When I start my truck (a 1995 XE with a V6) after it has sat for an hour or two and immediately have to climb a hill after starting, I get this rattle-clatter sound that I am sure is from the valves on the right hand side of the engine.

Happened yesterday after I got off the ferry after a two hour ride then had to climb the Upper Levels highway. (I'm in British Columbia)

Once the engine warms up, the clatter diminishes.

Is this a problem? Normal?

You sure it's not pinging? Try running a tank of higher octane fuel through it and see if it still does it.

My first thought would be a broken manifold stud.. which is a VERY common problem since its coming from one side of the engine.. Inspect all of your passenger side exhaust manifold studs to see that all the nuts are still there and that none are broken. It could also be a leaky exhaust donut on the downpipe on that side of the engine too.

Something else to think about.. there is a TSB concerning a certain range of 1995 Pathfinders and trucks that had incorrect pistons installed at the factory. Nissan will replace the engine if it is under 100k miles and if it falls in this VIN range.

Let me see if I can get the info for you.

Here you go

EM96-005A                  NTB96-065A                   November 13, 2000
1995 TRUCK/PATHFINDER ENGINE KNOCK AFTER COLD START

ATTENTION: This bulletin replaces NTB96-059 and NTB96-030, and amends NTB96-
065. The information in the Parts and Claims Information sections of NTB96-065 was
updated. Please discard all paper copies of NTB96-059, NTB96-030, and NTB96-065.
.

APPLIED VEHICLES: 
1995 Truck (D21)
1995 Pathfinder (WD21)

APPLIED DATES: 
Truck - April 21, 1995 to December 31, 1995
Pathfinder - April 20, 1995 to September 28, 1995

APPLIED ENGINE #S: 
Truck - VG30-816606C through VG30-912495C
Pathfinder - VG30-090208Y through VG30-164493Y

SERVICE INFORMATION
An engine knocking noise may be noted in some vehicles when the engine is started after
an overnight cold soak, especially in cold weather. If there is noise, it may be most
noticeable during the first several minutes after starting the engine, then gradually
diminishes as the engine nears operating temperature. The knock is loudest under light
load (1/8 throttle) at 1200-1800 RPM. It is audible in the passenger cabin and outside the
vehicle.

Thanks guys. I'll check the manifold.

Datz510, my truck has a manufacture date of July 1994 and has over 100,000 miles on it.