w108 4.5 cold start valve leaking - PeachParts Mercedes-Benz Forum

billhard · #1 09-21-2014, 07:05 PM

Smelled raw fuel today just after starting and upon closer inspection found cold start valve leaking fuel out the top. Is this a replace the valve situation or is there any other solution?

meltedpanda · #2 09-22-2014, 08:19 PM

replace not really worth the effort to refubish

ejboyd5 · #3 09-23-2014, 08:16 AM

You could try green Loctite. Might work, might not, but much cheaper than a new valve.
Personally, I'd replace it just to remove one more item from the "worry list."

meltedpanda · #4 09-23-2014, 11:08 AM

I just assumed it was leaking from the end of the nipple. If it is leaking at the threads and or line , that is a different issue. From the threads is concerning, since we are working with soft metal, I personally would not use locktite . Lines should be replaced if leaking, all lines if they are old. Number one cause of fire in these ol gals ( other then CATS)

billhard · #5 09-23-2014, 11:32 AM

Quote:

Originally Posted by meltedpanda

I just assumed it was leaking from the end of the nipple. If it is leaking at the threads and or line , that is a different issue. From the threads is concerning, since we are working with soft metal, I personally would not use locktite . Lines should be replaced if leaking, all lines if they are old. Number one cause of fire in these ol gals ( other then CATS)

No it's leaking from the top front of the valve, where the plastic meets the metal. Looks like a $240 valve in my future.

meltedpanda · #6 09-23-2014, 01:45 PM

FWIW. You may try a pick n pull if you have one around you or post in wanted section. Fairly common item

Tomguy · #7 09-23-2014, 02:12 PM

pretty sure I have some laying around in Scranton... How much you drive it? If you can wait a few weeks, I can look next time I go up.

vandor · #8 09-23-2014, 08:49 PM

The early 350/450SLs and w116 cars used the same engine and fuel injection, so those are donors too. Up to 1974, I believe.

ejboyd5 · #9 09-24-2014, 08:05 AM

Quote:

Originally Posted by billhard

No it's leaking from the top front of the valve, where the plastic meets the metal.

Just where I thought the leak would be. Green Loctite with its wicking action might very well seal the gap. In the long run, I would still look for a replacement valve.

Idle · #10 09-24-2014, 01:05 PM

You might also check on Ebay.

Graham · #11 09-24-2014, 04:45 PM

I have never heard of a CSV leaking externally. The leak on injectors ( and CSV) may look like it is from valve, but invariably, it is from the hose connection and the leaked material collects on the valve.

If you remove the CSV and apply air pressure to the inlet, that might show if the body is really leaking.

I had to find a picture to remind myself of just what a CSV looks like!

Idle · #12 09-24-2014, 08:44 PM

Quote:

Originally Posted by Graham

I have never heard of a CSV leaking externally. The leak on injectors ( and CSV) may look like it is from valve, but invariably, it is from the hose connection and the leaked material collects on the valve.

If you remove the CSV and apply air pressure to the inlet, that might show if the body is really leaking.

I had to find a picture to remind myself of just what a CSV looks like!

That's some good info. The solution to this could be as easy as replacing the hose and the clamp.

It would not hurt to try that before replacing the valve.

billhard · #13 10-01-2014, 08:17 PM

I'm pretty sure it's the valve body. I removed it and the plastic portion of the valve is quite loose in the metal body. Checked the hose crimp before pulling the valve and it was quite tight, new hose to boot.