Oil cooler thermostat

[nobears]

So my little 4.3 in my 88 doesn’t have an oil cooler from the factory. As I am stabbing a motor anyways (and quite possibly swapping grill if all goes right) I’m going to go ahead and add one. On my old shovelhead Harley I have an oil cooler thermostat that bypasses the oil back to the filter and doesn’t go through the cooler until the oil reaches 180 degrees. Would using the same setup be beneficial for engine warm up? I mean I can see no down side to the oil following the factory path but about 12” longer until it warms up and starts going into the cooler.

 

[df2x4]

The factory setup used an oil cooler built into the radiator, so it had the added benefit of helping to bring the oil up to temperature quicker due to heat transfer from the coolant. You could put in a radiator that includes the factory oil cooler line connections if you wanted to go that route.

 

[Supercharged111]

Yep, just grab a 34" radiator from the parts store that has provision for oil and trans coolers and toss a factory housing and new lines in there and be done. All the crap for a 350 should fit.

 

[alpinecrick]

First, in order to bypass the sometimes hysterically confusing threads when it comes to coolers, in GM nomenclature the AUXILIARY coolers are the heat exhangers located in the radiator tanks. The EXTERNAL cooler is the separate cooler located front of radiator/condensor.


I'm considering a thermal bypass also as I plan to put engine oil coolers on my two trucks. The auxiliary coolers in the radiator tank (both trans and engine) serve to warm up the oil(s) on cold startup and cool the fluids when they get warm.

Now, the trans oil goes through the auxiliary heat exchanger located in the radiator tank and with most trucks then goes to an external cooler, which I think would cool the trans fluid down on really cold mornings--hypothetically negating the heat exchanger benefit. Yet the system seems to work just fine.

I would think to get the full benefit of the auxiliary cooler for the engine oil a thermal bypass would have to be located after the oil travels through the auxiliary cooler then back to the engine, bypassing the external cooler until the thermal bypass opens up and directs oil to the cooler. This may be more important for a engine than a transmission.

I have a Derale 1/2" thermal bypass sitting in my parts bin for when I decide to relocate my oil filter to somewhere appropriate in the engine compartment ( I haven't decided where--it's kinda' crowded on the drivers side).

 

[alpinecrick]

The question I have is do the factory external engine oil cooler setups have a thermal bypass? Or are they routed just like the trans cooler system?

 

[Supercharged111]

I don't know why you'd want an external oil cooler. If you put a gauge on the truck you'd see it doesn't get that hot. Cooler is not better with engine oil, you want it 200+ to minimize wear.

 

[alpinecrick]

I don't know why you'd want an external oil cooler. If you put a gauge on the truck you'd see it doesn't get that hot. Cooler is not better with engine oil, you want it 200+ to minimize wear.

Yes, there is a optimum range we want the fluids to operate in. I live in Colorado. As many a flatlander discovers their vehicle does just fine at sea level but where the air is thinner and doesn't cool as well fluids can run hotter. Advancing the timing on conventional distributors and working fine at sea level often doesn't work at altitude, for example. My trucks can spend time grinding along two-track trails 10 mph in the summer at 10k ft, not as much air flow. Lastly I don't like the tiny oil filters on the 4wds, even though I change my oil often & frequently, but nor can I say my engines have suffered from the small oil filters. Although I have a 05 Sierra TD, I do sometimes tow with my K1500's also.

All the GMT400 7.4 and 5.7 K2500/3500 trucks I've seen in Colorado have external coolers, and to my knowledge was an option on the 1500's.

 

[Supercharged111]

Yes, there is a optimum range we want the fluids to operate in. I live in Colorado. As many a flatlander discovers their vehicle does just fine at sea level but where the air is thinner and doesn't cool as well fluids can run hotter. Advancing the timing on conventional distributors and working fine at sea level often doesn't work at altitude, for example. My trucks can spend time grinding along two-track trails 10 mph in the summer at 10k ft, not as much air flow. Lastly I don't like the tiny oil filters on the 4wds, even though I change my oil often & frequently, but nor can I say my engines have suffered from the small oil filters. Although I have a 05 Sierra TD, I do sometimes tow with my K1500's also.

All the GMT400 7.4 and 5.7 K2500/3500 trucks I've seen in Colorado have external coolers, and to my knowledge was an option on the 1500's.

I live in CO and own 2 that came from here. Neither has an aux oil cooler. Creeping along a trail at 10mph does NOT heat the oil. Idling in bumper to bumper traffic does NOT heat oil. The ONLY thing that heats oil is high coolant temps and prolonged high RPM operation. I suggest you get a gauge before wasting time and money to shorten the life of your engine. I tow regularly and have zero desire for an oil cooler because my prolonged engine RPM simply is not enough to warrant it. My coolant temps are rock solid. My Camaro and Z06 do have oil temps gauges and they have been instrumental in teaching me about when engine oil temp rises and when it doesn't.

 

[454cid]

I think the Gen5 era trucks could get an external oil cooler.... could have been a Suburban thing, too. I think I recall someone adding one. My 99 just has the oil cooler integral to the radiator, but I have it disconnected because I got tired of lines leaking.

 

[alpinecrick]

I live in CO and own 2 that came from here. Neither has an aux oil cooler. Creeping along a trail at 10mph does NOT heat the oil. Idling in bumper to bumper traffic does NOT heat oil. The ONLY thing that heats oil is high coolant temps and prolonged high RPM operation. I suggest you get a gauge before wasting time and money to shorten the life of your engine. I tow regularly and have zero desire for an oil cooler because my prolonged engine RPM simply is not enough to warrant it. My coolant temps are rock solid. My Camaro and Z06 do have oil temps gauges and they have been instrumental in teaching me about when engine oil temp rises and when it doesn't.

I'm listening, and it's interesting what you're saying. So you're experience the auxiliary cooler is sufficient to keep the oil at operating temps when driving slow or towing with the 5.7's. An engine oil and trans temp gauge pod is something I have been considering.

Also, a thermal bypass can keep the temps up in operating range in cold weather.