Hi everyone. I went for my inspection today and couldn't pass as the engine light came up. PO171 + PO174. Seems to be vacuum leak. Is anyone familiar how serious this could be and how expensive to repair? Thanks in advance

 

dragana, you have a very common problem with our cars. This is normally fairly easy to fix and shouldn't cost you a lot of money. Lets first start with what normally causes these codes. It comes down to 3 hoses:

-the PCV valve to intake hose, a 3/4" vacuum line
-IMT valve o-rings, located on passenger side of your car behind the 4" black plastic plates on the side of the intake
-brake booster hose, runs from the top center of the intake to the brake booster on the firewall.

The PCV hose is known for developing a split in the hose on the under side of the hose where it passes over a support to keep it off the engine block. Remove the plastic cover from your engine and you will see this hose running to the left of the incoming air. If the hose is smooth, you will want to replace it regardless of whether it is bad or not. The new hose will be ribbed and much stronger.

The IMT valves. You will find that the o-rings will be 1 of 2 colors, yellow or green. You want the green o-rings as the yellow ones are from the factory and are known to crack and fail with age. Installing new o-rings isn't hard either overall. The top IMT valve is pretty easy: disconnect the plug, undo the two 8mm bolts, slide the IMT valve out, remove o-ring, put new o-ring on, reverse the rest of the steps. The bottom one is a bit more tricky. In short, you are going to disconnect the plug, undo the two 8mm bolts, slide the IMT valve out slightly and then once you can grab on to the o-ring, you are going to stretch it up and over the end of the IMT valve to remove. From here, you will need to stretch the new o-ring over the IMT valve and put everything back together. You can not remove the IMT valve on the lower portion unless you remove the whole intake which takes about an hour.

The final common point is the brake booster hose. If you follow this hose, you will notice a plastic "football" shaped piece in the center of this line. IT is really a check valve right there. Rub the plastic here and if it is cracked and/or crumbly (ie, turns to dust as you rub it), it needs replaced.

Start with these. If you are still having issues, then it may be that you need new upper/lower intake o-rings. They cost about $50 for the set of 12 o-rings and take about 2-3 hours to install if you do it yourself. If you need more info, let me know and I can step you though doing this job.

 

Thank you Chris. I will work on this over the weekend and get back to if (as) needed All the help and knowledge is greatly appreciated.