Oil cooler
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3rd Gear
Joined: Apr 2026
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From: Pennsylvania
Oil cooler
How could I go about deleting the oil cooler on my 89 corvette to make room for the oil filter because it is touching the header
Last edited by Garrett88; May 19, 2026 at 10:38 PM.
Racer
Joined: Feb 2010
Posts: 371
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From: south wilmington il.
The cooler will drop oil Temps by 25° but if you want to delete it the parts are readily available. It's cheaper to fix a leaking system but if you don't want it, here's what's involved. Google is your friend when checking on prices for parts.
Coolant Loop Bypass
The oil cooler was fed by the engine's coolant system. If left open, coolant will spill; the lines must be rerouted. [[ame=https://www.youtube.com/watch?v=cfz1V0fL030]1, https://www.corvetteforum.com/forums/c4-tech-performance/4679598-1989-corvette-replacing-aluminum-oil-cooler-lines-with-heater-hose.html]
- Remove the Cooler: Drain your oil and coolant. Unscrew the old, longer threaded nipple holding the cooler/oil filter adapter to the block.
- Standard Oil Filter Stud: Replace the long stud with a standard non-oil cooler threaded stud (you can find these at most auto parts stores or by ordering a standard small-block Chevy oil filter adapter fitting).
- Oil Filter: Reattach a standard oil filter directly to the block using the new, shortened stud.
Coolant Loop Bypass
The oil cooler was fed by the engine's coolant system. If left open, coolant will spill; the lines must be rerouted. [[ame=https://www.youtube.com/watch?v=cfz1V0fL030]1, https://www.corvetteforum.com/forums/c4-tech-performance/4679598-1989-corvette-replacing-aluminum-oil-cooler-lines-with-heater-hose.html]
- Water Pump to Heater Core: On an 89 Corvette L98, locate the metal bypass tube/rubber hose that runs from the passenger's side hard heater lines (around the front of the oil pan) to the radiator or water pump.
- The Fix: Completely remove the restrictive hard line and any "T" fittings associated with the auxiliary oil cooler. Replace it with a single, continuous pre-bent heater hose (or a molded 5/8" heater hose) running directly from the heater core to the water pump fitting. [[url=https://www.corvetteforum.com/forums/c4-tech-performance/3451458-i-need-pics-of-a-oil-cooler-in-an-automatic-l98.html]1, 2, 3, 4]
Last edited by merc49; May 19, 2026 at 01:10 PM.
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I don't really believe that bit about the cooler dropping the temp 25 degrees. If anything, it's more of an oil warmer.
It may be a different scenario on the track, but in terms of normal roadway driving, I don't believe it.
My temp actually dropped between four and six degrees when I uninstalled the system. Not much of a decrease, but a decrease none the less.
It may be a different scenario on the track, but in terms of normal roadway driving, I don't believe it.
My temp actually dropped between four and six degrees when I uninstalled the system. Not much of a decrease, but a decrease none the less.
Race Director
Joined: Oct 2012
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From: Melbourne, FL
I don't really believe that bit about the cooler dropping the temp 25 degrees. If anything, it's more of an oil warmer.
It may be a different scenario on the track, but in terms of normal roadway driving, I don't believe it.
My temp actually dropped between four and six degrees when I uninstalled the system. Not much of a decrease, but a decrease none the less.
It may be a different scenario on the track, but in terms of normal roadway driving, I don't believe it.
My temp actually dropped between four and six degrees when I uninstalled the system. Not much of a decrease, but a decrease none the less.
Melting Slicks
Joined: May 2019
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My coolant is always hotter than my oil.
Last edited by Natty C; May 22, 2026 at 02:51 PM.
Pro
Joined: May 2025
Posts: 595
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From: OK
There is a pretty well documented advantage to getting ones oil up to temp as quickly as possible on a street driven car, and if you've ever had an oil temp gauge you've seen it takes twice or more as
long for oil to get up to temp as coolant. And you want your oil to be somewhere around 190-230ish degrees is what I have always read and heard from anyone that should know such.
Which is conveniently, about what your coolant temp runs. I can understand the leaks and plumbing issues and space constraints or track use but overall on a street car it's a good thing to have, or GM and countless
other manufacturers wouldn't have used virtually identical setups for many many decades. It's not a cooler really(usually), but it's not without function either.
The Europeans generally refer to them as a heat exchanger which is more accurate.
long for oil to get up to temp as coolant. And you want your oil to be somewhere around 190-230ish degrees is what I have always read and heard from anyone that should know such.
Which is conveniently, about what your coolant temp runs. I can understand the leaks and plumbing issues and space constraints or track use but overall on a street car it's a good thing to have, or GM and countless
other manufacturers wouldn't have used virtually identical setups for many many decades. It's not a cooler really(usually), but it's not without function either.
The Europeans generally refer to them as a heat exchanger which is more accurate.
Last edited by wolf_walker; May 22, 2026 at 04:32 PM.
Melting Slicks
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In the interest of transparency, I've never driven my C4 more than 50 miles at a time.
Melting Slicks
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Keep in mind that the L98 is a "hot side" thermostat cooling system. Coolant is circulated in the engine until the outlet temperature reaches the thermostat-controlled temperature. As hot coolant is returned to the radiator, 'cold' coolant is introduced to the block through the water pump inlets. The coolant's temperature increases as it circulates towards the thermostat and outlet. The temperature at the bottom of the block is lower than the outlet gtemperature.
The KC4 cooler inlet is from the bottom of the block "V". This coolant is "cold-side" radiator water that hasn't absorbed much heat from the engine because it hasn't circulated to the thermostat yet.
My experience has been that the oil temps in my 85 with KC4 are lower than in my no-cooler LT1 when driven under the same conditions that elevate oil temps. (Canyon running at high RPM.) I believe that KC4s are beneficial under 'performance' conditions where increased engine output is sustained over a period of time. A 50 mile trip every now and then, probably not.
The KC4 cooler inlet is from the bottom of the block "V". This coolant is "cold-side" radiator water that hasn't absorbed much heat from the engine because it hasn't circulated to the thermostat yet.
My experience has been that the oil temps in my 85 with KC4 are lower than in my no-cooler LT1 when driven under the same conditions that elevate oil temps. (Canyon running at high RPM.) I believe that KC4s are beneficial under 'performance' conditions where increased engine output is sustained over a period of time. A 50 mile trip every now and then, probably not.
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