Thinking about removing factory oil cooler from OBS Ford F250

[MacManus99]

So while I am really not looking for an argument, you are telling me that oil splashed onto cylinder walls and connecting rods right after combustion stays cooler that the water in the block. The block does not magically get hot. Like a pan on a stove full of water the pan has to get hot to transfer the heat to the water. Now if you are saying that the oil in the pan after it has gone through the cooler has cooled down before it goes back to the engine is colder than the water sitting stationary in the block waiting for the thermostat to open then I might agree. It really depends on where and when you measure the fluid. But if you run an engine for 4 or 5 min on a cool day I guaranty the oil coming out of the oil filter return will be hotter than the water drained from the radiator. The water cannot get hotter than the block but the oil can and does.

I agree, there is no need for an argument. So please understand that I do not mean to be offensive, I just would like to keep from misinformation being spread. Correcting your statement isnt done for my own pride, but rather to keep other readers from relying on information that just isn't true.

While you are correct in stating that oil making it's way to the cylinder walls and rod/main journals will heat up, it does not do so at the rate of the coolant in the water jackets surrounding the combustion chamber and exhaust ports. On top of this, the oil being pumped through the engine is being pulled from the cold sump first, so it is cold when it reaches the mains/rods/cams, etc.

Oil becomes hotter than block temperatures because the coolant-to-oil heat exchanger is very small, and the oil is being "cooled" there by coolant that is already 195° or greater. Therefore, the primary purpose of the coolant-to-oil heat exchanger is to bring oil temps up more quickly, and to help regulate oil temps. They are often referred to as oil coolers, and this nomenclature is misleading. More often than not, true oil coolers are air-to-oil type, and are typically thermostatically controlled as well.

I'm not always the best at explaining these things, so maybe some others can chime in to fill in the gaps that I left. Cheers!

 

[samven]

I understand your point, the only point I was trying to make with regard to the OP's question is that after you start the engine the oil starts to warm up immediately and possibly the coolant in the block but the exchange takes place at the heat exchanger (radiator) and for the first 4 or 5 or maybe longer mins the thermostat is closed and the water in the exchanger is still cold so the heat exchanger is actually taking heat from the oil at this time. By the time the thermostat has opened the oil is already in a fairly warm state and the flush of cool water rushing into the block can be seen on some temp gauges as it actually drops. So my only point here is that on a cold start there is no warm water in the radiator to transfer heat to the oil and wont be until the thermostat opens which on a short trip may never happen on a really cold day. Anyone rushing to work in the winter and waiting for the heat to kick in can testify to how long it might be.

 

[Zaedock]

Now if you are saying that the oil in the pan after it has gone through the cooler has cooled down before it goes back to the engine is colder than the water sitting stationary in the block waiting for the thermostat to open then I might agree.

And what is that stationary water sitting next to......?
How about the cylinder walls and head.

 

[eljefino]

So, where's the coolant supply for this exchanger? Part of the engine side of the thermostat or the radiator?

If it's on the radiator side it'll overcool your oil a lot of the time. Engine side, less so.

If someone's monitoring their coolant temp, that's on the engine side of the t-stat and irrelevant data if the cooler isn't.

 

[MacManus99]

I understand your point, the only point I was trying to make with regard to the OP's question is that after you start the engine the oil starts to warm up immediately and possibly the coolant in the block but the exchange takes place at the heat exchanger (radiator) and for the first 4 or 5 or maybe longer mins the thermostat is closed and the water in the exchanger is still cold so the heat exchanger is actually taking heat from the oil at this time. By the time the thermostat has opened the oil is already in a fairly warm state and the flush of cool water rushing into the block can be seen on some temp gauges as it actually drops. So my only point here is that on a cold start there is no warm water in the radiator to transfer heat to the oil and wont be until the thermostat opens which on a short trip may never happen on a really cold day. Anyone rushing to work in the winter and waiting for the heat to kick in can testify to how long it might be.

This is all true, except for one thing. The coolant-to-oil heat exchanger is routed much like the heater core, in that the coolant is circulated through it pre-thermostat. So as the engine coolant warms up, it is transferring some of this heat to the oil. The thermostat does not need to open for this to happen. My car, being a Subaru engine, may not heat up at the same speed as this 351, but coolant temps are generally 30° greater than oil temp, until the thermostat opens. From there, oil temps may go slightly higher, depending on load and rpm. Street driving, I never see above 220° oil temp, on track I have not crested 260°.

 

[samven]

And what is that stationary water sitting next to......?
How about the cylinder walls and head.

But not the heat exchanger which is what he wants to eliminate.

 

[PandaBear]

So while I am really not looking for an argument, you are telling me that oil splashed onto cylinder walls and connecting rods right after combustion stays cooler that the water in the block. The block does not magically get hot. Like a pan on a stove full of water the pan has to get hot to transfer the heat to the water. Now if you are saying that the oil in the pan after it has gone through the cooler has cooled down before it goes back to the engine is colder than the water sitting stationary in the block waiting for the thermostat to open then I might agree. It really depends on where and when you measure the fluid. But if you run an engine for 4 or 5 min on a cool day I guaranty the oil coming out of the oil return will be hotter than the water drained from the radiator. The water cannot get hotter than the block but the oil can and does.

The hot part of the engine is in the head, not the block, so if the amount of coolant flow through the head is fast and the amount of oil reaching the head is little, yes it would heat up the coolant faster than the oil.

Also another thing, the coolant has a thermostat to REGULATE the temperature, so it should not get too hot or too cold. I do not think oil temperature is REGULATED, so if the oil can get too hot (say you are towing and the oil in the head / cam near the exhaust valve) they may be way hotter than the coolant temperature being regulated by the thermostat, yet during cold start the coolant is warmer than the oil.

 

[samven]

We are all talking at cross purposes. At start up and for a few min after there is no heat exchange from water to oil. Heat moves to cold and the water is colder in the exchanger. I cant speak to Subaru but I have never seen an old Ford Chevy Dodge with a coolant bypass. At startup the oil in the radiator or exchanger is warming faster than the water at least until the thermostat opens and even then the oil has a head start.

 

[ripcord]

So, where's the coolant supply for this exchanger? Part of the engine side of the thermostat or the radiator?

If it's on the radiator side it'll overcool your oil a lot of the time. Engine side, less so.

If someone's monitoring their coolant temp, that's on the engine side of the t-stat and irrelevant data if the cooler isn't.

The coolant supply for the oil cooler on my truck is from the cold side (lower hose) of the radiator. I can drive several miles and the bottom hose will only be warm to the touch even though the temp gauge shows most of the way up to normal temp. Thinking about it, I would guess there is actually very little coolant flow through the oil cooler until the thermostat opens.

 

[MacManus99]

In any car that I have monitored via OBD port, coolant temp starts to rise immediately after startup. It rises very quickly at first and starts to taper off as it gets hotter. In my 6.0L Chevrolet engine, the coolant temp rose 34° in the first 60 seconds after startup. About 90° ambient.

 

[ripcord]

In any car that I have monitored via OBD port, coolant temp starts to rise immediately after startup. It rises very quickly at first and starts to taper off as it gets hotter. In my 6.0L Chevrolet engine, the coolant temp rose 34° in the first 60 seconds after startup. About 90° ambient.

That makes sense due to where the coolant temp sensor is located, usually in a head or near the thermostat. If you moved the sensor to the bottom of the radiator, I think you would find that the temperature increase would be delayed by quite a bit.

 

[SOHCman]

The one reason you might want to replace the oil cooler adapter is it can eventually corrode through on these OBS and mix oil with coolant. If you maintain your cooling system you may have nothing to worry about, but you can always swap on a air/oil cooler in place so there is no chance of mixing oil and coolant.

 

[D60]

I've removed those stupid afterthought coolers from all my OBS's over the years.

They did fine before the oil coolers, it's just a case of a solution looking for a problem. Team TTB was looking for their next thing to F-up and management didn't know what to do with them after they'd finished designing the noisy, weak C2 p/s pumps, so they told 'em to maybe work on an oil cooler just to give them something to do. (Fortunately Team E-series knew Team TTB was overpaid and under qualified and rejected the C2, favoring instead the tried-and-true Sag). There's some corporate trivia for ya which is totally fabricated.....or is it?????

Plus you can use a one-piece lower rad hose (get one with expansion spring) and the larger FL-1A filter as mentioned.

 

[Zaedock]

All this for a $50 hose. LOL

 

[IndyIan]

We are all talking at cross purposes. At start up and for a few min after there is no heat exchange from water to oil. Heat moves to cold and the water is colder in the exchanger. I cant speak to Subaru but I have never seen an old Ford Chevy Dodge with a coolant bypass. At startup the oil in the radiator or exchanger is warming faster than the water at least until the thermostat opens and even then the oil has a head start.

What I've got in bold is probably true at start. Thermostats don't block all the coolant flow though and if you are driving with some rpms then I'd think the coolant flow would be significant enough to get some coolant temps in the radiator, exchanger and hoses. 3+ miles down the road though, the coolant will be flowing a bit more and in the block will be warmer than the oil(my outback reports both on the screen) and oil never catches up cruising at 55mph, 1600rpm. Give it some revs though, like towing up a hill, and the oil will warm up to coolant temps eventually.
All that said, the oil cooler on the truck is really there for heavy hauling, 3-4k rpm for miles which will really get the oil temps up there above coolant temps so the heat exchanger keeps the oil a reasonable temps. So for not towing, I don't think the losing the oil cooler will matter one bit. I would weigh the difficulty in removing the system successfully though. Plugging passages or looping lines etc needs to be done properly.

 

[ripcord]

Following up on this... I had put off removing that oil cooler until this weekend. I'm pretty glad I did. That cooler was very corroded inside and who knows how long it would have held up.

Also, following up on the discussion of whether it would speed up or delay the oil getting to temp, after getting it apart and looking at how it all works, I'd have to say that it would not probably have much effect, either way, before the thermostat starts to open. The water is drawn through the cooler via a venturi effect in a hose adapter located several inches down from the inlet side of the water pump. On startup, and until the thermostat is staying open, there is minimal coolant flow, so it would not have much cooling effect on the oil until the water pump is circulating water through the radiator rapidly.

I'll take some measurements with my temp gun and post a follow up.