Head gaskets 1999 jimmy gmc

Check to make sure both hoses are getting hot. A significant amount of temperature differential could indicate a bad or incorrectly installed thermostat, air in the system or a plugged radiator. I would also put a block tester especially if it overheated badly as it could have blown the head gasket. The block tester will indicate if exhaust gasses have found their way into the cooling system by way of a blown head gasket which may cause vehicle to overheat.

I had the same problem on a 2000 Jimmy and it turned out to be the intake manifold gaskets not the head gasket so you may wanna check that out before you start the grueling job of head gasket replacement intake gaskets are a much easier fix

I had this happen to me the first time I replaced my intake manifold gaskets. It was hard to install the intake and gasket moved just enough and I had a coolant leak. Removed manifold and installed new gaskets and problem was solved. Good Luck.

Yes and no. With a chilton repair manual and a torque wrench it's not hard to replace heads on the trucks (LABLE EVERYTHING) The problem is the heads won't be fixable, and at a $1000 a piece for rebuilt ones its not cheap. Most junkyard motors will be there for the same reason as her truck, so don't use heads you don't know are good. Also, buy a complete engine rebuild gasket kit. There are a lot of little gaskets that you cannot but separately and should be replaced as you go. If there is water in the oil (light brown / bubbles) the motor is probably junk, and a motor swap would be better. Lastly give it a shot, most places will just say replace the motor for $3000, so you can't do any more damage and don't forget to replace the thermostat, as this is probably what caused the problem.

Hello,

Here is a detailed summary on the procedure of how to replace the intake manifold gasket on a 1996 gmc jimmy;
REMOVING THE UPPER INTAKE MANIFOLD(PLENUM)
STEP 1 Disconnect Battery (may not be absolutely necessary, but a good practice to avoid shorting a positive wire to ground).


STEP 2 Remove serpentine belt.

STEP 3 Drain the coolant.

STEP 4 Remove air cleaner ducting and disconnect wires.

STEP 5 Disconnect throttle linkage and bracket.

STEP 6 Disconnect cruise control cable.

STEP 7 Remove brake booster vacuum hose at manifold.

STEP 8 Remove PCV hose.

STEP 9 Remove ignition coil and bracket.

STEP 1O Remove purge solenoid and bracket.

STEP 11 Relieve fuel pressure at test port.

STEP 12 Remove fuel lines and bracket.

STEP 13 Remove upper intake manifold.

REMOVING THE LOWER INTAKE MANIFOLD
STEP 1 Remove the distributor and label the spark plug wires.

STEP 2 Remove heater hoses and bypass hose.

STEP 3 Remove upper radiator hose.


STEP 4 Remove EGR valve?

STEP 5 Remove sensors and bracket on right side.

STEP 6 Remove EGR tube, clamp and bolt.

STEP 7 Remove PCV valve (and replace).

STEP 8 Unbolt A/C compressor and move it aside.

STEP 9 Loosen compressor bracket and slide forward, but do not remove it.

STEP 10 Remove alternator bracket bolt (or remove alternator and set aside)

STEP 11 Unplug all vacuum lines from intake manifold.


STEP 12 Unplug all electrical connectors from manifold.

STEP 13 Take note of the intake manifold bolts and mark the location of the bolts.


STEP 14 Remove intake manifold bolts, and manifold.

STEP 15 Clean mating surfaces

THE MAIN INSTALLATION
STEP1 Set the new gaskets in place and apply silicone to flat areas on front and rear of engine block.

STEP2 Apply thread locking compound to manifold bolts.

STEP 3 Install the manifold and tighten bolts to 35 ft-lbs, in proper sequence.

STEP4 Install the distributor.

STEP5 Install the upper intake manifold.



The remaining installation procedures are basically the reverse of removal.


Have a nice day.

Intake manifold gaskets

I guess the burning question is , where is the coolant going.
Is this a 4.3 engine? How many miles does the vehicle have?
Has the intake gasket been changed?
I'm guessing a can of "Bars Leak" may cure your problem.
Let me know.
Regards,

As long as the heads are not damaged from overheating repairing would be an option rather than replacing the engine. Get advise from a mechanic you trust. The intake manifold gaskets are the most common problem with this vehicle if you have the V6 engine.

http://www.autozone.com/shopping/repairGuide.htm?pageId=0900c152800bfc68
hope this helps

It's on your fuel injection rail BELOW the upper intake manifold. The upper intake manifold MUST come off first.

Chris