Hi guys,

I towed my 5th wheel (37' WW loaded) this past week and had a question about operating temps. The ambient temps were 80-90 and for the most part on flat terrain my ECT was 200-212 with the EOT never varying more than 10-12 degrees from the ECT.

On really long pulls (EGT's below 1250) my ECT got as high as 230 and the EOT saw temps as high as 245-250 TRANS never got above 175. The SGII showed my FSS (fan speed sensor) actuating the fan at the correct temps and RPM (3200rpm+ sustained until temps got down to ~212 ish). It looks like the ECT/EOT deltas were always within 15* or less of each other throughout the trip and for the most part.

After the long hill pulls I experienced the occasional 20-22* delta spread between the two but again the temperature deltas came back normal ranges within 2-4 minutes. Those temps would taper quick enough to not raise a concern in my head, but I could be wrong. At no time did I receive any type of defueling scenario OR a pegged ECT sweep gauge on my OEM dash so I never let it concern me too much, just kept monitoring. My operating temps are pretty much perfect during unloaded conditions with the occasional 18* spread between the above temps after a good throttling or hill climb, but the temps come down quickly and taper to the desired temps.

What do you guys think of my temperature scenarios?

Time for an oil cooler or am I ok?

Thanks for the time
Joe

 

Temps look great.

Engine oil takes longer to cool and is always chasing ECT.

Josh

 

Thanks Josh.

I understand the deltas are a "guideline" and many other factors play into determining if the oil cooler is plugged or not. I think so far my truck is healthy and will be better once I tear into the top end and stud it.

Joe

 

Looks good to me. All temps in line with what my truck does except that my deltas are a little closer together. You however have no worries in my op.

 

Thank you buddy. You mentioned your deltas are closer in range. Have you recently changed your oil cooler?

 

It was changed app. 3 years ago. I have been running a coolant filter the whole time since I bought the truck so it had a head start on cleaning the system up. My block originally was loaded with casting sand. First filter plugged in less than 500 miles.

 

Ok thanks....my oil cooler is original and I have 72k miles on the truck. I installed the coolant filter @ 35-40k miles and have since changed the coolant 6 times but never flushed it as some of the guys do with distilled water. I do run a coolant/distilled water mixture as most do. I am on my 5th filter and the first which I changed @ 1k miles didnt have much casting sand in it at all....I guess I got lucky huh?

When I did my FCDP egr delete 5 yrs ago I updated the turbo lines but just didn't know about the oil cooler deltas (weren't talked about then)....kinda kick myself in the butt for not but oh well.

I have been throwing the idea around of changing the oil cooler anyway since I am pretty sure I do not have the updated screen and who knows what condition it is in.



Thanks
Joe

 

I would wait till your deltas dictate change. Some have gone years with a 12 to 13 degree delta and it never got any worse.

 

I can only assume that during normal baseline driving, the delta spread would be < 15* constant to dictate change or when is a good baseline for change consideration?

The deltas don't have me as worried as the OEM HPOP plastic screen that is so infamous for failing.

Thank you for the help
Joe

 

Your EGR cooler is deleted so that changes things a bit. With no EGR cooler I would expect your temps to stay closer together.

 

I don't see the logic behind your statement? Coolant still cools the oil and air still cools the coolant. The oil temp. is still going to follow the coolant temp. no matter where it is and unless the coolant radiator is borderline the coolant temp. will still be the same based on t-stat function.

 

Mister CMK,

I too am curious about your statement.

My deltas fall within the normal ranges from what I have been reading and to my surprise, stay consistently spread unless I am really hammering the truck. I understand that with an EGR cooler the coolant temps could be hypothetically higher since the heat exchanger is doing it's job. My tstat rad air flow and fan maintain the temps regardless of an egr cooler being there or not. Since the oil temp is dictated by the ECT and my deltas rarely exceed "supposed" dangerous levels unless I am towing up a grade, how does this make the operation of the truck any different than a vehicle with an EGR cooler still in place?

Why do you suggest that with my EGR cooler deleted my temps spark concern?

Thanks
Joe

 

explanation please

 

I tried....maybe he forgot I asked.

 

The reason for monitoring the delta is that when the oil cooler starts to clog the EGR cooler gets starved of coolant and begins to be at risk of failing. That's point one. Point two is, total coolant temp load is affected by all elements that put temperature into the engine. The EGR cooler is a large temp input to the total cooling load so deleting it removes that load and will make the engine run cooler easier. That means that under high loads, with resultant high EGT's, no EGR cooler will let the cooling system run far better and result in lower overall coolant temps that would otherwise be the case.

In your situation, commenting on the original point, your oil temps are too high at 250 degrees and you should slow down before they get that high. I suspect that with the EGR cooler delete you may have fouled up the engine fan strategy, based on what I've read here, but you don't mention the fan ramping up to high speed, and that is something that a SGII might be able to monitor for you. Your year of truck will not throw a wrench light (2005 and up and only with the latest flashes, which everyone seems to want to back-step) for high delta's, and may not have the same de-fueling strategy as the latest programming. Based on what I read in the original post, you are plain running too hot at the worst case, which can be the cooling system, the engine fan strategy, or just a hot day and a big load running too hard. Your basic performance is probably just fine. for comparison, when I tow a tall 10K trailer in decent hills at 90 degree plus ambient, my coolant rarely spikes over 220 and oil never goes over 225. As noted, one of the keys to oil cooler monitoring is recovery time, and your report suggests that the oil temp recovers quickly when the load is reduced, so that is the really good news.

Brian