that plenum duct.

gino9
06-21-14, 10:45 AM
Today nice hot day made trip 100 miles 40 min in traffic and fine,perfect.When reverse on huge hill to park my car temp nidle go over 12 clock after back to 12.Normal?

maeng9981
06-22-14, 02:34 AM
Refer to the temp gauge notations by Submariner409 - Post 20 in this thread.