Installed new MTS 500 stock rebuilt with small RV cam. Cooling system has following: New water pump. 180 thermostat New radiator - early '60s GM pickup 3-core 2400 cfm electric fan on motor side 3000 cfm electric fan on front side installed plug in intake under thermostat after running 15 minutes @2200 rpm in garage with door open on a 45 degree day it reaches 230 degrees. There is circulation in radiator when running. I'm stumped. Would appreciate any input.
Are your fans fighting each other? make sure that they are both moving air in the proper direction. After that check your timing, and make sure that you are spot on. By the way I do not understand why you have a fan on both sides of the radiator, I have never set one up that way. maybe your front fan is just in the way.
A concern of mine as well. I was wondering if they would cancel each other. I will try the front 3000 by itself. Timing is spot on. Thanks for the input!
Ditch the electric fans and run an engine driven fan. May son has a 47 International pickup with a 472 Cad engine. It overheated with an electric fan. Put the engine driven fan with a shroud and it cools just fine now.
'55 Cadillac with 500" Caddy, upright aluminum radiator (smaller than yours), 180 degree thermostat, mechanical (stock) fan and home made shroud... ...N-E-V-E-R overheats, even in "parade" traffic on a 90 degree day... My suggestion: remove the electric fans and go back to a mechanical fan driven by belts...!!! R-
I have a 75 Coupe Deville stock with the 500. I installed a new radiator because the original kept leaking. It started to over heat with the new radiator. Turns out its harder on a Caddy then on most engines to get the air out. Drill an 1/8 or next size smaller hole in the ring around the part of the thermostat that opens. You want it as close to the opening part as possible so it wont get covered by the thermostat cover where the radiator hose attaches. Then refill it and let it run with the cap off, it will bleed out a lot better and probably run cooler too. The other thing is a Caddy does run hotter then most other engines. If I remember right MTS said they run best around 210. Also if youre running the stock intake put brush on pipe sealer on the threads of all the bolts that go through the compressor into the intake, one or 2 seal the intake runners and you can get some odd vaccum leaks from them. Dont use the stuff to glue pipes its just a compound you brush on 2 pipes that thread together to make a seal and keep them from seizing home depot sells it. Last just make sure youre not running too much initial timing mine got very hot when I advanced it.
I would need the distance measurement to see if I can. I would prefer mechanical. 'fess up time! Front fan needed to be reversed. Just to check the two fan theory, I ran the rear until 220, then flipped on the front (now that it's pushing right) and it dropped to 200. The engine builders tell me that 220 is normal. It's been many years for me since playing with the 4-wheels and these hotter temps makes me cringe. Hard to get use to. Would still prefer mechanical. If anyone has the distance measurement forward from the water pump, I can see if there is room. Caddy parts around here are nill. Thanks for all the reply's.
A Stock Cad 500 thermostat is rated at 205 degrees. That's what I have in the 500 in my 71 GMC 3/4 ton. These engines like to run a bit warmer than most others to be able to work efficiently.
That's a 2 inch spacer between pulley and fan in this pic...so you can figure out what you need from that... My Cadillac engine is internally stock...and I run a mechanical water temp gauge...it runs right at 195 degrees all the time, highway or city. I was not aware these engines ran hotter than other engines, mine must be one of the rare ones that doesn't run at 200 degrees or hotter...!!! R-
For the record, the as delivered thermostat in these engines was a "two stage" thermostat, to facilitate a quicker warmup. Passages below the thermostat kept the water circulating in the block longer, to get qucker heat in the cabin. Once this happened, the "primary" opened, exposing the "secondary" portion of the thermostat for normal operation.
Yeah, What Chuck said. Cadillacs have a unique looking and proper thermostat. Others will fit but won't work real well. I've fought the overheating issue in my daily driven '63 International 1 ton 4wd truck that has a rebuilt 500 from 72. My problems have been many. From a stuck distributer, to 2 big block Chevy radiators, shroud, water pumps.... Here's where I am currently; New distributer with a Pertronix set at 11* initial A Cadillac Fleetwood radiator (which is the only one that brought temps down) A Flow Kooler water pump (still don't believe they do anything) Full shroud and proper front ducting Stock non-thermal fan I drive this truck hard, sometimes very hard. Constantly towing with it. It weighs over 9000lbs. My temps stay at about 200-210 and will creep to 220 at long stops during the hottest days. I was told years ago that I will fight to keep temps down below 220 and I have fought my ass off. 220 is the proper temp for these and the idiot lights are designed to come on at 260!!! The systems are rated at 20lbs of pressure. I run an 18lb cap. I've put over 50,000 miles on this engine since the rebuild in about 3 1/2-4 years. I couldn't be more pleased with the combination of parts that make up this truck, especially the 500. The engine looks a bit grimey these days but has a more era appropriate, louvered air cleaner. Good luck man. BloodyKnuckles
My wife's step brother could not get his 500 to cool till he put in a TWO core radiator, then it was constantly at 190-200 degrees..He tried everything, finally happy.
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