I use an Edge Engine Monitor and when the truck has reached operating temps I can double my IAT reading which is close to my TFT, then add approx. 40 to 60 degrees to it and that will be a good estimate of the EOT. Note that when the IAT is approx. 100 deg. the above numbers are not as accurate, but with IAT's around 75 to 90 deg. it works quite well. When on long trips there isn't much to do but watch the engine monitor and notice the relationships between the numbers. I have seen my EOT up to 216 deg. with no real external loads but in some toasty heat.

 

Here's an old pic of the front of the vehicle, but it still looks the same. Could the lights and license plate be enough of a restriction to cause a problem?



If you look really closely, you'll see a TruCool tranny cooler just behind the grill. That's no longer there, replaced by a 6.0 cooler a couple of years ago.


Mark

 

And there lies the problem.

Once I drove a PSD (not mine) from Texas to South Carolina. On flat lands the temp gauge on the dash never moved. Hit some decent hills with a trailer behind me, and the temp gauge started to rise. The bigger the hills, the hotter it got. A couple of times I had to pull over and let it idle. Come to find out, the water pump was failing. Just an example there.

Keep in mind the cooling system on the PSD is over-engineered as long as it's functioning properly. It's designed to keep the engine at NOT under the absolute worst conditions imaginable. Towing uphill is not one of the worst conditions, but yours is struggling to keep temps down anyway. The problem isn't in the oil system, it's in the cooling system. The stuff you have on the front of your truck hasn't caused a problem in the years before, so it's not to blame now.

Unfortunately that's a loaded question. It varies by quite a bit. Different mods, different tuning, different oil used, different conditions..... the list goes on and on. I've seen quite a bit of variance from one truck to the other. I do know that regardless of oil temps, the coolant remains far more steady temp-wise.

That being said I'm no longer surprised to see oil temps on trucks reach 230-240 at altitude under load.

 

Agreed. The radiator seems to be the most likely culprit, both because the other components (e.g. water pump, bottle, cap, hoses) are pretty much new, and because this is a truck that lives most of its life in the garage.

Again, that makes sense, and I'm pretty sure that oil temp range is associated with a coolant temp that leaves the stock coolant temp needle painted on the dash.

Thanks man. I tried to rep 'ya, but I'm in jail.


Mark

 

Mark,
What if you tried the drive at the old speed that you used to drive at and monitor oil temp or...
Install a coolant temp gauge, so you could monitor coolant temp-that way you can tell if there really is a problem with the coolant system, before going out and spending money on something that isn't really problem.

The real issue for you is that you are using the vehicle on the edge of its capabilities, so you more than others need to know the real numbers of what the coolant temp is doing.

And this type of subject has come up before in other threads relating to having to know the real number for some bit of information relating to the engine/running gear. It is so important to absolutely know what is happening, that it then becomes more important to find out what the number is, before deciding if there is a problem. In a way since we don't have all the numbers, we are all flying blind unless we get those extra gauges, like coolant, exhaust temp, etc.
Larry

 

Slow down? Blaspheme, you say!!

Actually, I'm not exactly flying. The speed limit on most of these grades is 65mph, and I never exceed it when towing and, in the case of the eastbound approach to the Eisenhower tunnel, for example, I'm EGT-bound to about 60mph at the top. Even before the chip, I was probably only going about 5mph slower. I could certainly be wrong, but I don't think I'm at the limit of a properly performing truck.

I do understand what you're saying, though, and you're right. I hate to throw money at something that's not a problem, even more than I hate throwing money at the wrong solution to a problem. That's actually why I hijacked this thread (sorry OP!), and am soliciting opinions.

I've thought about a real coolant temp gauge, though I was ridiculed in a thread once when I suggested that one would be valuable. The truth is they are like any other gauge: You don't need them until they read out-of-normal-range, and then they are really handy.

Mark

 

Mark,
This illustrates how often we humans criticize someone for a valuable idea, without really thinking it through. You are in a situation where coolant temp would be helpful, most of us don' t get into towing at the limits, but you could be closer to the limits. Only a gauge will tell you how your coolant system is doing.
Larry

 

This is where the laser/IR thermometer steps up. ECT is too easy to check by hand, and you know your EOT from the scan gauge. Once you've established the difference between the two, you have your EOT and ECT numbers at all times, within reason. One can't get hot without bringing the other one along for the ride - because of the oil cooler.

 

Though I'd like some really warm weather tows to confirm it, I'm ready to say the radiator was the problem. I replaced it and rebuilt the oil cooler at the same time (documented in other threads), and have towed the same trailer to Moab and back three times since then. The highest oil temp I saw was 230.9* yesterday, and that was on the nine minute, 60-65mph, 1250-1300* climb on the westbound approach to the Eisenhower tunnel. Coolant temp gauge stayed painted on the dash through all three trips.

Thanks for everyone's help!

Mark

 

isn't that the side the Fast Lane Truck, http://www.tfltruck.com/, guys use to test truck at load.. that is one devil of a pull.

I know it fun to be the first one to the top but it seem to me if we slow down a bit on long hard pulls say back to 55 MPH or so you save fuel and run cooler.

but that is just me.

 

I recetny installed a bulldog tuner and running my performance tune mostly stock other than that with some mild exhaust and intake mods and my oil temp at 200-205 at 75 mph and in city driving it drops to 195 ish let me know at what temp I should worry about it?

 

Welcome to FTE, I wouldn't worry about oil temp until at least 250F but I do not know what it's ceiling is. BTW, it would be best to start a new thread here over reinvigorating a three year old one.