Vacuum hose from intake manifold

farupp · Post by **farupp** » 17 Mar 2011, 07:43

1996 850 turbo. There is a a vacuum hose that runs from the intake manifold to near the fresh air intake where it connects with the turbo. The hose diagram on the hood indicates that it should connect to the PTC connection. But, there is a vacuum hose already connected to that connect along with the PCV hose. Where is this vacuum hose supposed to be connected?

Thanks.
Frank

Post by **jblackburn** » 17 Mar 2011, 08:20

I believe there are two that run in that direction. One is slightly to the side of the PTC connection; the PTC hose connects from the left side of the intake manifold.

farupp · Post by **farupp** » 17 Mar 2011, 08:30

Thanks, jbalckburn. Our hose is connected correctly to the left side of the intake manifold. Where does the other end of this hose connect? Right now the vacuum line that runs along with the PVC hose to the turbo air inlet is connected at the PTC.

Thanks

Alecw81 · Post by **Alecw81** » 17 Mar 2011, 09:17

The other end connects at the PTC.

If you have a hose connected there, it likely should be in the TCV.

The PTC should have a larger hose connected and he small one from the manifold, along with the electrical connection.

farupp · Post by **farupp** » 17 Mar 2011, 11:06

Ok. I am a little confused not being that familiar with Volvo abbreviations. What exactly does PTC mean? Below are pictures of the hose I am talking about; it is the one with the silver duct tape on the end. It is connected to the intake manifold at the left (timing belt) end of the manifold. The vacuum hose diagram on my hood says it connects to the PTC. I have all the hoses connected to the turbo control valve (TCV) and the turbo works properly.

The vacuum hose connected next to the PCV nipple on the cold air intake runs along with the PCV hose from the left side of the engine. The hose connected to the bypass valve goes to the TCV.

Do I have the vacuum lines connected wrong?

: Volvo vacuum tubes 001.jpg (443.58 KiB) Viewed 11437 times

: Volvo vacuum tubes 002.jpg (436.03 KiB) Viewed 11437 times

Post by **jblackburn** » 17 Mar 2011, 11:58

Positive temperature coefficient or something like that. Basically, it's a heater to keep the oil vapor from freezing in the winter.

That vacuum line attached to the PTC nipple looks right - jury-rigged, but it's going to the right place (left side of the intake manifold). The one beside it, with the duct tape or whatever that is, should go to a small port beside that valve on the intake hose.

farupp · Post by **farupp** » 17 Mar 2011, 14:17

Thanks. We went back and checked all of the vacuum hose connection to be sure they were correct.

The PTC conenction that you said was jury-rigged is the line that runs inside the foam sleeve that also includes the PCV hose. That small line in the foam sleeve does not connect to the intake manifold, and I'm not sure where it goes. So, we disconnected that small line from the PTC.

Then we connected the vacuum hose that does go to the left side of the intake manifold to the PTC nipple. This conenction is the way you described it and is also the way the vacuum hose diagrams show how it should be connected.

So, my question now is where does the small line connect that is inside the foam sleeve with the large PCV hose?

Alecw81 · Post by **Alecw81** » 17 Mar 2011, 15:28

There are 2 hoses to connect to the PTC from the PCV box. 1 is the larger hose that goes in on top of the PTC, the other has an elbow and goes on the firewall side of the PTC. The "extra" hose goes on the nipple on the hose, not the PTC.

Post by **jblackburn** » 17 Mar 2011, 15:43

The one that runs through that hose connects to the left side of the intake manifold as I showed above in the picture with the arrow. It runs under the manifold and past the seperator box to that connection shown there.If your car does not have a port there (some of the earlier model 850's - I thought only the '94), then connect it to the vacuum tree/front of the intake manifold like you have and you're done.

farupp · Post by **farupp** » 19 Mar 2011, 12:25

Mystery Solved! Thanks for the help jblackburn and Alecw81.

It turns out that the original vacuum line that runs inside the foam hose and used to connect to the left side of the intake manifold broke off at the intake manifold end. A previous owner, instead of replacing the fitting at the end of that line and reconnecting it, replaced the entire line with a new one that now runs under the intake manifold.

One end of new line connects to the intake manifold and the PTC nipple at the other end. The original line doesn't do anything but was still in place causing my confusion. I incorrectly thought I had two vacuum lines to connect when I only had one.

Everything is now connected properly and the engine runs as it should.

Thanks again.