Keep popping heater cores

[85_Ranger4x4]

I suspect my C5 is to blame, I think cruising at 3k rpm is doing them in. I am on #3 since I did my V8 swap and only changed them once in the 10 years before I swapped it.

I am smelling antifreeze again in the cab. I have heard about Mustangs using a bushing in the hose to reduce the pressure that the cores sees during high RPM... and also read that people use a 13mm 3/8" drive socket to accomplish this.

Some have said that if the thing moves around it can cause a moaning sound and you are supposed to clamp it in place, should it be more towards the engine end or the firewall end of the hose?

 

[RonD]

Max. Pressure in the system is set by the rad cap, check yours, or use a lower PSI rating.
Operating temp of engine is 190-200degF
Pulling a load or climbing a long grade on a hot day can increase temp to 240degF
1/2 on Ford temp gauge is about 215degF, so you should be running below 1/2 most of the time.
250degF is about 3/4, when gets to there pull over

Straight water boils at 212degF
50/50 water/coolant boils at 223degF

If you add pressure you get about 3degF per 1psi
So a 10psi rad cap would increase 50/50 boiling point to 253degF, +30degF

Common rad cap pressure is from 12PSI to 16PSI


If you think flow thru heater core is the issue, then next time engine is warmed up turn on the heat and feel each heater hose, warmer one is the IN from engine.
After cool down pull off the IN hose from the heater core at firewall.
Insert a restrictor that fits tightly into the hose, push it in far enough to reattach hose to heater core, make sure clamp is tight there will be slightly more pressure on it as restrictor will eventually be pushing against heater core fitting.

Restrictor can be smaller hose, a socket, or ??

Google: heater core inlet restrictor images

You can buy in-line restrictors for about $20