1971 442 convert

Just had my 455 rebuilt for 71 442.
Nothing crazy .30 over mild cam 340 hp 478 torque.
Car is running hot and boiled over after a short idle time.
Replaced gauges to rally pac at the same time so had no real frame of reference as I have read that the temp gauge seems to show a Little hotter than it may be??? Running between 3/4 and hot.

I believe I have a 2 core with no shroud 4 blade.
Have the shroud coming and wondered about rebuilding my current rad to a 3 or 4 core.
Is this possible and advisable?
Trying to keep car as stock as possible.

Thanks Boys

DarrylJ

I would also replace the fan clutch as well. I replaced the one on my 71 Cutlass Supreme coupe and it seems to help. I'm still in need of a shroud though. Also go with the biggest rad that will fit. If you put a 4 core in you will need a different top plate. My 70 Convertible has the 455 and they do run warm! Good luck.

72 cutlass455

the 455 needs a 4 row and shroud to keep it cool. The 2 row just is too small. That being said it will pee fluid if the rad is over filled dang side tank rads.

oldsonharmont

Get at least a 3 row radiator, and make sure it's clean inside and out. Look for a 6 blade fan and a heavy-duty fan clutch. Make sure you have a fan shroud, and a 180 degree thermostat with a 50% coolant mix. That's what I use here in the Arizona desert and it's been good so far.

Theo's '67

I too am having having overheating issues. After my car sits idles for approx ten minutes my hot light comes on. (No i have not install temp guages yet but they are in the plan. Once i start moving the light will go off. I have changed my thermostat thinking that maybe that was the issue but my light still comes and and once i turn the engine off i get steam coming from the overflow tube.

1971 442 convert

Can I rebuild my stock rad and turn it to a 4 core?

mmurphy77

X2! The proper shroud is a MUST!!

dc2x4drvr

You don't need a HD fan clutch, but a 6 blade fan with shroud is a must.

joe_padavano

No. The 4 row radiator uses thicker end tanks, which is why the top plate and bottom brackets also need to change. A three row will be marginal, or consider an aftermarket aluminum radiator that fits your current brackets.

knighthawk

since I rebuilt my '69 with a 350, it also runs hot. I'm told a ''new'' motor will run a little warm till it's broke in , , this I don;t know.... but, i bought an aluminum rad, thicker and with alot more cooling fins, for $200. Check with your neighborhood 'dirt track' guys, they know where the rad deals are. Also make sure ALL the shrouds and seals are in place.....mine still will get hot with extended idling, but normal driving it's good

WhatIf

1) Find a factory GM shroud.
2) Find a factory clutch fan, or you can get an 18" clutch fan from Hayden. Looks stock, pulls a ton of air.
3) Check your timing at idle, and make sure your vacuum advance is working.
4) Find a factory 4-row radiator. If you have the funds, an aluminum radiator is superior, and you can paint it black.

1971 442 convert

Thanks guys.
So if I go with an aftermarket 4 core aluminum rad any idea where I can get one that will fit my existing top plate and brakets.

dc2x4drvr

If you have a 2 core top plate, it won't fit a 4 core radiator, and the lower brackets on your core support will have to be changed for wider brackets.

TexasMagnus

Also coolant mixture makes a difference. To much antifreeze will make your engine run warmer. Had the same issue on a 454bbc . I got better result with 20% antifreeze 160f thermostat . Also added " water wetter" from oreillys. That all dropped the temp with about 10-15 degrees.

1971 442 convert

Added a 7 blade fan and a shroud seems to be helping somewhat?
Had to adapt my original top plate to fit the shroud.

Question for the wise ones
Will the 4 core rad top plate from fusick fit my existing rad which I believe is a 2 core??

dc2x4drvr

If you have a true 442 it came from the factory with something larger than a 2 core radiator. Post up a pic if you can, and maybe we can help.

1971 442 convert

A few pics if they help?

Yellowstatue

I didn't realize that over-heating had options...

dc2x4drvr

Hard to tell from the pics, but your top plate looks like a 4 core. Did you have to squeeze the brackets a little to hold the 2 core radiator? You really need to find a good 4 core factory or aftermarket radiator, the 2 core isn't going to handle summer time weather.

1971 442 convert

Finally - sorry for the late update

Replaced thermostat to 180, added a proper shroud, changed to flex fan - this seemed to help some but finally went to a proper 4 core rad and now she is running around 180 and up to about 195 .

Thanks for all your help.

Question - what difference will a clutch fan make and where might I find one of these.

TexasMagnus

Don't under estimate a good shroud, glad it Solved your problem. just went to a cruise in Vernon, Texas 105f and lots of idling worked fine. 4core and electric fan. I am currently using a 160f thermostat.

DeltaPace77

Dont let the let the core row count of modern rads factor into thing's. Most new rads are actually two row, but really wide/narrow cores to get the job done. You gotta have a shroud though, or just wasting your time.