One improvement to the 4.0 that I know of around that time was the
revision of the oil filter boss housing; it used to be a 2-piece
assembly with a problematic O-ring between the boss and the engine
block. They finally changed the block casting and machined into it, an
oil filter boss that is one integral piece eliminating the O-ring and
associated leakage problems. Also, I *believe* that in 99 they went to
the coil-on-plug assembly, eliminating secondary ignition wiring. Small
stuff, but a good deal for buyers.

 

One improvement to the 4.0 that I know of around that time was the
revision of the oil filter boss housing; it used to be a 2-piece
assembly with a problematic O-ring between the boss and the engine
block. They finally changed the block casting and machined into it, an
oil filter boss that is one integral piece eliminating the O-ring and
associated leakage problems. Also, I *believe* that in 99 they went to
the coil-on-plug assembly, eliminating secondary ignition wiring. Small
stuff, but a good deal for buyers.

 

One improvement to the 4.0 that I know of around that time was the
revision of the oil filter boss housing; it used to be a 2-piece
assembly with a problematic O-ring between the boss and the engine
block. They finally changed the block casting and machined into it, an
oil filter boss that is one integral piece eliminating the O-ring and
associated leakage problems. Also, I *believe* that in 99 they went to
the coil-on-plug assembly, eliminating secondary ignition wiring. Small
stuff, but a good deal for buyers.

 

The year for the coil on plug was 2000. My 99 had a distributor, my 00 does
not.

Carl


"Outatime" <user@example.net> wrote in message
news:CZmdnZpJ5pn1QBPYnZ2dnUVZ_oWdnZ2d@softcom.net. ..
> One improvement to the 4.0 that I know of around that time was the
> revision of the oil filter boss housing; it used to be a 2-piece assembly
> with a problematic O-ring between the boss and the engine block. They
> finally changed the block casting and machined into it, an oil filter boss
> that is one integral piece eliminating the O-ring and associated leakage
> problems. Also, I *believe* that in 99 they went to the coil-on-plug
> assembly, eliminating secondary ignition wiring. Small stuff, but a good
> deal for buyers.

 

The year for the coil on plug was 2000. My 99 had a distributor, my 00 does
not.

Carl


"Outatime" <user@example.net> wrote in message
news:CZmdnZpJ5pn1QBPYnZ2dnUVZ_oWdnZ2d@softcom.net. ..
> One improvement to the 4.0 that I know of around that time was the
> revision of the oil filter boss housing; it used to be a 2-piece assembly
> with a problematic O-ring between the boss and the engine block. They
> finally changed the block casting and machined into it, an oil filter boss
> that is one integral piece eliminating the O-ring and associated leakage
> problems. Also, I *believe* that in 99 they went to the coil-on-plug
> assembly, eliminating secondary ignition wiring. Small stuff, but a good
> deal for buyers.

 

The year for the coil on plug was 2000. My 99 had a distributor, my 00 does
not.

Carl


"Outatime" <user@example.net> wrote in message
news:CZmdnZpJ5pn1QBPYnZ2dnUVZ_oWdnZ2d@softcom.net. ..
> One improvement to the 4.0 that I know of around that time was the
> revision of the oil filter boss housing; it used to be a 2-piece assembly
> with a problematic O-ring between the boss and the engine block. They
> finally changed the block casting and machined into it, an oil filter boss
> that is one integral piece eliminating the O-ring and associated leakage
> problems. Also, I *believe* that in 99 they went to the coil-on-plug
> assembly, eliminating secondary ignition wiring. Small stuff, but a good
> deal for buyers.

 

Marty writes:

> The '99 and up models are a couple grand more with comperable
> or more mileage but nobody has been able to justify why.

Two inevitable problems of the 97 TJ were the exhaust manifold cracking and
the air conditioning evaporator leaking. Design flaws took a few years to
correct, not sure if it was 1999.

 

Marty writes:

> The '99 and up models are a couple grand more with comperable
> or more mileage but nobody has been able to justify why.

Two inevitable problems of the 97 TJ were the exhaust manifold cracking and
the air conditioning evaporator leaking. Design flaws took a few years to
correct, not sure if it was 1999.

 

Marty writes:

> The '99 and up models are a couple grand more with comperable
> or more mileage but nobody has been able to justify why.

Two inevitable problems of the 97 TJ were the exhaust manifold cracking and
the air conditioning evaporator leaking. Design flaws took a few years to
correct, not sure if it was 1999.