Oil temps and towing

oakvad · Jun 13, 2014

So im guessing I already know the answer but gonna ask anyway,
ive got a 10 f350 ccsb running a 2.5" level kit on 35's spartan dpf deleted still running egr and coolers and stock air cleaner.
My question is my eot is between 198 to 206 depending how hard I drive it, normal right? And my ect is about 5 to 10 lower until I hook up my trailer then eot can jump to 240 before the fan kicks on and drops back to 210 ish. Now those high temps are pulling a hill or under stress but if my fan does not kick on my temps will stay 220- 230.
Sound like a plugged oil cooler?

probably sent from me at work!

tbsimmons · Jun 14, 2014

Might be depending on how the temps act. The fan wont come on till the ECT gets to I think 225, might be a little lower dont really pay too close attention to it.
I have had mine that hot a couple of times till the fan kicks in. That is pulling a long 7% in the summer. If the ECT and EOT go up and down together most likely the oil cooler is fine, like over the crest of the hill they drop back down.
With everything working right, RPM plays a huge role in oil temp.

oakvad · Jun 14, 2014

The farther the oil temp goes up the farther apart the eot and ect spread apart. When my eot hits 240 my ect will be 225 and yep that's when the fan will kick on

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tbsimmons · Jun 14, 2014

Miles and have you changed your thermostats?

oakvad · Jun 14, 2014

It just turned 57k and no have not changed stats

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tbsimmons · Jun 15, 2014

I would start with a flush and thermostats. Mine started splitting like that a few years ago, that was it.

oakvad · Jun 15, 2014

Boy I sure hope so. That would save me some cash, more camping trips! Lol
I was wondering if it could be something else because of no deltas when not pulling. When my oil cooler in my old 6.0 went it was 20° or more delta all the time.

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B585Ford · Jun 17, 2014

tbsimmons said:
I would start with a flush and thermostats. Mine started splitting like that a few years ago, that was it.

I understand why the flush could help, but unless I am missing something I don't see how Tstats could cause large deltas. If you are saying a Tstat issue could cause high deltas, please explain.

OP,
I gross over 30k and never see deltas that high. I also don't see my ECT get that high. I agree 100% that doing numerous flushes and replacing the Tstats might help your overall temps. Also agree RPMs are a big factor on temps. My deltas definitely get bigger when I have downshift and run higher RPMs.

tbsimmons · Jun 17, 2014

These trucks have 2 thermostats in them and they like to hang partially open. Been a problem since they came out.

B585Ford · Jun 17, 2014

tbsimmons said:
These trucks have 2 thermostats in them and they like to hang partially open. Been a problem since they came out.

NO, I get that. What I was asking is how would a Tstat acting up cause the passage (of coolant) to the oil cooler to run hotter than the other 2 passages going to CC? Obviously, if the bottom Tstat stays closed/partially closed the coolant will go through the bypass and hot coolant will be directed to the pump, but I would think that would cause both ECT and EOT rise. Am I missing something?

Dzchey21 · Jun 17, 2014

It sounds like to me the thing is running hot all the time anyway. I think maybe thats why he recomended the t stats. when i used to tow with mine tuned and deleted i was lucky to ever get over 209 coolant temp and 215 on the oil even up here in thin air.

B585Ford · Jun 17, 2014

Dzchey21 said:
It sounds like to me the thing is running hot all the time anyway. I think maybe thats why he recomended the t stats. when i used to tow with mine tuned and deleted i was lucky to ever get over 209 coolant temp and 215 on the oil even up here in thin air.

I agree 100%. Like I said, I have never seen temps that high even when grossing over 30k lbs. That is why I recommended flush it and replace Tstats. I was just trying to find out if there was something I was missing with how the cooling system works where a funky Tstat could cause EOTs rise but not raise ECT.

oakvad · Jun 18, 2014

But it only runs hot when towing witch is whats really throwing me for a loop. If it was a plugged oil cooler I believe it would run hotter with higher deltas all the time so im gonna do a few flushes get some new fresh coolant in it and hook up the trailer and put some stress on it. If that dont work ill flush again change t stats and do the same. If that dont work all take it to my local shop

probably sent from me at work!

B585Ford · Jun 18, 2014

oakvad said:
But it only runs hot when towing witch is whats really throwing me for a loop. If it was a plugged oil cooler I believe it would run hotter with higher deltas all the time so im gonna do a few flushes get some new fresh coolant in it and hook up the trailer and put some stress on it. If that dont work ill flush again change t stats and do the same. If that dont work all take it to my local shop

probably sent from me at work!

Your truck is producing a lot more heat when towing vs not towing. If there is a problem such as Tstats staying partially closed, when empty your cooling system can keep up with heat production even though the cooling system is getting weak, but when you are towing, the cooling system cant keep up.

oakvad · Jun 18, 2014

Ok got it. Hopefully within the next couple weeks I can get those changed well whet my work will allow me to. Lol

probably sent from me at work!

tbsimmons · Jun 19, 2014

My split was in the 20 range in the summer towing 18000 over a 7 plus percent grades and the temps would stay split for a while following. The coolant would come back down but not the oil. Read about the thermostats being faulty and changed them and pretty much fixed it. Only reason I can comp up with is since oil heats up quicker than coolant with rpm and if the coolant flow is not enough through the thermostats then you will get a split. The truck will still get to 235 225 in the heat of summer over the hills. Biggest split is 13. Main reason is rpm. A 450 with 4.88's and a down shift the truck is spinning 2500 to 2700 range. If the truck stays in overdrive the temps will climb gradually but not get as hot and split below 10.

Sent from the bat phone near a drilling rig.

B585Ford · Jun 19, 2014

tbsimmons said:
My split was in the 20 range in the summer towing 18000 over a 7 plus percent grades and the temps would stay split for a while following. The coolant would come back down but not the oil. Read about the thermostats being faulty and changed them and pretty much fixed it. Only reason I can comp up with is since oil heats up quicker than coolant with rpm and if the coolant flow is not enough through the thermostats then you will get a split. The truck will still get to 235 225 in the heat of summer over the hills. Biggest split is 13. Main reason is rpm. A 450 with 4.88's and a down shift the truck is spinning 2500 to 2700 range. If the truck stays in overdrive the temps will climb gradually but not get as hot and split below 10.

Sent from the bat phone near a drilling rig.

OK, I guess that is the explanation will do. More than anything, I just wanted to make sure there wasn't something I was missing about the cooling system. I never ran into ECT temp issues to date. IIRC the highest I have seen is 209 and that was a 6 or 7% grade for several miles grossing 32500. My observations are the same as yours though...my truck has 3.73s (SRW) and 35s but I do have a manual tranny. I try to keep it in OD at all times to keep oil temps in check. Of course that does raise the EGTs but they are almost never an issue with my setup and tuning. Like yours, my oil heats quicker the coolant and I can see close to 20 degree deltas under extreme conditions. The only difference I have is once I crest a hill, my EOTs come down almost as fast as the ECTs, but I am dropping into OD as soon as I can and I have a lot taller gears so that might be more RPM related.