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2003 Volkswagen Passat 1.8T Vacuum Lines Repair

So this is a Passat which was having serious engine misfire issues. The thumping misfires were loud enough to hear. I had a look at the firewall area and noticed there was a broken check valve. The hose connecting to it ran to the vacuum regulator. The area is relatively cramped and I tried removing the broken ends of the plastic check valve from the hoses.  But ended up snapping something below the manifold. It was a plastic tee and I noticed that these plastic fittings were pretty much dried out and extremely brittle. Getting all this fixed required the manifold to be removed upon which another broken tee was found (evap lines). If you happen to have a broken plastic fitting on these VWs, you might as well get all of them replaced because sooner or later, they will all break (low quality plastics).

April 2016

↑ Here is the engine bay of the 2003 Passat. Three plasting turn pins (circled) to remove the so called "Beauty cover".

↑ The vacuum lines are located below the intake manifold. Several things to consider here. The cold water return consists of a hard tube that goes over the manifold and is bolted to the block near the firewall. The fuel injector assembly is also connected the manifold which will have to be removed. The coolant tank is an easy one that will ofcourse need to be removed - three screws circled in red.

↑ I decided to take the surge line from the coolant tank instead of the cold water tube. Thats because the plastic extrusion on the tank was broken and had to be addressed (was leaking) but ideally, you would want to take it off the hard tube to prevent possible damage to the plastic tube end on the surge tank.

↑ Coolant level sensor right below the coolant tank.

↑ So this is the tube to which the broken check valve interfaced with via a hose. I had this removed earlier.

↑ You probably noticed from the previous pictures of how the fuel pressure regulator goes over the cold water tube. So the vacuum hose connected to it has to be removed as part of taking the injector assembly off. I chose to pull the clip out and dissassemble the regulator itself because of how easy it was. But later on I would regret this and I will tell you why. You might as well cut the permanent hose clap instead and take hose off.

↑ Two bolts hold down the injector assembly onto the manifold.

↑ The injectors are snug fit into the manifold ports so they need to be carefully removed. Plus, avoid contacting the injectors ends with hard surfaces as they are sensitive and can be damaged easily.

↑ I covered the fuel regulator and its housing with sandwich bags. The slightest amount of dirt can block the micro sized injector openings. You won't have to do this if you decide to disconnect the regulator from the manifold by cutting the permanent hose clamp I mentioned earlier. I placed the injector assembly in a way so that the injetor ports float in space (no contact).

↑ There are several vacuum lines that connect to the intake manifold. This one (one of the two brake booster lines) is part of a network of lines that hover around the cold water tube interface with the engine block. I wanted to remove them to give me the space I need to take the hard tube off. Plus plastic check valves and junctions are VERY brittle so given my earlier experience, I did not want to take any chances by forcing my way around them. I cut the tightening feature using snippets to untie the hose clamps.

↑ Two more on the driver side Clamps cut and released like the one before.

↑ Air temperature sensor harness.

↑ The larger hoses adhere to the tubes (This is the booster line I believe). The reason is due to the effect of heat and aging. I usually just twist them using a pipe wrench to break them loose and since this hose interfaced with a metal tube, risk was minimal (plastic ones can break).

↑ There is a bracket that holds the rear network of vacuum lines onto a stud on the manifold. Plucked it off easy with a nose plier.

↑ So this is where the hard tube interfaces with the cylinder block. Two 10 mm hex heads here. One is visible but the other one is below the bend which you will have to feel and locate. Cramped area here.

↑ 10 mm socket and 6 inch extension is ideal.

↑ There is a cold water return from the heater core I believe that is branched to the main return line. This one has to be removed as well.

↑ Bent nose grip worked well for this application.

↑ Same for the main return line.

↑ There is only one bolt holding the tube assembly down to the manifold. Allen key style..

↑ This one was really tight. A big twisty was required. Used a pipe wrench.

↑ Pulled out and swayed clear of the manifold. I also had the manifold ports blocked with tissue paper to prevent debris from going into the intake valves.

↑ Hose clamp for the air intake from the charge air cooler.

↑ Throttle actuator disconnected. This allowed additional grip on the hose and needs to be removed anyway.

↑ Pulled out and swayed away

↑ Removing the temp sensor plug provided the clearance required to remove additional vacuum lines. Hose clamp cut with snippets as usual.

↑ Then I decided to dissassemble the intake manifold from the cylinder head. This is not the final step in removing the manifold. There was more that had to be done. The dipstick, tie down bar and the EGR solenoid module follows.

↑ The dipstick bracket shares the same bolts as that of the intake manifold. There is a clip on the dipstick tube that needs to be pressed in order to release the bracket. The plastic on the tube was so brittle and expired that it broke.

↑ Here is the dipstick tube bracket.

↑ There is a tie down bar that connects the manifold to the engine block. Noticed the manifold was snug after releasing it from the cylinder head and then I figured this bar exists and has to be removed.

↑ There is one of these on the manifold and another on the block. The one on the block is the easiest to access and removing it is enough to allow the manifold to float.

↑ There are two harnesses connected to the EGR module. One is green (Shown) and the other one is brown.

↑ Here are the two harness ports on the EGR manifold (circled). In order to release if from the manifold, three bolts (arrowed) needs to be unfastened. Releasing the manifold from the cylinder head and unfastening the tie down bar earlier allowed me to tilt the manifold and gain access to these three bolts.

↑ Here is the EGR module released from the manifold. Note the green and brown plugs.

↑ The EGR line runs from the solenoid to a port on the front side of the manifold. This was my final step before taking off the manifold.

↑ And the manifold was released. Please excuse my midnight expression.

↑ Here is the situation.

↑ Close up view.

↑ The evap tee interfaced with other two 13 year old dried plastic check valves with barbed tube ends. The tee was completely stuck in the hoses and playing with it would have 100% broken the check valves. So I decided to slit the hoses (boxed in red) in order to take them off the plastic fittings.

↑ Broken tee pieces and hoses. The missing end of this tee ran to a port on the manifold.

↑ The vacuum line tee had a valve that was clamped to a rubber junction with larger permanent hose clamp. My snippets were too large and not rigid enough to cut that clamp so I carefully used my rotary disk cutter.

↑ And off it was.

↑ The cut out clamp.

↑ The broken tee end (circled) that runs to the firewall side vacuum regulator via a check valve. The hose end is the primary vent (vacuum) line I believe.

↑ This is the part of the broken tee (evap) that runs to the two check valves (few pictures back) below the EGR module. Cut the clamp as usual and remove the broken plastic tube.

↑ Since the other end of this hose was connected to the steel tube so I was comfortable yanking the plastic tube out with a pipe wrench.

↑ So on the replacement tees, I used plastic tie wraps instead of hose clamps to fasten the tube and the hose together. Works fine and tightens adequately in my opinion.

↑ So I had to replace the hose that extended to the vacuume regulator. Fuel hose is all I had and getting it to fit on the 3/8 tube proved to be a bit difficult. I tried to heat the tube with the intent of making it soft and simultaneously pushing it into the tube. But I figured the heat was making the hose rapidly adhere to the tip of the plastic tube it was in contact with and made it impossible for me to slide the tube into it.

↑ So I gave up on heating it with a heat gun and instead used nose pliers to stretch the inner perimeter of the hose.

↑ I sprayed just a little bit of WD 40 on the replacement tee.

↑ And it slid on easily. Tied down as usual.

↑ Back on the three way engine vent junction. I had a hose clamp that I used on the larger end.

↑ Back to the evap tee. You may recall that I had slit the hoses to take em off the two check valves in order to prevent any possible damage to them. So simply cutting out the replacement ones here with a blade.

↑ I could not find the exact OEM barbed tee. So I got this 3/8 tee from Parts Source that should do the job.

↑ So the tee and the two hoses conecting to the canister check valve and the tank pressure sensor. All damaged tees and check valve replaced by now.

↑ Removing the duck tape over the intake ports. Next step was to place the manifold in and let it float inorder to put the evap line back on. The duck tape left a thick adhesive residue on the interface that I had to clean up using thinners. Would have used masking tape instead if I foresaw this.

↑ Manifold gasket back on after cleaning the surface.

↑ Once the manifold has been placed over the area (aplogies didn't take a picture). I plugged in the approproate line that extended from the manifold back to the evap tee. Now to bolt the EGR module back onto the manifold

↑ I fastened the three short 10 mm hex heads using a gear wrench as per the pic.

↑ Plugged in the solenoid harnesses.

↑ Now is the time to hand tighten the manifold back on the head. Let it float so that we can..

↑ Locate, position and fasten the manifold tie down bar to the block.

↑ Tighten everything down.

↑ Now ready to put the injector back on. Tissues pulled out of the ports.

↑ Pressed in place followed by having it bolted down. Heat gun used as a heater during the cold night. I did not re-assemble the fuel regulator valve yet because it has to go over the cold water tube.

↑ Injector harness plugged in.

↑ So before clamping down the rear vacuum hoses. I wanted to fasten the cold water tube. Wanted flexibility around the dash board area to make it easy for me to bolt on the tube flange to the engine. Btw the customer did not want to replace the broken dipstick so it did not have to be bolted on.

↑ Tube flange bolted on with the two 10 mm hex heads.

↑ Now to put the remaining hoses back on. This is the heater core return line. Plugged before bolting down the tube ofcourse.

↑ Bent nose grip to pull the hose clamp onto the tube interface.

↑ Recall earlier when I said that I regret disconnecting the regulator from the injector assembly? Here is why, the clip that slides into the regulator housing has corroded and inflamed over time. It was easy to slide it out but sliding it in was close to impossible. So I decided to use my angle grinder to remove some material on the extremities as to provide a larger/less steep chamfer.

↑ So I pressed the regulator valve onto the housing while I simultaneously pushed in the clip using a pry bar. Had to be careful while doing this to prevent breaking the injectors. Though the injector assembly was bolted down. Prying thi clip in did make it want to flex.

↑ There it is on.

↑ Now putting the remaining hoses back on. This is the recirculation line going on back into the manifold. Not investing in steel clamps here. Plastic tie wraps is adequate for an old vehicle that is getting closer and closer to the scrap yard.

↑ The two brake booster lines and the primary engine vent line plugged in and tied down.

↑ Charge air temperature sensor plugged back in.

↑ Throttle actuator plugged back in.

↑ Perhaps a bit delayed but here is the manifold tie down bar bolt fastened.

↑ Cold water tube bolted down.

↑ Hose clamp for the cold water tube...

↑ Hose clamp for the manifold intake tube.

↑ The final check valve by the firewall tied down to the hoses and connected to the vacuum regulating valve. Note the orientation of the check valve. You can also blow into one end of the check valve to figure out the right orientation.

↑ Coolant level sensor plugged back onto the reservoir.

↑ Coolant reservoir screwed down. Surge hose attached. Coolant topped up. Beauty cover back on. Battery boosted and good to go. No more misfires.