Yummybud924

I have this kind of "hissing" sound or like the sound of water running coming from the back of my engine bay. I replaced my coolant tank today and when I was running it to bleed the air I noticed it.

I looked around for a loose vacuum hose and nothing was loose. I'm pretty sure the sound is coming from the full pressure regulator. The one on the fuel rail where the hose clamps onto nearest the firewall. not sure if this is the regulator.

anyways I think the noise is coming from that and it's making me a bit worried.

also my new coolant tank also leaks like the old yellow one where the big hose clamps on. is it likely bc of a bad clamp? I'll try switching clamps and see if that fixes it.

FRporscheman

If your car isn't a turbo, a hissing sound in the engine bay is bad.

I've never had a hissing FPR, but you could check around for fuel leaks. If you want you can also hook up a fuel pressure gauge at the front of the rail, and see if the pressure is good. Use Clark's Garage for a procedure.

Maybe there's air trapped in your heater core from when you flushed the coolant?

John_AZ

Have you checked the heater control valve?
When you replaced the coolant recovery tank, you should have opened the heater control valve to circulate the coolant using the dash slide ****.

J_AZ

mytrplseven

I'm with John on this. When you bleed the cooling system, you need to open the heater valve, warm the engine up and then bleed the bubbles out. Also, if you suspect there might be an issue with the fuel pressure regulator, remove the vacuum line to it and see if you can smell gasoline in the rubber line. If so then the diaphragm (sp) inside is bad. Also, if the engine doesn't stumble a bit when you do then that's another indication. Doing so should lean out the mixture. Take a look at the coolant tank cap for proper security. It's not unheard of for it to be improperly installed (crooked).

Yummybud924

thanks for the response guys. I'm pretty sure I found the source. I'm pretty sure the intake manifold gasket closest to the firewall is leaking.

I used a hose placed against my ear and the other end placed next to the gasket and I can hear the whooshing noise coming from there and also gasket sticking out from that area. I changed the intake manifold gaskets few years ago not sure why it'd fail.

also I will have to bleed my cooling system again for sure. I just opened the bleed screw and had coolant gushing out and closed it again.

mytrplseven

Intake Manifold gaskets for some reason, don't stay torqued. I replaced mine the other day and some of the bolts were not the proper torque, even though two years back, they were installed new. When I installed these this time, I went back over them three times and they had to be re-torqued until they were all tight.