DEI Radiator Relief supercharges your radiator by transferring heat more efficiently through the radiator. Similar to the original formula this proven coolant additive will reduce your operating temperature up to 30ยฐF reducing engine wear that occurs during extreme use. Radiator Relief is also formulated with a corrosion inhibitor that reduces mineral deposits. This is the first additive that maintains pH levels that otherwise fluctuate over time resulting in core damage.
- No mixing required; just add to cooling system and reduce engine operating temperature up to 30 degrees Fahrenheit
- Formulated with a corrosion inhibitor and reduces pre-existing scale build-up
- For use in all water cooled engines
- Compatible with water and all anti-freeze mixtures
- Safe with all alloys – 100% biodegradable, non-corrosive and non-toxic additive
- Fit type: Vehicle Specific




















JayGoat –
Simply put, it works. Before adding this additive to my 05 Pontiac GTO, I’d run around 180 on the highway and steadily climb to 200 in slow traffic. This is with an all aluminum radiator, 160 thermostat, and a 30/70 Zerek G-05/distilled water ratio. After adding the DEI additive, I’m around 175 on the highway. However, I’ve yet to crest 190 while in slow traffic. It climbs from 175 much slower and cools off much quicker once I get moving again.In my opinion, works much better than Water Wetter which I noticed no difference on.
eugene wilson –
I used it in my baseboard heat system! It dropped the return temperature by 5 degrees from a 60 degree drop (180 to 120) to a 65 degree drop (180 to 115) This tells me the extra 5 degrees were radiated into heating the house! not just returned back to the furnace. It has also shortened the run times of the furnace. This would be due to a better heat transfer in the boiler from the fire box to the water jacket!
Robert P. Bowden –
I have a BMWโฆ Itโs about 10 years old and like a lot of other BMWs it has cooling issuesโฆ I live in LA and usually the summer time is the only time itโs an issueโฆ Lots of idling because of trafficโฆItโs been hot lately and so I thought I would give this a try because my mechanic has tried a bunch of things and the temp gauge will sometimes โcreep up.โ I drove it today and it was in the 80s and zero creeping problem ….for the first time in a while (with it being that warm) iEnough said! (I run straight distilled in the summer and this has anti corrosion additives. Set!!
Gregory G. Maze –
I liked what I read about it but the car I have does not have a temperature gauge! So how can I really tell? I have a GM Northstar V8 and it gets hot!!
robert amrine jr –
Use this in all my cars.Awesome productSeller is greatWill use again as needed
Anthony –
Overall temp isn’t that much lower but the turbos don’t seem to get as hot with this in my coolant tank. Way less turbo heat sink.
Eric –
Texas heat forced me to try this out. I flushed my system and did a 90/10 mix and the results are great. It keeps my truck running cool no matter how hard I push her.
Mark Clark –
Dumped this in my Humvee pressurized coolant reservoir and it didn’t lower temps at all. It has a hydraulic fan that turns on like clockwork at a specific point in my commute, so even a 5* drop in temp would be noticeable. Zero change after driving for a week. It might be better if I ran just this with distilled water. Also, smells like urine.