My manual say's use dot 3 or 4 LV high performance brake fluid. I've called 4 dealerships and not one can tell me which one to use. The cap on the fluid reservoir says dot 3. What is the correct fluid to use?

 

This seems like a trick question, but I'll bite? Manual says dot3, cap says dot3. Why wouldn't you use dot3?

 

Dot 3 and 4 are virtually the same, many times they are sold in the same Bottle. Personally I've always used Valvoline Brake Fluid in all my vehicles.
Never.. DO NOT Mix Dot 5 with ANY other Brake Fluid. Not even after a complete Brake Fluid flush.
It will NOT give your Truck better Braking Performance. Actually it will Contaminate your Entire
Brake System. It's purpose is solely for vehicle that require a Brake Fluid with a High Boiling point. For example Cars like Porsche's, BMW's & Motor Cycles such as Ducati's alike.
Vehicles built with EXTREME Braking Temperatures in mind.

 

Maybe he's wondering whether DOT3 and DOT4 are compatible, on account it sounds like either type may be installed?

The next question is, what are you trying to do? It's a little early for a flush. DOT3 on the cap means DOT3 as I see it. Good stuff.

 

The confusion was when I looked at the manual it say's use dot 3 LV or dot 4 LV brake fluid. The dealer carries dot 4 LV But only dot 3 without the LV. The parts guy at metro ford where I bought the truck said regular dot 3 would be ok to use. He also told me dot 4 is silicon based and not to use it. He's wrong there. I think dot 5 is different. What the hell does LV mean anyways? I think it might mean light viscosity which would mean regular dot 3 wouldn't be good?

 

Again, Dot 3 & 4 is sold in the Same Bottle. You can not separate the 2 Brake Fluids when they are in the Same Bottle. Respectfully, there is no confusion. Go to the parts store and read the Bottles. Then read the Dot 5 bottle.

 

I would follow what the cap says, DOT 3 from Ford is part number PM-1-C.

 

I did get the dot 3 fluid. Must be a misprint in the manual where it says Motorcraft High performance Dot 3 LV brake fluid because nobody has that.