Last post on Mar 10, 2010 at 6:30 AM
You are in the Cadillac DeVille
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Cadillac DeVille, Sedan
#14 of 23 Re: 2002 Cadillac Deville 4.6 [bena8837]
Oct 28, 2008 (11:28 pm)
I comes from the factory with orange Dexcool. That is what GM recommends.
By 2002, I think Cadillac may have stopped recommending the coolant tabs. On older models, there was a sticker on the motor/plastic fan cover/somewhere under there, that gave the part number for the tabs.
You only need to add tabs if you dump all the old coolant out. Since you can't get all of it out by opening the radiator or pulling a lower hose, I only put three in.
DON"T PUT THE TABS IN THE "OVERFLOW" TANK. (It really isn't an overflow tank, because it is pressurized and has the rad cap on it. It is correctly called the 'surge tank'.) PULL A RADIATOR HOSE AND PUT THE TABS IN THERE. There is not enough coolant flow thru the 'surge tank' to move the tab material out of there, and it is mainly useless if put in there.
The tabs are used mainly for very minor leaks - seepage type, or porisity opening in the block/head castings. The tabs were developed for the earlier 4.1 and 4.9 motors and carried over into the Northstar motors up until about 2001 where there were some redesigns made to the Northstar and I think GM no longer recommends their use.
#15 of 23 Re: 2002 Cadillac Deville 4.6 [bolivar]
Nov 03, 2008 (8:16 am)
Thanks for the info., appreciate it!
#16 of 23 99 caddy deville
Dec 08, 2008 (6:18 pm)
my coolant ran up to 260...i shut the engine off. mechanic replaced surge tank, thermostat, and radiator for 800 bucks parts and labor. now heat does'nt work and i ran up to the steamin' 260 again...of course i shut down and the mechanic says he will look at it again. he says there are no signs of a blown headgasket and will have to look into it some more. before i left he said he had it idle for two hours with no problems...that my coolant problem was fixed. he also suggested that i replace all those parts in order to fix the problem! two questions...what could the problem possibly be? what obligation does this shop have after telling me the problem was fixed? he said there were no signs of a head gasket problem.
#17 of 23 Re: 99 caddy deville [hagerhorst]
Dec 08, 2008 (10:24 pm)
You have to 'load' the motor before a leaking head gasket starts to cause overheating. (Unless it is really bad leak.)
If driving slowly does not overheat, but going to high speed (60mph+), or driving up a hill, does start an overheat - blown head gasket problem.
There might be a problem with the small belt that drives the water pump. This is driven off the rear of the left head cam. Which means it it near the front of the car on the driver's side. This belt is under a metal cover. Or might be a problem with a sticking thermostat or bad water pump. But these usually don't cause a problem.
I don't understand why this causes the heat to fail. I'm not going to get into whether or not the mechanic owe you anything for the problem continuing. This is between you and him.
#18 of 23 98 calillac deville water pump?
Dec 26, 2008 (2:39 pm)
Every 5-6 days had to add about 1-1.5 gallons of water to system. Water has been leaking from left front of vehicle for abour 2 months. the other day on 60 min drive engine heated up to 260 degrees and warning light came on. got home and had to add about 2 gallons of coolant. could the water pump be leaking? dont think this model has a weep hole like others. The pump is the type that sets in the housing and seals with an o-ring. Any help?
#19 of 23 Re: 98 calillac deville water pump? [jpix1]
Dec 27, 2008 (3:56 am)
The water pump is leaking. Replace the water pump. It comes with a new o-ring seal. It takes a special tool to remove. It has 'left hand' threads when removings. An auto part house should loan you the special tool.
Or, the cross over pipe is leaking. Much more involved to repair.
Both are on the left front on the motor area (Essentially the 'rear' of the motor since it sits in there cross-wise).
What aren't you fixing this leak? You are going to burn the motor up if you continue to run it while low on coolant. Or blow a head gasket - which is already a weak point of Northstar motors, and very, very expensive to repair.
#20 of 23 Re: 98 calillac deville water pump? [bolivar]
Dec 27, 2008 (6:56 pm)
Thanks Bolivar. replaced it today. It only overheated the other day. I guess the pump got so bad that it lost more coolant that one time. Couldn't tell if the pump was bad when I took it out and replaced it. But did it anyway. Figured that could be the only place leaking.... No leaks so far.
Dec 10, 2009 (9:45 am)
I am replacing my head gaskets on a 99 northstar motor. My kid and I are decent mechanics. He has been on the net looking into the take down, BTW we have it down to the point of pulling the heads. The problem is the timing chains. How do I take them off with out pulling off all of the passenger side of the engine parts? I.E. powerstreering pump, vibration damper etc. I find it hard to believe that they would be that shortsighted on the repair of this. Can or should you pull the timing gears off the cams or is this a bad idea? Any help here is greatly appreciated. I really can't afford the cost of the repair in a shop.
#22 of 23 Re: bullet6 [bullet6]
Dec 10, 2009 (6:21 pm)
All I know is what I read.
I can't help with the disassembly of the cams.
But I CAN tell you about the head gasket (from long reading forums about CAdillac Northstar motors.)
You CANNOT just replace the head gaskets on a Northstar!!!!! The problem is that the heads have loosened up - steel headbolts into an alumium block. And, when you unbolt the heads, more bolts will probably strip out their threads.
You MUST put a Timesert kit into this car. This is a kit where you must drill out all the headbolts, rethread the holes, and then screw in a special insert, a Timesert. Then, new head bolts can be screwed into these inserts. This will 'fix' the head gasket problems.
Search for Timesert on the internet. If you just slap a new gasket on the head, it is not going to work!
The Timesert kit is about $400. This gives you a bolt-down jig to aid in the drilling and tapping, and one set (20, both heads) of the special inserts. You will have to pull the motor to get to the rear head
#23 of 23 99 deville overheating issue
Mar 10, 2010 (6:30 am)
i have a 99 deville with the northstar. i recently replaced the upper water hose, lower water hose, used radiator (6 month ago), water pump (1yr 6 months ago), over flow coolant bottle (1yr ago). This car was fine (199- 205 degrees) for about a 25 mile drive and around on the 26th mile it started to overheat to 212, 215, 212, 219, 215, 222,215, 233, 222, 238, 221, 243, 233, 245, 235, got to 251 and stayed at that temp for last mile and never dropped till after i parked and let it cool. It didnt overflow. it did steam the windshield for bout 15 seconds then the overflow bottle gargled bout 10 secs and that was it. if i let it sit 8hrs while im at work. then drive home it does the same thing. it will be good for the 1st 25 miles then start overheating the same way. i checked the oil it looks fine, i chainged the thermostat and same thing. however on the back of the engine, up aganst the firewall side of the engine, i noticed a trace of seepage and a steam sound after it overheats. my mechanic says its a chanel that runs across the block thats leaking, not the heads but idk wat to do. the fans do kick on at 222 and one of them blows on high the other at normal speed. any clues? thanks 4 ur time peeps! im at work now today it got to 261 when i parked. only ran it at that temp for maybe last 10 secs of drive. and also no check engine light. i am in houston, tx i work in the medical center for st lukes hospital dgarcia77373yahoo.com