LT5 Cooling and Radiators

[5ABI VT]

Originally Posted by RussMcB

The oil cooler stays in place (but you will need to disconnect the lines - just one bolt).

With the radiator out you can blow out the oil cooler's and A/C fins.

It's encouraging that your temps come down pretty fast when the car is moving.

When you go to the race, keep in mind that the coolant in the water pump begins to cavitate at high RPMs, so you can short shift to avoid that if needed.

I need to do some searching on cleaning out the oil cooler as well I recall people saying they were full of sludge etc. the event is only a half mile so it's not very long at all. I'm wot through 3-4 gears all the time and never see any temp issues . I usually watch the oil temps and they're never too high. I think for a wot run oil will have a big impact on cooling as well and with the capacity and oiling on the LT5 it does an excellent job.

As for water pumps I definitely will be moving to electric water pumps I need to do more research on available setups but after having one in my last 388 lt4 build that I used at high rpm all the time for extended periods .. Worked wonderfully (with a stock rad).

[Fully Vetted]

If you don't mind I'm curious what you find is available on the electric wp's. Please repost.

[Dynomite]

Originally Posted by RussMcB

The oil cooler stays in place (but you will need to disconnect the lines - just one bolt). With the radiator out you can blow out the oil cooler's and A/C fins.

I checked my Ron Davis Radiator with Debree Screen installed (1/4 inch mesh) and found trash on the front of the Ron Davis Radiator that had gotten through the screen. Following a Silage Truck with lots of small trash on the pavement did not help

What one needs for a perfect Debree Screen is a mesh size equal to or a bit smaller than the radiator pass through openings. But if one had a Debree Screen with that mesh size you are actually decreasing the air flow since the front Duct for Air Flow is actually smaller than the Front Face of the Radiator.
So......We are left with inspecting and cleaning the Radiators of trash from time to time and leave the Debree Screen to stop plastic bags, leaves, Dragon Flys

You can clean the Radiator without removing as I found out. With a pressure washer I first pressure washed from the oil cooler adapter side the gap between the radiator and Oil Cooler.

Then carefully pressure washing directly (perpendicular to the surface) from the fan side of the radiator (each fan opening). Then again pressure washing from the oil cooler adapter side the gap between the radiator and Oil Cooler. But....be carefull with the pressure washer holding too close to the surface of the radiator or at an angle that may cause damage to the aluminum fins. On My Ron Davis absolutely no damage was done using a pressure washer as described herein.

Originally Posted by GOLDCYLON

The lower screws for the rad shroud are a PITA but the rest of the job is pretty straight forward. GC

You can reach in with a long open end and taking your time
.........remove the three (I think 7mm) screws on each side holding the lower part of the Radiator cowling in place. I replace ONLY the lower single 7mm screw when replacing the cowling. I will check if it is 6mm screw

[RussMcB]

Originally Posted by Dynomite

<snip> ... since the front Duct for Air Flow is actually smaller than the Front Face of the Radiator.

In race cars (and probably street cars, too), this is by design. Having a smaller opening than the radiator surface area slows down the air so it can transfer heat better.

[5ABI VT]

This has been on my mind a lot as of late. So far I am stuck with the multiple threads on corvette forum and other forums showing the cheaper brand radiators to work as well as the $$$ ones we have available. Personally I have an issue with trusting them because I want the best option regardless of cost but some posts show nearly identical rads for 1/3rd to 1/3 the price :/.

Anyhow I wanted to ask about cleaning methods. Anyone have any input on the best way to clean the rads out? My thoughts were soap and spray but if the crud is packed in the fins.. Maybe a long bristle brushed pressed into the rad? I don't want to be bending any fins etc.

I know generally oem stuff isn't the best vs aftermarket but I have spoken to a few people including Tom Dewitt about the actual benefits of more cores etc. from what I know, aluminum radiator requires much more surface area vs a brass/copper core radiator. I don't even remember what the oem radiators are made from?

My car is too clean to take down for rad cleaning I may drive it a few times first and let it get dirty before pulling it out. I will do a higher % mix of water with coolant and water wetter. I will make a thread showing what I find for sure. We had a very hot week last week but temps are dropping now so I don't really feel there is a 'need' for more cooling capacity like some of you who drive in extremely hot weather. I will start with cleaning it out and doing a t stat and drilling holes.

[5ABI VT]

Are lower temp t stats available for the lt5?

[QB93Z]

I have cleaned and reinstalled stock ZR-1 radiators 3 times and have removed and replaced 4 radiators, 2 DeWitts and 2 Ron Davis.

From my experience. the only way to "clean" a radiator that has blocked air flow is to remove the radiator from the car. The problem that I have seen is fine grit that is lodged between the fins. I have been able to remove most of the grit by laying the radiator flat on a concrete floor, lift it a few inches off the floor and then slamming in down flat against the floor. Do this once and then feel the grit that will be on the floor under the fin areas. Sweep the floor clean and repeat. Repeat until there is no more (or very little) grit coming out of the fins.

Do a before and after visual inspection through the fins looking toward a light or the sun. After the mechanical shock cleaning, you should see a noticeable difference in the air passages.

The first time I tried this method, I had removed the radiator and "cleaned" it with 100psi air blown "through" the radiator. The air cleaning is effective for removing leaves and candy wrappers from the front of the radiator, but proved to be ineffective at removing the grit blocking the air passages.

I would not recommend trying to clean the air passages mechanically because it is very hard to not deform the fins.

Good luck.

Jim

[GOLDCYLON]

Originally Posted by 5ABI VT

Are lower temp t stats available for the lt5?

Yes im running a Ron Woods 160 T-Stat

[GOLDCYLON]

Originally Posted by 5ABI VT

This has been on my mind a lot as of late. So far I am stuck with the multiple threads on corvette forum and other forums showing the cheaper brand radiators to work as well as the $$$ ones we have available. Personally I have an issue with trusting them because I want the best option regardless of cost but some posts show nearly identical rads for 1/3rd to 1/3 the price :/.

Anyhow I wanted to ask about cleaning methods. Anyone have any input on the best way to clean the rads out? My thoughts were soap and spray but if the crud is packed in the fins.. Maybe a long bristle brushed pressed into the rad? I don't want to be bending any fins etc.

I know generally oem stuff isn't the best vs aftermarket but I have spoken to a few people including Tom Dewitt about the actual benefits of more cores etc. from what I know, aluminum radiator requires much more surface area vs a brass/copper core radiator. I don't even remember what the oem radiators are made from?

My car is too clean to take down for rad cleaning I may drive it a few times first and let it get dirty before pulling it out. I will do a higher % mix of water with coolant and water wetter. I will make a thread showing what I find for sure. We had a very hot week last week but temps are dropping now so I don't really feel there is a 'need' for more cooling capacity like some of you who drive in extremely hot weather. I will start with cleaning it out and doing a t stat and drilling holes.

The OEM stuff is fine unless you started modding the engine. Keep in mind you have more than 20 years of sand and grit that has built up over the years between the fins and the end on the old units tend to be brittle and swell with age. You can get an OEM replacement for pretty cheap. I would pull it and make an assessment. If you start scrubbing you going to stat bending fins. After you pull it and tap it lighty on the driveway sand and silt wil stard dropping.

[Billy Mild]

Would it be worth having a radiator shop to clean the radiator?