Radiator hose HELP please!

[Vegas69]

I see that the temp sensor is in the front of the intake. I found that the bypass hose from the water pump to the intake was crucial on my big block. Without the bypass, the pump would aerate with the t stat closed and cause an air pocket. That resulted in many messes out the overflow until I realized why GM had designed it that way.

[69hugger]

Thanks for the input, Todd.
As part of the Vintage Air Frontrunner system, I have a Stewart water pump, which has no provision for a bypass hose. The V/A instructions don't call for a bypass hose....matter of fact, I don't think one would fit any more.
Although there are bypass holes drilled in the t-stat.
Been this way since I bought it & seems to work...
Thanks again for the suggestion!

Bill

[Vegas69]

That's all that matters...

[Hydratech®]

I have been down this road and report my findings that drilling a .125" to .164" hole anywhere into the main flat outer body of the thermostat will allow for a coolant flow / temp signal to the T-stat at all times to prevent hassles of the discussed nature. I actually do this to everything I work with as of the last 30 years, as while it may delay a full warm up for about a negligible minute or two, this mod reaps vast rewards in so many other directions it is well worth the troubles (despite the EPA wanting to get everything warmed up as quickly as possible for emissions control reasons). Some of you may have seen this in some newer late model t-stats (little pintel valve or notched valve seat surface).

* Full time coolant actual temp signal to the T stat at all times (MUCH more stable overall coolant temps) (no temp gauge crazy wandering around)
* Slightly delayed warm up, which helps dramatically with dissimilar metals (aluminum versus cast iron)(expansion and contraction can "itch" head gaskets into trouble)
* Helps "burp" cooling systems ASAP during service (priceless)
* Will not run too cold during severe cold weather circumstances
* Will still provide stringent emission testing results where needed (after thorough warm up)
* So simple, yet so elegant (amazing what a little drilled hole can do in the right place)

Since while we're talking about cooling systems, how many of you have blown heater cores during high RPM blasts? I have popped quite a few, and figured I may as well put this in here too in the hopes that it can help somebody somewhere.

So what's the deal? Imagine most of us thinking rad cap pressures.... Block pressures can be in excess of 75+ PSI at times due to water pump output pressures. I'm sure some of you have seen the bizarre late model T-stats that look like sci-fi space ships? An extra spring with an extra disc thingy?

Those bizarre late model T-stats have excess block pressure blow off valves built into them, which is what that extra springy disc thing is. That's designed to prevent excessive block pressures building up during high RPM blasts when the T-stat isn't open. Haha, like when the kids are late for school OR when you are late for work and the machine isn't fully warmed up yet (DOH!)...

Sooooo, if you keep popping heater cores, what you need to do is to install a restrictor into the feed / outlet going into the heater core of about a 1/4" or so. Take your pipe nipple coming out of the intake / water pump / whatever feeds the heater core inlet and modify it as needed with a restrictor that limits the flow to a 1/4" or so orifice size of flow. This will in some cases actually help produce better heat through the climate control system by slowing down the flow to the heater core (contrary to what you may initially think), but more importantly will handle "ballooning" of the heater core during high RPM blasts.

Just my .02 that may help someone somewhere, right?

FYI / BTW - I was the previous owner of Paul's Performance Shop, and also Unlimited Racing in Detroit, before many of you came to know me as "Hydratech", veteran ASE Master Tech blah blah blah... so I know my way around the tool box and just can't leave these types of discussions alone at times.