Help -- Oil filter housing leak or crack? - PeachParts Mercedes-Benz Forum

300sd2000 · #1 09-10-2003, 11:30 PM

Hello,

Today as I pulled in to my driveway on my older 300SD I noticed a huge oil leak...underneath the hood, I found that it was dripping steady from the oil pressure sender....

The sender had been going bad I figured since for the past month it reads 3 bar (wiring okay as reads 0 when grounded). It was on my list of things to do soon...

Upon removing it today and instaling a new sender and tightening it, I notice that it just spins freely in place...I cannot engage it all in the threads.

Which leads me to think the oil filter housing is cracked or the threads are now stripped...I tightened just by hand for 90% and then used a 19 mm wrench with one hand on the remaining. I'm usually careful not to cross thread and I can't see how I ruined the threads and now embarrased and upset that I've got an expensive repair on my hands.

It's definitely coming from right where it screws in. I removed it and put another one from the other car (a extra unit that had gone bad and same result...the threads are worn, stripped or cracked?

Another problem: I tried another sender that had been lying around (from my other car's replaced sender)...I installed it there temporarily (it engages in the threads.

Anyway, what do I need to do? I'm thinking new oil filter housing? How much would this even cost? Is there some way to replace the threaded area without needing a new housing altogether?

Will ground the car for now. Probably still driveable to the garage as the leak is minimal now after tightening it slightly and it's fairly snug, just not wrench-tight.

confused:

stevelewis · #2 09-11-2003, 07:48 PM

try wraping some plumbers tape around threads, then see how the threads bite. I would clean the area real good and get a good look at what is going on with the threads first. steve

kerry · #3 09-11-2003, 08:05 PM

Now you have me spooked. I was going to replace the sender on my 409d but it has a filter housing aimed towards the back of the engine. If I strip the housing, I'll only be able to find another in Europe. Any idea at all how it happened. Could it have happened removing the old one?

A used housing from a pick and pull junkyard would be about $20 around here.

300sd2000 · #4 09-11-2003, 09:27 PM

Only thing that I can think of is that I ordered a replacement from Performance Products, and the product looked slightly different, yet the thread pitch is same...

Wonder if the slight variation stripped the threads...seems unlikely. Was made by Meyle.

I will show the car to a friend of mine...Scared to think what an oild filter housing would run...probably would need to find from a junkyard if irreparable?

Will consider trying the teflon tape---actually I tried that last night with some help (hand tight but not wrench tight), but I feel uncomfortable leaving it there like that...what if it becomes loose?

kerry · #5 09-11-2003, 09:41 PM

Yes, you want to be sure the sender does not fall out. It could lead to major engine problems.
It seems very odd to me that the filter housing would strip before the sending unit itself. The senders I have seen are made of some kind of alloy. Wouldn't that strip long before the filter housing? Are you sure there wasn't an existing problem when the first one was leaking?

kerry · #6 09-11-2003, 09:47 PM

Another thought: Those threads are usually pipe threads I think--which means they taper and get tighter as they are screwed together. Are you sure both are pipe threads?
I'm not sure what happens when a non-pipe thread is screwed into a pipe thread, but it seems quite possible to me that the result could be something that would not tighten.

I was looking at a VW sender on Fastlane yesterday (since mine is an idiot light and MB does not sell idiot light senders in US) and I noticed that the description said "sender may require sealing ring". That made no sense to me because I have no idea how a sealing ring would operate on pipe threads. But it does raise the possibility in my mind that there are different kinds of threads available.

300sd2000 · #7 09-11-2003, 10:07 PM

yes, that's why I'm afraid there's a crack or something as I'm sure its hard to strip it AND it was leaking BEFORE i messed with it (as soon as I pulled into my driveway).

300sd2000 · #8 09-11-2003, 11:19 PM

Question is how to repair it....new oil filter housing? Is it one giant piece or does it disassemble? I think I have removed it before once to change the gasket but it was a royal PIA.

kerry · #9 09-12-2003, 09:09 AM

One giant piece from what I can see in the engine manual.

jbaj007 · #10 09-12-2003, 11:49 AM

Sender unit is NOT a tapered pipe thread. It is parallel thread and uses an aluminum crush washer for seal. Don't remember positively the size, but 12 x 1.5 comes to mind.

300sd2000 · #11 09-12-2003, 02:15 PM

anyone know how much a new oil filter housing might run?

300sd2000 · #12 09-13-2003, 12:26 AM

If anyone needs to know a new Oil Filter Housing runs between 400-500$. A used one from Fastlane (Tri Star) is 150$.

The sender screws in okay but the last set of threads at the final tightening part are the one's involved.

As it turns out, the car is running right now thanks to the tip to use teflon tape on the threads stevelewis's idea....I had to use quite a few wraps (8-10 wraps), but it seems to be holding snug to moderate wrench tightening and certainly cannot be undone by hand right now. Anyone know the torque on this part (can't be that much).

I'm not sure if it will hold long-term like this but at least my daily car is back in business...no other leaks seen so probably no crack in the oil filter housing just a case of stripped threads; I can keep an eye on the gauge but I don't think that it is under that much pressure that it would loosen and fall out on its own.

Anyway, the oil pressure gauge was faulty....the new gauge (I used the Meyle one from performance products ($35)) is reading 2 bar at idle and 3 on accel (similar to previous!)