Running warm... Any suggestions?
 

Hello all. This is my first time posting in the first gen section as most of my web posts pertain to the 5th gen car. My beloved '69 is running a 8.5:1 355 with Edelbrock performer RPM heads, Edelbrock blower cam, B&M 142 blower at 6 pounds, a boost referenced Holley 750 DP, MSD 6AL and distributor, Stainless works long tubes and Magnaflow header back exhaust. I've got it set up with a Griffin 4 core radiator, 180 degree thermostat, mechanical water pump and dual electric fans, but it still operates at 220 degrees no matter the ambient air temperature. On the warmer days, after I shut the car down, the water temp will climb to a scary 250+ degrees unless I leave the fans running.

My question is... Can anyone think of anything I'm over looking that may help the motor run cooler? Am I overreating about the temperature? Any help or suggestions would be greatly appreciated.

Thanks!

Out of my league if not normally aspirated, but if it ran cooler before maybe your timing needs a check?

Been through this with my Vega/built 350 and learned a lot. Assuming you also have a mechanical fan and shroud and that the top of the radiator is above the thermostat housing.

Questions:

1. did it run warm/hot before the engine changes?
2. if you start it up and let it idle, does it climb to 220 consistently?
3. does it run hot while cruising on the highway?

If 1 is true, could be the radiator.
If 2 is true, could be the thermostat.
If 3 is true, could be you need an air dam or headers need to be wrapped or hood vents.

Nick:thumb:

Make sure if you do have a mechanical fan, the blades are actually stiff enough to pull air. I had a fan on my 55' belair 350 SB that I thought was ok but when it spun the blades flattened out and didnt pull enough air. The car used to run at 220degrees and used to have to shut it down while in traffic. Bought a more aggressive fan with stiffer blades and car ran at 185 for the rest of the time I had it.

Thanks Nick. I've considered the header wrap to try to get some of the heat out of the engine bay. I'm currently running a 4" cowl hood to clear the blower and dual Spal 12" fans shrouded to the back of the Griffin 4 core. Since it's been built, it's always operated at 220 when cruising or sitting in traffic. It can sit there all day and never move.

I actually ran a mechanical fan for a long time at 220. I switched to the dual Spal's in hopes of getting it to run cooler with no results.

:frusty::frusty::frusty::frusty:

Did I get this right - no mechanical fan and it always operated at 220, even before the build?

What CFM are the SPALs rated for? Radiator is new? Since the build and high temp issue, have you changed the thermostat on suspicion with no effect? Is the top of your radiator above the engine thermostat housing? Do you have an air dam under the front grill/splitter/radiator? Is there a license plate blocking air flow?

Pics of the front and engine bay will help.

Please answer all the questions, otherwise it just gets old trying to drag out the answers...

n

Just a quick suggestion to help with diagnosis, try pulling the thermostat completely out and see if you get the same temps. T-stat may be sticking partially closed?

I have too much experience with this LOL

Do you have a fan shroud on the motor side?
Have you verified that your temp gauge is accurate?

I have struggled with this here in AZ and here is some leanings.

Anybody that says a shroud is not needed does not need it :doh:

My 79 with a LS7 uses two electric fans and a custom shroud.

My 69 with a 468 BB has two electric fans and a shroud.
The shroud also has small square rubber flaps that open at high speed to allow air to flow thru the shroud and at low speed they close so that the fans can pull air around the whole radiator. This allows for it to cool off at highway speeds and provides better cooling at stop signs.

Other things to pay attention to:
Bigger 2 or 3 core Alum radiators are more efficient than the 4 core brass.
I know you said your using a 185 but for others Is your thermostat A 160 deg thermostat that is open in the summer all the time!
Try a 185 or 195 to allow it to close and provide more cooling to to the water.
Get a high flow thermostat so it does not restrict the flow when it opens.
Use Water Wetter with WATER not antifreeze .... water transfers heat better "It really works".

Check your radiator level and use an overflow that works - make sure your cap is working get it pressure tested and pressure test your radiator.
Be sure your timing is not too advanced or causing detonation -
With an automatic trans - use an external to the radiator trans cooler so your not heating up the radiator water as much. Some people buy pass the radiator all together and get one with a small fan on it.

Hope this is helpful -

do not paint the radiator. The paint will restrict air flow if applied to heavy

Allrighty... let's see... Not sure on the CFM on the SPALs. I know they move a TON of air. Radiator is new. No effect by changing the thermostat. Radiator is above the housing. I do have an air dam under the front grill. There is a license plate. I'll try to get some pics if I can figure out how to post them on here. Lol.