Hi all, have a simple (I hope) question. I have an 86 GMC Sierra with a 305/350T. I'm in the process of deleting all the emissions equipment on the truck and will be removing the heat riser as well, once i can pull it out.
Until then, when cold there is an audible ticking or similar sound coming from the passenger side near where the heat riser is. My friend at work says it sounds like a bad push rod or flat cam lobe. But, once it warms up it goes away, making me think it may be a leaking heat riser gasket which I know is a common issue.
So, this morning I went out when the motor was cold, started it and immediately heard the regular ticking noise. I pulled the vacuum line off of the heat riser and it stopped, plugged it back on and it started again.
So my question is this, with vacuum off, is the heat riser valve open or closed?
Until I can pull it and find a suitable spacer, can I just pull the line and drive, or will have have to physically wire the valve into a certain position?
As of now, my plan is to pull it when I can, pull everything out of the valve and welding the holes shut and reinstalling it. A spacer costs around $60, a weld is free.
Thanks in advance for any information.