I noticed this today coming back from a camping trip - the EGT's seemed to be dropping quite a bit faster than usual when getting off the highway, from stop light to stop light, etc. But where I really noticed the difference was when we pulled into the driveway and I only had to idle the truck at 1300-1400 rpm's for about 20 seconds to get it to drop below 300 degrees. It usually takes just under a minute.

Now there's a couple of theories I have about this, and I'm looking for some input from those of you that might be able to help:

1) The temp today on the way home was about 85, but the humidity was much lower than it usually is this time of year. Would the lower humidity make the EGT's drop faster, and I'm just so used to being in high humidity the last couple of months that it surprised me?

2) I'll admit I'm a wuss about towing and hauling the loads that some of you on this board talk about every day. I just don't have the loads to haul, nor do I have any trailers to tow (I'm working on that though). But this camping weekend I did have about 1000 lbs in the bed and three people and a dog in the cab. Could it be that the truck, with that kind of a load, and a little over 30K on the odometer, is finally getting broken in? Do broken in trucks' EGT's drop faster than non-broken in trucks?

3) Or is there something I should be checking on the truck that may be broken? The power was fine, no smoke, no funny noises, the boost was normal, and the EGT's while on the highway, etc. were normal...

4) OR - - - this is probably the correct answer - am I just being paranoid?

 

Can't answer your question directly... but I also notice a variation in how fast EGTs drop off. I do tow heavy and I cannot guess how long it will take me to cool down in a given situation -- which is why I have the gauge.

I've heard the old "after you pull off the highway an into a gas station you will be cool for sure..." In my experience it's just not so. Coming home towing last night I had some stops where the EGT was at 300 before I thought to check it and some where I idled until I finished fueling and was still a little over 300 when I got back in.

 

I have noticed that the EGTs drop quicker with the A/C off than on.

MikeyB

 

As a side note - should you let the EGT drop past a certain point before shutting off the truck?

 

I usually let the EGTs drop to 300 degrees or lower before shutting down.

MikeyB

 

Instructions that came with my gauges said to turn off below 350* F. If I remember right it also said to wait 3-5 minutes after it drops to 350* if heavy towing. I have found that by the time I get to a station and get all set it is 400* and drops to 350 in a minute or less. I do a walk-around, check the trailer & wheels then turn off the truck. With the accesory switch on I can see the temperature. The temperature does not get near 400* just holds and drops to 300*. Someone wrote in that they turn off at 400*. I like 350, and it does cool better w/AC off.

 

Egt probe get old after time and some times read off or can cool off faster because of soot build up check the probe and clean it see if it helps

 

That's a good idea - though the probe hasn't even been installed a year... Good thing I put anti-seize on it when I installed...:-)

What would you suggest I clean it with?

Also - as a side note - it was even cooler today, and the EGT's seemed to be closer to what I would consider 'normal'. Who knows - maybe I was just a little foggy yesterday after a weekend of camping.

 

FWIW...I find the EGT's drop QUICKLY with the jake engaged, coming up to a stop.

i.e. Cruising at 65-70, ~800F. Let off the go pedal & egt's will fall to <300F when the jake disengages at 20mph, then climb back to ~400 as the egnie idles.

Tony

 

I use brake clean but I dont think you have a problem at all. as far as probe life depends how long you stay at high EGTs tow quite abit probe life wont be as long because of high EGT temps.