North American Turbocoupe Organization

Boost affecting Heater?
NIMROD Offline
Junior Member
So I just bought this 87 TC 5speed and it has only been getting to 6psi in all gears. I installed an after market boost/vacume guage and I get a perfect 20lbs of vacume but I still only get 6psi. Last night I was driving with the heater on high and noticed that when the motor builds positive manifild pressure the heater would lose pressure and then build up again. Very odd... I'm going to check all the intercooler hoses in the morning. Any ideas?
"That thing got a 5.0?!"

Redbone Offline
Senior Member
What exactly do you mean by "heater would lose pressure"? My guess is maybe you've got some cracked vacuum hoses. Inspect your vacuum lines and replace any that look suspect.
All your boost are belong to us
1988 TC 5m 3" elbow back exhaust(with cat and muffler), Walbro 255, gillis mbc, airbox removed w/ K&N cone, A/C removed, Spec clutch, Ranger roller swap.

John A.

Jeff K Offline
^^^^ +1

Explain "heater looses pressure".
Jeff Korn

88 Turbo Coupe: Intake and exhaust mods, T3 turbo at 24 psi, forced air IC, water injection, BPV, Ranger cam, subframes, etc., etc.
86 Tbird 5.0 (original owner): intake, exhaust, valvetrain mods, 100 HP N2O, ignition, gears, suspension, etc., etc.
05 Taurus SEL Duratec daily driver
04 Taurus Duratec (wifes car)
02 Pontiac Grand Prix GT
95 Taurus GL Vulcan winter beater
67 Honda 450 Super Sport - completely customized

4cammer72 Offline
Posting Freak
id say the check valve on the passenger side for the heater is toast and thats your problem...try doing the same thing again and ill bet the heater is transfering from the front vents to the defroster when it happens.....
88tc (sold) but keeping an eye out.

NIMROD Offline
Junior Member
^ 4cammer72; that is exactly what the heater is doing this morning. I pulled the check valve and it works with just my lung power but as soon as the part stores open up im gonna grab a new one.
"That thing got a 5.0?!"

NIMROD Offline
Junior Member
I replaced the check valve that 4cammer72you suggested but it did not rectify the issue. It is still only producing 6psi on a new aftermarket gauge. I checked all the hoses and they are all in good shape. The only thing I found wrong is my pcv valve has blow by on the intake side. I do have a small puddle if oil on the turbo compressor intake tube. Would that cause my boost issue?
"That thing got a 5.0?!"

thumper Offline
Posting Freak
When you blow through your PCV valve to simulate boost, do you fill anything on the lower side (i.e. the side going TO the crankcase)? If you feel even the smallest amount of air, replace the valve with the Ford part only or install a check valve... preferably both. ]

I don't see that affecting your heater, but it could affect you low boost pressure.
A.K.A. Corey Bennett

1988 TC: white, all options, 5-speed swap, K&N cone filter, "Ranger" roller camshaft, .60/.63 T3, NXS (Gillis-style) Boost Valve, Bosch BOV w/ check valve, Stinger 3" with axle dump (18" glass pack), 95A 3G

Some pictures:

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