I finished putting the gauges in my stock 03. These are the Autometer gauges and I have a question as to what I should be reading on the EGT. I placed the probe into the manifold between the fifth and sixth cylinder. When Idling it is at 500 degrees and at around 70 mph it will register 800 degrees. Is this normal. What is the max temp that I should not exceed?

 

sounds about right. . .you are reading off the last cylinder, which is the hottest BTW.

as long as you dont go over 1350-1400F your ok. but limit yourself to around 1250 to be safe.

 

Drew is correct.
When idling, Ill see between 350 and 450.
At WOT , Ill get 1000 easy.
Doing 70 , Ill run between 6-800.
JFYI

 

500 at idle sounds high, with my mods... I'm at around 300 depending on the outside temp...

why is it some are saying the #6 cylinder is the hottest? the design of the exhaust manifold has only 2 cylinders collected from the rear of the motor & 4 for the front.. I'd think the #4 would be the hottest as all of the e-gasses from cyl's 1-3 have to pass by it heat soaking that part of the manifold more...

 

My oh my how times have changed to be able to see a engine be OK if the pyro was to read at or above 1250 degrees. When I was driving OTR many days ago when a pyro would read 1150 we would hope and pray we could cool the engine off fast enough so that it never hit 1250 ever. I was taught that the engine would be shot at those temps and that you could almost bet that you had put a hole in at least one or more pistons and a lot of damage to the block. So either the probes are more accurate then years ago, they have made the pistons and block to where they can take one hell of a lot more heat or all three.

 

OTR engines I believe are still the same way. 1100 and your asking for trouble, 1200 and your probably justmelted the turbo and a few valves.

our 5.9's have a different alloy for the valves, and the valve seats can handle more heat as well. The turbo is also the same way, different alloy of metal for the turbine blades to handle higher heat.

 

How long was your truck idling before you took the reading? If I am working mine hard and then stop it will idle that high for a short while, but it will fall back to 350 or so after about a minute and then if I let it idle a little longer it will be low 300's.