She plateaus at 215° and though it doesn't spit any fluid out it concerns me. Here's some background on my van:
Just had the engine rebuilt. (385 series-it was a 427 truck engine before the machining and Ran hot)
installed engine oil cooler-approximately 30" x 30" cooler size with 3/8 line (ran hot)
Replaced 3 core copper radiator with 2 core aluminum radiator-has 1/4 inch or 5/16 tubing (can't recall exactly but manufacturer claims it should run 30% cooler than a 4 core copper radiator, Ran hot)
Replaced stock water pump with high flow Edelbrock water pump (runs hot but now plateaus at 215°)
Also, C6 transmission on its own cooler (12" x 16"cooler size)
ANY suggestions on keeping this thing cool? I have read through all your forms concerning overheating vans and have tried many tricks including boring a quarter inch hole in my 160° thermostat. Radiator cap has been swapped out several times in hopes it was defective (same result). And the radiator hoses are flex style hoses and cannot collapse.
Thank you for any and all help.
PS this problem doesn't exist on days cooler than 100° which is a short window here in the Southwest

 

Hi. Does this engine have the original exhaust manifolds? I have been told, but never ran into it myself, that some of the 427's came thru with miscast exhausts that caused to much holdback and made them prone to overheating.

 

Yes, stock exhaust manifold's and not that it should matter but I did forget to mention it has a cam for towing but beyond that the rebuild the stock. Other aftermarket add-ons is Edelbrock intake with 650 Edelbrock. If you think exhaust manifold's will fix it I will definitely try that as of arty have over 10 grand in the rebuild so what's a couple more hundred. Is there a recommendation for a good heavy header that is designed to go into a van?

 

check the timing
do not drill a hole in t-stat
215 isn't overheating

 

I agree with vertex that I wouldn't worry about 215 if its not going higher or the caps not venting. As to the exhaust, I myself, never ran into any bad manifolds. But I was told they had some that caused problems. Since you said it ran warm before rebuild, and I assume timing would have been checked when you set the rebuild up, it should be something that didn't change when you rebuilt. Are you sure it is going to 215? Not just an off gauge or sending unit?

 

Timing is good but will check on possible faulty gauge.

 

Any tricks for removing all the air out of your cooling system? New high flow waterpump was supposed to minimize this but apparently this is another issue as my factory electric temperature gauge ran normal today and the aftermarket temperature gauge ran to 225, puzzling, yet nothing bubbled out or over. Waiting on a new gauge I ordered will let you know results when that is installed. Still looking for good aftermarket headers but none of them look conducive for a van set up. Thanks again.
By the way: why would some recommend drilling a quarter inch hole in your thermostat and others would say no way?

 

With a hole the engine pumps water thru it when cold and the engine doesn't heat up as fast. But these engines were designed to heat as fast as possible so they got up to operating temp quickly. Once warm with the therm open the hole doesn't really do anything.

 

To help get the air out of the system I've drilled 1/8" in mine before. Some new ones come with the hole now. How is your shroud? Thermostat doesn't fully open til 220. Any air bubbles in the radiator from a head gasket? Compression tested?

 

usually you can just loosen a hose but a 16th max is sufficient to bleed air if it's that hard to get to a hose

 

Shroud and duel fan combo is brand-new; it came with the radiator

 

Stewart and Warner temp gauge in and the engine maxes out at 217° but that doesn't include pulling a trailer yet or going up the mountain pass. I haven't been able to locate headers that would fit my van but still looking

 

Did you possibly buy the wrong rotation water pump? They will look the same but the blades are different? I think '89 would be a reverse rotation but you may need to check. It will kill your flow.

 

Btw that 429 is from an early model vehicle so not sure if you need to change the timing cover for the pump if its reverse rotation. I'll check my '92 460 tomorrow and see which way it rotates. Also make sure your fan is correct rotation also. That is pretty easy to tell though.

 

Have you checked your airflow at different RPMs? I once swapped engines from a car to a truck that had a flex fan. The higher RPMs I had to run in the truck caused the fan to flatten and blocked the air flow at speed. Drove me crazy till I figured that out.