1994 E420 vacum leak

[mariot]

On my 1994 E420 I have a vacum leak,and check engine light on. I am olmost sure where that leak is. Should I just replase the broken hose. And will that automaticly solve my problem? Or I need to do something else to fix the problem? Thanks.

[White_Knuckles]

If you clearly see hose damage replace it. MB uses silicone high temp hose material but your basic auto store black vac hose will work fine.

If you're unsure of the leak source, spray starting fluid near the suspect area with the car idling. The idle may pick up when you hit the leak. Some vac line devices are solenoid controlled and won't effect idle unless the condition is right to fire the valve introducing vac to the component.

Where or what does the line operate? What codes are tripping the CEL? Test the old one plugging one end and suck or blow through it. You may have to reset or pull the Neg. battery terminal to clear the CEL when you repair the leak.

[mariot]

Thanks for the reply. I do not have computer and do not read codes but I see the hose that coming from the top of the engine and goes somewhere to the passenger side fender is damaged. I will replace it probably tuesday and let see what will hapen. Thanks again.

[White_Knuckles]

You don't need a computer or a hand-held code reader. There is a small box with a lid facing upright near the passenger side firewall (under the hood). When the cover is removed you should see a series of numbered female pins and an LED next to a push button.

With the car running, press the button for two seconds the LED remains steady then flashes stored codes. Note the flash count. Press again for two seconds and another series will flash. This will continue until all codes have been displayed and pressing the button does nothing.

Post your numbers and we'll identify them.

[Thorgod]

Mariot, you need to check the OVP ( over voltage protection relay). They were a very common item replaced on that year car. I had to replace mine on the 1994 E-320 wagon w/ 67,000 miles on it. use a mirror or just remove it and ck. the manufacture date. 1994 replace it. More than likely it is what kicked on the check engine lamp. Just wanted to add my thoughts. I maybe right or I maybe wrong, either way if its dated 1994 replace it anyway. Let us know..........Thor

[mariot]

It took me a long time but i needetd to work. Replaced the vacum line,reset the computer and no problem now.