Heater outlet block off caps - BLOW OUTS! - Ford Forums - Mustang Forum, Ford Trucks, Ford Focus and Ford Cars

TruBlu351 · 11-22-2004, 08:06

I've just changed my second heater outlet block off rubber cap in 2 days!

It's the rearward one that comes out of the block. Cruising is OK but one right boot load and SPLIT, it lets go (bursts the end out) and dumps several litres of coolant. I can't believe it creates so much pressure at this outlet.

Anyone had this problem? I've had to go back to the old set up by joining the two holes with one small hose (seems to relieve the pressure build up), but this looks crap.

Any other options?

northiam · 11-22-2004, 11:58

Joining thr heater hose connections would make the engine run hotter as it acts as a radiator bypass. It could be the radiator cap is faulty or a to higher pressure rating should be about 15psi.

Also the thermostat could be restricting flow to much,try a hi flow.

TruBlu351 · 11-22-2004, 16:07

Quote:

Originally Posted by northiam

Joining thr heater hose connections would make the engine run hotter as it acts as a radiator bypass. It could be the radiator cap is faulty or a to higher pressure rating should be about 15psi.

Also the thermostat could be restricting flow to much,try a hi flow.

Fitted a brand new radiator cap a few weeks ago.

Also has a new RS high flow thermostat.

JG33PY · 11-22-2004, 17:48

i ran hoses to my heater but the core leaked, so i joined the two outlets with a small section of hose and had no increase on the temp guage.
an alternative is to tap a thread and put a screw in cap with thread tape.
the guy who rebuilt my engine did this but instead of the cap, he put a hose outlet there. my pump still has the push in type outlet, but wouldn't be that hard to tap a thread.

xdclevo · 11-23-2004, 02:04

I find they don't blowout, but are soft and can be overclamped. I went through a few and ended finding it was the crappy rubber splitting from the hose clamp. I went another way, and fitted good hose and blanked off with some bright bar. It won't win you car shows, but will save your motor.

TruBlu351 · 11-23-2004, 02:42

I like the idea of the plugged heavy duty hose end. Thanks.

Never heard of "bright bar"...........but some brass plugs will work.

One cap split from the clamp being tight (this one didn't leak). The other two had their ends blown clean out.

rod051 · 11-23-2004, 11:35

I have had the two rubber block off caps on my car for over 10 years with no problems. Its not a daily driver though. The ones I were told to get and ended up using were off a commodore

xdclevo · 11-24-2004, 00:21

Thats probably it. Everyone i know that has no problems have had them for years. Try out the new, crappy, cheap, chinese, softassed rubber of today and see how it goes.