Replaced Head Gasket, Hard Start

[danelectro]

Hello, I've used the posts on this forum as I've been trying to troubleshoot my 1995 Nissan Pathfinder, but I'm at the end of my rope trying to figure out what is amiss with this truck- I'm an amateur mechanic at best, I'm hoping that if I describe the truck's behavior and what I've done so far, someone may have some insight or be able to clue me in to a next step. Thanks in advance for the time!

The truck is a 1995 Nissan Pathfinder XE with a 5spd. I bought it recently, and the head gasket failed a few days later. I replaced the head gasket myself (that being the only option), along with timing belt, water pump, front seals, spark plugs, distributor cap and rotor, and new gaskets for the exhaust manifolds, intake manifold, and intake plenum. After back together, however, it wouldn't start.

I checked the obvious stuff - ignition timing, valve timing, spark to each plug, all looked appropriate. I next assumed it was a vacuum leak and went about replacing all of the rubber under hood as well as the throttle body gasket. The car now starts, though with great difficulty, and has an idle that fluctuates between ~500-1100rpm. No service lights are on. I'm pulling my hair out trying to make a reliable car out of this Pathfinder, and am about ready to throw the towel in on it.

Two things to note:
a) When I installed the timing belt, the punch marks on the crankshaft and camshafts lined up generally, though they would not line up precisely. When I lined the crankshaft's punch up exactly, the punch on the driver's side camshaft was very slightly to the right when looking into the engine bay, while the passenger side punch was slightly to the left. I checked the FSM, and the number of teeth on the belt between the cam sprockets and between the driver's cam sprocket and crank sprocket respectively are correct.

b) I've been driving it, and it has been consuming oil at an alarming rate (roughly a quart every 100mi). It isn't leaving any on the pavement when parked, I can only assume that it is burning it. I'm not sure if this is or isn't related to its difficulty starting, but is alarming nonetheless.

Again, I am not an experienced mechanic, and any insight into what the problem could be or what my next step should be is very much appreciated.

[MisterH]

That's tough; especially since it failed so soon after purchase. To me, the first thing to do verify the health of the engine. I'm guessing that since the head gasket blew so quickly after you bought it that you really weren't able to get a sense of its condition. Do a wet and dry compression test. If you're burning a quart of oil every 100 miles then the compression numbers would show exactly how and where.

[EdBwoy]

Yep! Reading through historical posts, it seems that PCV valves in less than perfect shape would cause oil consumption issues. This has mostly been the 3.5 engines. I don't know if the rates could get as bad a 1qt/ 100 mi due to that alone though.

[danelectro]

Thanks for the suggestions! I'm dropping it off at the shop on Wednesday to look into both of those possibilities. I'll post with the ultimate diagnosis if they can come up with one. Cheers!

[amc49]

The fact it overheated so quick after the sale seems to indicate it was sold due to the problem and the other owner could have overheated it more than once and the amount of overheat says much about the engine condition. New gasket does not touch dead cylinder walls due to warp and the oil use there.

People tend to think now that all you do is change the head gasket and nothing else is wrong and most of the time could not be further from the truth since most of those same people refuse to stop at an overheat, they commonly drive the vehicle all the way home and then the damage. No insult pointed at anyone at all but after many years of working on cars like that it pays to be pessimistic about that. I myself quiz POs pretty hard and will not buy any car that has overheated AT ALL. It's the number one question I ask.

Compression check will tell the tale there and hoping I'm wrong there. Test will also point at incorrect cam timing too.