How to bypass fuel heat exchanger - PeachParts Mercedes-Benz Forum

mikemass1221 · #1 09-26-2016, 10:34 AM

I broke the plastic off the top of my fuel heat exchanger. I am wondering how to bypass this while I temporarily try to get the car running until I order a new one. Can someone suggest how to do this please?

In this diagram below I need to understand what to do with fuel line # 32 - The one that goes from the pre filter to what is now a broken piece on my heat exchanger.

Also, not shown in this diagram there would be a black coolant line going into the heat exchanger just to the right where the #32 fuel line attaches. What do I do with that when bypassing?

This is for a w210 OM606 engine 1999 Turbo

moon161 · #2 09-26-2016, 02:20 PM

Without knowing more particulars, I would say remove the inlet and outlet hoses, get a double male barb and join the two. Simpler would be to use new hose to plumb the situation as if the fuel heater did not exist.

ROLLGUY · #3 09-27-2016, 11:41 PM

The 606 fuel heater has a quick disconnect for the outgoing, and a barb for a rubber hose on the incoming. That would make it hard to bypass the heater without destroying the outgoing hose assembly (cutting off the end and hose clamping the rubber hose on the plastic hose). The bigger problem is that the intake manifold would need to come off to replace the heater, so bypassing it completely by running a new hose directly from the hard line to the cut plastic line would be easy, and the manifold could remain. When and if you decide to replace the heater, you would have to remove the manifold (and replace the gasket) and replace the one plastic hose assembly as well......Rich

treetops · #4 09-28-2016, 07:52 AM

Ive used Line 32 connected to std fuel hose for a diesel purge setup. It works short term but not reliable for driving purposes IMO. Theres not enough length on the plastic plug, which is designed to mate into the pre heater, to get a hose clamp to work properly. I'd suggest the part be ordered and replaced before trying to drive the car on a regular basis.

BTW which coolant hose do you mean. I dont recall seeing one when I took my IM off. I thought the pre heater sits in/near to the heads water jacket. Curious to know.

mikemass1221 · #5 09-28-2016, 08:16 AM

Thanks for the replies gents.

Rollguy - IM is already off and the broken piece is the top of the fuel heater where the quick connect fuel line connects on top. I'll embed a pic.

Treetops - I intend to order a new fuel heater at some point but for other reasons the engine may be toast until I can get a re manufactured head. (Others may recall my current dilemma from a previous thread which not worth getting into again here). For now if I can just bypass the busted heater I will know if I can get the car running. If successful I will spend the 100 bucks and get a new heater.

As for the 'coolant line' ignore my ignorance, the car has been sitting all summer with a bunch of stuff disconnected and I was forgot what goes where. I was confusing the 2 black rubber fuel lines to be coolant lines. I now know they are the suction from the fuel tank and the return line to the tank respectively.

treetops · #6 09-28-2016, 02:35 PM

Well if you want to run it then do soemthing similar as in this video, just use diesel instead of diesel purge. Get some std fuel hose to fit the pre filter hose and another for the return, put them in jug of choice and give it a start.

https://m.youtube.com/watch?v=1u2ZMenlxA8

mikemass1221 · #7 09-28-2016, 03:05 PM

That's ingenious. Thanks for sharing that video.