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Discussion Starter · #1 ·
Hello everyone,

I'm really new to the 6.5L engine so my questions are the following:

1) What is the difference between a 1994 6.5L vs 1998 6.5L

2) On the RPO codes, I noticed there were 6.5L Turbo HO and 6.5L Turbo,
can someone tell me the difference between the two engines?

I didn't see this information in the FAQ document so if someone could shed some light on these questions then that would be great.

Thank you,

Pete..:)
 

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1. The main differences between the 94 and 98 6.5's was the blocks changed in 97 to piston oil spray cooling. They also changed turbos and updated the IP's(if it has been replaced though it has the updated one). And the cooling system changed in 97 as well to a higher volume pump and dual t-stats. The 94 is actually a more desireable block thean the 97+ block.
2. The main distinction between the HO's and the standard turbo was the HO engine was the F engine(non EGR), and the turbo engine was the S engine(with EGR). People often refer to them as F for fast and S for slow.
 

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Discussion Starter · #3 ·
Hello Fermanator and thank you for answering my questions. Are the HP/Torque ratings similar or the same?

Thanks again,

Pete
 

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'94 is OBD-I, '98 is OBD-II, with better functionality..

Main mechanical difference in F and S engine is the pre-cups - larger outlet port for more power in the F engine

Or - smaller-port pre-cups in the S engine for emissions and economy.

Remove the S EGR, you still do not have an F engine, even with the F PCM.

All else is the same, but with better coolant passages in the head, ca'98.
 

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so how do u know if u have an egr engine, F or S?
CBD welcome to the site take a minute to read through the welcome notes and FAQ in my signature link for info how to update yours.

8th letter of your VIN is either S or F is the quick way to tell, EGR valve dead center of intake with "Turbo Power" cover off, or 3 solenoids in a row just under brake booster
 

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thanks TD. this is my first experience with a diesel, so dont know a lot about them
 

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Spend some time in FAQ section & welcome notes and you will be up to speed pretty quick.
 

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I think all of the 1500's have an S engine.

The problem is that your exhaut is getting into the intake on an S engine. Something needs to be done to stop the EGR from leaking into the intake if it is, or you will have a lot of soot in the intake. For all I know you may have a lot of soot there anyway. If you take it off and clean it up and change the gaskets it should help some.

I just cleaned mine. I am probably going to try to open up the area around the snorkle on the plenum(top part of the intake where the EGR valve is mounted) n mine.

There is also a round seal there in the snorkls(tube where the exhaust comes out at the base of the EGR valve).

Search for more info on EGR you should find some mod ideas.
 

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