Engine Knocking

[Midwest_Drift_Shop]

Im new here to the NICO forums, although I have been on many other Nissan forums. I have a question about my 01 Pathfinder 3.5.

For a while now the engine has had a timing chain rattle, and an oil leaking problem. This has been going on since about 90,000 miles. Now It's at 103,500 miles, so this has been going on for several months now.

I went to start it up one night, and I heard a slight knocking sound from the engine. I reved up the engine and the sound went away, at about 2K rpms. It was driven for about a day through very cold colorado blizzard weather, the sound wasnt too bad. The only thing I noticed with the engine, was it seemed to hesitate at low rpm's to get the car moving. A day after I got home, the knocking was worse. I checked the Oil, and It was about 3.5 quarts low. Added Oil and it still has this knocking.

Right now I have a timing chain kit on order from my local nissan dealer. Im hoping this Is a timing problem, and not a serious engine problem.

I have worked with many other VQ's before, but never experienced this problem, and never replaced a timing chain on a VQ (Only SR's and KA's).

Could the timing have skipped a single tooth on the cam? Would a single tooth on the cam cause the valves to hit the pistons?

Or would this be a problem with starving the engine of oil?

It will be about 6 days or so till I have access to an OBDII scanner, which would be nice to have tell me whats wrong, but this cant wait. Im trying to get the vehicle running normal now, cause its my only transportation in my current location.

[elwesso]

That could possibly explain the hesitation, does it idle realy rough too???

Running 3.5 quarts low on oil is bad news, Id conduct an oil pressure test to see where you stand there..

Welcome to NICO!!!

[Midwest_Drift_Shop]

I was finally able to get ahold of my friend in the parts department at the local nissan dealer. He told me that it could be the Varible Valve Timing Solenoid.

Makes sence why that would cause a knocking, cause the valves would not be opening properly. He also told me that part is a comon replacement on VQ's. The sound also seems to be coming from the left valve cover.

Working over 6 years there, he has only sold one VQ timing chain kit, because someone was rebuilding their engine. But he has recieved many VVT solenoids for VQ's.

As far as the oil preasure goes, it's fine now. Idle is fine at times, some times it will run slightly rough... nothing like my VG30ET though, which idles really rough.

Thanks for the welcome, this is a great forum, I hope to post here frequently.

[elwesso]

well i assume your going to be replacing the solenoids, let us know how that works out for you!!

[Midwest_Drift_Shop]

Have any information on replacing the VTC solenoids?

Where are they located? Inside the vavle cover? If so I get to have "fun" removing that intake manifold.

It kinda makes sence why teh VTC solenoid could go out if the oil were low, cause the VTC system is powered off of oil presure, so if there is none, or sludge build up, they could fail. Or so this is what i heard about teh VTC problem the 3rd Gen Maxima VE30DE's had. Someone was talking about grounding the VTC solenoids to disable them on the VE30, but im not sure if this same thing would work on a VQ. Althought on newer engines, the VTC plays more of a role in giving the engine power and espically low end torque. The RB24DET Neo, has very little low end torque if VTC is disabled.

[elwesso]

Im not doing this to "cop out" but goto http://www.phatg20.net to get the FSM. I dont mind posting the pages but i figure itd be more useful for everyone if you just got the FSM...

You might also check our Infiniti J30 forum if you havent, theres a couple guys roaming around with twin turbo J....

[Midwest_Drift_Shop]

Thanks for the help. Once I can get to a broadband connection, I will download the FSM, or just use Mitchel at my school when the semester starts back up.

Im pertty sure its the VTC Solenoid, someone on another forum said that the lack of oil would have done it. There is oil in there now, but its damaged. I hope no other part of the VTC system is messed up.

I've seen those TT J30's, that swap is a ***** and a half!!! SR20 Swaps are easy compared to the VG30DETT swap in the J. Right now Im contemplating a 5-Speed swap tho, cause my AT is toast. Once that engine goes, it's time to try the VG30DETT swap.

[Pisspi]

You mentioned 3.5 quarts low on oil. I've read on other Nissan forums that the 3.5L engines have a PCV problem. What could be happening is the oil is being sucked through the PCV valve. Only way to correctly rectify this issue is to replace the valve and the valve cover.

Keep checking your oil level every now and then.

[Midwest_Drift_Shop]

Well... Life is horrible. That was NOT a VTC solenoid.. It was indeed an engine knock.

As I was driving into town to pick up new solenoids and replace them, the engine threw a rod...

Now Im looking for a used VQ35DE, or hoping that my block, heads, cams, and the crank are fine, so I can rebuild the engine. I found a VH45DE at a local junkyard. I know these are in the QX4, but is the transmission different?

If anyone has info on a used VQ35DE, please let me know.

[kheyse]

Hi: Where did you find the QX4 engine and what year was it? My power valve screw came loose in my 2002 QX4 engine and now I have major knocking noises. We believe we will need to replace the engine. The vehicle will still run, but is very loud. If you did not get the engine could you let me know where you found it or ideas where I might find a rebuilt one. Thanks.

[fueler]

What is a power valve screw?? Anyways - check a junkyard - there are multiple QX4's in the junkyards near San Diego.

You can also use the engine out of a 2001-2004 Pathfinder - it is the same exact engine (VQ35).