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Temps getting more than 15* apart

4K views 16 replies 7 participants last post by  P7M8 
#1 ·
My coolant and oil temps are more than 15* apart on occasion. This is during regular city driving. No load.

This morning driving the kids to school it was around 70* outside. It got up to about 19* apart. Coolant temps stayed in the 186-190 range with the oil temps around 200-205. At a point I was at 186* coolant 205* oil.

What should I check? Already replaced the degas cap with a Stant. I want to go from cheapest on up. Could it be the thermostat?

'07 stock with 4" Turbo back exhaust. Running canned SCT performance tune. I'm not hard on the throttle.
 
#2 ·
Oil cooler time! The true test is driving 65 mph on flat highway for a while, THEN check the deltas.
 
#4 ·
I wasn't able to be at 65 for that long but on a generally flat section of interstate with some overpasses I was 186*/209. Planning on a full coolant drain and thermostat change.

What's the recommended coolant to replace the Motocraft Gold?
 
#7 ·
Not for a 6.0, although that is basically what it shipped with. The Zerex G-05 is, essentially, Ford Gold. It is not a bad coolant chemistry in general application. The silicates make it a problem for vehicles with high heat conditions (EGR) and small coolant passages (oil coolers). It could be fine on an EGR deleted vehicle if replaced according to schedule.

You are better off with ELC and - in particular - EC-1 rated ELC. That is a Caterpillar standard.
 
#8 ·
From the two youtube videos I just watched a coolant flush on a 6.0 looks like a PITA. Is it worth paying a shop to do?
 
#9 ·
It depends upon how much cash you have in your pockets and how much time you have on your hands. Ten different people would give you ten different answers.

That said... It's not that bad if you install valves in the block drains - or at lease the driver's side. I cannot imagine doing it without.
 
#10 ·
Don't be too worried about a >15* delta, but it is an indication of a cooler replacement at some point down the road - not down the road as in broken down! If you still have the EGR cooler you probably should replace it sooner than later; but if you have already removed the EGR cooler, you could easily wait until the delta is much greater. Remember the problems that occurred in the past were exasperated on trucks with the EGR cooler failure causing all the havoc.

FWIW I bought a cooler 3 years ago in anticipation of replacing it and still have not done so yet. I did a flush and changed to ELC 3+ years ago and my deltas stayed under 10* until this year. I don't know why (maybe some junk broke loose but I don't see any particles in the degas), but this past summer my delta started to climb and it has been sitting about 16-18* for about 3-4 months. I will probably change out my cooler next summer or earlier if I decide to replace any other item on the top side of the engine like a turbo or a Thumper HPOP. Call me practical or lazy. :dunno:
 
#11 ·
^^^ Lot's of good in this post.

Regarding the delta... in my view, it isn't the absolute delta that matters as much as the movement of the delta. I'd be much more worried about a 12deg delta increasing 1deg/day than a 20deg delta that is holding steady. But, as @twoicebergs suggests, as the stable delta gets higher, you need to be more ready for the inevitable.

Before my oil cooler relocation, my delta climbed to 20 rather quickly and then just stayed. I swapped out my dino oil for synthetic, put a spool plug in place of my EGR valve, and kept a close eye out for coolant loss (to know if my EGR cooler ruptured). Everything held firm while I got organized. When my delta started climbing again, I tore into it.
 
#12 ·
Is there a benefit to the Mishimoto 200* T-Stat over the stock? Reading good things about the Mishimoto.
 
#13 ·
I installed a Mishimoto 200* T-Stat today. Ran it around 60-65 on a stretch of highway. Coolant temps pretty much stayed @ 202* with a high of 204*. EOT got as high as 221* but stayed at 220* consistently. I had the AC off. No load. Outside temp 78*.

How costly is an EGR cooler install? I have to tow ~4k all day long from Louisiana to South Carolina in a couple of weeks. Do you think it would be okay to do it without replacing the EGR cooler?
 
#16 ·
I would change back to the other thermostat for that tow you will be doing. Personally, i think 220 oil temp is WAY to high without towing. Now imagine adding some weight to that run. I've never gone over 210 oil temp while towing @ 8K lbs. Hard to get it over 200 not towing unless im getting on it good then end up in stop and go traffic. Still cools back to the low/mid 190s pretty quick at a stop.

Normally my coolant temps range from 186-194 warmed up.
 
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#14 ·
First... what differential gearing do you have? Anything other than a 3.73 and you are fine.

Regardless, you are basically at 18F, which isn't very far from 15F. I don't like making recommendations on things like this because anything can happen. ...but you don't seem to be in any danger zone.

Your issue is more the oil cooler swap than the EGR cooler swap. The reason for the EGR cooler swap is because the OEM ones for your year were not great and a clogged oil cooler causes a sucky OEM EGR cooler to rupture.

I would guess a oil cooler/EGR cooler swap to be $1600. (?) There are better people here than I to answer that.

If I were going to do your run without first doing the swap, I'd definitely replace any dino oil with synthetic.

You could also flush/replace the coolant with ELC and stick a spool plug in place of your EGR valve, but that might be overkill. It's cheap and relatively easy, though. So...
 
#15 ·
IMO, and based on the limited information given, you are in a range where you are significantly reducing coolant flow to the EGR cooler. It may be fine for some time, but it may cause excessive heat in the EGR cooler and lead to a rupture and subsequently blown head gaskets. Towing, even just 4k, will add to this risk. One option would be an EGR cooler delete, but that doesn't solve the problem, just buys you some time. The real solution is a full coolant system flush, replacing the oil cooler and either an EGR cooler delete or a BPD EGR cooler.

"Replacing the oil cooler" also opens up options. Going back with the OEM (cheapest option), installing a BPD remote system utilizing the the OEM cooler (second cheapest, easiest, other than OEM itself, and easy to replace future coolers, if needed), IPR remote system (about the same cost as the BPD but you will be ridiculed) and the final, end all, be all option of the BPD remote air to liquid cooler (most expensive, by far, but should solve any future oil cooler problems).
 
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#17 ·
Just got my truck back from having a coolant flush, EGR delete and oil cooler change. One of the plastic intake hoses had a hole in it and was replaced. The degas bottle top was deformed which was causing the pressure leak. New degas bottle installed.

Now my temps are running 200/206. Truck seems to be running much smoother.
 
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