Oil Pressure

[wheel366]

Well, as most of you know I have had issues with my mechanic and my truck.

 

Most of that is about over. He is now done putting it all back together but he is having an oil pressure problem. When he hits the gas, the pressure is fine, but when he lets it idle, the pressure drops really low and the driver side head/cam/lifters are clacking. He thinks that because I got the filter relocation kit that might be giving me some trouble since the oil pump is the original pump which has 184,487 miles on it and might not be strong enough to pump up the hoses to the filter. So, tomorrow he is gonna bypass the filter kit and put the filter directly on. If that doesn't work, he is going to try a different oil weight. I have 5W-30 conventional oil in there now, but he is going to try 10W-40. After that, he has to take the cover off and see what is happening. His other thoughts are maybe that Jim Wolf sent me two different size cams by mistake with the driver side being the larger one. He can't get the distributor to line up properly. It's almost correct but not.

 

I was thinking that the problem was because he didn't cut the crank when he put the new rods and bearing on along with the new rings and that compression is higher and screwing with my oil pressue.

 

Any thoughts? I'm so close, but I have this feeling that the crank is going to need to be cut and there is another 9 months worth of work.

[lgranch]

Bad oil pump. Oil pumps are cheap by comparison to cutting the crank and alot less work. When you rebuilt a VG30 or VG33 always replace the water pump and the oil pump. I have 3 oil pumps in my garage and 2 of them are probably fine.

 

The only other potential is a bad pickup fo rthe pump. Nissan really did a engineering nightmare to design the pan on the Pathy. This should have been a 2 piece pan so that is could have bene serviced.

[wheel366]

Well, the bypassing the reloaction kit and using heavier oil did not work. So, it looks like I will be getting a new oil pump.

 

New problem. He doesn't have the time to do so he says. So tonight I will be getting it from him and taking it home then taking it somewhere else to have the work done. Man, I can't win! This time I am taking it to a reputable shop.

[Precise1]

Good wheel366... You haven't payed him yet I hope...

 

B

[edta1]

I'm curious...where is the oil pump and how do you change it out?

 

I'm asking cuz my dad used to have an old dodge caravan and the oil pump light would intermittently turn on. You wait a few minutes, and everything would be fine again. :confused:

[wheel366]

From what I understand you need to take the oil pan out to take the oil pump out. The pump is in front but there are some bolts that areinside the pan...

 

I haven't paid him anything yet. He checked my oil pressure and it is where it is supposed to be, but the light is still coming on and we have that clacking noise still. He is going to take the top off tomorrow and look at the drivers side cam and turn the crank to see if something is monving that shouldn't be. He said it sounds like a valve is walking. We didn't replace the springs, so I may have to. Now, from what I understand from the Nissan dealer in my area they were replacing motors in the 90 - 95 pathfinders because of the same clacking sound and they couldn't determine what the problem was. I also heard that some older fords had a problem with the block and the oil passages that caused the same problem. We are going to try and see we can find out if Nissan ever determined what the problem was. Pretty much everything is new except the block, crank and a few other things. I've replaced all the hoses, heads, gaskets, headers, cams, belts, water pump, rods, rings, rod bearing, etc...

 

Before he started working on it, I had a tapping noise that we thought was a rod knock but ended up not being the rods.

 

I already made an appointment with another shop to take it in the week after next. It is my Lawyers mechanic. Supposed to be a reputable shop in Montclair NJ.

 

 

Any ideas????? I'm open to suggestions. I even had Ben from Jim Wolf on the phone with us today.

[lgranch]

The change out of the pump requires the pan to come off. I do not remember if your truck is a auto or a 5 speed. The auto is easier and the 5 speed is trouble. This is because the auto will disengage from the engine while the tranny is still in place. The 5 speed has to be moved back out of the way.

 

Based on your descriptionof this mechanic I think he is guessing. With this new data about the oil pressure being ok I would put a quart of autotranny fluid (type F) in the oil and drive the truck a 100 miles or so. Type F is a very high detergent fluid. It will clean up any dirt and deposits from the valves and lifters. As for the walking valve... valves "walk" under high revs not low revs. The VG30E will almost run without valve springs at a low idle. (I did say almost for those of you ready to beat me with a stick). If the oil pressure is fine, the most likely problem is a sticky lifter. Lifters can collapse, but Nissan's are not noted for this problem. I suggested the oil pump when you said that the pressure dropped off at low RPM. Low pressure a low RPM is a sign of a worn pump. A worn pump would reduce the oil flow to the heads at low RPM and can cause them to make noise.

 

Not knowing your level of aptitude on these things.... if I owned the pathy I'd just add the AT type F and drive the truck noise and all. With everything you have had replaced on the engine I believe that you have been working with someone who either does not care or does not know Nissans. I say this because I can believe anyone would replace the rods,rings,cams, bearings woter pump and not replace the oil pump. The rebuild kit with all those parts (except cams) and the pistons and the oil pump is under $500 and all the parts are included... even the oil pump.

 

Get to someone who knows Nissans. In the mean time just drive it. Ok 88 and Mookie and Precise1 ... comments sssh

[Precise1]

Well lgranch, from all thats been said over the last year, I agree with you that this guy is a chump. Because of that, I hesitate to make any real recommendations as I have no confidence in the work he did to the motor. Something may be worng with the work he did on that side. Personally, if I tear comething down significantly, I like to reassemble soon while it is still fresh in my mind. I have heard of the AT type F trick, and know a few mechanics who use it. I'd say no harm doing it, but I'd need to hear, feel the truck run before I said go ahead and drive it. This is one of those situations where it is difficult to advise. I'd probably take it to a good mechanic who knows nisssans and get their opinion. One thing that may be informative is the compression check all the cylinders...

 

B

[parthy]

:confused: Are the head gasket's on the right way

[wheel366]

Well, I just got home from a business trip in CT. I haven't spoken to him personally but he called my father today and said now I have a sound on the other side, oil pressure drops to 40 lbs when keeping the rpms around 3000 and now I have no pressure at idle.

 

Since I have all new lifters and the rocker arms are relatively new, I would saw that everything is clean and that I wouldn't need to run AT type F since it was all clean to begin with.

 

My take on it is that it may be a combination of things. Old valves, not cutting the crank and an oil pump going bad. Somebody told me that a piston might be off balance or might be lifting to high and hitting the head.

 

This place in where I am taking it next week is supposed to be really good and it is a REAL shop. Worse case scenario is that it gets rebuilt again, but this time EVERYTHING gets done. BTW, my truck is a 5 speed.

 

I have no idea if the gaskets are on correctly, but since he has replaced them for me before with no problem, I would think that he did put them on correctly.