Lucas Oil says it’s essential that brake installers appreciate the differences between the DOT 3, DOT 4 and the latest DOT 5 brake fluid specifications.
If you have a vehicle that requires a brake fluid with a DOT 4 specification and a vehicle that requires a DOT 3 specification, you can put the DOT 4 in both. What you cannot do is put the DOT 3 specification brake fluid in both.
DOT 5 is not recommended for use with DOT 4 or DOT 3 systems because it would be very expensive to do.
Moreover, an increasing number of high performance vehicles on the market are using DOT 5 specifications. It doesn’t matter whether this is branded as DOT 5, DOT 5 Plus or DOT 5 Heavy Duty, they are all the same specification because it is an international standard to which they all must conform.