2002 Infiniti QX4 Check Engine Light on & Engine Heating Up!

[hussain00]

Current mileage on car - 184000:

After getting frustrated multiple times, I am desperate for some direction advice. I am going to post my entire story and maybe we can connect some dots in the process. I am not a mechanic and have very minimal mechanical knowledge but I am learning a few things as I am trying to troubleshoot the issue with my car. So here is when I started seeing issues with my car. Please be patient

About a year ago, I started hearing a weird noise coming from the vents which sounded like my stomach was growling. This noise was only noticed when I would turn off the ignition after driving a distance. Also after some time, my car started missing while driving constant at different speeds and was diagnosed by the Nissan dealership to be a coil pack issue on Cylinder 5. Also note, when this issue of misfiring arose while driving, no Check Engine light turned on! So as per their recommendation, I had the coil pack replaced. Right after I had them change coil pack and took my car back to work, I realized that my heater was blowing cold air when at idle and going at slow speeds. I asked the mechanic and he basically said that I should check the air pressure and that he wasn’t anywhere close to that area to affect it. Two days later, I start my car and it was misfiring when initially started. The engine felt really rough in idle but after 2-5 seconds, the engine would smooth out! Soon after, a Check Engine light turned on. I went to Advance Auto Parts to have them read the code and it read P0103 for a cylinder 3 misfire. Since I have had the spark plugs replaced on my car like 15000 miles ago, I figured that since it's misfiring again, that maybe coil pack 3 has gone bad as well. I take it to another shop and the mechanic concurred and replaced coil pack 3! Well when I had them change the coil pack and took it back with me, I drove it for about 5 miles and I started hearing some weird noise as if there is a lot of pressure building…. I turn off the ignition but the pressure building noise kept on increasing and as soon as I get out, I see that radiator fluid is basically draining don from the driver side. I take it back to the shop and the guy told me that my overflow hose has gone bad. That there seems to be a kink in that hose? He told me that my radiator is acting as if it is full and it tries to push antifreeze fluid out to the reservoir tank and when it sees that the reservoir tank is full as well, it had to disperse the fluid somewhere…and that’s what I saw coming out… Note that during this time, my engine did not heat up and the temperature gauge inside read normal temperature readings. Anyways, as per their recommendation, I have them replace the over flow hose as well and that pressure building issue did not happen again until just recently. After driving it for a while, just over a month ago, as soon as I get home, I look at the temperature gauge and see that the needle was at the H level. And I was like what the hell! So I pop the hood and look at the reservoir tank and see that it is currently at the max level. So I wait overnight and the next morning, open the radiator cap to see if there was fluid in the tank and see that the radiator tank is empty. I look outside if I see any anti freeze coolant and there was no fluid. Therefore, I fill up the radiator with anti-freeze and drove it for about 230 miles at varying speeds. After this time, my car heated up once again. After stopping the car and cooling the radiator, I take the cap off and see that the radiator is empty again. Again to my surprise, the overflow tank is still at the max level. I fill the radiator yet once again and come back home which was about 200 miles away to take it to the shop that had initially replaced all the other parts I was having issues with thinking that maybe he did not put the overflow hose in correctly! Note that I had to put more fluid into the tank before taking it to the shop once again. The mechanic said that there is no issue with the work that he did! That the issue I was having before replacing the hose is now gone! To try to figure out what was going on, he pressure tested the radiator and told me that the car held pressure for 45 minutes. Last week I worked with a guy that I know and we performed a compression test on cylinder 1, 3, and 5 and to look for any visible fluid in the valves after taking the spark plugs out. There was no visible sign of fluid in these three locations. When we were performing the compression test, note that the needle would not stay still and just kept on flickering up and down when the engine was being cranked. Cylinders 1 and 3 read a reading of around 140 psi and Cylinder 5 read a reading of around 110 psi? Also, after evaluating spark plugs, it was noted that spark plug 1 was super clean. Plug 3 was a light brown color from the area where the gapping is done. However, plug 5 looked messy and there was even some brownish looking material on the white side of the plug. Not sure what made this appear as such because the computer reading was throwing a cylinder 3 misfire and not a cylinder 5 misfire……..

I was going to take the car to another mechanic that I know of but he was 200 miles away and I was afraid that possibly it was a head gasket issue and not sure if it was safe enough to drive or not. I was suppose to drive it this past weekend but because of certain reasons, I was not able to. Then this past Tuesday, I drive my car to work and before heading back home at the end of the day, I make sure all fluids are intact and then I saw that the reservoir tank was showing antifreeze fluid a lot higher than the max level. I say my praises and start driving the car only to come to a haul after 10 miles. I pull over my car and see that the temperature gauge is at boiling level and when I get out, I hear water just bubbling right out. I open the hood and see that the reservoir tank is showing antifreeze all the way to the top and it’s boiling….I cook the engine down and open the cap but there was no pressure in the cap! At this time, I start the engine again to see if the antifreeze fluid will go back down from the reservoir tank into the radiator and it did. So I change the cap and put on a new one. I then fill up the radiator tank again and start driving. Two miles later, I see that the temperature has started to increase yet once again so I just pull over again…..again the fluid level was raising quiet high on the reservoir tank and no pressure was present in the radiator cap. I took it straight to the shop and they think that it is a thermostat issue but again not certain!

This mechanic is different than the one I had been taking to and this mechanic did some sort of fluid test on my radiator. The technique is that he puts this solution in this testing product and puts a tube in the radiator. If the color of this fluid changes to yellow from blue, then it’s a bad head gasket. But he told me that when he did this test, color stayed blue! However, after running the engine for a while, he said that this tool that h had in the radiator blasted off and radiator fluid fell all over the place……

I have currently bought the thermostat kit required for the QX4 from an Auto Parts shop but not sure if I should use this or try to get a factory part? Also, I bought this solution called Blue Devil’s Head Gasket fix. It says on the bottle that it is suppose to be a permanent fix for Blown heads, cracked/warped heads, heater core cracks, and freeze plugs without damaging the engine since it’s some chemical based. This is not like that Bars Leak product that is copper based and forms a clot in the radiator. I was planning on getting this mechanic to change the thermostat assembly and apply this blue devil’s product but if you guys have any other suggestions, please let me know. I am all ears and hope at this time!!

One other thing to note, oil on the stick is not milky at all. I really appreciate everyone help in this form in advance for taking the time to read and assess my problem!

[ARKQX33V6]

On first reading your story I came up with head gasket failure. Your spark plug being real clean helped confirm this as did your over heating many time.

You must do further investigations:
Your compression test at 140 vs 110 is a bad sign.
Redo all 6 cylinder compression test cold, hot, dry and wet, then a leak down test.

I think you will find a head gasket failure.

Also drain your oil and measure the quantity exactly. Any gas in it will reaffirm gasket problems.

When cold open your rad cap, leave expansion tank closed. With rad open run the engine and examine inside the rad, look for bubbles, if any maybe air bubbles head gasket is leaking.

Drain your coolant and examine for any oil, if any gasket failure.

Oil, coolant are separate entities, if they mix could be signs of head gasket failure. Spark plugs will be excessively white as coolant cleans them, head gasket failure.

It's not looking good but the many problems you have endured presents as a head gasket failure...but this must be tested and confirmed.

[hussain00]

Thanks for your reply. I alongside a technician replaced the thermostat without any luck. Following is the procedure we followed:
1. Drained radiator fluid. It was clean. but then again, i didn't drive it that much after my car got heated up and i refilled it with radiator fluid.
2. removed bottom hose that goes into the thermostat housing assembly.
3. removed the thermostat.
4. reinstalled it.
5. cranked the engine and let it sit idle for about 10 minutes with the cap on.
6. turned the AC on and saw that the temperature started creeping up really quickly.
7. Turned the ignition off and saw water going crazy in the reservoir tank. The return hose to the radiator was extrement hot.
8. After cooling it down, turned the car on again and took it for a very short drive with the A/C running. Needless to say, the car heated up within approx 400 ft of driving....
9. opened the hood again and started cooling the radaiator again and could still hear the gurgling sound from the antifreeze being so hot.. at that time, turn the ignition switch to on but not starting it, i saw that the temperature gauge was at quiet normal temperature. two lines below the center.

I will try to get up with the technician today and see if we can do compression testing on the other cylinders as well. Let me just iterate something about when we did the compression testing, the gauge did not stay still on these readings. It kept on flikering up and down but the highest peak that could be determined at the blink of the eye was approx. 145 psi in cylinder 1 and 3 and 110 in cylinder 5. What i was thinking about doing today was apply the Blue Devil Head Gasket Sealant (from usasealants.com) and see if it would work. But my concern was that if the engine is heating up just sitting idle, then how can i do this. Because in the instructions, i am suppose to run the engine for 50 minutes for this....

One other question i do have though is what are the chances this issue could be water pump related or the water control valve related? Secondly, what is the purpose of the water control valve and when does it actually open? This data is not provided in the FSM for this car! If also possible, can u give me a 101 class how is this car's cooling circuit working? It is uner the LC section (LC-11) to be specific. In simple words, how is the cooling system suppose to work in this vehicle. I really appreciate your support!

[ARKQX33V6]

Class is in session!
Readings of a compression test done on 1/2 the car are not very valid, but readings with over 30 PSIG differential between any cylinders is an indication that the compressed gases on that lower number cylinder are losing compression.

Getting fluctuations from a linear pressure gauge during compression strokes is normal because the compression rate must build up as you drive the motor through the starter. As the starter works when compression testing is done that little 1-1.5 HP series wound DC motor works up to 300% of full load. But you are reading only 1/2 the engine, you have not removed the other side spark plugs. With the plugs still installed you are killing that battery. Have you opened the throttle plate wide open. Compression needs a lot of air, without a WOT your readings may be low.

When you do a compression test remove all plugs and number them. Inspect them, gauge them. Lock the throttle wide open. Install a good battery charger on the battery while you do the testing. Keep an eye on the charge rate. You need a minimum ENGINE SPEED OF 300 RPM. Use a good tested that screws into the plug holes, make sure it seals, a little anti seize on the threads will help.

With all plugs removed start and record your highest pressure in PSIG. Do each cylinder as soon as you stop the car so you can do it while the engine is still hot. Do a hot compression, a cold compression, a dry compression a wet compression. With all these test you can compare.

A dry hot test should be an honest test, does compression stay the same when oil, does compression rise warm vs. cold. Record all readings, all the time the battery is charging because a low battery will chage the compression readings.

If you find a cylinder about 10-15 PSIG lower than the rest there may be a problem. If the compression as new is 140 PSIG and they all read 110 PSIG don't worry but if you get a real low 1 or 2 side by side or anywhere that is cause for concern.

With all these test results try a leak down test. A homemade tool is easily made to allow compressed air pushed in a cylinder through the spark plug hole by modifying an old spark plug.

With a test plug installed and 120 PSIG put into that cylinder and then rotated to close both exhaust and intake to seal the cylinder, with a built in gauge in that modified plug adapter read the maximum pressure you get for that cylinder. Take a five minute break, read it again.

If pressure is the same good do the other low compression reading, if time permits do all 6, record them and get back to us.

Break

Cooling system
Parts
liquid to air heat exchanger front rad.
liquid to air heat exchanger inside of car heater
Expansion tank bottle in engine compartment to take hot liquid and return liquid when cool.
Rad cap pressure control, release when hot
Thermostat with bypass to heat up engine and allow coolant flow through bypass when engine is cold.
50/50 glycol and pure water is the medium to transfer the heat to the rads
Fan at front of engine behind rad to cause air flow to travel through the rad for cooling
Internal fan(s) to create air flow to comfort us and remove vapor from the windows
A/C to cool us
Controls and there are different some manual some automatic but they all work in the same fashion to make our closed in environment as comfortable as can be.

Why cool
An internal combustion engine, ICE, is a heat producer, so it must be cooled, from the explosions of gas and air. The engine is a friction machine so the friction causes heat, the oil cools the heat, the glycol and water cools the heat but only when they travel through the radiator. The exhaust is hot! All this heat travels to and through the cooling system to enter our atmosphere.

Temperatures
Explosions at 2500F
Running temperature 220F
Water boils 212 F
To keep the system from boiling over we increase the pressure and we use a glycol/water mixture that needs a higher temperature to boil and needs a lower temperature to freeze. This coolant has a slippery texture it flows easier than water alone. If contains rusting prevention additives.

Thermodynamics
Have you ever sat in a classroom and let out a deadly but quiet one. Soon everyone knows somebody farted. How? Well that fart from your butt left from an area of high concentration to the room full of lower concentration and in time that smell is everywhere. Well heat is like a fart, it travels to areas of cooler.

The cold engine displaces the hot energy of combustion into the metal and coolant surrounding the combustion chamber and soon that cold coolant is hot. Mechanical pumps aid movement of that coolant and through the rad it goes. The air temperature is always colder than the hot coolant so the rad has a cooling effect. But the thermostat the size of the coolant container maintains the best operating temperature by design. The thermostat has an opening with built in bypass, when cold the T-stat flows little coolant through to the rad to aide warm up. But when at operating temperature the stat is wide open as it can be and maximum flow go through it.

The expansion tank takes on the expanded coolant because of heat. That tank is there to keep the pressure vessel closed, after all the coolant chamber is a large enclosed pressure tank, albeit a weird shape but enclosed it is and must stay to operate correctly. When the engine is stopped the coolant loses heat and shrinks in volume. Hot things are bigger than when they are cold.

The controls from the heating/cooling/ventilating system are all for our creature comforts. We have no controls about how hot or cold the engine gets, but the heat from that engine can be used to warm us, cool us, humidify us dry us. All these actions are done by adding or removing heat. The air conditioner is a heat pump. Freon R 12, R24, R134A all work because the various gasses are compressible, in there different states as a liquid or a gas they take on or get rid of heat. Remember that evaporation causes cooling, putting heat to a liquid as in the Sun on a sweaty body causes the sweat to evaporate and cool the skin. The same as the interior heat exchanger, the evaporator and the external heat exchanger, the condenser.

The systems for heating and cooling is really the same system but throw in a few valves and change the direction of flow, add a few more controls are there you have it ....today's modern self contained mini environment.

Class dismissed!

PS if I have forgotten anything, well if

[Chris.m]

^^ Good read, Thanks ARK

[hussain00]

Thanks a lot for that lecture ARK! I will try to get my mechanic do these things today as I work with him. I am not sure how the different compression tests (hot, cold, wet, and dry) are performed. But hopefully he will. Just one question I do have and I realize that many mechanics don't really agree with this but does this BlueDevil Head Gasket sealant ever been tried on Nissan engines and does it work? My only concern is that since my engine is already heating up, would that be because of a blown head gasket? Should I just give it a shot?

Also, in the FSM after installing the new Thermostat, there was no procedure on how to bleed all the existed air out of the system. Can you please provide procedures on what I am suppose to do to ensure that there is no air left in the system! A friend of mine told me that in one of his cars, he had a nut or something that he had to open to get water into the air pockets? Does my infiniti have a nut that I have to open? I read in one of the Nissan’s posts that there is a plug? Is this the one sticking out towards the center of the engine from the back? If you can please provide me with a picture of that plug as well? Also, if it is the same plug as I am talking about, there was grease in there when I opened it. Should that be cleaned and if so what can I use to clean that line?

Thanks again for all of your help!!

[hussain00]

Interesting findings from yesterday's work performed:

1. The airflow plug tube was clogged up. My technician tried to put a hangar in there to try to open the clog up but he said that it was really really hard! Therefore, he took a drill gun and drilled through the tube which made the water out from that tube again.

2. Tried the BlueDevil stuff. We screwed up in one of the instructions as it was listed on the website that read that engine should be at idle before mixing the BlueDevil chemical with water. With the engine off, my technician put in the water, then the blue devil, and topped off with more water. We then started the engine and let it run for 50 minutes as it has specified on the directions with the heater set at highest temperature. I am not sure if this would have made a difference if it was a cracked head or not.

NOTE: cold air still blows from the heater vents when idling!

3. After letting it sit for 50 minutes, we took it for a test drive without the engine heating up.

4. Came back and installed the new thermostat in the car, drained all the BlueDevil /water mixture and filled the tank and reservoir tank with anti-freeze. One thing to NOTE here is that when we were filling the radiator, antifreeze did not automatically come out from the air flow plug. However, when my technician put his hand on the radiator and pressed on the hose, water would spew out from the air flow plug! Is this normal or is water suppose to automatically come out as we top off the fluid in the radiator tank?

5. Started the engine and turned on the AC and the car started heating up again. When we opened the air flow plug after shutting off the engine, nothing came out of there! So we thought maybe it’s the 2nd thermostat (Water Control Valve) that would cause that?

6. I remembered reading in one of the blogs that one guy had issue with the air in his line so he jacked up his vehicle from the front and with the cap open, he started the vehicle and let it just run. After some time, he saw a huge drop in water level which he then topped off and everything was good. The conclusion made in that case was that there was a lot of air in his line which was causing his engine to overheat! Therefore, I got my technician to jack up the vehicle from front and with the radiator cap off, we started the engine and let it run and water was not coming out from the radiator anymore. At that time, my technician opened the air flow plug and water was coming out. So we were like, okay we do have a good flow at least. Note, at this time, I turned on the AC and the car was not heating up anymore!!! We let it run like this for at least 10 minutes!

7. He then closed the radiator cap and the air flow plug and we lowered the vehicle. After 5 minutes, while the car was still running, he then opened the air flow plug and after just a little bit of water, only air was coming out from there!!! Then steam started to come out. Outside temperature at this time is around 75 degrees.

8. Thinking that there is a lot of air in the system, we repeated the step 2 or 3 different times. Another thing to note is that when the car was running and it was heating up and he opened the air flow plug, the temperature stayed constant and eventually came down a bit instead of creeping even higher!

9. So the dilemma still continues…… Any explanations for these results????

[ARKQX33V6]

Most head gasket sealants would have to be authorized by the manufacturer and that is a tough scenario to do. When the head(s) were taken off the machine surfaces would have been visible, if this is so then a sealant would not be likely.

A sealant seals, but a gasket arrangement does too. But some gaskets need O ring controllers and gasket material to withstand the high and low temperatures. This sealant material that you used must meet these operating temperatures and pressures.

Once the head gasket is on, sealed, then torqued, the holding pressure of torquing the bolts will now have a sealed material to offer thermal change to the torque values. Does this material seal recommend a re-torque after the initial break in?

As far as compression goes a compression test with a PSIG gauge done dry, wet, cold hot is an everyday experience for a motor mechanic. It is a basic immediate see if the engine is OK, but when problems pop up there are other more demanding tests that prove a go, no go engine.

As to coolant in a totally enclosed system, what you experienced is par for the course and some engines contain various restrictions built into the enclosure. Even a simple QX4 with air bleed offs can present struggles in the emtying and filling of the coolant system.

Every car today has a cooling system and expansion system with designed upgrade to allow cooling over a great many conditions. Filling a jug by bending that jug has been done for years, but when that jug is a V6 configured block the idea is to get the air out.

An empty vessel on this earth is not empty...it is full of air. When filled with water, coolant the air within escapes somewhat but the air that must move out near the bottom or is trapped by nooks and crannies becomes compressed by the action of the denser water being put in.

And as you have discovered, that air must be out of the system, because that compressed air under pressure may be equal to or greater than the internal pressure of the vessel and as such will stop flow of water, coolant until that air is released. Although air is lighter than water, if it is under pressure it can act heavier than water.

When you look at air release vents on the engine they are up high, with the thought that air is lighter than water. But if trapped air under pressure remains in a pressurized container that air may never move, so when you fill the coolant chambers up leave the rad cap off, leave the expansion cap off, heat thing up and give enough time to burp that engine.

As the air leaves the coolant will take its place and you must add more to fill it up. Run the engine at temperature the coolant gets hot and expands, goes into the expansion chamber and drops in the rad.

Still hot dum,p in more, the rad is full, the expansion bottle if full, put the expansion cap on, engine still running no more burping, put the rad cap on.

Test drive it at different loads, no overheating, shut off. Record expansion level, come back next day check expansion level at minimum level, top if needed, keep an eye on the system for a week, then off you go.

It is up to the person doing the coolant exchange to do it correctly, no rush, burp the system until it flows and stops growing, seal it up and then tell the owner to keep a careful atch for about a week.

[hussain00]

okay it has been quiet some time since my last login...i still have not really figured out what is going on with the car because of other priorities.... i towed the car to one of my family mechanics a couple of hours away and their mechanic took a look at my car. As soon as they started the car, the anti-freeze coolant spat out from the radiator. So they said that it's def. a cracked head or a head gasket failure. Then they used the special tool required to take the air out of this system and got all the air out from the cooling system and started it again. At that time, the misfire went away, and water did not spatter out of the radiator. Their mechanic drove the car for 4-5 miles and came back without the car overheating with the AC on. then when i got there, i took it for a test drive with the AC on and i drove it for another 5-10 miles and came back to the shop. The car did not overheat and i opened the hood and looked at the reservoir tank and it was slightly above the max point. THen they basically told me that they don't think there is any other problem with the car. The problem was with the air that was in the system. So i went home which was about 20 miles away and when i got home and opened the hood, i saw that the anti-freeze coolant in the reservoir tank was almost to the tip and some coolant had actually come out as well. Also, i saw a lot of steam water on the heater-core line which dried up after a few mins. So after I called them back telling them that this is what happened, they said that if it did this, then it's definitely a cracked head or a head gasket issue. Because the engine runs sooooooo smoothly, i am still not being convinced that cylinder head is an isue here....any thoughts??? could a water pump issue cause this same symptom???? right now, there was no check engine light on.... Thanks for all the help you guys have provided so far!!

[hussain00]

oh and let me also add that there is curently no thermostat installed. Also, during this symptom, the car did not heat up......

[ARKQX33V6]

Expansion of coolant beyond the normal fill range:
could be an over full coolant chamber
A way to high mix of anti-freeze compared to pure water
A head gasket or head leak.
This is a more than slight thing to diagnose and can be expensive to find out.
A leak down test and a compression test are needed.
Checking the rad inlet while hot and the rad open, look for bubbles coming up out of the coolant. Also look in the oil reservoir of the crankcase, is oil and coolant mixing?
Make sure the air valves are closed, used for bleeding air from the cooling system when looking for bubbles in the coolant at the rad inlet with the rad pressurized cap removed.
With the engine at temperature do either an OBDII scan for temp or use an independent IR tool at the rad, go across the face of the rad, all sections looking for hot or cold spots.

Running without the thermostat will create a cooler coolant temperature and that engine will have other problems running cold.