Very strange, since most people who own the Pathfinders would disagree with you.
Your belt tensioner (and presumably the entire belt drive system) - who did you have replace it? What parts were used?
Underpowered, sure. Not by the standards of the day, but now certainly. Inefficient? Not so sure. The gas mileage isn’t great but some modern SUVs in the same size and power class don’t do any better.
Short timing belt change interval? It’s 60K or 105K, depending on year. That’s not short. Short is the idiot at GM who produced a V6 that needed timing belt changes every 30K.
Headgasket issues? I’ve never heard of VG30s having headgasket problems. Lifter issues and exhaust manifold bolt problems, yes, but they just don’t have headgasket issues. The early ones even had fire problems due to Hitachi screwing up the fuel hose they supplied, but still.... What makes you say that?
You did remind me of some other problems I had with those engines -
On the ‘87 -
Multiple fuel injector failures.
A fuel pressure regulator failure.
An ignition control module failure.
The EGR canister rusted out.
Warped exhaust manifold + broken studs on both engine banks, one side had the same repair work done twice.
2 starter failures.
A fan clutch failure.
The engine always ran warm too thanks to the factory fitted undersized radiator.
An alternator failure.
It also had a handful of pitted lifters when I tore it down after the belt incident but what did that matter. All 12 valves were bent and who knows if it managed to crack any of the piston skirts. I didn’t bother to tear it down further to look.
We did have it quite a while, but when things fail for a second or third time and on multiple vehicles, you get the feeling you’re seeing design flaws, not normal wear.
The ‘93 was better but IMO only because we didn’t drive it as long thanks to the rear frame section rusting out. Unlike the front portion of the frame, the rear section wasn’t finished well enough to prevent major rust. I guess the folks at Nissan couldn’t be bothered with that. Maybe it was built on a Friday eh?
Problems with the ‘93 -
Broken exhaust manifold studs and warped manifolds.
A starter failure.
An alternator failure.
A fan clutch failure.
And a slightly leaking head gasket that turned up during a routine oil analysis.
The local import shop and the dealer told me it was common, as were all the other problems I’d seen.
I think you can see why I’m less than impressed with the reliability...