[wheeliemanmc]

First and foremost let me apologies for submitting the same content below in the introduction section of this club - chalk it up to me being a newbie.

Hello,

I am new to this forum and excited to have found it. I have a 2004 Desert Runner 5spd (3.3L). I purchased it ~ 2yrs ago with 85K and hoped to keep for a long time as I saw these motors hit the the 200K mark all day long.

I only put ~5k miles per year so my oil change frequency (full synthetic) is twice per year. I drive 7 miles to work each way every day. Temp gauges indicates full operating temp when I get to work (same position if I go on longer drive).

In the first year of ownership I noticed a ticking noise upon start up. After some research I concluded it was the well known "noisy lifter" issue that is common for this motor, and figured it is what it is.

On the last 2 oil changes made two observations: 1) right after the oil change the famous "lifter noise" practically disappeared and 2) the amount of oil I drained (with filter replacement) was just shy of 2 liters. Side note, there is NOT a single oil leak from this motor nor is there any signs (puffs of smoke) of oil being burned and coming out the tail pipe. Tail pipe looks absolutely perfect. Also, I just did an oil change 300 miles ago so I am yet to measure how much oil is being consumed.

My temporary conclusion is that the lifter noise is driven lack of oil (result of being burned). I ran a compression test and the results as follows:

cylinder 1 = 150
cylinder 2 = 148
cylinder 3 = 150
cylinder 4 = 125
cylinder 5 = 145
cylinder 6 = 140

Per the manual, standard is 173 and minimum is 128. My trucks cylinder 4 is at 125 psi. I did NOT add oil to the cylinder to determine if the low reading is indicative of rings vs valves. I do NOT own the tools to perform a leak down test. However, I speculate it is the rings since oil from the crankcase must past the rings to be consumed.

So, here is my question(s):

1) Is this a common problem with this motor? Meaning 5 cylinders have good compression and 1 not?

2) If you have encountered this challenge on the 3.3L (either your own or customer of yours if you are a mechanic), what solutions have you attempted and what were the results?

3) Based on internet readings a plausible notion is that we have carbon deposit build up or a busted ring of some kind. If its the carbon build up what do folks think about treatments such as Sea Foam to break up the "sludge" and carbon build up? I see Sea Foam can be used in the crank case, via the induction system, and also via fuel system.

4) Basically, was recommendations do you offer to potentially solve the low compression on this one cylinder?


Many thanks to all for your time!

 

[smj999smj]

Oil can also be burned via a sticking PCV valve. If the intake lifter at the cylinder is the faulty one and not opening the valve fully, it could also cause low compression on that cylinder. When you performed the compression test, did you have a battery charger hooked up to the battery and the throttle plate wedged open? If not, these will affect your readings. The "wet test" and cylinder leakdown tests would be needed to properly diagnose your engine's condition. You also should do a fuel pressure leakdown test to make sure there's not a fuel injector leaking on that cylinder that is washing the walls partially and causing the low compression.
As far as carbon build-up in the rings, it's really a crap shoot as to what will possibly work. I know some who have poured some Sea Foam or Marvel's Mystery Oil into the cylinders and let it sit overnight. You can try adding Sea Foam to the oil; it may or may not work, but it's worth a try if that is your problem. An oil back-flushing system, like Envirolution, "may" also help.

 

[fastfed]

was this done on a hot engine or cold?

 

[wheeliemanmc]

SMJ & Fastfed.... thank you for your reply. Some additional info based on your questions as follows:

1) Compression test performed per the Nissan manual - warm engine with someone holding the gas pedal to the floor.

what the manual did not tell me was the idea of having a battery charger hooked up while performing the test. I completed the compression test, testing all cylinders 2 times (once with warm motor-within 10 minutes of turning off and once with cold motor - about 1.5 hours later) and received nearly identical readings across all cylinders. I found it strange as I would have imagined a diff readings due to the temp change and the fact that the battery would have been getting weaker.

2) I agree I need to perform the leak down test and the wet test to properly diagnose the low compression. I will also investigate what additional tools are needed to test the injector.

3) As for the PCV valve, I am aware that a faulty one can result in burning oil. I plan to replace it and see if it makes a difference. That said, I am not too hopeful.

4) As for the carbon build up, I plan to try the sea foam treatment in the oil and intake system this weekend and then change the oil the following weekend. Once complete I will run the compression test again and validate if there is an improvement. If no improvement I will move to the leak down as I need to get the tools.

again, a big thanks for the replies..