Using antifreeze had intake valve replaced and still using antifreeze

Check hose going into firewall leading to heater core

EGR valves connect to the intake manifold and are subject to corrosion. Check that this unit is not leaking . have a coolant pressure system check done.
Run fault codes to check if a sensor is leaking.

Blown or warped head egr runs on vacuum and exhaust

If you have the V-8 Engine, just totally disregard this post.

If you have the 3.8L V-6 engine, your oil consumption problem is most likely to be caused by the PCV Valve if you cannot find any external leaks. These are also known for the upper intake plenum leaking antifreeze. The ports in the manifold that go to the throttle body are made of very thin plastic. The EGR tube, with its hot exhaust gasses, goes right between them. This causes the plastic to heat up and crack, causing an antifreeze leak that goes directly into the intake and gets burned in the combustion chambers.

DORMAN makes a replacement upper plenum kit to fix this problem. The kit includes the upper plenum with thicker coolant passage walls, an intake manifold gasket set, a smaller-diameter EGR orifice, and a new PCV Valve. This kit will probably fix BOTH of your problems.

The DORMAN part number for your car is 615-180 Shop around...prices vary considerably.

did u check heater core , do u smell antifreeze inside the car when running the heater if not then the most likely cause is either a leaky head gasket or intake gasket

If the engine oil was full of antifreeze when the intake gasket went bad, then there is a good chance that there may be some cam and/or lifter damage. A more likely cause of your problem would be that the push rods got mixed up when you put it back together. The intake and exhaust rods are different lengths. If this is the case, and you have turned the engine over, there is a good chance that you now also have a bent pushrod and intake valve. The exhaust pushrod is the longer one and if you mix them up, the piston will contact the intake valve because it will not be able to close due to the longer pushrod. This will bend or break the pushrod and bend the valve stem.

If your water ports are in the Intake manifold, it would be possible to crack the casting with a mounting stud. If you were to remove the mounting studs for the throttle body there is a chance the stud would show staining from the Antifreeze.

You need to pressure test the cooling system with a Radiator pump. You may be able to get a loaner from Autozone or Oreillys by leaving a deposit. When the Radiator is pressurized on a warm engine. the thermostat will be partially open and the Intake water jackets should pressurize too! There can be pressurization from the lower Radiator return hose on a Cold engine test as it is a closed system, but you could have an air pocket in the Intake. The air would have to bleed out before you had flowing Antifreeze.

In either the Warm or Cold test of your Radiator, the Pressure would drop in the gauge as you have a hole in the system. You should also be able to tell by looking at the sparkplugs to see what it is they are burning.

You may be able to stop the leak with a good leak sealer. If the leak is in the Intake, the induction system is evenly(?) spreading the Antifreeze to all 8 cylinders and the valves are keeping high pressure away. It is not a combustion chamber leak.

The more modern stop leak products can cost about $16. You add this product, run the engine, then drain the Radiator and put in fresh Antifreeze. Its that potent. Or you can go to a Salvage yard and get another Intake manifold. I hope you have found my solution helpful.

itr could be or it cold just be little blow by, i would just clean it up and replace the pcv valve

If you don't know where the EGR Valve is located, it is safe to assume that you did not properly diagnose your EGR system...how do you know the valve needs replacing?

If you are trying to fix a trouble code P0401 " Exhaust Gas Recirculation (EGR) Insufficient Flow" (This is a very common code with 3.1L GM Engines)
An EGR Valve replacement will most likely make you about $125 poorer than you were before and will not fix the problem.

Your EGR port into the intake manifold is most likely clogged up and needs to be cleaned out.

You will need a Throttle Body Gasket, an EGR Gasket, a can of ThrottleBody and Intake Cleaner, and a little antifreeze. (You will lose just a little when you remove the throttle body.)


Remove the EGR Valve and the Throttle Body. Use a screw driver or pick to chip out the carbon buildup in the EGR port going into the intake manifold. You will probably have to work it from the intake side as well as the EGR side to get as much of the black carbon out as possible. Be careful not to let this stuff go down into the intake plenum - you will burn some valves if it gets in there. Then use the Throttle Body and Intake cleaner to finish the cleanup. (It helps to take a rag and stuff it into the intake manifold just past the EGR port to catch the gunk so it doesn't go down into the plenum...just don't forget to remove the rag before putting the Throttle Body back on)

Put everything back together and top-off your antifreeze and clear your computer codes. That should fix it.

If you have some common tools the knock sensors are no big deal.  If you take a lexus they will make is sound like you need to completely disassemble the engine and scare you off.
First, do you really have a problem with preignition causing real knocking due to carbon buildup, or diluted gasoline or do you have failed knock sensor(s).  Try to decarbon the engine first.
There is a technique used with water being sprayed into a warm engine intake.  This will clean up the valves and carbon buildup which can result in engine knocking.  

The job will be a couple hundred for the parts and a couple hours of your time.  After you are done, you have entitled yourself to approximately $500 in new tools for your tool chest since this is what Toyota and Lexus will charge to fix (about $1k+).

You will need to buy the following to address the knock sensors and a couple other items while you're in the neighborhood.
- 1x upper intake plenum gaskets - 2x lower intake plenum gasket - coolant bypass hose found in the same area as knock sensors - 2x knock sensors (bank1 and bank2) - short pig tail cable which connects both knock sensors to common wire harness. - toyota antifreeze  (2 gallons, if i remember correctly... when mixed to 50/50 (antifreeze/ water) you will have 4 gallons.
drain the radiator drain the front of the engine using the engine drain plug - this plug is on the front right side facing the engine, behind the right hand exhaust manifold. (this will lower antifreeze enough to avoid dumping antifreeze all over the engine later) remove the air filter box remove the connections into the throttle body remove the cable from the throttle control remove the upper air intake plenum remove the two lower air intake plenums remove the antifreeze fill port
Knock sensors will be in the valley between the lower intake plenums.  You will need to remove the rubber antifreeze bypass hose (little short hose blocking access to the knock sensors).
By the way, the reason you bought a replacement, is that if this short hose splits from normal wear, you need to spend this money and effort to reach it, so just do it now.
The little pig tail cable which connects both knock sensors to the wire harness is said to cause a big majority of the problem due to the plastic getting hot and brittle, falling off and shorting to the engine.  While in this mode the engine thinks knock is occuring and starts to retune the air fuel mixture to get rid of the knock until it goes into minimal operations mode.
After replacing the knock sensors (and tighten to torque specs), replacing pig tail cable, and reinstalling your new short by pass hose.  Replace the lower gaskets, antifreeze fill port, lower intakes, upper gasket, upper intake, air intake, air filter, reattach everything, reconnect all the rubber lines you pulled off, make sure there are no splits in the air intake passage anywhere, retighten the engine antifreeze drain plug, and the drain on the bottom of your radiator, and your done!
Don't forget the easy stuff.  Dilute the antifreeze with water and fill the radiator and overflow tub.  Run the engine for several minutes until its hot and opens the thermistat to allow antifreeze into the empty engine cavities.  Turn the engine off and get a cold one as the engine cools.  Once absolutely sure engine is cold, refill the radiator with antifreeze and refill the reserve tub.  Do this at until all the beer is gone and you are both full of antifreeze (in one form or another)..... obviously red stuff in the car, amber down the gut.