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What is the best coolant additive to run? I have tried Redline, VP and Purple Ice all in antifreeze. I changed Antifreeze each time I changed coolant additive because of doing different mods to it. None of them worked not even 3 degrees cooler. I run the AC Delco antifreeze maybe it won't work with any of the additives. I'm thinking of maybe trying Antifreeze with coolant already mix in it. I have seen some say 230 degrees is not to hot for the LS engine, but I prefer to keep mine under 220 degrees max if possible. I run my fans switch on 100% I have several friends with Corvettes here in Alabama and there's runs hot as well but they don' care! Anyone have any suggestion? I just put some Trans Specs Heat exchangers on my hood just drove it one time they help on the open road but not so much in stop & go traffic. I know how to work on my on Vette and don't mind spending the money, but hate wasting money on things that don't work. Thanks for everyone's help in advance!
I think these additives are “snake oil”…just make sure your radiator is clean and I wouldn’t run your fan at 100% since it is designed to work at a 90% duty cycle…you don’t want to overheat and melt your connector.
DeWitts rad. You’ll get 50% more heat exchange through that rad. The hottest my LS3 ever got with that rad was 223°F when I got stuck in Oatman behind some burros. Ambients were like 106°F that day. You’ll also reduce the duty cycle on the fan because you get more heat transfer for the same amount of airflow. The The DeWitts is plug and play, but obviously a more expensive solution.
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the biggest additive that does is higher water %.
this
Originally Posted by FatsWaller
DeWitts rad. You’ll get 50% more heat exchange through that rad. The hottest my LS3 ever got with that rad was 223°F when I got stuck in Oatman behind some burros. Ambients were like 106°F that day. You’ll also reduce the duty cycle on the fan because you get more heat transfer for the same amount of airflow. The The DeWitts is plug and play, but obviously a more expensive solution.
and this - increase radiator efficiency. 230° is getting warm but not abnormal for summer heat & humidity. you'll see that on a track day easy - even with a good cooling setup.
and be careful running the fans all the time. they're designed to "turn off" above 35mph because the airflow windmills them faster than the motors normally turn, so apart from the duty cycle aspect of heating the wiring & motors more than necessary, it's also to preclude tearing up the motors by not "power braking" the fan blades.
Supposedly additives like Redline water wetter can lower temps by lowering the surface tension of water to allow it to better wet the internal surfaces of a radiator. But from what I have read, this really only will work in a cooling loop where there is no thermostat such as a water intercooler loop for a supercharger.
For your engine cooling system, the best thing to do is increase the cooling fin surface area. A DeWitts radiator is really what you need.
I put a DeWitts in my GS when I installed my Edelbrock E-force and the hottest I have ever seen the coolant is in the 220s and that is on a south Louisiana summer day after a spirited run. Normally, my car never gets much above 210. And that is with the stock fan and stock fan settings.
I had to bypass the plastic connector the 2nd day I had my Vette. I used some marine female & male connectors to replace the plastic connector that I know what its there for but can't understand why they would use.
I have replaced my stock one" tube radiator with a custom built Griffin radiator with 2, 1 1/4" tubes. I have been using Griffin custom built radiators to my specs for years. They all fit perfect but due to the angle or something I overlooked I had to do make some changes to make it fit. If I ever buy another radiator for my Vette it will be a stock size upgraded radiator.
Mine does stay under 230 degrees 95% of the time if I stay out of Atlanta stopped in traffic. It runs about 195 degrees on the road but at stop and go traffic lights it will get up over 220 quickly .I built the engine in my Vette changing about everything on it but the block. Been Drag Racing for years building my own engines an cars, but I can't seem to fix a simple cooling problem! I might just have to get use to it running the temp that high, but would be much happier if I could lower the temp just 10 degrees.
I think these additives are “snake oil”…just make sure your radiator is clean and I wouldn’t run your fan at 100% since it is designed to work at a 90% duty cycle…you don’t want to overheat and melt your connector.
Someone mention a higher water percent. At present I'm running 100% water I just wanted to see if it made any difference, I don't think it did! I have been running the correct AC Delco 50/50 antifreeze. I really don't think the brand of anti-freeze matters as long as its the right antifreeze for your car. I read where the old green antifreeze for the older cars run cooler, but do not think it would be wise to run it in a newer model car. Does anyone think I should change the AC Delco to a different brand? I'm think of trying the Jegs antifreeze with the coolant already mixed in it!
I had to bypass the plastic connector the 2nd day I had my Vette. I used some marine female & male connectors to replace the plastic connector that I know what its there for but can't understand why they would use.
I have replaced my stock one" tube radiator with a custom built Griffin radiator with 2, 1 1/4" tubes. I have been using Griffin custom built radiators to my specs for years. They all fit perfect but due to the angle or something I overlooked I had to do make some changes to make it fit. If I ever buy another radiator for my Vette it will be a stock size upgraded radiator.
Mine does stay under 230 degrees 95% of the time if I stay out of Atlanta stopped in traffic. It runs about 195 degrees on the road but at stop and go traffic lights it will get up over 220 quickly .I built the engine in my Vette changing about everything on it but the block. Been Drag Racing for years building my own engines an cars, but I can't seem to fix a simple cooling problem! I might just have to get use to it running the temp that high, but would be much happier if I could lower the temp just 10 degrees.
Sounds like you need an aftermarket fan setup too.
The stock fans are fairly powerful I have a new Hi-Performance GM fan on it about 3 years. But open to suggestion's on what aftermarket fan setup would be best! I have a intercooler & AC condenser in front of the radiator but they like the radiator are clean and look new. I have a friend that does installs home and repair a/c service. He come by the shop when I had the engine out about 6 months ago and cleaned them.
In my cars that do not have a warranty and are heavily modded, I use distilled water and Justice Bros
Rad Cooler and Protector....no antifreeze/coolant. They sleep inside.
Regardless of the rad and fan(s) that that you have, unless you’ve made other arrangements, you’re at the mercy of the fan table parameters.
The fan doesn’t go to max (90%) duty cycle until the coolant reaches 225°F. If you’re not going fast enough to push enough air through the rad, then the fan needs to make up the difference. You can modify the fan table so that the fan ramps to max sooner, but that puts more stress on the connector to the fan control module, which is a known weak point. IMO , GM underprovisioned that part of the wiring, and possibly the control module as well. Some folks have spliced out the connector and I’ve not heard of a case where that nuked the controller, though. I suppose you could also slice in a beefier connector.
and i should also clarify: heat protection versus heat dissipation. higher antifreeze concentration prevents boiling up to higher temperatures, but higher water concentration will cool down faster via transferrance through the radiator.
also, in the Dexcool (organic acid) versus Green (methanol+ethylene glycol) debate, domestic manufacturers have switched to Dex over the last 10-25yrs due to its longer service life/interval. other manufacturers have been using OATs & hybrid OATs for even longer.
Distilled water is what is recommended for aluminum engines, from I've seen in print for many years. Ive tried water wetter, and really saw no difference. However, IIRC they say in the instructions that it doesnt work as well when mixed with antifreeze. Depending on where you live, 100% water is something I'd never do. If you forget one time that you have no freeze protection.....you'd be surprised how many smart people have ended up with cracked blocks. I've known several over the years. If you're having cooling issues, a new DeWitts is a Helluva lot cheaper than a new block!! As for DeWitts quality, mine was 18 years old last month. Enough said......
Last edited by grinder11; Aug 15, 2024 at 09:15 AM.
I'm still open to suggestions, but I just ordered 4 gallons of Jegs premixed Racing Antifreeze & coolant with LP3. I'm gonna try most coolant additives say to use distilled water and like Grinder 11 said if I forget that could cost me a engine block or a head or both. And I would say I would not forget to add antifreeze in the winter but one winter I forgot to drain the antifreeze out of my dragster and about 1/2 way though summer it put a rod out the side of the block. I got over off the racing surface as quickly as possible but the still had to clean some oil & antifreeze off the track! So its possible I could forget to add antifreeze. Someone posted a thread below and it said burp the cooling system to get all the air out! I used to put my pressure checker on my dragster that the radiator laid flat and that pushed the air out of the system. I might try that when I put the new Jegs antifreeze/coolant in.
Bowtie Billy, BE CAREFUL!!! If I were you I'd check with Jegs and see if this "racing" coolant contains propylene glycol. Some of the "racing" antifreeze out there is propylene glycol, not to be mixed with water. Yes, it has a higher boiling point than ethylene glycol, and helps eliminate steam pockets better than ethylene glycol. HOWEVER....It has less capacity to absorb heat than ethylene glycol. In other words, if you run propylene glycol you may end up running slightly HOTTER than before. I once ran Evans coolant. I used it only because I had a Darton wet sleeved LS1 based 427, and Steve Dimirjian at R.E.D. recommended it. Mainly because sometimes the wet sleeves seeped small amounts of coolant into the oil, and propylene glycol mixes with oil better than ethylene glycol, possibly better protecting the engine. It is a great product for racing. But sometimes racing equipment isn't the best product for street/strip use. I can speak with experience on this.....
Last edited by grinder11; Aug 15, 2024 at 06:47 PM.
So I agree with most here, I think the proper solution is to upgrade your cooling system to something like a dewitt with either a prospeed or spal fan, but I will say as far as additives go, I've used water wetter in every vehicle I've ever owned. Back in my poor kid with an F-body and lots of time on my hands days we experimented with it quite a bit and the car would on average run 10 degrees cooler with it than without it. Those test were in no way scientific just observation so take that for what its worth but... I still use it to this day because of that.
What is best coolant additive?
