OM606- Sanity check fuel line air leaks
OM606- Sanity check fuel line air leaks
I noticed a steady stream of air at the very first line going from the heat exchanger to the pre filter. It appeared the air was coming in with the fuel coming from the tank. So I went back and inspected and tightened every connection. That seemed to correct the visible air bubbles going into the first clear line and all the lines then appeared to be solidly filled with fuel... that is until I shut off the engine.
Once the engine shuts off, an air bubble appears to exit from the pre filter and it appears the fuel is very slowly draining backwards towards the tank and the bubble grows. I have no fuel pump other than the lift pump on the IP. SO- i was planning on adding a back flow preventer (check valve) on the rubber hose before the heat exchanger.
The problem is... this morning the clear line at the bottom of the pre filter that goes to the SOV, is also empty of fuel and I see no leak?? Am I correct that even if the fuel were getting sucked back to the tank, it should NOT suck fuel backwards and against gravity at the base of the pre filter?
Am I missing something? Is it normal to have to install a check valve on the fuel feed line on these conversions? I' rather not add an electric pump but I'd also like to not fight air problems? Suggestions?
I'm wrapping up my 606 conversion and I've been having an issue with air in the fuel lines. So yesterday, I replaced all 6 plastic fuel lines in the filter/injection pump area. Brand new OEM mercedes parts. At the same time, I also replaced the SOV seal, the pre filter , and the pre filter seal. Everything went on snugly and snapped in positively. I lubricated every o ring with diesel prior to insertion. I Primed the system and got the engine running.
I noticed a steady stream of air at the very first line going from the heat exchanger to the pre filter. It appeared the air was coming in with the fuel coming from the tank. So I went back and inspected and tightened every connection. That seemed to correct the visible air bubbles going into the first clear line and all the lines then appeared to be solidly filled with fuel... that is until I shut off the engine.
Once the engine shuts off, an air bubble appears to exit from the pre filter and it appears the fuel is very slowly draining backwards towards the tank and the bubble grows. I have no fuel pump other than the lift pump on the IP. SO- i was planning on adding a back flow preventer (check valve) on the rubber hose before the heat exchanger.
The problem is... this morning the clear line at the bottom of the pre filter that goes to the SOV, is also empty of fuel and I see no leak?? Am I correct that even if the fuel were getting sucked back to the tank, it should NOT suck fuel backwards and against gravity at the base of the pre filter?
Am I missing something? Is it normal to have to install a check valve on the fuel feed line on these conversions? I' rather not add an electric pump but I'd also like to not fight air problems? Suggestions?
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