Oil cooler thermostat

I could see the oil hitting 300 with coolant at 240-260 with the right conditions. When my water shows 210 in the Camaro, oil is 300. When the coolant is 250, well, my oil temp gauge doesn't go that high. The only reason I don't lift when it's that hot is because I have a spare long block fully built and ready to go should the worst happen. Would be a shame to waste a 4 bolt main block even though it doesn't mean that much in the grand scheme of things.

Supercharged,
They were engine oil coolers. I have two friends with K2500's, one a 7.4 and the other with the 5.7, they both have oil coolers on the drivers side out front.

L31,
I bought the composite 9 blade fan from RA and installed it on my 97--the stupid thing was out of balance, so it's now sitting in the corner of the shop......

Those 9 blades and especially the new style clutches Rob zero power when they're not running. They freewheel like crazy.

What year are the K2500 trucks that belong to your friends?

My 99 C1500 suburban with 5.7 vortec consistently keeps the water temperature gauge almost all the way to the left. Only time I have seen it move much was that one time I almost ran it dry, then that needle moved plenty quick! It stays the same usually, just at operating temperature whether in traffic or hauling a load of Hot Wheels and tables. Radiator is stock for a/c, has the stock 11 blade plastic fan and pretty new HD fan clutch. I remember back in my parts store days, too many people didn't want to put out the extra $$ for the heavy duty fan clutch and then wonder why the car or truck overheats in Houston summer traffic. So this is something Dad always looked at on all our GM vehicles. Only Mopars we had had dual electric fans

454cid said:

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.

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I think on the Burb and Tahoe the towing package includes the external engine oil and transmission fluid coolers, both of mine came that way

HotWheelsBurban said:

I think on the Burb and Tahoe the towing package includes the external engine oil and transmission fluid coolers, both of mine came that way

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What year? I believe on the Vortecs it included radiator oil cooler and aux trans cooler.

Supercharged111 said:

What year? I believe on the Vortecs it included radiator oil cooler and aux trans cooler.

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Both my trucks are 99s, built in the Mexican plant,both with the towing package option. The oil filter is mounted on an aluminum block that has the auxiliary cooler lines plumbed into it, between the filter and the block.

HotWheelsBurban said:

I think on the Burb and Tahoe the towing package includes the external engine oil and transmission fluid coolers, both of mine came that way

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I don't think all of them did. My '98 K1500 Z71 with towing package has the engine oil cooler in the radiator (which I thought all of the Vortec 5.7 engines got, but I could be wrong) and has the transmission cooler in the radiator like every automatic GMT400 has, but does not have the additional external transmission cooler.

I did not think there was an external engine oil cooler option? I thought it was just the cooler in the radiator end tank.

My Tahoe Limited has external trans and even has a power steering cooler, but no external engine oil cooler.

The K1500 definitely heats up the transmission on long grades, where the Tahoe doesn't seem to have a problem. Both of them heat the engine oil up based on watching the pressure gauge, and I would definitely not want to delete the cooler entirely. Essentially every modern car has an engine oil/coolant heat exchanger, either in the radiator or built into the engine somewhere. It's critical that oil temperature stays in the happy range between around 190F and 250F with the extended oil drain intervals most people like to run. You can get away with running outside of those limits if you change the oil more often, and synthetic oils can handle a bit more (intermittently) on the high end without seeing viscosity and shear film degradation.

@Supercharged111 300 degrees oil temperature is hot! I used to get about that high (285F in the pan, which is aluminum, finned, and hangs in the air stream under the car) in my turbo BMW track car after ~5 hot laps and then I would back off. Eventually had a mild engine failure caused in part by cooking the oil behind the rings and seizing them in place. Came off track after seeing oil pressure start to bounce only to find I'd been pumping oil out the breather and had filled the catch can and overwhelmed the separator. It was a quart low before it started to starve. Cylinder pressure straight into the crankcase with seized rings...had 75 psi compression on all cylinders.

That car now has a very nice external oil filter head with an integrated thermostat from Improved Racing, which would work great in one of these trucks too. Oil temperature would then stabilize around 270...and some further tuning showed I had too much advance. Pulling 2 degrees at WOT dropped my oil temperature to 240 degrees (30 degree drop!!) with almost no impact to power.

I had a 4th gen (1994 Z28) for a while, that's a tough application for cooling. Only did one track day with it, but that sucker setup feeding the radiator managed to pull in an unbelievable amount of rubber and track debris.

I remove the radiator and blow the tire turds out every year. I rebuilt the motor back in 2015, wadded up a rod bearing. I'd pushed the water pump drive oil seal out and a full quart overfill wasn't enough to have it be full by the end of a race so it starved. Every other part of the motor was immaculate, so while 300+ is HOT, it's not enough to get me to lift because 1: it's clearly not a death sentence and 2: almost every other racer is in the same boat and we're just not blowing up motors as a whole. Sure, the "experts" will tell you 260 kills bearings, but I've seen otherwise first hand.

Supercharged111 said:

Were they engine oil coolers or trans coolers? I just don't see that many at all when I'm in the junkyard. I like my Autometer trans temp gauge and do aspire some day to add oil/trans temp to the dually. I got some plastic dual gauge pod off of Summit made of plastic for my 1500, it goes on top of the stock piece and fit well. I used SEM grey interior paint from Napa and it matched halfway decent.

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You got Pic of it? I'd like to see