I had probs with little water in toilet bowl,and gurgles,it was suggested it was a venting prob,either outside vents were frozen or poor venting.I went to local hardware bought 2 cheater vents put one under kitchen sink,and one under bathroom sink.beforehand if I flushed toilet,tub would gurgle,if I ran washer toilet would gurgle and syphon water when washer was spinning.so after insatlling these two,toilet still does same not quite as bad,tub same.. etc.BUT if I remove vent from under bathroom sink,so it is fully open I have no probs.Can I add another vent to plumbing at tub or washer?I haven't yet done the hot water down the outside vents it has been terribly cold here.what else can I do to improve this situation?

Those chyeaters are actuallu called AAV or Studor vent and you need one for every fixture, also not legal in many places. Can you safely go on your roof this time of the years? If not call 3 plumbers for a bid on rodding the stack.

They are legal here,checked lol.my vents do not pass the overhang of my roof they stop just UNDER fascia and soffit,and with a ninety degree 1 1/2,all venting 1 1/2 inch,and plumbing.thanx.and no can't get on roof safely here right now.

Your ventstack is not built correctly and even AAV aren't going to fix your problem. Call 3 pro for bids and then deciode if you can do it or hire one of them

It may surprise you to find that the problems you're having are not related to venting. Have the drains thoroughly augered and cleared before getting the vents rebuilt.

Also, if your house has a trap for the sewer, see if you can look inside for obstructions.

Yah one plumber told us that too.but we alao know that are vent stacks are a joke,so we going through everything in steps.thanx

If you seen my vent stacks you would flip,they are very funky,and no doubt built wrong.going through things in tiny steps.thanx for your suggestion

Siphoning water and gurgling most often are caused by poor venting. A clogged drain will not siphon water from fixtures. Your vent stack may be a joke and needs to be rebuilt but it may also be clogged. It should terminate above the roof line, never below and eave

Siphoning water from toilets and gurgling are most often caused by drainage issues. Siphoning from vented p-traps due to an obstructed vent are very rare. Most people who assume that the vents are clogged and have them snaked will also clear the drainage system and believe that the vent was the problem. You say that the vents are 1 1/2" and 90 degree out below the soffit and fascia. If these in fact are your plumbing vents, they are wrong, but should still allow enough air to flow for poor operation of the fixture's traps. The siphoning and gurgling are another issue. When removing the AAV, the air being pushed back through the vents from water rushing against the clog is relieving into the atmosphere. There is more than likely several obstructions throughout the drainage piping and enough back ups will leave debris in the lowest connected vents that fill with sewage. Another plumber made the recommendation and you may save some time and money by taking this as a first step.