Below are instructions for installing a 1955-1957 Chevy Radiator. Click on the links to bring up a picture of the area your working on.

Instructions for 1955-1957 Chevy cars.

The big block version is approximate 31 and ½ inches wide by 16 and ½ inches tall. It comes with two electric fans that are 3.7 inches thick at the motor and are 11 and ½ inches in diameter. The fans draw 12.5 amps each and are 1390 cfm. You can order separately a thermal fan sensor. The two types are 185 on, 160 off or 195 on, and 180 off. We recommend the 195 kit for most cars. You can get an additional relay for the second fan as well. If you have A/C you should have an A/C relay that will turn on the fans when the A/C is turned on. We like to wire the A/C relay to the A/C button so when it is pressed it turns on the fans. You can usually fit a 13 inch overflow bottle along side of the radiator. You can order a 13” mount bracket that will use the same holes you use to mount the radiator. We also have a polished or unpolished bent hard tube that will take you from the overflow tube underneath the cap to the tube that can go thru the core support. You will have to drill this hole. A grommet is also available.

Big block using you’re core support
* Small block using you’re core support use the (* steps)

*Step One
 Remove old radiator, hoses and disconnect transmission lines if used. If it has a shroud remove it as well. Make sure nothing else is connected to the radiator. Remove the engine fan if using electric fans. You may have to use shorter bolts if using the engine fan. Make sure the thread size is the same.

Step Two
 It’s easier to remove the core support panels to drill the holes. Tape the template and mark the holes on the panels. We like to make sure to double check the holes before we actually cut or drill them. Make sure it lines up for you’re application. Make sure to cut only the holes you need. The template is made with all the holes for all the applications so if you don’t have A/C or a transmission cooler, don’t make the holes for these.

*Step Three
 At the bottom of the support is an air dam or air block that is connected to the support with spot welds. Take a chisel and remove this piece. If you look at you’re new shroud this will help you see what has to be removed on you’re old support. The new shroud is straight on the top and rounded at the bottom. The new shroud will take the place of the old one. The small block version will have one fan and shroud that is connected to the support instead of the radiator.

Step Four
 Use a die grinder to cut off the lip or tabs that protrude towards the front of the support. They are identified in the six cylinder mount because they face the grill side. The flange that runs from top to bottom needs to be cut back to allow for the fan shroud to set flush against the support. If you take you’re new fan shroud and hold it up against the support with the flat straight part of the shroud on top and the rounded side on the bottom with the fan motors on the engine side you will see why you need to trim this. Some versions may need to be trimmed only towards the bottom part of the support.

*Step Fve
Wire up the fan or fans using the diagram for the relays (Using these parts which can be purchased in kits 1 2 3 4 5)

Step Six
Place the cut out panels on the support using the top two bolts closest to the fenders. Do this with both sides. Place the shroud up to the vertical holes in the support. There are three holes that will hold these on. They are the same ones that hold the panels on to the support. If there is a 1/8" difference on the bottom hole, that’s because it is a different year then what was ordered. The easiest solution is to oval this hole out. Place the fan shroud against the support and bolt it on using the existing bolt pattern. The shroud should be set in with the flat part on top and the rounded part on the bottom. The fan motors will be facing the engine and the fan blades will be facing the front of the car.

Step Seven
 Place the radiator up to the support and tighten it up using the holes you drilled in the support. The radiator will be up next to the fan shroud. There will be a little gap in between. Don't worry it will hold a paper up to the radiator without much difficulty.

*Step Eight
If used with our A/C condenser .Place the A/C manifold (bulk head) into the hole you cut out for the A/C. Connect the lines up to the bulk head and to the condenser. If they need to be tweaked a little that’s ok.

*Step Nine
Change the thermostat housing to a swivel neck 90 degree. This will help give you flexibility in choosing a hose. If using a small block motor with the small block radiator you can try gates hose# 20840 (top) 20606 (bottom).
Connect Trans lines and connect hoses, except the top radiator hose on the radiator side, Radiator hoses can be matched by using the coat hanger trick by bending around obstructions. Trans connections are ¼ npt. You can use a ¼ npt male to 3/8 or 5/8 hose barb for what ever size Trans line you’re running. You can run adapters on the other side of the line or cut the lines back next to the frame right before they come across the opening in front. Do not use hose all the way from the transmission to the radiator it can burn through when it gets to close to the exhaust. Use Antizize on Threads, DO NOT USE Teflon tape.

*Step Ten
 Connect overflow to the system. To find out which one goes to the ground look inside and located the one that sticks up closest to the top. This one goes to the ground and the other one goes to the radiator.

*Step Eleven
 When everything is inspected and tight, make sure the drain plug is closed. Fill the radiator up by filling the thermostat up first. Do this by using the hose that goes to the thermostat housing. Attach the hose to the radiator and add an additive at this time then fill the rest of the radiator up. Leave the cap off then start the car. Wait for the fluid to bubble over a little then put the cap on. Make sure to rinse off all antifreeze with water. Use a mix of 50/50 water and antifreeze. Use the green antifreeze not the red kind. It is recommended to change antifreeze once a year.

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How to Instructions Page

To our valued Customer:

You have purchased a high quality custom aluminum radiator from Mattson's Radiator, a leader in the automotive cooling industry. Before installing our product, carefully read the information provided below.

Thank you for your purchase.  If you require additional information on any of our products or services, please check out our website at or call us at (714) 826-0357 or (800) 814-4238.

Sincerely Yours,


Mattson’s Radiator


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