Will a cooling system pressure test show if the water pump is working or if the seal is leaking??. Have a small leak in the right inside rear floor area and cannot find the source.

Right inside rear floor area? So you have coolant behind the passenger seat? I feel awfully silly asking, but it's how it sounds. If this is in fact correct, the heater core is leaking and coolant is pooling behind the seat by means of driving or parking uphill...

..eh, I meant the GARAGE FLOOR...inside to the left of the right rear tire.

Won't tell you if the water pump is working, but will tell you if it's leaking.

Pressure Test can show leaks anywhere but not WP function.

Problem is most test sets won't fit Fiero because rad cap area is too small to fit the adapters w/o hood removed.

You can try drilling out Tstat cap rivet and replace w/ bolt in tire valve assemble.
Can Pressurize the system until rad cap think the car is at "boils over" but likely leak will show up before that.

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Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should.
(Jurassic Park)

The Ogre's Fiero Cave

Why didn't I think of that. So much more cost effective than a 200.00 test kit.

Why would you do a pressure test anyway? You already know its leaking!

Ah, Andrew... LOL...if we knew it was the water pump leaking , why would we post the problem. Nothing seems to be coming out the " weep hole"

quote Originally posted by Gwhite18: Why didn't I think of that. So much more cost effective than a 200.00 test kit.

You can get them thru Loaner Tools from many Auto Parts Stores but as said above... they won't fit w/ hood on.

Also... Some stores sell a "store brand" or other Tstat cap all made by same company.
I had trouble using them. May look the same but won't fit my 87 duke. Get a Stant cap solves this.

quote Originally posted by theogre: Pressure Test can show leaks anywhere but not WP function. Problem is most test sets won't fit Fiero because rad cap area is too small to fit the adapters w/o hood removed. You can try drilling out Tstat cap rivet and replace w/ bolt in tire valve assemble. Can Pressurize the system until rad cap think the car is at "boils over" but likely leak will show up before that.

Great idea....someone should sell these.

quote Originally posted by 85fieroguy: LOL...if we knew it was the water pump leaking , why would we post the problem. Nothing seems to be coming out the "weep hole".

That's what I thought a couple years ago as well, but eventually discovered it was... Where the heck is this coolant leaking from?

[This message has been edited by Patrick (edited 10-22-2016).]