Injector pump leaks out red vent

[upside2k]

Firstly, let me thank all of you who contribute to this forum. I have found so much info here that cannot be found elsewhere. It's a real lifesaver.

Now my problem:

I have a 67' 230sl with an oil fed injector pump( not a fixed resevoir type with dipstick). Recently, I find oil dribbling out of the red vent cap while the engine is running. Obviously, on a long trip this could empty the crankcase, creating a disaster. I assume that there is a drain system in the pump but with the inspection cover off I cannot detect it. Or, am I wrong?. Does the pump oil not vent through this cap? If not what would cause this?

Thanks in advance for any help.

John

[J. Huber]

Hey John. Sorry I have no answer for you. I am a little surprised you have the non-dipstick type with a 230SL. Replacement, maybe? Anyway, welcome to the site and good luck. I notice you are from SB --that makes at least 3.5 active members, I think. (I'm the 1/2 since we still have our "second home" there!). You may run into Rod H. or Bo before too long...

James
63 230SL

[jameshoward]

John,

What's the pump model number on the manufacturers plate? It should end with R## (the original 230 FI pump being R11).

Note that even the original 230 FI pump has an oil feed and is not completely isolated. (It also has a dipstick at the back which can be hard to see because it's under the solonoid).

JH

[hands_aus]

Hey John,
I think the self contained pumps have the red cap breather but not the later engine oil supplied.
Here is JA17s' Injection Pump Tour
http://index.php?topic=790

Could it be the oil reservoir is full to over flowing?
see pic showing Oil test point. (slotted screw with T pieces)

Download Attachment: IP OIL DIP STICK 250SL.jpg
41.33 KB

Bob Smith (Brisbane,Australia)
RHD,1967 early 250 SL, auto

[upside2k]

WOW!! I'm overwhelmed by the quick response!!

You are right: it is an R11 pump and I was too lazy in trying to find the dipstick. I found it. I am the second owner of this car and have the service records, so I'm pretty sure it is the original pump.

I assumed it was oil fed because I had a small leak at the inspection plate and removed it to reseal it. Very little oil was present when I removed the plate. The resevoir must be below this area?
I also assumed it was oil fed because I lost about 1.5L of oil simultaneously with noticing the leak.

Can you advise what might be the source of the problem based on the above?

Thanks again, I will contact the other SB members.

[upside2k]

OOPS!, I just saw something else in one of your photos: The line that enters the pump on the engine side ( about 1/8") shows a check valve. Without understanding if this is a feed or drain line, could this the source of the problem?

Is there any kind of manual that is available with drawings, and such, available for these pumps?

Thanks again.

[J. Huber]

quote:Originally posted by upside2k


Is there any kind of manual that is available with drawings, and such, available for these pumps?

Thanks again.

Hey John. I think the easiest "manual" to get a hold of is Joe Alexander's thread about the Injection Pump. Try searching here for Injection Pump Tour. Anything beyond maintenance and a little bit of fiddling is best left to specialists such as Hans (again mentioned much in archives)...

One possibility for the leak could be that it is overfilled. This is fairly common. The level can also rise if the seals in the pump are letting fuel in. I think the only way to know that is to empty the pump, refill to correct level and monitor. (which you may want to do anyway -- may not have been done for a long time?)

PS * I just realized there is already a link to Joe's tour! Man, you guys are gooooood.

James
63 230SL

[jameshoward]

John,

Do a search using fuel injection pump. You need to read up on them and there's a ton of good posts that will address many quesitons you might have. I have a post out there that identifies, it seems, the same problems you are having. As Bob says, you need to open the dipstick and see if there is a considerable outflow of oil. The pump should contain about 200-250ml only.

JH