VQ w/ possible blown headgaskets, how to be sure

[Canadian]

Hey guys, I am finally back and settled in my house and able to work on my 2001.5 with Vq35de. I put it away about a month ago when I believe the headgaskets blew, but I am not positive, and would like to be more sure before going balls deep in this project as head gaskets seem like a huge job on this truck.

When the truck overheated, the radiator basically exploded, aswell as a hose under the intake manifolds that connects the crossover tubes to the block. I was hoping I was lucky a month ago and changed those parts by taking all 3 pieces of the intake manifold off, and put it back together. The truck starts and runs PERFECT, but I noticed when filling the rad up, the coolant seeps right into the engine and fills the crankcase/oil pan with coolant as you are pouring it into the radiator neck.

Is this a sure sign of a blown headgasket, or could it possibly be a hose SOMEHOW connected wrong, maybe somehow a coolant hose is plugged into a vacuum port.... or possibly one of the intake manifold gaskets didnt seal properly? As I did re-use the gaskets, only sprayed them with permatex copper gasket spray, but I dont believe there are any coolant passages through the 3 piece intake manifold, but I didnt take a very good look...

How would you guys go about diagnosing this?

[bushnut]

I think you answered your own question...never re use a gasket, they are cheep enough to always use a new one.

 

worst case scenario...you may have a crack in the block or the heads are warped. this can happen when an engine overheats.

[Canadian]

All the intake manifold gaskets were steel and in good shape, but yes I was definetely being hasty reusing the gaskets. But does coolant run through the manifold anywhere that one of those gaskets not sealing could allow coolant passage into the engine crankcase?

 

Thats the worst part, I dont even know how hot the car got exactly, I was standing inside the store just 30 feet away and left the truck idling because I was supposed to be 2 minutes. As soon as something let go and HEAVY steam started pouring from my hood, someone noticed, and her face was :cry:

So I ran out to the truck, thinking I possibly had an engine fire on my hands. (didnt notice the coolant lake around the tires) and I opened the driver door to get the keys out and pop the hood to find a mess of coolant from the radiator tank exploding. So ibought a new rad and installed, went to fill and noticed a coolant leak under the bottom intake manifold, took the intakes apart, fix hose, put it all back. Now when I fill the coolant from the neck it pretty quickly fills the engine oil with coolant

The truck currently sits flushed with new oil, and the rad completely empty, it runs and starts as normal, no white smoke (but theres no coolant in there to smoke mind you) ive only started it twice to flush the oil and move it into the garage.

I dunno why I have it in my head something is connected wrong and may not be headgaskets, How fast it fills the crankcase surprised me, I dont think a small headgasket failure could drink coolant that fast, its like it has a more clear path... make sence?

Edited April 7, 2014 by Canadian

[Rebelord]

You didn't accidentally hook up the bypass to the crankcase vent? Just throwing a idea.

 

Sent from my Moto X

 

 

[Canadian]

Whats the bypass? on a VQ?

 

I might have done anything lol... beer fridge is only 5 feet away

[Canadian]

Pulled all of the ignition coils, all 6 spark plugs everything at once and did the compression test cold and these were my numbers.

 

2- 185 1- 185

4- 185 3- 180

6- 180 5- 180

 

 

Pretty consistent. There was also no oil or milkshake on any of the plugs (mind you the engine isnt filled with coolant right now)

 

[Canadian]

Does anyone have insight on the intake gaskets, does coolant pass through them? Mainly the bottom gasket that attaches the intake to the block, it was the sturdiest gasket and each port was rubber oringed. But I dont remember seeing a coolant passage.

 

The ammount of coolant it will drink into the engine is just to fast for me to think its guzzling it through a small head gasket failure, when i was filling it when this first happened it swallowed 3 gallons in a few minutes before I realized something was severely wrong and pulled the dipstick.

[Alkorahil]

^{The upper and lower intake gaskets do not have water passing through them.}

^{You also have an oil cooler at the bottom wher ethe oil filter goes that could possibly be leaking coolant into the engine oil.}

[Canadian]

I do indeed have an oil cooler on the passenger side, I actually just changed the 0-ring gasket on that last summer because it was leaking. Would the o-ring be the source, or do you think the cooler has failed internally?

[Canadian]

Someone pointed this service bulletin out to me for the VQ

 

http://airtexwaterpumps.com/wp-content/uploads/2010/12/Infinity-Nissan-Coolant-Leak1.pdf

 

Im not positive if Im reading it right, but its saying when the water pump seal fails it will fill the crankcase with coolant BUT also leak out a weep hole? I did not see an external engine leak when filling the coolant before I noticed it was mixing with the engine oil

 

 

[Canadian]

And look at this video I found of a seemingly professional mechanic doing a water pump job on the VQ, skip to 3:40 where he talks about the blown seal and people thinking they have blown headgaskets

 

http://infinitihelp.com/diy/common/infiniti_vq35_timing_chain_tensioner_water_pump_replacement_procedure.php

 

What are the odds this could be my problem?

 

Even though a water pump job doesnt seem like any small task either!

[jgrote]

Consistent compression #'s are a good start. A bad WP would be a much better option, and there seems to be some evidence it can cause the problem you have. I say replace the intake gaskets anyway and replace the WP. For as bad as yours is leaking, you should know right away if the WP is bad (once you get it off).

[Canadian]

I might just do that, a water pump and tensioner is about $150 online, or $200 local. I just priced it on courtesyparts online, and then ofcourse I added new oil cooler hoses, rad hoses, new corbin clamps everywhere... $330 shipped.... yikes!

 

Better than a headgasket I suppose, but my water pump never leaked out of that weeping hole as far as I ever knew, which makes me skeptical of this amazing second option

 

Would an O-ring just obviously be broken and I could feel confident this was the problem? The way buddy says it in the video he makes it sounds common, but after an hour of searching I found nothing of the water pump failure causing milkshake

Edited April 9, 2014 by Canadian

[Rebelord]

From the way the video makes it look. Where the water pump sits. If its seal was toast and your weep hole is plugged up. Yea the coolant would just drop straight down the timing chain into the pan.

What you can do is try to just access that cover for it. And get a actual good look at it. Pour some fluid into a upper or your lower hose and try to see if you can see any weeping.

 

Sent from my Moto X

 

 

[Canadian]

I got the covers off but the pump is just set to far back to try and fill the engine and watch it leak, maybe if the front end of the car was off and the ac condensor and rad was out, but the pump is just to far set back. I got the tensioner out and the chain properly slacked around the water pump. I need to go find some 50+mm M8 bolts though, off to the store I go, wll post pics when I get the pump out!

[Canadian]

Waterpump o-rings are intact, all the coolant behind the pump looked brand new fresh aswell, no sign of any milk shake back there.. :eek: :eek:

I was really hoping the rings were going to be cooked. Hoping to find the smoking gun. Should I order the water pump and change it first anyways?? No matter what its getting a new pump, but it takes 3 days average for my nissan parts dept to get parts, so I either order a new pump and wait and try that first... or assume the worst and order all the parts needed for the full headgasket repair, likely a $600 bill just for parts

How can I pinpoint the leak to ensure I have a headgasket failure, hopefully with a tool I have or can buy cheaply and do myself.

Edited April 9, 2014 by Canadian

[Canadian]

Well since im inpatient and I wanted to pull the rear water control valve, I had to pull all 3 pieces of the intake manifold again, fuel rail and injectors. Alot easier this time with the air ratchet. I pulled the rear water control valve and plan on boiling it to check operation for the hell of it and replacing it. I also had to get that voice in the back of my head to shutup telling me I hooked a coolant hose to PCV, but I didnt, all was perfect no chance of mixup

Again under the rear crossover valve was perfectly clean green fresh coolant. Why is there no oil mixing into the coolant, if the coolant can mix with the oil without the engine even running, why has the oil never made it into the coolant? even a the tiniest ammount...

Maybe that points to a certain area?

It gave me a very good look at the intake valves aswell which I took a good look at and they were all dry

[Canadian]

Might have found my smoking gun as to WHY the truck overheated in the first place. As I said I pulled the rear water control valve earlier, which is a primary "thermostat" in the vq35 engine. I noticed it a few minutes ago when I was inspecting it that it was not sealing at room temperature tightly, and when I put it in water and slowly boiled it to 105* celcius (rated for 95*) it didnt budge a bit. Its seized.

 

The water control valve also happens to be just inches from the hose that burst on me a month ago when this whole fiasco started. Its on the right under the neck. *this pic is from a month ago, before I replaced the hose and radiator*

 

 

 

Edited April 11, 2014 by Canadian

[Canadian]

put the water pump in, still drinking water into the crankcase, I listenned hard for it to while filling, I would pause and its definetely "glugging" from the passenger bank

Oh well, time for a new engine. Wish I didnt like this truck so much Id kick it to the curb

[Rebelord]

Just pull the head. See what you find. May not need a new long block.

 

Sent from my Moto X

 

 

[Canadian]

What about the oil cooler? Could that somehow fail and allow the coolant to mix into the oil?

[Canadian]

Does anyone know of a diagram for the freeze plug location on the vq35de? Last thing I want to rule out is an internal freeze plug popping and causing the contamination

[Canadian]

I cant even find the block freeze plugs in the fsm, anyone seen any info on the plugs in the VQ? I found a similar chat on yahoo about a guy with a qx4 saying his frost plugs were causing his coolant and oil to mix. Cant find CHIT though!

[Canadian]

Anybody?

I looped the oil cooler coolant lines today just to rule out the oil cooler possibly failed internally, to no luck unfortunately, my last hope is the possibility of an internal frost plug, can anyone confirm or deny there existance and WHERE they are on the engine.

It makes sence to my problem if there are infact internal plugs

[Canadian]

hey guys I got some hope from a member on another forum that there is this plug in our heads that could be the source. Looks threaded though, not a frost plug...?



Aparently that is a vq35de head internally and stripped down, can anyone confirm this plugs existance at all? I am debating pulling the manifolds again and trying to pull the valve cover to see if I can see that plug and maybe remove it or get some jb weld on it.
Any idea how accessible it may be if I were to take the valve cover off? Or would the head internals completely cover it?

 

I dont think I have a headgasket problem for some reason, since I have good compression etc, but could this plug possibly be leaking THAT much?

 

Would love some experienced ears to give me a little advice, I feel like this plug could really be the problem, do you guys think its a possibility or should i stop wasting my time and Im pulling at dead ends