View Full Version : help! vac leak?

04-03-2003, 09:48 PM
o.k. i'm pretty sure i have a vac leak because when i'm sitting at a stop light or something the boost gauge reads something like 9 or 10 mm Hg. i know it's supposed to idle at close to 20. my upper radiator hose blew a couple of weeks ago if that makes any difference. i also have another leak involving coolant that i believe is coming from a short hose a little below and behind the upper rad hose. so i guess i am asking about two problems here, but i really need help. my car gets hot after about 15 minutes of driving and starts to smoke, but i looked under the hood and the smoke was coming from the leaking coolant so i'm not worried about damaging the engine from overheating, but i can't drive for very long. any help would be GREATLY appreciated. thanks

04-04-2003, 12:39 AM
One hose that is notorious on EGR-equipped cars is the hose that connects to the metal vacuum tree behind the intake plenum. The combination of years of oil vapor/mist on it & heat from the EGR plumbing will soften the hose until it's squishy.
Just follow your PCV line around the back and below where it connects to the metal tree is where you'll find the hose I'm speakin' of. It runs from that tree towards the passenger side and connects to a plastic barbed fitting near the relays on the firewall (in the rear passengerside of the engine compartment).
It's 5/16" in size, about 7" long. If it "squishes" easily when you pinch it then replace it. Fuel hose should work very well.

By the way, make sure your PCV fitting isn't cracked. The elbow on top of it can split & cause a heckuva vacuum leak also.

good luck,


04-04-2003, 01:44 AM
Correction tbird88, that hose has to be silicone, otherwise you might be replacing it again soon. I tried several types of hose on that EGR, after replacing my SC & plenum, before I got the silicone type from Ford and they charged me $35.US for an 8" piece. Other types lasted from 20miles to 3 days before they cracked from heat and the car started to detonate. It has to be able to withstand exhaust pipe heat and gas line hose is better than vacuum hose but it will still break down. Eventually I found my original hose and it was still in perfect condition after being on the car for 8 years. Someone in the club should start supplying silicone hose because I heard it can be purchased in rolls and replacing it has got to be one of the top ~~~~ fixes for our cars.
Good luck

04-04-2003, 06:21 PM
thanks for the help so far. i'll check out that hose tomorrow when i replace the radiator, or at least try to. are there any others i should check while i'm in there? what about the coolant leak? does my description sound like i found where it's leaking. the small hose under the upper rad hose. i just got my pcv valve replaced a couple months ago, but i'll check that too since new doesn't ALWAYS mean good. thanks for the help so far, it's greatly appreciated.

04-05-2003, 03:28 AM
Sorry, I didn't focus on the coolant leak. You should be concerned about overheating from what ever the cause. Overheating, Backpressue, and detonation will damage 3.8 SCs because they all affect the head gaskets. My manual says 1 to the heater & 1 to coolant bypass, it any are leaking you need to replace soon, feel the other hose and it it feels soft or brittle, replace it to. If you undo the belt on the water pump, you can try spinning it to see if it is smooth and quiet, it usually leaks near the bottom when its going bad but the hose leak will not let you inspect it. Good luck