Depending on the coolant system in your car will decide if you need an expansion tank and/or a catch can for the track. Liquids are to be kept off the track so a catch can is needed reguarless.
Short story long, if you have a conventional radiator in the car, with a filler neck pressure radiator cap and a vent port on the neck, you only need a catch can. The pressure cap keeps the system under the correct pressure when its warm, and keeps the pressure when it cools. This system has some air traped in side and thats the buffer you have to keep the coolant from expanding and having nowhere but out the vent port on the cap to go. You fill the system about an inch or so under the bottom of the filler cap. no ideal but it works and is simple to setup, bleed, and less crap under the hood to deal with.
Most new cars are have the pressure cap on an expansion tank instead of the radiator itself. The entire system; radiator, block, head, heat exchanger, etc. is 100% full of coolant. When it gets hot and expands it bleeds over to your expansion tank. When its cold, you fill the tank half way with coolant, so as the system heats up and expands, it still has the other half of the tank to push the air out the pressure vent and wont piss fluid out. As it cools and condenses, the pressure cap stays sealed and since its located up high on the coolant system, the vaccum created sucks the coolant back downstream into the system, keeping air pockets and bubbles out of the system. this is the most effective way to do it IMO, but slightly more complicated. To be tech inspector friendly, you still need a catch can to collect the fluid that may blast out the vent if its over filled.
First is the expansion tank idea I came up with.
Very simple design. Tank holds 2 quarts or so. Uses a 1/2" NPT fitting at the bottom to you can use AN or hose barb to plumb it to your system. Uses a standard radiator cap and 1/8NPT threads for a vent tube fitting. On the side are 90deg eblows and a section of clear tubing to use for a sight window to see how much fluid you have in the tank. Mounts with 4, 1/4" bolts.
The coolant catch can uses the same 2 quart tank as the expansion tank, but removes the radiator cap stuff, still uses a 1/2" NPT fitting on the side for filling, drain petcock at the bottom and a 1/2" NPT fitting on the top to allow air to bleed out as it fills with coolant. Inside is a small baffle around the vent port on the top, so as the coolant shoots in under pressure it wont try to blast right out the vent tube, defeating the catch cans purpose.
Thas about it. If you are in need of either of these, please PM me and I will give you a quote. If the tanks are too big, or two small, I could change the size to fit. :thumbup
